首页 > 最新文献

Science of Remote Sensing最新文献

英文 中文
Improved estimation of daily blue-sky snow shortwave albedo from MODIS data and reanalysis information 利用中分辨率成像系统数据和再分析信息改进对每日蓝天积雪短波反照率的估算
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-09-16 DOI: 10.1016/j.srs.2024.100163
Anxin Ding , Shunlin Liang , Han Ma , Tao He , Aolin Jia , Qian Wang

Snow albedo is a key geophysical parameter that controls the energy exchanges between the atmosphere and Earth's surfaces and has been widely utilized in climatic and environmental change studies. However, recent studies have demonstrated that current albedo satellite products still have large uncertainties in snow-covered areas. In this study, we estimated the blue-sky shortwave albedo of snow surfaces using the eXtreme Gradient Boosting (XGBoost) algorithm with Moderate Resolution Imaging Spectroradiometer (MODIS) top-of-atmosphere (TOA) reflectance values, ERA-5 land reanalysis snow parameters (e.g., snow cover, snow density and snow depth water equivalent) and in situ measurements. In the XGBoost model, the MODIS MCD43 albedo values were input as prior knowledge, and the random sample validation results showed that the R2 and root mean square error (RMSE) values of this model were approximately 0.953 and 0.044, respectively. The typical sites for independent validation were subjected to in situ measurements at the UPE_L, AWS5, and CA_ARB sites. Finally, the retrieved XGBoost albedo values were compared with the official NASA MODIS (MCD43, collection 6), the Global Land Surface Satellite (GLASS), and the National Oceanic and Atmospheric Administration (NOAA) Visible Infrared Imaging Radiometer Suite (VIIRS) SURFALB albedo products. The validation results indicated that the proposed approach achieved much greater accuracy (RMSE = 0.052, bias = 0.002) than did the corresponding official MODIS (RMSE = 0.087, bias = −0.033), GLASS (RMSE = 0.089, bias = −0.031) and VIIRS SURFALB albedo (RMSE = 0.100, bias = −0.032) products. The improved shortwave albedo captured the rapid temporal changes in surface snow conditions.

雪的反照率是一个关键的地球物理参数,控制着大气与地球表面之间的能量交换,已被广泛用于气候和环境变化研究。然而,最近的研究表明,目前的反照率卫星产品在积雪地区仍有很大的不确定性。在本研究中,我们利用极端梯度提升(XGBoost)算法,结合中分辨率成像分光仪(MODIS)的大气顶反射率值、ERA-5 陆地再分析雪参数(如雪盖度、雪密度和雪深水当量)以及实地测量数据,估算了雪表面的蓝天短波反照率。随机抽样验证结果表明,该模型的 R2 值和均方根误差值分别约为 0.953 和 0.044。进行独立验证的典型站点是 UPE_L、AWS5 和 CA_ARB 站点。最后,将获取的 XGBoost 反照率值与 NASA MODIS(MCD43,第 6 集)、全球陆地表面卫星(GLASS)和美国国家海洋和大气管理局(NOAA)可见红外成像辐射计套件(VIIRS)SURFALB 反照率产品进行了比较。验证结果表明,与相应的官方 MODIS(RMSE = 0.087,偏差 = -0.033)、GLASS(RMSE = 0.089,偏差 = -0.031)和 VIIRS SURFALB 反照率(RMSE = 0.100,偏差 = -0.032)产品相比,建议的方法实现了更高的精度(RMSE = 0.052,偏差 = 0.002)。改进后的短波反照率捕捉到了地表积雪状况的快速时间变化。
{"title":"Improved estimation of daily blue-sky snow shortwave albedo from MODIS data and reanalysis information","authors":"Anxin Ding ,&nbsp;Shunlin Liang ,&nbsp;Han Ma ,&nbsp;Tao He ,&nbsp;Aolin Jia ,&nbsp;Qian Wang","doi":"10.1016/j.srs.2024.100163","DOIUrl":"10.1016/j.srs.2024.100163","url":null,"abstract":"<div><p>Snow albedo is a key geophysical parameter that controls the energy exchanges between the atmosphere and Earth's surfaces and has been widely utilized in climatic and environmental change studies. However, recent studies have demonstrated that current albedo satellite products still have large uncertainties in snow-covered areas. In this study, we estimated the blue-sky shortwave albedo of snow surfaces using the eXtreme Gradient Boosting (XGBoost) algorithm with Moderate Resolution Imaging Spectroradiometer (MODIS) top-of-atmosphere (TOA) reflectance values, ERA-5 land reanalysis snow parameters (e.g., snow cover, snow density and snow depth water equivalent) and in situ measurements. In the XGBoost model, the MODIS MCD43 albedo values were input as prior knowledge, and the random sample validation results showed that the R<sup>2</sup> and root mean square error (RMSE) values of this model were approximately 0.953 and 0.044, respectively. The typical sites for independent validation were subjected to in situ measurements at the UPE_L, AWS5, and CA_ARB sites. Finally, the retrieved XGBoost albedo values were compared with the official NASA MODIS (MCD43, collection 6), the Global Land Surface Satellite (GLASS), and the National Oceanic and Atmospheric Administration (NOAA) Visible Infrared Imaging Radiometer Suite (VIIRS) SURFALB albedo products. The validation results indicated that the proposed approach achieved much greater accuracy (RMSE = 0.052, bias = 0.002) than did the corresponding official MODIS (RMSE = 0.087, bias = −0.033), GLASS (RMSE = 0.089, bias = −0.031) and VIIRS SURFALB albedo (RMSE = 0.100, bias = −0.032) products. The improved shortwave albedo captured the rapid temporal changes in surface snow conditions.</p></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100163"},"PeriodicalIF":5.7,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666017224000476/pdfft?md5=e99e57265aeb05eddcd22708dbcf028e&pid=1-s2.0-S2666017224000476-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Use of light response curve parameters to estimate gross primary production capacity from chlorophyll indices of global observation satellite and flux data 利用光响应曲线参数从全球观测卫星和通量数据的叶绿素指数估算总初级生产能力
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-09-13 DOI: 10.1016/j.srs.2024.100164
Kanako Muramatsu , Emi Yoneda , Noriko Soyama , Ana López-Ballesteros , Juthasinee Thanyapraneedkul
The photosynthetic rate has a nonlinear relationship with PAR during the day. We previously developed an algorithm for estimating GPP capacity, which is defined GPP under low-stress condition, using light response curves (LRCs). In this study, we studied the characteristics of LRC parameters of the initial slope and the maximum gross photosynthesis rate (Pmax), and formulas to calculate Pmax from the relationship between the chlorophyll index of the green and near-infrared (NIR) bands (CIgreen) and the GPP capacity at PAR = 2000 μmol m−2 s−1 (GP2000) for nine vegetation types spanning tropical to subarctic climates on the Eurasian and North American continents using eddy covariance flux measurements and Moderate Resolution Imaging Spectrometer (MODIS) data. The slope of the relationship between CIgreen and GP2000 was highest for sites dominated by herbaceous plants such as open shrubland, savanna, and cropland (rice paddy); it was lower at sites dominated by woody plants. The yearly GPP/GPP capacity ratio was close to one in flux data. When the method was applied to satellite data, the daily GPP capacity exhibited a similar seasonal pattern to that of the Flux GPP and MODIS GPP products. Under high dryness conditions, Flux GPP showed the drop from the GPP capacity estimated from CIgreen and diurnal PAR data around noon, and they were nearly identical during the early morning and late afternoon. The instantaneous GPP capacity could be considered the baseline of the instantaneous GPP with stress-free conditions and important for quantifying midday depression at the sub-day scale.
光合速率与白天的 PAR 呈非线性关系。我们之前开发了一种利用光响应曲线(LRC)估算 GPP 能力的算法,即低压力条件下的 GPP。在本研究中,我们研究了 LRC 的初始斜率和最大总光合速率(Pmax)参数的特征、通过使用涡协方差通量测量和中分辨率成像光谱仪(MODIS)数据,研究了欧亚大陆和北美大陆从热带到亚北极气候的九种植被类型的绿色和近红外(NIR)波段叶绿素指数(CIgreen)与 PAR = 2000 μmol m-2 s-1 (GP2000)条件下 GPP 能力之间的关系,以及计算 Pmax 的公式。CIgreen 与 GP2000 之间关系的斜率在以草本植物为主的地点(如开阔灌木林、热带草原和耕地(水稻田))最高;在以木本植物为主的地点则较低。在通量数据中,年 GPP/GPP 容量比接近于 1。将该方法应用于卫星数据时,日 GPP 容量表现出与通量 GPP 和 MODIS GPP 产品相似的季节性模式。在高干燥度条件下,通量 GPP 在中午前后显示出与 CIgreen 和昼夜 PAR 数据估算的 GPP 容量相比的下降,而在清晨和傍晚则几乎相同。瞬时 GPP 容量可视为无胁迫条件下瞬时 GPP 的基线,对于量化子日尺度的正午郁闭度非常重要。
{"title":"Use of light response curve parameters to estimate gross primary production capacity from chlorophyll indices of global observation satellite and flux data","authors":"Kanako Muramatsu ,&nbsp;Emi Yoneda ,&nbsp;Noriko Soyama ,&nbsp;Ana López-Ballesteros ,&nbsp;Juthasinee Thanyapraneedkul","doi":"10.1016/j.srs.2024.100164","DOIUrl":"10.1016/j.srs.2024.100164","url":null,"abstract":"<div><div>The photosynthetic rate has a nonlinear relationship with PAR during the day. We previously developed an algorithm for estimating GPP capacity, which is defined GPP under low-stress condition, using light response curves (LRCs). In this study, we studied the characteristics of LRC parameters of the initial slope and the maximum gross photosynthesis rate (P<sub>max</sub>), and formulas to calculate P<sub>max</sub> from the relationship between the chlorophyll index of the green and near-infrared (NIR) bands (CI<sub>green</sub>) and the GPP capacity at PAR = 2000 μmol m<sup>−2</sup> s<sup>−1</sup> (GP2000) for nine vegetation types spanning tropical to subarctic climates on the Eurasian and North American continents using eddy covariance flux measurements and Moderate Resolution Imaging Spectrometer (MODIS) data. The slope of the relationship between CI<sub>green</sub> and GP2000 was highest for sites dominated by herbaceous plants such as open shrubland, savanna, and cropland (rice paddy); it was lower at sites dominated by woody plants. The yearly GPP/GPP capacity ratio was close to one in flux data. When the method was applied to satellite data, the daily GPP capacity exhibited a similar seasonal pattern to that of the Flux GPP and MODIS GPP products. Under high dryness conditions, Flux GPP showed the drop from the GPP capacity estimated from CI<sub>green</sub> and diurnal PAR data around noon, and they were nearly identical during the early morning and late afternoon. The instantaneous GPP capacity could be considered the baseline of the instantaneous GPP with stress-free conditions and important for quantifying midday depression at the sub-day scale.</div></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100164"},"PeriodicalIF":5.7,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Enhancing the temporal resolution of water levels from altimetry using D-InSAR: A case study of 10 Swedish Lakes 利用 D-InSAR 增强测高法水位的时间分辨率:10 个瑞典湖泊的案例研究
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-09-10 DOI: 10.1016/j.srs.2024.100162
Saeid Aminjafari , Frédéric Frappart , Fabrice Papa , Ian Brown , Fernando Jaramillo

