The occurrence of extreme weather conditions, such as cold waves and heat waves, is increasing due to changes in climatic parameters. Increasing temperature and high anomaly of precipitation increase the Glacial Lake Outburst Flood (GLOF) susceptibility in the Himalaya. This study primarily focuses on the GLOFs-induced floods in the Himalayas through a systematic review of articles published from 2000 to 2024. The selected number of articles was taken as 119 to analyse the flood locations, frequencies, intensities, and damages of the study area. The analysis showed that the majority of selected articles were focused on the GLOF, which occurred in the Indian Himalaya. The record of GLOFs also shows that the Sagarmatha region in Nepal, Uttarakhand, Sikkim, Himachal Pradesh in India, and Bhutan were the places where GLOF occurs frequently. Previous studies have also shown the increasing frequency and destruction of GLOFs after the year 2000. In the season of summer (April to June) and monsoon (June to Sep), GLOF occurs frequently. The study also illustrated that the use of remote sensing data has increased gradually since 2000 in GLOF studies. It was mainly used to demarcate the boundary of flood-affected areas and calculate the possible damage due to the flood. This article will provide clear information on GLOFs in the Himalayan region from 2000 to 2024, and it will be beneficial for researchers to emphasize the recent trends of research, methods, and identify the research gaps of GLOF studies.
{"title":"Impact assessment of Glacial Lake Outburst Floods (GLOFs) in the Himalaya using satellite imageries over the last 25 years (2000–2024): A comprehensive review","authors":"Arun Mondal , Anupam Pandey , Souvik Mondal , Sananda Kundu","doi":"10.1016/j.rsase.2025.101845","DOIUrl":"10.1016/j.rsase.2025.101845","url":null,"abstract":"<div><div>The occurrence of extreme weather conditions, such as cold waves and heat waves, is increasing due to changes in climatic parameters. Increasing temperature and high anomaly of precipitation increase the Glacial Lake Outburst Flood (GLOF) susceptibility in the Himalaya. This study primarily focuses on the GLOFs-induced floods in the Himalayas through a systematic review of articles published from 2000 to 2024. The selected number of articles was taken as 119 to analyse the flood locations, frequencies, intensities, and damages of the study area. The analysis showed that the majority of selected articles were focused on the GLOF, which occurred in the Indian Himalaya. The record of GLOFs also shows that the Sagarmatha region in Nepal, Uttarakhand, Sikkim, Himachal Pradesh in India, and Bhutan were the places where GLOF occurs frequently. Previous studies have also shown the increasing frequency and destruction of GLOFs after the year 2000. In the season of summer (April to June) and monsoon (June to Sep), GLOF occurs frequently. The study also illustrated that the use of remote sensing data has increased gradually since 2000 in GLOF studies. It was mainly used to demarcate the boundary of flood-affected areas and calculate the possible damage due to the flood. This article will provide clear information on GLOFs in the Himalayan region from 2000 to 2024, and it will be beneficial for researchers to emphasize the recent trends of research, methods, and identify the research gaps of GLOF studies.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101845"},"PeriodicalIF":4.5,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-19DOI: 10.1016/j.rsase.2025.101839
Sri Priyanka Kommula , Bharat Lohani , Dongryeol Ryu , Stephan Winter
Accurate identification of micro-surface rainwater harvesting (RWH) sites depends on the quality of topographic data. Commonly used DEMs such as SRTM, ASTER, and CartoDEM are limited by their coarse resolution and often fail to capture the fine-scale geomorphic features required for identifying these structures. Their radar- and optical-based acquisition methods also struggle in hilly and densely vegetated terrains, further restricting their ability to represent terrain accurately. To address these limitations, this study develops a GIS-based decision-support framework using the Analytical Hierarchy Process (AHP) to compare satellite-derived CartoDEM (30-m) with LiDAR DEMs at 30-m, 10-m, 5-m, and 1-m resolutions. Seven parameters — runoff, slope, land use/land cover, soil, lithology, flow accumulation, and geomorphology — were integrated to generate suitability maps for gabions and loose stone check dams. Validation against 116 expert-verified sites demonstrates that the 1-m LiDAR DEM achieves the highest performance (OA = 0.87, Precision = 0.98, Recall = 0.98), substantially outperforming CartoDEM (OA = 0.62). While discrepancies existed between CartoDEM and LiDAR DEM at 30-m resolution, these differences were not reflected in OA values, likely due to the limited validation dataset. High-resolution LiDAR DEMs significantly improve the delineation of slope and flow accumulation, enabling more reliable micro-RWH site identification. The proposed framework provides a practical and transferable method for watershed managers designing micro RWH structures in complex terrains.
