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Spatio-temporal characteristics of rainfall and drought conditions are using the different drought indices with geospatial approaches in Karnataka state 在卡纳塔克邦利用不同的干旱指数和地理空间方法分析降雨和干旱状况的时空特征
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-16 DOI: 10.1016/j.jastp.2024.106372
Karnataka state drought conditions are assessed via drought indices. Over the past several decades, several indices of drought (DI) have been developed and presented, although some of them are region-specific and have problems regarding their applicability to other climatic circumstances. Additionally, choosing the best DI time step to illustrate the drought condition is difficult because of the DIs' various time steps. The study compares the Standardized Precipitation Index (SPI), Statistical Z-Score, China Z-Index (CZI), Rainfall Anomaly Index (RAI), and Rainfall Departure (RD) to determine which one is most appropriate for the districts of the Karnataka state that are prone to both dry and rainy conditions. This study has pointed out that the best drought indices are SPI and RD, and the least accountable drought indice is China Z index. Droughts were most common in 22 districts in 2009, which represent around 70.97% of the state's landmass. In comparison with the rest of the districts, the Ramanagara district noticed the worst drought conditions in 2003, with rainfall reaching 92.47 mm and SPI -3.68, RAI-6.04, MCZI -2.39, and Z score −2.62. Overall, the results of the study will aid in the organization and improvement of drought, flood, agriculture, and water resource management approaches in the state.
卡纳塔克邦的干旱状况是通过干旱指数来评估的。在过去的几十年中,已经开发并提出了多个干旱指数(DI),但其中一些是针对特定地区的,在适用于其他气候条件方面存在问题。此外,由于 DIs 的时间步长各不相同,因此很难选择最佳的 DI 时间步长来说明干旱状况。本研究比较了标准化降水指数 (SPI)、统计 Z 值、中国 Z 指数 (CZI)、降雨异常指数 (RAI) 和降雨离差 (RD),以确定哪种指数最适合卡纳塔克邦既干旱又多雨的地区。这项研究指出,最好的干旱指数是 SPI 和 RD,最不可靠的干旱指数是中国 Z 指数。2009 年,22 个县的干旱最为普遍,约占该邦国土面积的 70.97%。与其他地区相比,拉马纳加拉地区在 2003 年的旱情最为严重,降雨量达到 92.47 毫米,SPI 为-3.68,RAI 为-6.04,MCZI 为-2.39,Z 指数为-2.62。总之,研究结果将有助于组织和改进该州的干旱、洪水、农业和水资源管理方法。
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引用次数: 0
Identification of the Driving factors impacts of Land Surface Albedo over Iran: An analysis with the MODIS data 确定影响伊朗陆地表面反照率的驱动因素:利用 MODIS 数据进行分析
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-15 DOI: 10.1016/j.jastp.2024.106378
Albedo is a key parameter in climatic research and depends on environmental and climatic factors. Modeling these factors greatly contributes to understanding environmental variations. To this end, the data of Land Surface Albedo, Land Surface Temperature (LST), Vegetation, Snow, Elevation, Slope, and Aspect of the MODIS sensor from 1/1/2001 to 30/12/2021 with a 1000-m spatial resolution were used. After pre-processing, monthly, seasonal, and annual albedo modeling was performed using multiple linear regression (MLR) in the highlands of Iran. The results of monthly modeling revealed the salient direct role of snow on the albedo of Iran's highlands in all months, except for July, August, and September. In these months, due to the lack of snow coverage and the fruiting of agricultural lands and gardens, the inverse role of vegetation on albedo variations is determining. Seasonal examinations also showed that snow plays a significant role on the albedo of Iran's highlands in winter, spring, and fall; however, vegetation has a determining role in the summer. The annual results indicated that snow, vegetation, elevation, slope, LST, and aspect, respectively, are the factors affecting albedo in the highlands of Iran. Furthermore, the role of snow, LST, and aspect is positive, while the role of vegetation, elevation, and slope is negative on albedo.