Lakes provide societies and natural ecosystems with valuable services such as freshwater supply and flood control. Water level changes in lakes reflect their natural responses to climatic and anthropogenic stressors; however, their monitoring is costly due to installation and maintenance requirements. With its advanced hardware and computational capabilities, altimetry has become a popular alternative to conventional in-situ gauging, although subject to the temporal availability of altimetric observations. To further improve the temporal resolution of altimetric measurements, we here combine radar altimetry data with Differential Interferometric Synthetic Aperture Radar (D-InSAR), using ten lakes in Sweden as a testing platform. First, we use Sentinel-1A and Sentinel-1B SAR images to generate consecutive six-day baseline interferograms across 2019. Then, we accumulate the phase change of coherent pixels to construct the time series of InSAR-derived water level anomalies. Finally, we retrieve altimetric observations from Sentinel-3, estimate their mean and standard deviation, and apply them to the D-InSAR standardized anomalies. In this way, we build a water-level time series with more temporal observations. In general, we find a strong agreement between water level estimates from the combination of D-InSAR and Satellite Altimetry (DInSAlt) and in-situ observations in eight lakes (Concordance Correlation Coefficient - CCC >0.8) and moderate agreement in two lakes (CCC >0.57). The applicability of DInSAlt is limited to lakes with suitable conditions for double-bounce scattering, such as the presence of trees or marshes. The accuracy of the water level estimates depends on the quality of the altimetry observations and the lake's width. These findings are important considering the recently launched Surface Water and Ocean Topography (SWOT) satellite, whose capabilities could expand our methodology's geographical applicability and reduce its reliance on ground measurements.

湖泊为社会和自然生态系统提供了宝贵的服务,如淡水供应和洪水控制。湖泊水位的变化反映了湖泊对气候和人为压力因素的自然反应;然而,由于安装和维护要求,对湖泊的监测成本高昂。凭借先进的硬件和计算能力,测高法已成为传统现场测量法的热门替代方法,但受制于测高观测数据的时间可用性。为了进一步提高测高数据的时间分辨率,我们在此将雷达测高数据与差分干涉合成孔径雷达(D-InSAR)相结合,以瑞典的十个湖泊为测试平台。首先,我们使用 Sentinel-1A 和 Sentinel-1B SAR 图像生成跨越 2019 年的连续六天基线干涉图。然后,我们累积相干像素的相位变化,构建 InSAR 衍生水位异常的时间序列。最后,我们检索 Sentinel-3 的测高观测数据,估计其平均值和标准偏差,并将其应用于 D-InSAR 标准化异常。这样,我们就建立了一个具有更多时间观测数据的水位时间序列。总体而言,我们发现 D-InSAR 与卫星测高相结合(DInSAlt)得出的水位估计值与 8 个湖泊的现场观测值高度一致(一致相关系数 - CCC >0.8),与 2 个湖泊的水位估计值中度一致(CCC >0.57)。DInSAlt 的适用性仅限于具有适合双弹散射条件的湖泊,例如有树木或沼泽的湖泊。水位估计的准确性取决于测高观测的质量和湖泊的宽度。考虑到最近发射的地表水和海洋地形(SWOT)卫星,这些发现具有重要意义,因为该卫星的功能可以扩大我们方法的地理适用性,并减少对地面测量的依赖。
{"title":"Enhancing the temporal resolution of water levels from altimetry using D-InSAR: A case study of 10 Swedish Lakes","authors":"Saeid Aminjafari ,&nbsp;Frédéric Frappart ,&nbsp;Fabrice Papa ,&nbsp;Ian Brown ,&nbsp;Fernando Jaramillo","doi":"10.1016/j.srs.2024.100162","DOIUrl":"10.1016/j.srs.2024.100162","url":null,"abstract":"<div><p>Lakes provide societies and natural ecosystems with valuable services such as freshwater supply and flood control. Water level changes in lakes reflect their natural responses to climatic and anthropogenic stressors; however, their monitoring is costly due to installation and maintenance requirements. With its advanced hardware and computational capabilities, altimetry has become a popular alternative to conventional in-situ gauging, although subject to the temporal availability of altimetric observations. To further improve the temporal resolution of altimetric measurements, we here combine radar altimetry data with Differential Interferometric Synthetic Aperture Radar (D-InSAR), using ten lakes in Sweden as a testing platform. First, we use Sentinel-1A and Sentinel-1B SAR images to generate consecutive six-day baseline interferograms across 2019. Then, we accumulate the phase change of coherent pixels to construct the time series of InSAR-derived water level anomalies. Finally, we retrieve altimetric observations from Sentinel-3, estimate their mean and standard deviation, and apply them to the D-InSAR standardized anomalies. In this way, we build a water-level time series with more temporal observations. In general, we find a strong agreement between water level estimates from the combination of D-InSAR and Satellite Altimetry (DInSAlt) and in-situ observations in eight lakes (Concordance Correlation Coefficient - CCC &gt;0.8) and moderate agreement in two lakes (CCC &gt;0.57). The applicability of DInSAlt is limited to lakes with suitable conditions for double-bounce scattering, such as the presence of trees or marshes. The accuracy of the water level estimates depends on the quality of the altimetry observations and the lake's width. These findings are important considering the recently launched Surface Water and Ocean Topography (SWOT) satellite, whose capabilities could expand our methodology's geographical applicability and reduce its reliance on ground measurements.</p></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100162"},"PeriodicalIF":5.7,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666017224000464/pdfft?md5=884dbde39217c179b32aa224366ef5ea&pid=1-s2.0-S2666017224000464-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Evaluation of GEDI footprint level biomass models in Southern African Savannas using airborne LiDAR and field measurements 利用机载激光雷达和实地测量评估南部非洲热带稀树草原的 GEDI 足印生物量模型
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-09-07 DOI: 10.1016/j.srs.2024.100161
Xiaoxuan Li , Konrad Wessels , John Armston , Laura Duncanson , Mikhail Urbazaev , Laven Naidoo , Renaud Mathieu , Russell Main