{"title":"Improving micro rainwater harvesting site selection with high-resolution LiDAR DEMs: A GIS-based multi-criteria approach","authors":"Sri Priyanka Kommula , Bharat Lohani , Dongryeol Ryu , Stephan Winter","doi":"10.1016/j.rsase.2025.101839","DOIUrl":"10.1016/j.rsase.2025.101839","url":null,"abstract":"<div><div>Accurate identification of micro-surface rainwater harvesting (RWH) sites depends on the quality of topographic data. Commonly used DEMs such as SRTM, ASTER, and CartoDEM are limited by their coarse resolution and often fail to capture the fine-scale geomorphic features required for identifying these structures. Their radar- and optical-based acquisition methods also struggle in hilly and densely vegetated terrains, further restricting their ability to represent terrain accurately. To address these limitations, this study develops a GIS-based decision-support framework using the Analytical Hierarchy Process (AHP) to compare satellite-derived CartoDEM (30-m) with LiDAR DEMs at 30-m, 10-m, 5-m, and 1-m resolutions. Seven parameters — runoff, slope, land use/land cover, soil, lithology, flow accumulation, and geomorphology — were integrated to generate suitability maps for gabions and loose stone check dams. Validation against 116 expert-verified sites demonstrates that the 1-m LiDAR DEM achieves the highest performance (OA = 0.87, Precision = 0.98, Recall = 0.98), substantially outperforming CartoDEM (OA = 0.62). While discrepancies existed between CartoDEM and LiDAR DEM at 30-m resolution, these differences were not reflected in OA values, likely due to the limited validation dataset. High-resolution LiDAR DEMs significantly improve the delineation of slope and flow accumulation, enabling more reliable micro-RWH site identification. The proposed framework provides a practical and transferable method for watershed managers designing micro RWH structures in complex terrains.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101839"},"PeriodicalIF":4.5,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-18DOI: 10.1016/j.rsase.2025.101837
Simon Ramsey , Karin Reinke , Andrew Edwards , Simon Jones
This research presents a method to produce fire reconstructions with a high spatial and temporal resolution by downscaling geostationary satellite observations using a deep learning segmentation framework. This was achieved by training a U-Net on low earth orbit active fire detections paired with synchronous observations from the geostationary satellite Himawari-9/Advanced Himawari Imager (AHI) resampled to the resolution of the 500 m RED channel. Geostationary satellites provide a means for continuous monitoring of fire behaviour but are constrained by the low spatial resolution of the infrared channels used to detect active fires. Localising fire activity using information from the higher spatial resolution solar reflective channels of geostationary satellites enables detailed fire progression mapping with a comparable spatial resolution to low earth orbit satellite systems. Six case study fires in the northern Australian savannahs are reconstructed with their lifecycles compared to the burn scar mapped by the Northern Australia and Rangelands Fire Information (NAFI), with F1-scores ranging from 0.80 to 0.96. Model predictions synchronous to VIIRS active fire detections during the selected case study fires were used to test performance during case study events. The results indicate a high positive detection rate (75%) for detections with a fire radiative power (FRP) above 12.4 MW during day-time and 3.1 MW at night-time which degraded with decreasing FRP as the fire signal becomes increasingly difficult to detect within the 2 km instantaneous field of view (IFOV) of the AHI infrared channels against the high day-time background temperatures within the northern Australian savannahs.
本研究提出了一种利用深度学习分割框架，通过对地静止卫星观测降尺度，产生高时空分辨率火灾重建的方法。这是通过训练U-Net在近地轨道上进行主动火灾探测，并与地球同步卫星Himawari-9/高级Himawari成像仪（AHI）的同步观测结果进行配对，重新采样到500 m 0.64μm RED通道的分辨率。地球同步卫星提供了一种持续监测火灾行为的手段，但受到用于探测活火的红外通道的低空间分辨率的限制。利用来自地球静止卫星的高空间分辨率太阳反射通道的信息来定位火灾活动，能够以与低地球轨道卫星系统相当的空间分辨率绘制详细的火灾进展图。本文重建了澳大利亚北部稀树大草原的六个火灾案例，并将其生命周期与北澳大利亚和牧场火灾信息（NAFI）绘制的烧伤疤痕进行了比较，f1得分从0.80到0.96不等。在选定的案例研究火灾期间，与VIIRS主动火灾探测同步的模型预测用于测试案例研究事件期间的性能。结果表明，在澳大利亚北部的热带草原上，在高白天背景温度下，AHI红外通道的2公里瞬时视场（IFOV）范围内，火灾信号越来越难以被探测到，因此，在白天高于12.4 MW和夜间高于3.1 MW的火灾辐射功率（FRP）探测的阳性检出率很高（75%），夜间随着FRP的降低而降低。
{"title":"Reconstructing savannah wildfire events using a deep learning framework","authors":"Simon Ramsey , Karin Reinke , Andrew Edwards , Simon Jones","doi":"10.1016/j.rsase.2025.101837","DOIUrl":"10.1016/j.rsase.2025.101837","url":null,"abstract":"<div><div>This research presents a method to produce fire reconstructions with a high spatial and temporal resolution by downscaling geostationary satellite observations using a deep learning segmentation framework. This was achieved by training a U-Net on low earth orbit active fire detections paired with synchronous observations from the geostationary satellite Himawari-9/Advanced Himawari Imager (AHI) resampled to the resolution of the 500 m <span><math><mrow><mn>0</mn><mo>.</mo><mn>64</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> RED channel. Geostationary satellites provide a means for continuous monitoring of fire behaviour but are constrained by the low spatial resolution of the infrared channels used to detect active fires. Localising fire activity using information from the higher spatial resolution solar reflective channels of geostationary satellites enables detailed fire progression mapping with a comparable spatial resolution to low earth orbit satellite systems. Six case study fires in the northern Australian savannahs are reconstructed with their lifecycles compared to the burn scar mapped by the Northern Australia and Rangelands Fire Information (NAFI), with F1-scores ranging from 0.80 to 0.96. Model predictions synchronous to VIIRS active fire detections during the selected case study fires were used to test performance during case study events. The results indicate a high positive detection rate (75%) for detections with a fire radiative power (FRP) above 12.4 MW during day-time and 3.1 MW at night-time which degraded with decreasing FRP as the fire signal becomes increasingly difficult to detect within the 2 km instantaneous field of view (IFOV) of the AHI infrared channels against the high day-time background temperatures within the northern Australian savannahs.