反照率是气候研究中的一个关键参数,取决于环境和气候因素。建立这些因素的模型大大有助于了解环境变化。为此,我们使用了 MODIS 传感器从 2001 年 1 月 1 日至 2021 年 12 月 30 日空间分辨率为 1000 米的地表反照率、地表温度、植被、积雪、海拔、坡度和朝向数据。经过预处理后,使用多元线性回归(MLR)对伊朗高原进行了月度、季节和年度反照率建模。月度模型的结果显示,除七月、八月和九月外,雪对伊朗高原所有月份的反照率都有显著的直接影响。在这几个月里,由于积雪覆盖面积不足,加上农田和花园正在开花结果,植被对反照率变化的反向作用是决定性的。季节性研究还表明,在冬季、春季和秋季,积雪对伊朗高原的反照率起着重要作用;但在夏季,植被起着决定性作用。年度结果表明,积雪、植被、海拔、坡度、LST 和地势分别是影响伊朗高原反照率的因素。此外,积雪、低海拔气温和相向对反照率的影响是积极的,而植被、海拔和坡度对反照率的影响是消极的。
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引用次数: 0
A comprehensive analysis of factors affecting GNSS observation noise 全面分析影响全球导航卫星系统观测噪声的因素
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-12 DOI: 10.1016/j.jastp.2024.106371
Observation noise is one of the most significant error sources in the Global Navigation Satellite System (GNSS). It can be influenced by various factors. Analyzing these factors is crucial for developing a stochastic model for GNSS navigation and positioning. This process ensures that the statistical properties of the observational data are accurately characterized, leading to more reliable and precise positioning results. Previous research has predominantly focused on code type and PPP techniques, often limited by the inability to separately assess observation types across different frequency bands due to ionospheric delay. If based on short baseline, these studies were generally constrained by limited experimental data. This study provides a detailed analysis of the affecting factor on observation noise, including elevation, SNR (signal-to-noise ratio), different receiver and antenna type, different GNSS system, and different frequency bands etc. In addition, environmental effects on observation noise are investigated by comparison between short baseline and zero baseline.
观测噪声是全球导航卫星系统(GNSS)中最重要的误差源之一。它可能受到各种因素的影响。分析这些因素对于开发 GNSS 导航和定位随机模型至关重要。这一过程可确保观测数据的统计特性得到准确描述,从而获得更可靠、更精确的定位结果。以往的研究主要集中在代码类型和 PPP 技术上,但往往受限于电离层延迟而无法分别评估不同频段的观测类型。如果基于短基线,这些研究通常会受到有限实验数据的限制。本研究详细分析了观测噪声的影响因素,包括海拔高度、SNR(信噪比)、不同接收器和天线类型、不同 GNSS 系统和不同频段等。此外,还通过比较短基线和零基线,研究了环境对观测噪声的影响。
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引用次数: 0
On the long-term stability of the association between foF2 and EUV solar proxies 关于 foF2 和 EUV 太阳代用指标之间联系的长期稳定性
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-05 DOI: 10.1016/j.jastp.2024.106363
Solar extreme ultraviolet (EUV) radiation is the main source of heating and ionization of the Earth's upper atmosphere, forcing most of this system's time variability, which in annual scales corresponds to the solar activity ∼11-year cycle. Due to the difficulties in obtaining solar EUV time series covering extended periods of time or during periods without measurements available, the use of solar EUV proxies became a solution. In the case of the ionosphere, and in particular the F2-layer critical frequency (foF2), in addition to the solar activity cycle variation, it may also exhibit the effect of long-term trend forcings, like the monotonous increasing greenhouse gas concentration since the industrial revolution. To accurately detect and measure this weak trend against the solar activity variability, it is crucial to account for the solar forced variation. Traditionally, it is modeled as a linear association between foF2 and a given solar EUV proxy. However, the stability of this association has become a controversial issue. It would be reasonable to assume, in turn, that if the ionospheric environment is undergoing a trend forced by a non-solar diver, like the greenhouse gas concentration increase, the relationship between foF2 and solar proxies may be affected, ceasing to be stable if this additional driver is not introduced in the modeled association. Using rolling regressions over the period 1960–2023 to analyze this stability, our results suggest that the issue may not only lie in the steady trend expected in foF2 from a non-solar source or the need to include terms in the simple linear regression commonly used, but also in the possible deviation of the different proxies from the 'true' EUV solar flux, which is the ultimate main driver of F2 region ionization, a deviation that has been intensifying over the last two decades. We assert that it is a deviation from the actual EUV behavior because the indices diverge from one another, something that should not occur if they all reflect the same solar EUV.