Savannas cover more than 20% of the Earth and account for the third largest stock of global aboveground biomass yet estimates of their above ground biomass density (AGBD) are very inaccurate. The Global Ecosystem Dynamic Investigation (GEDI) sensor provides near-global full-waveform LiDAR data with 25 m footprints, from which various structural metrics are derived that are used to predict footprint level AGBD. The current GEDI L4A AGBD product uses a comprehensive Forest Structure and Biomass Database (FSBD) to develop models for specific plant functional types and geographic regions, but southern African savannas have been underrepresented in the reference data. The objectives of this study were to (i) validate GEDI L4A AGBD in South African savannas using field measurements and ALS datasets and (ii) develop and evaluate local GEDI footprint-level AGBD estimates from multiple L2A and L2B metrics. The local GEDI AGBD models outperformed GEDI L4A AGBD (R2 = 0.42, RMSE = 12 Mg/ha, %RMSE = 79.5%) with higher R2 and smaller error measures. The local GEDI AGBD using a random forest model (RF) had the highest R2 of 0.71 and lowest %RMSE of 53.3%, while the generalized linear model (GLM) results provided the lowest Relative Mean Systematic Deviation (RMSD) of 9.2%, which was half that of RF model. L4A significantly underestimated AGBD with an RMSD up to −37%. This highlights the importance and benefits of local calibration of biomass models to unlock the full potential of GEDI metrics for estimating AGBD. The field and ALS data have subsequently been contributed to the GEDI FSBD and should be used in calibration of future versions of GEDI L4A AGBD product. This research paves the way for the integration of the local GEDI AGBD estimates with other sensors, notable the eminent NISAR mission, to derive regional to global gridded AGBD products that will enable the monitoring of savanna carbon stocks.

热带稀树草原占地球面积的 20% 以上,在全球地上生物量中占第三位,但对其地上生物量密度 (AGBD) 的估计却非常不准确。全球生态系统动态调查(GEDI)传感器提供了近乎全球的全波形激光雷达数据,其足迹为 25 米,从中得出的各种结构指标可用于预测足迹水平的 AGBD。目前的 GEDI L4A AGBD 产品使用全面的森林结构和生物量数据库 (FSBD) 来开发特定植物功能类型和地理区域的模型,但参考数据中非洲南部稀树草原的代表性不足。本研究的目标是:(i) 利用实地测量和 ALS 数据集验证南非热带稀树草原的 GEDI L4A AGBD;(ii) 根据多个 L2A 和 L2B 指标开发和评估本地 GEDI 脚印级 AGBD 估计值。本地 GEDI AGBD 模型的表现优于 GEDI L4A AGBD(R2 = 0.42,RMSE = 12 兆克/公顷,%RMSE = 79.5%),R2 较高,误差较小。采用随机森林模型(RF)的本地 GEDI AGBD 的 R2 最高,为 0.71,RMSE%最低,为 53.3%,而广义线性模型(GLM)的结果提供了最低的相对平均系统偏差(RMSD),为 9.2%,是 RF 模型的一半。L4A 严重低估了 AGBD,RMSD 高达 -37%。这凸显了生物量模型本地校准的重要性和益处,以充分释放 GEDI 指标在估算 AGBD 方面的潜力。野外数据和 ALS 数据随后被纳入 GEDI FSBD,并将用于校准未来版本的 GEDI L4A AGBD 产品。这项研究为将当地的 GEDI AGBD 估算值与其他传感器(尤其是著名的 NISAR 任务)整合在一起,以获得区域到全球的网格 AGBD 产品铺平了道路,从而能够监测热带稀树草原的碳储量。
{"title":"Evaluation of GEDI footprint level biomass models in Southern African Savannas using airborne LiDAR and field measurements","authors":"Xiaoxuan Li ,&nbsp;Konrad Wessels ,&nbsp;John Armston ,&nbsp;Laura Duncanson ,&nbsp;Mikhail Urbazaev ,&nbsp;Laven Naidoo ,&nbsp;Renaud Mathieu ,&nbsp;Russell Main","doi":"10.1016/j.srs.2024.100161","DOIUrl":"10.1016/j.srs.2024.100161","url":null,"abstract":"<div><p>Savannas cover more than 20% of the Earth and account for the third largest stock of global aboveground biomass yet estimates of their above ground biomass density (AGBD) are very inaccurate. The Global Ecosystem Dynamic Investigation (GEDI) sensor provides near-global full-waveform LiDAR data with 25 m footprints, from which various structural metrics are derived that are used to predict footprint level AGBD. The current GEDI L4A AGBD product uses a comprehensive Forest Structure and Biomass Database (FSBD) to develop models for specific plant functional types and geographic regions, but southern African savannas have been underrepresented in the reference data. The objectives of this study were to (i) validate GEDI L4A AGBD in South African savannas using field measurements and ALS datasets and (ii) develop and evaluate local GEDI footprint-level AGBD estimates from multiple L2A and L2B metrics. The local GEDI AGBD models outperformed GEDI L4A AGBD (R<sup>2</sup> = 0.42, RMSE = 12 Mg/ha, %RMSE = 79.5%) with higher R<sup>2</sup> and smaller error measures. The local GEDI AGBD using a random forest model (RF) had the highest R<sup>2</sup> of 0.71 and lowest %RMSE of 53.3%, while the generalized linear model (GLM) results provided the lowest Relative Mean Systematic Deviation (RMSD) of 9.2%, which was half that of RF model. L4A significantly underestimated AGBD with an RMSD up to −37%. This highlights the importance and benefits of local calibration of biomass models to unlock the full potential of GEDI metrics for estimating AGBD. The field and ALS data have subsequently been contributed to the GEDI FSBD and should be used in calibration of future versions of GEDI L4A AGBD product. This research paves the way for the integration of the local GEDI AGBD estimates with other sensors, notable the eminent NISAR mission, to derive regional to global gridded AGBD products that will enable the monitoring of savanna carbon stocks.</p></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100161"},"PeriodicalIF":5.7,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666017224000452/pdfft?md5=73e6de19f0a4636ffb39019a392d7591&pid=1-s2.0-S2666017224000452-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142232395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Characterizing annual leaf area index changes and volume growth using ALS and satellite data in forest plantations 利用 ALS 和卫星数据确定人工林的年叶面积指数变化和体积增长特征
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-09-02 DOI: 10.1016/j.srs.2024.100159
Gonzalo Gavilán-Acuna , Nicholas C. Coops , Piotr Tompalski , Pablo Mena-Quijada , Andrés Varhola , Dominik Roeser , Guillermo F. Olmedo