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101837"},"PeriodicalIF":4.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Considering that seaweed gathering is a highly relevant socioeconomic activity in northern Chile, estimating available biomass is vital for its sustainable management. The direct and indirect evaluations used are difficult and untimely, apart from their high costs and imprecisions due to spatiotemporal resolution. This study aims at assessing the macroalgal biomass and its spatial distribution faster and more accurately for the resource's management. To do this, an indirect assessment model for the Lessonia Nigrescens biomass complex, which comprises photogrammetric surveys of multispectral images from unmanned aerial vehicles (UAVs) and their geoprocessing through geographical information systems (GIS), is proposed. Such geoprocessing includes a mathematical algorithm calibrated with in situ non-extractive sampling in order to indirectly get the macroalgal biomass of the areas under study. The model was applied in the Atacama and Coquimbo regions over winter and summer. Thematic layers were built through GIS, digital surface models and supervised classification, using the maximum likelihood method. The indirect biomass results obtained from the algorithm were correlated with the results of the biomass obtained from the direct sampling, showing an average association (R2) of 67 % in winter and 86 % in summer, and its spatial distribution with an accuracy of 70 % in winter and 73 % in summer. The model enabled to get the spatial distribution of the resource's biomass in the short term, displayed as geospatial databases and thematic cartography to support the decision making process in the sustainable management of this resource.
{"title":"A model for the macroalgal assessment of the Lessonia Nigrescens complex through unmanned aerial vehicles (UAV) and Geographic Information System (GIS)","authors":"Eduardo Manzano , Álvaro Pacheco , Carlos Manzano , Macarena Álvarez","doi":"10.1016/j.rsase.2025.101843","DOIUrl":"10.1016/j.rsase.2025.101843","url":null,"abstract":"<div><div>Considering that seaweed gathering is a highly relevant socioeconomic activity in northern Chile, estimating available biomass is vital for its sustainable management. The direct and indirect evaluations used are difficult and untimely, apart from their high costs and imprecisions due to spatiotemporal resolution. This study aims at assessing the macroalgal biomass and its spatial distribution faster and more accurately for the resource's management. To do this, an indirect assessment model for the <em>Lessonia Nigrescens</em> biomass complex, which comprises photogrammetric surveys of multispectral images from unmanned aerial vehicles (UAVs) and their geoprocessing through geographical information systems (GIS), is proposed. Such geoprocessing includes a mathematical algorithm calibrated with <em>in situ</em> non-extractive sampling in order to indirectly get the macroalgal biomass of the areas under study. The model was applied in the Atacama and Coquimbo regions over winter and summer. Thematic layers were built through GIS, digital surface models and supervised classification, using the maximum likelihood method. The indirect biomass results obtained from the algorithm were correlated with the results of the biomass obtained from the direct sampling, showing an average association (R<sup>2</sup>) of 67 % in winter and 86 % in summer, and its spatial distribution with an accuracy of 70 % in winter and 73 % in summer. The model enabled to get the spatial distribution of the resource's biomass in the short term, displayed as geospatial databases and thematic cartography to support the decision making process in the sustainable management of this resource.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101843"},"PeriodicalIF":4.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-15DOI: 10.1016/j.rsase.2025.101833
Yu Lei, Lin Liu, Yuhuan Cui, Kerun Jiang, Shuang Hao
Rapid urban expansion in the Chaohu Lake Basin (Anhui Province, China) has profoundly altered the land use and ecosystem characteristics over the past two decades. This study investigates the spatiotemporal dynamics of this expansion and its coupled relationship with ecological sensitivity. Using Landsat imagery on the Google Earth Engine platform, we quantified land use and ecological sensitivity changes from 2000 to 2020. The land use change was dramatic, driven by urban expansion: the built-up area increased from 311.0 to 3885.9 km2, while cropland decreased by ∼41 % (4112.48 km2). Concurrently, the proportion of the ecologically insensitive areas (dominated by new built-up land) increased from 2.91 % to 28.35 % of the basin, while the extremely sensitive areas (protected forests and water bodies) remained at ∼4 %. Geodetector analysis revealed that land use type was the dominant driver (q > 0.75) of the spatial variations in ecological sensitivity. The coupling coordination modeling revealed a marked increase in the synergy between land use and ecological sensitivity, especially from 2010 to 2020. Overall, 45.8 % of the basin experienced improved coordination, underscoring that targeted land use planning and conservation policies can be effective in mitigating ecological pressure even during periods of rapid urbanization. These results clarify the co-evolution of urban-driven land use dynamics and ecological vulnerability, providing a scientific basis for achieving targeted ecological protection and sustainable development.
{"title":"Spatio-temporal dynamics and coupling of urban expansion with ecological sensitivity in Chaohu Lake Basin","authors":"Yu Lei, Lin Liu, Yuhuan Cui, Kerun Jiang, Shuang Hao","doi":"10.1016/j.rsase.2025.101833","DOIUrl":"10.1016/j.rsase.2025.101833","url":null,"abstract":"<div><div>Rapid urban expansion in the Chaohu Lake Basin (Anhui Province, China) has profoundly altered the land use and ecosystem characteristics over the past two decades. This study investigates the spatiotemporal dynamics of this expansion and its coupled relationship with ecological sensitivity. Using Landsat imagery on the Google Earth Engine platform, we quantified land use and ecological sensitivity changes from 2000 to 2020. The land use change was dramatic, driven by urban expansion: the built-up area increased from 311.0 to 3885.9 km<sup>2</sup>, while cropland decreased by ∼41 % (4112.48 km<sup>2</sup>). Concurrently, the proportion of the ecologically insensitive areas (dominated by new built-up land) increased from 2.91 % to 28.35 % of the basin, while the extremely sensitive areas (protected forests and water bodies) remained at ∼4 %. Geodetector analysis revealed that land use type was the dominant driver (q > 0.75) of the spatial variations in ecological sensitivity. The coupling coordination modeling revealed a marked increase in the synergy between land use and ecological sensitivity, especially from 2010 to 2020. Overall, 45.8 % of the basin experienced improved coordination, underscoring that targeted land use planning and conservation policies can be effective in mitigating ecological pressure even during periods of rapid urbanization. These results clarify the co-evolution of urban-driven land use dynamics and ecological vulnerability, providing a scientific basis for achieving targeted ecological protection and sustainable development.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101833"},"PeriodicalIF":4.5,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Desert Locust (DL) infestations pose a significant threat to food security in arid and semi-arid regions, particularly in East Africa, Central Asia, and the Indian subcontinent. In 2020, during the COVID-19 pandemic, India witnessed an unprecedented upsurge of DL activity during the summer (zaid) season (April–June), severely impacting Rajasthan, Gujarat, and neighbouring states. This study investigates the environmental drivers of the DL outbreak and assesses crop damage using geospatial datasets, reanalysis products, and numerical weather models. Fifteen grid cells (100 km × 100 km) along the DL-prone corridor from East Africa to India were analyzed for environmental suitability, with seasonal Spearman correlation analysis applied to identify significant factors influencing locust activity. In winter, locust activity was significantly positively correlated with rainfall (ρ = 0.47, p = 0.021), dew point temperature (ρ = 0.76, p = 0.01), and soil moisture (ρ = 0.50, p = 0.05), highlighting the importance of moisture and temperature conditions in facilitating locust presence. In spring, significant positive correlations were observed with air temperature (ρ = 0.56, p = 0.027), soil temperature 1 (ρ = 0.65, p = 0.01), and a very strong correlation with soil temperature 2 (ρ = 0.73, p = 0.002). These findings showed the crucial role of temperature and moisture during the winter and spring seasons as key drivers of locust behaviour. The Linear Discriminant Analysis (LDA) model shows potential in locust presence prediction, though challenges remain due to data limitations. Crop damage was quantified using Normalized Difference Vegetative Index (NDVI), showing severe vegetation loss in affected areas (NDVI <0.3) and degradation due to locust feeding. The study further integrates weather forecast wind patterns, MODIS Leaf Area Index (LAI), and soil moisture from SMAP to track locust migration. Wind patterns, particularly westerly and south-westerly winds, guided the locusts' entry into western India. Despite moderate LAI values, the vegetation cover in central and western India provided sufficient sustenance for the locusts. Soil moisture from SMAP consistently supported locust dispersal across northern Rajasthan, central India, and parts of Uttar Pradesh. The integration of these environmental factors offers a comprehensive understanding of DL behaviour, enhancing early warning and control efforts.