While Leaf Area Index (LAI) is critical for understanding forest canopy, photosynthesis and forest growth, traditional field-based LAI measurements are laborious and costly. Remote sensing offers a practical alternative for extensive assessments. Satellite imagery provides broad-scale, long-term monitoring; however, may lack detail needed to guide specific forest management actions. Conversely, Airborne Laser Scanning (ALS) provides accurate LAI estimates at fine spatial detail but is limited by cost and temporal monitoring constraints. Combining ALS data with satellite observations could enhance plantation management decisions by balancing extensive coverage with detailed observations. This study explores the integration of ALS and satellite remote sensing as a comprehensive alternative for assessing LAI and stand volume growth rate (m3/ha/year) in operational Pinus radiata plantations in central-south Chile. Our approach comprised four major steps. First, we applied the Beer-Lambert law using ALS vertical profiles to estimate LAI across a forest plantation (LAIALS). We found that ALS accurately estimated LAI across 121 plots (R2 = 0.82 and RMSE = 0.51). Second, we built a simple linear regression to link LAIALS with the Normalized Difference Moisture Index (NDMI) derived from surface reflectance information from the Landsat/Sentinel-2 satellites, resulting in an R2 of 0.53 and an RMSE of 1.17. This step showed a higher correlation with satellite data compared to using only ground-based LAI estimates (R2 = 0.38; RMSE = 1.18). Third, we transformed biweekly NDMI time series to LAI, then derived peak annual LAI as an indicator of mean annual increment (MAI) (R2 = 0.51; RMSE = 5.27 m³/ha/year). This allowed us to characterize stand growth and LAI on a yearly wall-to-wall basis. Throughout the modelling steps, we incorporated error propagation, allowing final estimates to be error bounded. This integrated approach serves as a tool for identifying and visualizing growth irregularities, guiding adaptive management strategies to maintain or enhance stand productivity over time.

叶面积指数(LAI)对于了解森林冠层、光合作用和森林生长至关重要,但传统的实地叶面积指数测量既费力又昂贵。遥感技术为广泛评估提供了一种实用的替代方法。卫星图像可提供大范围的长期监测,但可能缺乏指导具体森林管理行动所需的细节。与此相反,机载激光扫描(ALS)可提供精确的 LAI 估计值,但受到成本和时间监测的限制。将 ALS 数据与卫星观测数据相结合,可以在广泛的覆盖范围与详细的观测数据之间取得平衡,从而加强人工林管理决策。本研究探讨了如何将 ALS 与卫星遥感结合起来,作为评估智利中南部辐射松人工林的 LAI 和林木体积增长率(立方米/公顷/年)的综合替代方法。我们的方法包括四个主要步骤。首先,我们利用 ALS 垂直剖面应用比尔-朗伯定律估算人工林的 LAI(LAIALS)。我们发现,ALS 能准确估算 121 个地块的 LAI(R2 = 0.82,RMSE = 0.51)。其次,我们建立了一个简单的线性回归,将 LAIALS 与根据 Landsat/Sentinel-2 卫星表面反射率信息得出的归一化差异水分指数 (NDMI) 联系起来,结果 R2 为 0.53,RMSE 为 1.17。与仅使用地面 LAI 估计值(R2 = 0.38;RMSE = 1.18)相比,这一步骤显示出与卫星数据更高的相关性。第三,我们将双周 NDMI 时间序列转换为 LAI,然后得出年 LAI 峰值,作为年平均增量 (MAI) 的指标(R2 = 0.51;RMSE = 5.27 m³/ha/年)。这样,我们就能以每年墙到墙的方式来描述林分生长和 LAI 的特征。在整个建模步骤中,我们纳入了误差传播,从而使最终估算结果具有误差约束。这种综合方法可作为一种工具,用于识别和直观显示生长的不规则性,从而指导适应性管理策略,随着时间的推移保持或提高林分生产力。
{"title":"Characterizing annual leaf area index changes and volume growth using ALS and satellite data in forest plantations","authors":"Gonzalo Gavilán-Acuna ,&nbsp;Nicholas C. Coops ,&nbsp;Piotr Tompalski ,&nbsp;Pablo Mena-Quijada ,&nbsp;Andrés Varhola ,&nbsp;Dominik Roeser ,&nbsp;Guillermo F. Olmedo","doi":"10.1016/j.srs.2024.100159","DOIUrl":"10.1016/j.srs.2024.100159","url":null,"abstract":"<div><p>While Leaf Area Index (LAI) is critical for understanding forest canopy, photosynthesis and forest growth, traditional field-based LAI measurements are laborious and costly. Remote sensing offers a practical alternative for extensive assessments. Satellite imagery provides broad-scale, long-term monitoring; however, may lack detail needed to guide specific forest management actions. Conversely, Airborne Laser Scanning (ALS) provides accurate LAI estimates at fine spatial detail but is limited by cost and temporal monitoring constraints. Combining ALS data with satellite observations could enhance plantation management decisions by balancing extensive coverage with detailed observations. This study explores the integration of ALS and satellite remote sensing as a comprehensive alternative for assessing LAI and stand volume growth rate (m<sup>3</sup>/ha/year) in operational <em>Pinus radiata</em> plantations in central-south Chile. Our approach comprised four major steps. First, we applied the Beer-Lambert law using ALS vertical profiles to estimate LAI across a forest plantation (LAI<sub>ALS</sub>). We found that ALS accurately estimated LAI across 121 plots (R<sup>2</sup> = 0.82 and RMSE = 0.51). Second, we built a simple linear regression to link LAI<sub>ALS</sub> with the Normalized Difference Moisture Index (NDMI) derived from surface reflectance information from the Landsat/Sentinel-2 satellites, resulting in an R<sup>2</sup> of 0.53 and an RMSE of 1.17. This step showed a higher correlation with satellite data compared to using only ground-based LAI estimates (R<sup>2</sup> = 0.38; RMSE = 1.18). Third, we transformed biweekly NDMI time series to LAI, then derived peak annual LAI as an indicator of mean annual increment (MAI) (R<sup>2</sup> = 0.51; RMSE = 5.27 m³/ha/year). This allowed us to characterize stand growth and LAI on a yearly wall-to-wall basis. Throughout the modelling steps, we incorporated error propagation, allowing final estimates to be error bounded. This integrated approach serves as a tool for identifying and visualizing growth irregularities, guiding adaptive management strategies to maintain or enhance stand productivity over time.</p></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100159"},"PeriodicalIF":5.7,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666017224000439/pdfft?md5=490f7a068eafcc92083ee3697de5608a&pid=1-s2.0-S2666017224000439-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Validation of the vertical canopy cover profile products derived from GEDI over selected forest sites 验证由 GEDI 导出的选定林地垂直冠层覆盖剖面产品
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-09-01 DOI: 10.1016/j.srs.2024.100158
Yu Li , Hongliang Fang , Yao Wang , Sijia Li , Tian Ma , Yunjia Wu , Hao Tang

Canopy cover (CC) quantifies the proportion of canopy materials projected vertically onto the ground surface. CC is a crucial canopy structural variable and is commonly used in many ecological and climatic models. The vertical CC profile product is currently available from the Global Ecosystem Dynamics Investigation (GEDI). However, detailed information about the accuracy and uncertainty of the GEDI vertical CC profile product remains limited. The objective of this study is to validate the GEDI CC product over selected forest sites using reference values derived from digital hemispherical photography (DHP), airborne laser scanning (ALS) point clouds, and simulated waveforms. The accuracy of CC was quantified and analyzed regarding GEDI observation conditions, waveform processing, and estimation methods. The results show that the GEDI total CC correlates well with those estimated from DHP, ALS, and simulated waveform data (r2 = 0.65, 0.71, and 0.71, respectively) but is systematically underestimated (bias = −0.05, −0.11, and −0.07, respectively) based on reference data. Compared with the ALS-estimated CC, needleleaf forest shows the highest correlation for vertical CC (r2 ≥ 0.65) and shrubland shows the lowest bias for total CC (bias = −0.13). The mean absolute error (MAE) of the GEDI CC decreases from 0.15 to 0.09 as the estimation height increases from ground to 35 m. The GEDI total CCs derived from the waveform interpretation algorithms A2 and A6 display the highest r2 (≥ 0.6) and smallest RMSE (≤ 0.23) compared to those of the other algorithms. The CC accuracy increases with beam sensitivity and decreases with increasing canopy cover. The GEDI CC was improved at moderate CC values using a canopy-to-ground backscattering coefficient ratio (ρv/ρg) determined with the regression method. The partial difference between GEDI CC and ALS CC is attributed to definitional discrepancies. Further improvement of the CC algorithm can be made by using vegetation-specific waveform processing algorithms and realistic ρv/ρg values.

树冠覆盖(CC)量化了垂直投射到地表的树冠材料比例。CC 是一个重要的冠层结构变量,常用于许多生态和气候模型。目前,全球生态系统动力学调查(GEDI)提供了垂直 CC 剖面产品。然而,有关 GEDI 垂直 CC 剖面产品的准确性和不确定性的详细信息仍然有限。本研究的目的是利用从数字半球摄影(DHP)、机载激光扫描(ALS)点云和模拟波形中获得的参考值,对 GEDI CC 产品在选定森林地点的应用进行验证。针对 GEDI 观测条件、波形处理和估算方法,对 CC 的准确性进行了量化和分析。结果表明,GEDI 总 CC 与 DHP、ALS 和模拟波形数据估算的 CC 相关性良好(r2 分别为 0.65、0.71 和 0.71),但根据参考数据,GEDI 总 CC 被系统性低估(偏差分别为 -0.05、-0.11 和 -0.07)。与 ALS 估算的 CC 相比,针叶林的垂直 CC 相关性最高(r2 ≥ 0.65),灌木林的总 CC 偏差最小(偏差 = -0.13)。波形解释算法 A2 和 A6 得出的 GEDI 总 CC 与其他算法相比,r2 最高(≥ 0.6),RMSE 最小(≤ 0.23)。CC 精确度随光束灵敏度的增加而增加,随冠层覆盖度的增加而降低。在中等 CC 值时,使用回归法确定的冠层与地面的后向散射系数比(ρv/ρg)可提高 GEDI CC 的精度。GEDI CC 和 ALS CC 之间的部分差异归因于定义上的差异。通过使用特定植被波形处理算法和真实的 ρv/ρg 值,可以进一步改进 CC 算法。
{"title":"Validation of the vertical canopy cover profile products derived from GEDI over selected forest sites","authors":"Yu Li ,&nbsp;Hongliang Fang ,&nbsp;Yao Wang ,&nbsp;Sijia Li ,&nbsp;Tian Ma ,&nbsp;Yunjia Wu ,&nbsp;Hao Tang","doi":"10.1016/j.srs.2024.100158","DOIUrl":"10.1016/j.srs.2024.100158","url":null,"abstract":"<div><p>Canopy cover (CC) quantifies the proportion of canopy materials projected vertically onto the ground surface. CC is a crucial canopy structural variable and is commonly used in many ecological and climatic models. The vertical CC profile product is currently available from the Global Ecosystem Dynamics Investigation (GEDI). However, detailed information about the accuracy and uncertainty of the GEDI vertical CC profile product remains limited. The objective of this study is to validate the GEDI CC product over selected forest sites using reference values derived from digital hemispherical photography (DHP), airborne laser scanning (ALS) point clouds, and simulated waveforms. The accuracy of CC was quantified and analyzed regarding GEDI observation conditions, waveform processing, and estimation methods. The results show that the GEDI total CC correlates well with those estimated from DHP, ALS, and simulated waveform data (r<sup>2</sup> = 0.65, 0.71, and 0.71, respectively) but is systematically underestimated (bias = −0.05, −0.11, and −0.07, respectively) based on reference data. Compared with the ALS-estimated CC, needleleaf forest shows the highest correlation for vertical CC (r<sup>2</sup> ≥ 0.65) and shrubland shows the lowest bias for total CC (bias = −0.13). The mean absolute error (MAE) of the GEDI CC decreases from 0.15 to 0.09 as the estimation height increases from ground to 35 m. The GEDI total CCs derived from the waveform interpretation algorithms A2 and A6 display the highest r<sup>2</sup> (≥ 0.6) and smallest RMSE (≤ 0.23) compared to those of the other algorithms. The CC accuracy increases with beam sensitivity and decreases with increasing canopy cover. The GEDI CC was improved at moderate CC values using a canopy-to-ground backscattering coefficient ratio (<span><math><mrow><msub><mi>ρ</mi><mi>v</mi></msub><mo>/</mo><msub><mi>ρ</mi><mi>g</mi></msub></mrow></math></span>) determined with the regression method. The partial difference between GEDI CC and ALS CC is attributed to definitional discrepancies. Further improvement of the CC algorithm can be made by using vegetation-specific waveform processing algorithms and realistic <span><math><mrow><msub><mi>ρ</mi><mi>v</mi></msub><mo>/</mo><msub><mi>ρ</mi><mi>g</mi></msub></mrow></math></span> values.</p></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100158"},"PeriodicalIF":5.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666017224000427/pdfft?md5=3e507f3a7fd1dc415673a49b89eef211&pid=1-s2.0-S2666017224000427-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142163676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Characterizing forest structural changes in response to non-stand replacing disturbances using bitemporal airborne laser scanning data 利用位时机载激光扫描数据确定森林结构变化对非标准替换干扰的响应特征
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-31 DOI: 10.1016/j.srs.2024.100160
Tommaso Trotto , Nicholas C. Coops , Alexis Achim , Sarah E. Gergel , Dominik Roeser

Characterizing the extent, severity, and persistence of natural disturbances in forests is crucial in areas as large and heterogeneous as the Canadian boreal forest. Non-stand replacing (NSR) disturbances, in particular, can produce subtle and lagged impacts to forest canopy and structure with mechanisms that remain elusive, and they are challenging to discern using typical remote sensing approaches including aerial photointerpretation and spectral analysis of satellite imagery. Consequently, there is a need for timely and accurate information on the structural modifications due to NSR disturbances to inform proactive forest management practices. To address these needs, we leveraged a unique bitemporal airborne laser scanning (ALS) dataset to characterize changes in the forest structure caused by eastern spruce budworm (ESB, Choristoneura fumiferana (Clem.)), responsible for one of the greatest tree mortality in Canada. A range of infestation severity with varying impacts to forest structure are examined in a mixedwood boreal forest in Lac-Saint Jean, Quebec, Canada. We derived 14 ALS structural change metrics at 10 m spatial resolution, including height, cover, and gappiness 7 years apart (2014–2020). Six distinct structural responses to cumulative ESB infestations severity were identified using cluster analysis from the combination of the 14 change metrics, with canopy cover, the 75th and 25th height percentiles (p75-25) driving cluster separability. Canopy cover and p25 consistently decreased as cumulative infestation severity increased, whereas p75 showed greater variability across the landscape. Photointerpretation of aerial imagery over the same period confirmed the validity of the structural characterization. Further, we studied the role of initial forest structures in modulating the severity of the infestation and found that sparser canopies with cover <65% and shorter trees (p75 < 7.5 m, p25 < 2.5 m) were associated with less severe ESB infestations after 7 years, and controlling for underlying environmental factors. These findings showed the potential of bitemporal ALS data in characterizing structural changes due to ESB infestations at fine scale based on canopy cover and height, relevant for forest management strategies to better target current and future infestations.