沙漠蝗对干旱和半干旱地区，特别是东非、中亚和印度次大陆的粮食安全构成重大威胁。2020年，在2019冠状病毒病大流行期间，印度在夏季（4月至6月）出现了前所未有的DL活动激增，严重影响了拉贾斯坦邦、古吉拉特邦和邻近邦。本研究利用地理空间数据集、再分析产品和数值天气模型调查了旱情暴发的环境驱动因素，并评估了作物损失。分析了东非至印度蝗灾易发走廊沿线15个网格单元（100 km × 100 km）的环境适宜性，并应用季节性Spearman相关分析确定了影响蝗灾活动的重要因素。在冬季，蝗虫活动与降雨量（ρ = 0.47, p = 0.021）、露点温度（ρ = 0.76, p = 0.01）和土壤湿度（ρ = 0.50, p = 0.05）呈显著正相关，突出了湿度和温度条件对促进蝗虫存在的重要性。春季与气温（ρ = 0.56, p = 0.027）、土壤温度（ρ = 0.65, p = 0.01）呈极显著正相关，与土壤温度（ρ = 0.73, p = 0.002）呈极强相关。这些发现表明，冬季和春季的温度和湿度是蝗虫行为的关键驱动因素。线性判别分析（LDA）模型显示了蝗虫存在预测的潜力，尽管由于数据限制仍然存在挑战。利用归一化植被指数（NDVI）对作物损害进行量化，显示受蝗灾影响地区植被损失严重（NDVI <0.3），且因蝗虫取食而退化。该研究进一步结合天气预报风向、MODIS叶面积指数（LAI）和SMAP的土壤湿度来跟踪蝗虫的迁移。风向，特别是西风和西南风，引导蝗虫进入印度西部。尽管LAI值适中，但印度中部和西部的植被覆盖为蝗虫提供了足够的食物。SMAP的土壤湿度持续支持蝗虫在拉贾斯坦邦北部、印度中部和北方邦部分地区的扩散。这些环境因素的整合提供了对深度学习行为的全面理解，加强了早期预警和控制工作。
{"title":"A geo-spatial assessment of desert locust risk over India during summer 2020 using GEO-LEO satellite observations and weather forecast","authors":"Rahul Nigam, Bimal K. Bhattacharya, Ayan Das, Mukesh Kumar, Prashant Kumar","doi":"10.1016/j.rsase.2025.101831","DOIUrl":"10.1016/j.rsase.2025.101831","url":null,"abstract":"<div><div>Desert Locust (DL) infestations pose a significant threat to food security in arid and semi-arid regions, particularly in East Africa, Central Asia, and the Indian subcontinent. In 2020, during the COVID-19 pandemic, India witnessed an unprecedented upsurge of DL activity during the summer (zaid) season (April–June), severely impacting Rajasthan, Gujarat, and neighbouring states. This study investigates the environmental drivers of the DL outbreak and assesses crop damage using geospatial datasets, reanalysis products, and numerical weather models. Fifteen grid cells (100 km × 100 km) along the DL-prone corridor from East Africa to India were analyzed for environmental suitability, with seasonal Spearman correlation analysis applied to identify significant factors influencing locust activity. In winter, locust activity was significantly positively correlated with rainfall (ρ = 0.47, p = 0.021), dew point temperature (ρ = 0.76, p = 0.01), and soil moisture (ρ = 0.50, p = 0.05), highlighting the importance of moisture and temperature conditions in facilitating locust presence. In spring, significant positive correlations were observed with air temperature (ρ = 0.56, p = 0.027), soil temperature 1 (ρ = 0.65, p = 0.01), and a very strong correlation with soil temperature 2 (ρ = 0.73, p = 0.002). These findings showed the crucial role of temperature and moisture during the winter and spring seasons as key drivers of locust behaviour. The Linear Discriminant Analysis (LDA) model shows potential in locust presence prediction, though challenges remain due to data limitations. Crop damage was quantified using Normalized Difference Vegetative Index (NDVI), showing severe vegetation loss in affected areas (NDVI <0.3) and degradation due to locust feeding. The study further integrates weather forecast wind patterns, MODIS Leaf Area Index (LAI), and soil moisture from SMAP to track locust migration. Wind patterns, particularly westerly and south-westerly winds, guided the locusts' entry into western India. Despite moderate LAI values, the vegetation cover in central and western India provided sufficient sustenance for the locusts. Soil moisture from SMAP consistently supported locust dispersal across northern Rajasthan, central India, and parts of Uttar Pradesh. The integration of these environmental factors offers a comprehensive understanding of DL behaviour, enhancing early warning and control efforts.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101831"},"PeriodicalIF":4.5,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-14DOI: 10.1016/j.rsase.2025.101840
Reddy R. Pullanagari , Mohammad Hossain Dehghan-Shoar , Junqi Zhu , Alvaro A. Orsi , Ian J. Yule
Sun-induced chlorophyll fluorescence (SIF) has emerged as a valuable proxy for estimating plant physiological activity. While empirical and one-dimensional (1D) radiative transfer models (RTMs) have shown reasonable success in quantifying SIF at the canopy scale using hyperspectral sensors, they face challenges in addressing complex, heterogeneous canopy structures, weak signals, and intricate sun-to-sensor geometries. In recent years, three-dimensional (3D) RTMs have made significant progress in overcoming these challenges.