确定森林自然干扰的范围、严重程度和持续时间,对于像加拿大北方森林这样面积大且分布不均的地区至关重要。特别是非立地重置(NSR)干扰,会对森林冠层和结构产生微妙和滞后的影响,其机理仍然难以捉摸,而且使用典型的遥感方法(包括航空照片判读和卫星图像的光谱分析)也很难辨别。因此,我们需要及时、准确地了解 NSR 干扰对森林结构造成的改变,从而为积极的森林管理实践提供依据。为了满足这些需求,我们利用独特的位时机载激光扫描(ALS)数据集来描述东部云杉芽虫(ESB,Choristoneura fumiferana (Clem.))对森林结构造成的变化。我们在加拿大魁北克省圣让湖(Lac-Saint Jean)的北方混交林中研究了一系列虫害严重程度对森林结构的不同影响。我们以 10 米的空间分辨率得出了 14 个 ALS 结构变化指标,包括高度、盖度和斑驳度,时间间隔为 7 年(2014-2020 年)。通过对 14 项变化指标的组合进行聚类分析,确定了对累积 ESB 侵害严重程度的六种不同的结构响应,其中树冠覆盖率、第 75 和第 25 高度百分位数(p75-25)推动了聚类的可分性。随着累积侵扰严重程度的增加,树冠覆盖率和第 25 百分位数持续下降,而第 75 百分位数在整个景观中的变化更大。同期航空图像的照片解读证实了结构特征的有效性。此外,我们还研究了初始森林结构在调节虫害严重程度方面的作用,发现在控制基本环境因素的情况下,覆盖率为 65% 的稀疏树冠和较矮的树木(p75 为 7.5 米,p25 为 2.5 米)与 7 年后较轻的 ESB 虫害有关。这些研究结果表明,位时 ALS 数据可以根据树冠覆盖率和高度,在精细尺度上描述 ESB 侵害造成的结构变化,这与森林管理策略有关,可以更好地针对当前和未来的侵害。
{"title":"Characterizing forest structural changes in response to non-stand replacing disturbances using bitemporal airborne laser scanning data","authors":"Tommaso Trotto ,&nbsp;Nicholas C. Coops ,&nbsp;Alexis Achim ,&nbsp;Sarah E. Gergel ,&nbsp;Dominik Roeser","doi":"10.1016/j.srs.2024.100160","DOIUrl":"10.1016/j.srs.2024.100160","url":null,"abstract":"<div><p>Characterizing the extent, severity, and persistence of natural disturbances in forests is crucial in areas as large and heterogeneous as the Canadian boreal forest. Non-stand replacing (NSR) disturbances, in particular, can produce subtle and lagged impacts to forest canopy and structure with mechanisms that remain elusive, and they are challenging to discern using typical remote sensing approaches including aerial photointerpretation and spectral analysis of satellite imagery. Consequently, there is a need for timely and accurate information on the structural modifications due to NSR disturbances to inform proactive forest management practices. To address these needs, we leveraged a unique bitemporal airborne laser scanning (ALS) dataset to characterize changes in the forest structure caused by eastern spruce budworm (ESB, <em>Choristoneura fumiferana</em> (Clem.)), responsible for one of the greatest tree mortality in Canada. A range of infestation severity with varying impacts to forest structure are examined in a mixedwood boreal forest in Lac-Saint Jean, Quebec, Canada. We derived 14 ALS structural change metrics at 10 m spatial resolution, including height, cover, and gappiness 7 years apart (2014–2020). Six distinct structural responses to cumulative ESB infestations severity were identified using cluster analysis from the combination of the 14 change metrics, with canopy cover, the 75th and 25th height percentiles (p75-25) driving cluster separability. Canopy cover and p25 consistently decreased as cumulative infestation severity increased, whereas p75 showed greater variability across the landscape. Photointerpretation of aerial imagery over the same period confirmed the validity of the structural characterization. Further, we studied the role of initial forest structures in modulating the severity of the infestation and found that sparser canopies with cover &lt;65% and shorter trees (p75 &lt; 7.5 m, p25 &lt; 2.5 m) were associated with less severe ESB infestations after 7 years, and controlling for underlying environmental factors. These findings showed the potential of bitemporal ALS data in characterizing structural changes due to ESB infestations at fine scale based on canopy cover and height, relevant for forest management strategies to better target current and future infestations.</p></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100160"},"PeriodicalIF":5.7,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666017224000440/pdfft?md5=43b2b88984cde901116c4e7c896d1146&pid=1-s2.0-S2666017224000440-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Combined use of multi-source satellite imagery and deep learning for automated mapping of glacial lakes in the Bhutan Himalaya 综合利用多源卫星图像和深度学习自动绘制不丹喜马拉雅冰川湖地图
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-28 DOI: 10.1016/j.srs.2024.100157
Xingyu Xu , Lin Liu , Lingcao Huang , Yan Hu

Himalayan glacial lakes have been rapidly developing and expanding in recent decades under climate change and glacier mass loss. These growing glacial lakes can produce glacial lake outburst floods (GLOFs) events with far-reaching and devastating consequences. However, the latest spatial distribution and temporal evolution of the Himalayan glacial lakes is not timely updated due to the inaccessibility of high mountain areas and the lack of an effective automated mapping method that can leverage the availability of wide-ranging remote sensing data. To frequently update glacial lake inventory in GLOF-vulnerable regions, we developed the state-of-the-art glacial lake mapping approaches based on deep learning technique and multi-source remote sensing imagery. DeepLabv3+, an advanced semantic segmentation algorithm, was trained to delineate glacial lakes with areas larger than 0.005 km2 from multi-source imagery and their derivatives, including PlanetScope red-green-blue (RGB), PlanetScope-derived Normalized Difference Water Index (NDWI), Sentinel-2 RGB, Sentinel-2-derived NDWI, Sentinel-1 Synthetic Aperture Radar (SAR), and Landsat-8 RGB images. The well-trained deep learning models achieved high mapping accuracy in the northern Bhutan test region, with the F1 score varying from 0.74 (Sentinel-1) to 0.91 (Planet-RGB) among the six types of images. We applied the well-trained models to automatically map the glacial lakes from multi-source satellite imagery. After manually cataloging the mapping results, we compiled a glacial lake inventory for the Bhutan Himalaya in 2021 that includes 2563 glacial lakes with a total area of 153.85 ± 9.33 km2. Our results demonstrated the mapping capability of deep learning on multiple satellite imagery, the key roles of PlanetScope optical images for accurate glacial lake mapping, and the essential supplementary usage of SAR images and NDWI images to complement the glacial lake inventory over Bhutan Himalaya. This study provides an advanced and transferable workflow for inventorying glacial lakes from multi-source satellite imagery, as well as provides a high-quality and comprehensive glacial lake inventory for outburst flood studies.

近几十年来,喜马拉雅山的冰川湖在气候变化和冰川物质流失的影响下迅速发展和扩大。这些不断扩大的冰川湖会产生冰川湖溃决洪水(GLOFs)事件,造成深远的破坏性后果。然而,由于高山地区交通不便,且缺乏有效的自动测绘方法来利用广泛的遥感数据,喜马拉雅冰川湖泊的最新空间分布和时间演变并未得到及时更新。为了经常更新冰湖洪水易发地区的冰湖清单,我们开发了基于深度学习技术和多源遥感图像的先进冰湖测绘方法。对高级语义分割算法 DeepLabv3+ 进行了训练,以从多源图像及其衍生图像(包括 PlanetScope 红绿蓝 (RGB)、PlanetScope 衍生归一化差异水指数 (NDWI)、Sentinel-2 RGB、Sentinel-2 衍生归一化差异水指数 (NDWI)、Sentinel-1 合成孔径雷达 (SAR) 和 Landsat-8 RGB 图像)中划分面积大于 0.005 平方公里的冰川湖。训练有素的深度学习模型在不丹北部测试区域实现了较高的测绘精度,在六种类型的图像中,F1得分从0.74(哨兵-1)到0.91(Planet-RGB)不等。我们将训练有素的模型用于自动绘制多源卫星图像中的冰川湖泊。在对测绘结果进行人工编目后,我们编制了 2021 年不丹喜马拉雅山脉的冰川湖泊清单,其中包括 2563 个冰川湖泊,总面积为 153.85 ± 9.33 平方公里。我们的研究结果证明了深度学习在多种卫星图像上的绘图能力、PlanetScope 光学图像在精确绘制冰川湖地图中的关键作用,以及合成孔径雷达图像和 NDWI 图像在补充不丹喜马拉雅冰川湖清单中的重要辅助用途。这项研究为利用多源卫星图像绘制冰川湖泊清单提供了先进的、可移植的工作流程,并为溃决洪水研究提供了高质量、全面的冰川湖泊清单。
{"title":"Combined use of multi-source satellite imagery and deep learning for automated mapping of glacial lakes in the Bhutan Himalaya","authors":"Xingyu Xu ,&nbsp;Lin Liu ,&nbsp;Lingcao Huang ,&nbsp;Yan Hu","doi":"10.1016/j.srs.2024.100157","DOIUrl":"10.1016/j.srs.2024.100157","url":null,"abstract":"<div><p>Himalayan glacial lakes have been rapidly developing and expanding in recent decades under climate change and glacier mass loss. These growing glacial lakes can produce glacial lake outburst floods (GLOFs) events with far-reaching and devastating consequences. However, the latest spatial distribution and temporal evolution of the Himalayan glacial lakes is not timely updated due to the inaccessibility of high mountain areas and the lack of an effective automated mapping method that can leverage the availability of wide-ranging remote sensing data. To frequently update glacial lake inventory in GLOF-vulnerable regions, we developed the state-of-the-art glacial lake mapping approaches based on deep learning technique and multi-source remote sensing imagery. DeepLabv3+, an advanced semantic segmentation algorithm, was trained to delineate glacial lakes with areas larger than 0.005 km<sup>2</sup> from multi-source imagery and their derivatives, including PlanetScope red-green-blue (RGB), PlanetScope-derived Normalized Difference Water Index (NDWI), Sentinel-2 RGB, Sentinel-2-derived NDWI, Sentinel-1 Synthetic Aperture Radar (SAR), and Landsat-8 RGB images. The well-trained deep learning models achieved high mapping accuracy in the northern Bhutan test region, with the F1 score varying from 0.74 (Sentinel-1) to 0.91 (Planet-RGB) among the six types of images. We applied the well-trained models to automatically map the glacial lakes from multi-source satellite imagery. After manually cataloging the mapping results, we compiled a glacial lake inventory for the Bhutan Himalaya in 2021 that includes 2563 glacial lakes with a total area of 153.85 ± 9.33 km<sup>2</sup>. Our results demonstrated the mapping capability of deep learning on multiple satellite imagery, the key roles of PlanetScope optical images for accurate glacial lake mapping, and the essential supplementary usage of SAR images and NDWI images to complement the glacial lake inventory over Bhutan Himalaya. This study provides an advanced and transferable workflow for inventorying glacial lakes from multi-source satellite imagery, as well as provides a high-quality and comprehensive glacial lake inventory for outburst flood studies.</p></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100157"},"PeriodicalIF":5.7,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666017224000415/pdfft?md5=b774ecb5b9dc4630c1dd34d70d190478&pid=1-s2.0-S2666017224000415-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142096131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Mapping the dynamics of aquatic vegetation in Lake Kyoga and its linkages to satellite lakes 绘制 Kyoga 湖水生植被动态图及其与卫星湖的联系图
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-13 DOI: 10.1016/j.srs.2024.100156
Yaxiong Ma , Sucharita Gopal , Magaly Koch , Les Kaufman

Lake Kyoga is a shallow, young, flooded basin just north of and about 30m lower than Lake Victoria. The catchment encompasses Lake Kyoga itself, and a constellation of several dozen small satellite lakes following valley contours mostly to its east. The Kyoga basin fish fauna shares many non-cichlid species plus a spectacular, partially endemic radiation of haplochromine cichlids most similar to but still largely distinct from those in Lake Victoria. This fish fauna is of high conservation concern, as it preserves remnants of the regional species flock that have disappeared from Lake Victoria and Lake Kyoga, leaving small remnant populations in some of the satellite lakes. Now, these too are imperiled by limnological dynamics, including fluctuations in the nature and extent of aquatic vegetation. The water bodies in the Kyoga Basin are highly dynamic due both to fluctuation in water level and large amplitude variation in marginal and floating vegetation. This variation has profound evolutionary and conservation implications, since it can create and destroy critical aquatic habitat. It can also alternately anneal and cleave gene flow over time, both between the main lake and its satellites, and among the satellite lakes. The aquatic vegetation cluttering these linkages can create a spatial refugium for many native fish species that are more tolerant of hypoxia than an introduced macropredator, the Nile perch. Anthropogenic impacts to this region have greatly increased in recent years, altering relationships between aquatic vegetation and endangered species, fisheries and other ecosystem services provided by the lake. Understanding these dynamics require a means of mapping aquatic vegetation, connectivity, and habitat through time. Here we develop a new and improved algorithm to map the spatial distribution and dynamics of floating and emergent aquatic vegetation via remote sensing. We utilize a time series of 440 Landsat images dating from 1986 to 2020. A series of water and vegetation indices are designed to reveal change in the aquascape over time. First, two types of water masks are derived using a majority rule - a separate water mask for each image and a composite water mask of the region over the study period. Second, the difference between the two masks is then used to delineate the potential location of macrophytes over the image. Third, an algorithm is developed to separate the floating vegetation from emergent vegetation; this algorithm uses Landsat spectral bands and two additional spatial and temporal metrics that considerably improve classification accuracy. A more extensive analysis of aquascape trajectories using remote sensing can inform fish conservation strategies and fisheries management and illuminate the role of landscape dynamics in macroevolutionary patterns of aquatic taxa.

基奥加湖(Kyoga)是一个浅水、年轻的洪泛盆地,位于维多利亚湖以北,比维多利亚湖低约 30 米。集水区包括基奥加湖本身,以及由几十个小型卫星湖组成的湖群,这些湖群主要分布在基奥加湖以东的山谷轮廓线上。基奥加湖流域的鱼类有许多非慈鲷类,还有一种壮观的、部分特有的单色慈鲷,与维多利亚湖中的慈鲷最为相似,但在很大程度上仍有区别。维多利亚湖和基奥加湖的鱼类种群已经消失,但在一些卫星湖中仍有少量残存种群。现在,这些物种也受到了湖泊动力学的威胁,包括水生植被性质和范围的波动。由于水位的波动以及边缘植被和漂浮植被的大振幅变化,基奥加盆地的水体具有很强的动态性。这种变化对进化和保护具有深远的影响,因为它可以创造和破坏重要的水生生境。随着时间的推移,它还会在主湖和卫星湖之间以及卫星湖之间交替出现退火和分裂基因流。水生植被杂乱无章地连接着这些湖泊,为许多本地鱼类创造了空间庇护所,这些鱼类比引进的大型食肉动物尼罗河鲈鱼更能忍受缺氧。近年来,人类活动对该地区的影响大大增加,改变了水生植被与濒危物种、渔业和湖泊提供的其他生态系统服务之间的关系。要了解这些动态变化,就需要一种方法来绘制水生植被、连通性和栖息地的时间分布图。在此,我们开发了一种新的改进算法,通过遥感技术绘制漂浮和出水水生植被的空间分布和动态图。我们利用了从 1986 年到 2020 年的 440 幅 Landsat 图像的时间序列。我们设计了一系列水和植被指数来揭示水景随时间的变化。首先,利用多数原则得出两种水掩模--每幅图像的单独水掩模和研究期间该区域的综合水掩模。其次,利用两个掩模之间的差值来划定大型水草在图像上的潜在位置。第三,开发一种算法,将漂浮植被与新生植被区分开来;该算法使用 Landsat 光谱波段和两个额外的时空指标,大大提高了分类的准确性。利用遥感技术对水生景观轨迹进行更广泛的分析,可为鱼类保护战略和渔业管理提供信息,并阐明景观动态在水生类群宏观进化模式中的作用。
{"title":"Mapping the dynamics of aquatic vegetation in Lake Kyoga and its linkages to satellite lakes","authors":"Yaxiong Ma ,&nbsp;Sucharita Gopal ,&nbsp;Magaly Koch ,&nbsp;Les Kaufman","doi":"10.1016/j.srs.2024.100156","DOIUrl":"10.1016/j.srs.2024.100156","url":null,"abstract":"<div><p>Lake Kyoga is a shallow, young, flooded basin just north of and about 30m lower than Lake Victoria. The catchment encompasses Lake Kyoga itself, and a constellation of several dozen small satellite lakes following valley contours mostly to its east. The Kyoga basin fish fauna shares many non-cichlid species plus a spectacular, partially endemic radiation of haplochromine cichlids most similar to but still largely distinct from those in Lake Victoria. This fish fauna is of high conservation concern, as it preserves remnants of the regional species flock that have disappeared from Lake Victoria and Lake Kyoga, leaving small remnant populations in some of the satellite lakes. Now, these too are imperiled by limnological dynamics, including fluctuations in the nature and extent of aquatic vegetation. The water bodies in the Kyoga Basin are highly dynamic due both to fluctuation in water level and large amplitude variation in marginal and floating vegetation. This variation has profound evolutionary and conservation implications, since it can create and destroy critical aquatic habitat. It can also alternately anneal and cleave gene flow over time, both between the main lake and its satellites, and among the satellite lakes. The aquatic vegetation cluttering these linkages can create a spatial refugium for many native fish species that are more tolerant of hypoxia than an introduced macropredator, the Nile perch. Anthropogenic impacts to this region have greatly increased in recent years, altering relationships between aquatic vegetation and endangered species, fisheries and other ecosystem services provided by the lake. Understanding these dynamics require a means of mapping aquatic vegetation, connectivity, and habitat through time. Here we develop a new and improved algorithm to map the spatial distribution and dynamics of floating and emergent aquatic vegetation via remote sensing. We utilize a time series of 440 Landsat images dating from 1986 to 2020. A series of water and vegetation indices are designed to reveal change in the aquascape over time. First, two types of water masks are derived using a majority rule - a separate water mask for each image and a composite water mask of the region over the study period. Second, the difference between the two masks is then used to delineate the potential location of macrophytes over the image. Third, an algorithm is developed to separate the floating vegetation from emergent vegetation; this algorithm uses Landsat spectral bands and two additional spatial and temporal metrics that considerably improve classification accuracy. A more extensive analysis of aquascape trajectories using remote sensing can inform fish conservation strategies and fisheries management and illuminate the role of landscape dynamics in macroevolutionary patterns of aquatic taxa.</p></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100156"},"PeriodicalIF":5.7,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666017224000403/pdfft?md5=3c55b1abdf343849640e800c87d754c3&pid=1-s2.0-S2666017224000403-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142048732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Identification of an optimal ground-based validation site for FLEX and quantification of uncertainties using airborne HyPlant data - A case study in Italy 利用机载 HyPlant 数据为 FLEX 确定最佳地面验证地点并量化不确定性 - 意大利案例研究
IF 5.7 Q1 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-12 DOI: 10.1016/j.srs.2024.100155
Lena Katharina Jänicke, Rene Preusker, Jürgen Fischer