This study employed multiple RTMs, such as PROSPECT-PRO, FLUSPECT, and LESS, to investigate SIF in kiwifruit orchards. High-resolution hyperspectral imagery and LiDAR data were collected over the orchards, along with ground-truth measurements. A 3D kiwifruit canopy was reconstructed using functional-structural plant modeling (FSPM) based on LiDAR point cloud data. Utilizing the LESS RTM, thousands of reflectance spectra were simulated based on the given leaf and soil optical properties and the 3D canopy structure.
A kernel ridge regression (KRR) algorithm was trained on these simulations in the SIF region (650–810 nm) and validated with the ground-truth measurements. This hybrid (3D RTM-KRR) model demonstrated a high correlation with the ground-truth data, outperforming empirical models (such as Fraunhofer line discrimination methods). This indicates its capability to extract SIF from coarse-resolution airborne and satellite-based hyperspectral missions (e.g., PRISMA and EnMAP). This approach offers a promising avenue for improving our understanding of plant physiological processes and their interactions with the environment at larger scales. This research provides a significant advancement for precision agriculture in orchards, proving the practical value of 3D RTM for heterogeneous canopies.
{"title":"Mapping of sun-induced fluorescence (SIF) in kiwifruit canopy using a 3D radiative transfer modeling and airborne hyperspectral imaging","authors":"Reddy R. Pullanagari , Mohammad Hossain Dehghan-Shoar , Junqi Zhu , Alvaro A. Orsi , Ian J. Yule","doi":"10.1016/j.rsase.2025.101840","DOIUrl":"10.1016/j.rsase.2025.101840","url":null,"abstract":"<div><div>Sun-induced chlorophyll fluorescence (SIF) has emerged as a valuable proxy for estimating plant physiological activity. While empirical and one-dimensional (1D) radiative transfer models (RTMs) have shown reasonable success in quantifying SIF at the canopy scale using hyperspectral sensors, they face challenges in addressing complex, heterogeneous canopy structures, weak signals, and intricate sun-to-sensor geometries. In recent years, three-dimensional (3D) RTMs have made significant progress in overcoming these challenges.</div><div>This study employed multiple RTMs, such as PROSPECT-PRO, FLUSPECT, and LESS, to investigate SIF in kiwifruit orchards. High-resolution hyperspectral imagery and LiDAR data were collected over the orchards, along with ground-truth measurements. A 3D kiwifruit canopy was reconstructed using functional-structural plant modeling (FSPM) based on LiDAR point cloud data. Utilizing the LESS RTM, thousands of reflectance spectra were simulated based on the given leaf and soil optical properties and the 3D canopy structure.</div><div>A kernel ridge regression (KRR) algorithm was trained on these simulations in the SIF region (650–810 nm) and validated with the ground-truth measurements. This hybrid (3D RTM-KRR) model demonstrated a high correlation with the ground-truth data, outperforming empirical models (such as Fraunhofer line discrimination methods). This indicates its capability to extract SIF from coarse-resolution airborne and satellite-based hyperspectral missions (e.g., PRISMA and EnMAP). This approach offers a promising avenue for improving our understanding of plant physiological processes and their interactions with the environment at larger scales. This research provides a significant advancement for precision agriculture in orchards, proving the practical value of 3D RTM for heterogeneous canopies.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101840"},"PeriodicalIF":4.5,"publicationDate":"2025-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.rsase.2025.101836
Aleksi Isoaho , Timo P. Pitkänen , Lauri Ikkala , Antti Sallinen , Parvez Rana , Hannu Marttila , Lassi Päkkilä , Aleksi Räsänen
Remote sensing (RS) methods are recognized as a potential solution for the increasing need to monitor peatland changes after restoration, but practical monitoring tools are lacking. To address this gap, our objective is to (1) test which optical satellite variables can be used for detecting hydrological restoration impact in treeless boreal peatlands, (2) develop a user-friendly Google Earth Engine (GEE) application based on the results, and (3) demonstrate its usage in practice. Firstly, by utilizing data from 24 peatland restoration sites in Finland, we used Mann-Whitney U test and Kruskal-Wallis test to determine which optical variables calculated from Sentinel-2 and Landsat 8–9 satellite imagery can be used as indicators for surface wetness changes after peatland restoration. The results from statistical tests indicated that near-infrared (NIR) and shortwave infrared (SWIR) bands were the most effective in detecting the impact. Secondly, we incorporated the NIR and SWIR bands into the GEE application to indicate the location and magnitude of restoration impact. The developed application uses a direct input from the openly available satellite imagery archives and requires only a few inputs from the user for the case-specific analysis, making it user-friendly. The application calculates cloudless and representative satellite image mosaics and uses change detection for the situations before and after restoration to show the hydrological restoration impacts spatially. The application provides researchers, stakeholders, decision-makers, and practitioners with limited technical experience the possibility to use satellite imagery for assessing restoration impacts in open or sparsely treed peatlands in boreal landscapes.
{"title":"An automated Google Earth Engine application for detecting the impacted area of treeless boreal peatland restoration – A tool for practitioners and decision-makers","authors":"Aleksi Isoaho , Timo P. Pitkänen , Lauri Ikkala , Antti Sallinen , Parvez Rana , Hannu Marttila , Lassi Päkkilä , Aleksi Räsänen","doi":"10.1016/j.rsase.2025.101836","DOIUrl":"10.1016/j.rsase.2025.101836","url":null,"abstract":"<div><div>Remote sensing (RS) methods are recognized as a potential solution for the increasing need to monitor peatland changes after restoration, but practical monitoring tools are lacking. To address this gap, our objective is to (1) test which optical satellite variables can be used for detecting hydrological restoration impact in treeless boreal peatlands, (2) develop a user-friendly Google Earth Engine (GEE) application based on the results, and (3) demonstrate its usage in practice. Firstly, by utilizing data from 24 peatland restoration sites in Finland, we used Mann-Whitney <em>U</em> test and Kruskal-Wallis test to determine which optical variables calculated from Sentinel-2 and Landsat 8–9 satellite imagery can be used as indicators for surface wetness changes after peatland restoration. The results from statistical tests indicated that near-infrared (NIR) and shortwave infrared (SWIR) bands were the most effective in detecting the impact. Secondly, we incorporated the NIR and SWIR bands into the GEE application to indicate the location and magnitude of restoration impact. The developed application uses a direct input from the openly available satellite imagery archives and requires only a few inputs from the user for the case-specific analysis, making it user-friendly. The application calculates cloudless and representative satellite image mosaics and uses change detection for the situations before and after restoration to show the hydrological restoration impacts spatially. The application provides researchers, stakeholders, decision-makers, and practitioners with limited technical experience the possibility to use satellite imagery for assessing restoration impacts in open or sparsely treed peatlands in boreal landscapes.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101836"},"PeriodicalIF":4.5,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.rsase.2025.101834
Anagha S. Dhavalikar
Oil spill detection is a crucial component of marine environmental protection and disaster management. Remote sensing technologies, using Synthetic Aperture Radar (SAR) imagery, offer a consistent and robust method for identifying and monitoring oil spills. In this study, transfer learning is employed to adapt three state-of-the-art deep convolutional neural networks (CNNs)—ResNet18, ResNet50, and EfficientNet-B0 which are pretrained on the ImageNet dataset, to the binary classification task of identifying oil spills and look-alikes in SAR images. With a balanced dataset having 278 images of oil spill and 262 of look-alike classes, across 10 epochs, ResNet18, ResNet50, and EfficientNet-B0 achieved high training accuracies in the range of 95–97 %. ResNet50 showed the best validation accuracy of 87.86 % and Test Accuracy 84.05 %. EfficientNet-B0, while lighter and faster, had slightly lower validation performance. ResNet18 offers a balance between speed and accuracy, whereas ResNet50 is optimal for accuracy if resources permit.