The Fluorescence Explorer (FLEX) satellite will carry the high-resolution Fluorescence Imaging Spectrometer (FLORIS) that measures the complete fluorescence spectrum emitted by chlorophyll of terrestrial vegetation. This small signal must be validated. One validation approach is comparing the fluorescence signal retrieved from satellite-based measurements with ground based measurements. However, the difference in spatial resolution of the satellite and ground-based instruments and a geolocation mismatch will result in differences in the detected signal and thus, in uncertainties of the validation strategy. In a case study, we identify a representative ground site for validating the fluorescence signal by analyzing surface reflectance measurements from an aeroplane.

We define requirements of representativeness for a validation ground site in vegetated areas. Based on those requirements, we identify a suitable position within a case study in central Italy using surface reflectance data from the airborne High-Performance Airborne Imaging Spectrometer (HyPlant) measured in summer 2018. The representativeness is quantified by the relative difference between the single HyPlant pixel representing a ground-based measurement and the averaged signal of several HyPlant pixels that mimics a FLORIS pixel. With this measure, we quantify the validation uncertainty due to spatial resolution and geolocation mismatch. The effect of the temporal evolution of the surface properties on the validation uncertainty due to spatial resolution is investigated.

We select the ground site position by minimizing the validation uncertainty due to spatial resolution. Especially for wavelengths larger than 700 nm, this uncertainty is smaller than 2 % for all different reference areas. The largest differences between ground-based like measurement and satellite-like measurement of the surface reflectance is due to geolocation mismatch. The uncertainty due the geolocation mismatch is very large for wavelengths smaller than 720 nm and moderate for wavelengths larger than 720 nm. Thus, the surface reflectance at the chosen position for the validation site is not homogeneous enough for validation purpose. Considering a reference area of 13.5 × 13.5 m2, we quantify temporal stable and small uncertainties for the spectral range between 720 and 800 nm. For an all-embracing validation of the surface reflectance of vegetated areas, the chosen site is not appropriate.

荧光探索者(FLEX)卫星将携带高分辨率荧光成像光谱仪(FLORIS),测量陆地植被叶绿素发出的完整荧光光谱。必须对这一微小信号进行验证。一种验证方法是将卫星测量获得的荧光信号与地面测量结果进行比较。然而,卫星和地面仪器空间分辨率的差异以及地理位置的不匹配会导致检测到的信号不同,从而给验证策略带来不确定性。在一项案例研究中,我们通过分析飞机的表面反射率测量结果,确定了一个具有代表性的地面站点,用于验证荧光信号。根据这些要求,我们利用 2018 年夏季测量的机载高性能机载成像光谱仪(HyPlant)表面反射率数据,在意大利中部的一个案例研究中确定了一个合适的位置。代表性通过代表地面测量的单个 HyPlant 像素与模拟 FLORIS 像素的多个 HyPlant 像素的平均信号之间的相对差异进行量化。通过这一指标,我们可以量化空间分辨率和地理位置不匹配造成的验证不确定性。我们通过最小化空间分辨率导致的验证不确定性来选择地面站点位置。特别是对于波长大于 700 纳米的波长,所有不同参考区域的验证不确定性都小于 2%。地基测量与卫星测量表面反射率的最大差异是地理定位不匹配造成的。波长小于 720 nm 时,地理定位失配造成的不确定性非常大,波长大于 720 nm 时,不确定性适中。因此,验证地点所选位置的表面反射率不够均匀,无法达到验证目的。考虑到参考区域为 13.5 × 13.5 m2,我们对 720 至 800 nm 光谱范围内的时间稳定和较小的不确定性进行了量化。对于植被区地表反射率的全面验证,所选地点并不合适。
{"title":"Identification of an optimal ground-based validation site for FLEX and quantification of uncertainties using airborne HyPlant data - A case study in Italy","authors":"Lena Katharina Jänicke,&nbsp;Rene Preusker,&nbsp;Jürgen Fischer","doi":"10.1016/j.srs.2024.100155","DOIUrl":"10.1016/j.srs.2024.100155","url":null,"abstract":"<div><p>The Fluorescence Explorer (FLEX) satellite will carry the high-resolution Fluorescence Imaging Spectrometer (FLORIS) that measures the complete fluorescence spectrum emitted by chlorophyll of terrestrial vegetation. This small signal must be validated. One validation approach is comparing the fluorescence signal retrieved from satellite-based measurements with ground based measurements. However, the difference in spatial resolution of the satellite and ground-based instruments and a geolocation mismatch will result in differences in the detected signal and thus, in uncertainties of the validation strategy. In a case study, we identify a representative ground site for validating the fluorescence signal by analyzing surface reflectance measurements from an aeroplane.</p><p>We define requirements of representativeness for a validation ground site in vegetated areas. Based on those requirements, we identify a suitable position within a case study in central Italy using surface reflectance data from the airborne High-Performance Airborne Imaging Spectrometer (HyPlant) measured in summer 2018. The representativeness is quantified by the relative difference between the single HyPlant pixel representing a ground-based measurement and the averaged signal of several HyPlant pixels that mimics a FLORIS pixel. With this measure, we quantify the validation uncertainty due to spatial resolution and geolocation mismatch. The effect of the temporal evolution of the surface properties on the validation uncertainty due to spatial resolution is investigated.</p><p>We select the ground site position by minimizing the validation uncertainty due to spatial resolution. Especially for wavelengths larger than 700 nm, this uncertainty is smaller than 2 % for all different reference areas. The largest differences between ground-based like measurement and satellite-like measurement of the surface reflectance is due to geolocation mismatch. The uncertainty due the geolocation mismatch is very large for wavelengths smaller than 720 nm and moderate for wavelengths larger than 720 nm. Thus, the surface reflectance at the chosen position for the validation site is not homogeneous enough for validation purpose. Considering a reference area of 13.5 × 13.5 m<sup>2</sup>, we quantify temporal stable and small uncertainties for the spectral range between 720 and 800 nm. For an all-embracing validation of the surface reflectance of vegetated areas, the chosen site is not appropriate.</p></div>","PeriodicalId":101147,"journal":{"name":"Science of Remote Sensing","volume":"10 ","pages":"Article 100155"},"PeriodicalIF":5.7,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666017224000397/pdfft?md5=a24cd18d7ea0ce7c56e2003d521fde23&pid=1-s2.0-S2666017224000397-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141985748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
期刊
Science of Remote Sensing
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1