{"title":"Enhanced transfer learning for marine oil spill pollution monitoring","authors":"Anagha S. Dhavalikar","doi":"10.1016/j.rsase.2025.101834","DOIUrl":"10.1016/j.rsase.2025.101834","url":null,"abstract":"<div><div>Oil spill detection is a crucial component of marine environmental protection and disaster management. Remote sensing technologies, using Synthetic Aperture Radar (SAR) imagery, offer a consistent and robust method for identifying and monitoring oil spills. In this study, transfer learning is employed to adapt three state-of-the-art deep convolutional neural networks (CNNs)—ResNet18, ResNet50, and EfficientNet-B0 which are pretrained on the ImageNet dataset, to the binary classification task of identifying oil spills and look-alikes in SAR images. With a balanced dataset having 278 images of oil spill and 262 of look-alike classes, across 10 epochs, ResNet18, ResNet50, and EfficientNet-B0 achieved high training accuracies in the range of 95–97 %. ResNet50 showed the best validation accuracy of 87.86 % and Test Accuracy 84.05 %. EfficientNet-B0, while lighter and faster, had slightly lower validation performance. ResNet18 offers a balance between speed and accuracy, whereas ResNet50 is optimal for accuracy if resources permit.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101834"},"PeriodicalIF":4.5,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.rsase.2025.101825
Roberto Calisti , Luca Regni , Raffaella Brigante , Laura Marconi , Alessandra Vinci , Fabio Radicioni , Primo Proietti
The olive groves, particularly the old ones, represent a significant carbon sink and so they are important for climate change mitigation. Also, many of these olive groves represent an important component of the landscape heritage. This study focuses on estimating biomass and carbon content in old olive tree groves, with a specific application in a 69-year-old olive grove in central Italy. The research used UAV (Unmanned Aerial Vehicle) survey data to evaluate the geometric features of some selected olive trees, using LiDAR (Light Detection and Ranging) and manual survey as basis for comparison and benchmark. The aim was to determine the effectiveness of UAV method, which this study showed to be less costly, less time-consuming, and less prone to drawbacks compared to the LiDAR and manual measurements. After felling the olive trees, their epigeal biomass was weighed. A strong linear correlation was found between the geometric parameters (trunk circumference, crown area, and crown volume) and the fresh weight of the trees. The results of this study show that UAV surveying provides a viable solution for assessing the carbon content of old olive groves, representing a significant improvement in relation to the methods still proposed by the IPCC (Intergovernmental Panel on Climate Change). As with all other proposed methods, the main issue concerns the estimation of the belowground biomass, for which there are currently no methods with a low degree of uncertainty, so there is a need to develop more accurate models.
橄榄林，尤其是老的橄榄林，代表着一个重要的碳汇，因此它们对减缓气候变化很重要。此外，许多橄榄园是景观遗产的重要组成部分。本研究的重点是估算老橄榄树林的生物量和碳含量，并在意大利中部一个69岁的橄榄树林中进行了具体应用。本研究利用无人机（UAV）调查数据对部分选定的橄榄树进行几何特征评价，以LiDAR （Light Detection and Ranging）和人工调查作为对比基准。目的是确定无人机方法的有效性，该研究表明，与激光雷达和手动测量相比，无人机方法成本更低，耗时更短，并且不易出现缺陷。采伐橄榄树后，对其表皮生物量进行称重。几何参数（树干周长、树冠面积和树冠体积）与树鲜重呈较强的线性相关。本研究结果表明，无人机测量为评估老橄榄园的碳含量提供了一个可行的解决方案，与IPCC（政府间气候变化专门委员会）仍然提出的方法相比，这是一个显著的改进。与所有其他提出的方法一样，主要问题涉及地下生物量的估计，目前还没有具有低不确定性的方法，因此需要开发更准确的模型。
{"title":"Estimating carbon storage in an old olive tree grove: A comparison of UAV, LiDAR, and manual surveys","authors":"Roberto Calisti , Luca Regni , Raffaella Brigante , Laura Marconi , Alessandra Vinci , Fabio Radicioni , Primo Proietti","doi":"10.1016/j.rsase.2025.101825","DOIUrl":"10.1016/j.rsase.2025.101825","url":null,"abstract":"<div><div>The olive groves, particularly the old ones, represent a significant carbon sink and so they are important for climate change mitigation. Also, many of these olive groves represent an important component of the landscape heritage. This study focuses on estimating biomass and carbon content in old olive tree groves, with a specific application in a 69-year-old olive grove in central Italy. The research used UAV (Unmanned Aerial Vehicle) survey data to evaluate the geometric features of some selected olive trees, using LiDAR (Light Detection and Ranging) and manual survey as basis for comparison and benchmark. The aim was to determine the effectiveness of UAV method, which this study showed to be less costly, less time-consuming, and less prone to drawbacks compared to the LiDAR and manual measurements. After felling the olive trees, their epigeal biomass was weighed. A strong linear correlation was found between the geometric parameters (trunk circumference, crown area, and crown volume) and the fresh weight of the trees. The results of this study show that UAV surveying provides a viable solution for assessing the carbon content of old olive groves, representing a significant improvement in relation to the methods still proposed by the IPCC (Intergovernmental Panel on Climate Change). As with all other proposed methods, the main issue concerns the estimation of the belowground biomass, for which there are currently no methods with a low degree of uncertainty, so there is a need to develop more accurate models.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"41 ","pages":"Article 101825"},"PeriodicalIF":4.5,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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