太阳极紫外线(EUV)辐射是地球高层大气加热和电离的主要来源,造成了这一系统的大部分时间变化,其年尺度与太阳活动 11 年周期相对应。由于难以获得涵盖较长时期或在没有测量数据期间的太阳极紫外时间序列,使用太阳极紫外代用指标成为一种解决方案。对于电离层,特别是 F2 层临界频率(foF2),除了太阳活动周期变化外,还可能受到长期趋势作用力的影响,如工业革命以来温室气体浓度的单调增长。要准确探测和测量这种与太阳活动变化相对应的微弱趋势,关键是要考虑太阳强迫变化。传统上,太阳强迫变化被建模为 foF2 与给定太阳 EUV 代用值之间的线性关系。然而,这种关联的稳定性已成为一个有争议的问题。我们有理由反过来假设,如果电离层环境正在经历一个由非太阳驱动的趋势,如温室气体浓度增加,则 foF2 和太阳代用指标之间的关系可能会受到影响,如果不在模型关联中引入这个额外的驱动因素,这种关系就不再稳定。利用 1960-2023 年间的滚动回归分析这种稳定性,我们的结果表明,问题可能不仅在于非太阳源的 foF2 的预期稳定趋势,或需要在常用的简单线性回归中加入项,还在于不同代用指标可能偏离 "真实 "的 EUV 太阳通量,而 EUV 太阳通量是 F2 区域电离的最终主要驱动力,这种偏离在过去二十年中不断加剧。我们断言,这是与实际超紫外线行为的偏差,因为这些指数相互背离,如果它们都反映了相同的太阳超紫外线,就不应该出现这种情况。
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引用次数: 0
Speed and accuracy investigations of neural network algorithms for ionospheric modelling at an equatorial region 用于赤道地区电离层建模的神经网络算法的速度和精度研究
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-05 DOI: 10.1016/j.jastp.2024.106365
Neural networks are very efficient tools for modeling, including ionospheric modeling. The training algorithm is important for achieving the optimum performance of the trained network. This research is therefore meant to evaluate and compare the performances of ten neural network training algorithms based on their prediction accuracies, and the duration/times taken by each of the algorithms to establish the optimum result. The neural networks were trained using electron density measurements by Radio Occultation (RO) technique from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites. Data for the period 2006 through 2021 was used. The networks were trained using about 2.9 million data points collected from the Kano region, Nigeria (5-degree rectangular region around geographic: 12.00° N, 8.59° E) after performing data quality control. The training algorithms considered in the work include: Bayesian Regularization (BR); Broyden-Fletcher-Goldfarb-Shanno Quasi-Newton (BFG); Conjugate Gradient with Powell/Beale (CGB); Fletcher-Reeves Conjugate Gradient (CGF); Gradient descent with momentum and adaptive learning rate (GDX); Levenberg Marquardt (LM); One Step Secant (OSS); Polak-Ribiére Conjugate Gradient (CGP); Resilient Backpropagation (RP); and Scaled Conjugate Gradient (SCG). The results showed that the BR and the LM algorithms gave the best performances in minimizing the errors of prediction (the mean RMSEs are respectively 112 and 114 ×103 electrons/cm3), but the RP algorithm, which came third in terms of accuracy, was significantly faster than both the LM and BR algorithms. The worst-performing algorithm in terms of accuracy was the GDX algorithm, although it was the fastest algorithm. The BFG algorithm was the worst-performing algorithm in terms of a combination of speed and accuracy. The developed neural network model was validated using ionosonde electron density measurements obtained from Ilorin, Nigeria (geographic: 8.5° N, 4.5° E; geomagnetic: 1.8° S). A comparison of the neural network, the NeQuick, and the IRI model predictions relative to the ionosonde measurements indicate that the neural network model was the best-performing model; the NN model predictions minimized the mean absolute errors (MAEs) in ∼44% of 399 ionosonde profiles investigated, the IRI model did so in ∼32%, and the NeQuick did so in ∼24%. The MAEs of the NeQuick however exhibited the best (least) variance. In overall, the NN model gave the least (best) mean of the MAEs (∼73 × 103 cm−3), compared to ∼82 × 103 cm−3 given by both the NeQuick and the IRI models, further supporting the idea that neural networks are excellent for present-day ionospheric modeling.
神经网络是非常有效的建模工具,包括电离层建模。训练算法对于实现训练网络的最佳性能非常重要。因此,本研究旨在评估和比较十种神经网络训练算法的性能,依据是它们的预测精确度,以及每种算法建立最佳结果所需的时间。利用气象、电离层和气候星座观测系统(COSMIC)卫星通过无线电掩星技术测量的电子密度,对神经网络进行了训练。使用的是 2006 年至 2021 年的数据。在进行数据质量控制后,使用从尼日利亚卡诺地区(地理位置周围 5 度矩形区域:北纬 12.00°,东经 8.59°)收集的约 290 万个数据点对网络进行了训练。工作中考虑的训练算法包括贝叶斯正则化(BR);布洛伊登-弗莱彻-戈德法布-山诺准牛顿(BFG);鲍威尔/比尔共轭梯度(CGB);弗莱彻-里夫斯共轭梯度(CGF);具有动量和自适应学习率的梯度下降算法(GDX);Levenberg Marquardt 算法(LM);一步 Secant 算法(OSS);Polak-Ribiére 共轭梯度算法(CGP);弹性反向传播算法(RP);以及缩放共轭梯度算法(SCG)。结果表明,BR 算法和 LM 算法在最小化预测误差方面表现最佳(平均 RMSE 分别为 112 和 114 ×103 电子/立方厘米),但 RP 算法在准确度方面排名第三,速度明显快于 LM 算法和 BR 算法。精度表现最差的算法是 GDX 算法,尽管它是速度最快的算法。BFG 算法是速度和准确性综合表现最差的算法。利用从尼日利亚伊洛林(地理位置:北纬 8.5°,东经 4.5°;地磁:南纬 1.8°)获得的电离层探测仪电子密度测量数据对所开发的神经网络模型进行了验证。神经网络、NeQuick 和 IRI 模型预测结果与电离层探测仪测量结果的比较表明,神经网络模型是性能最好的模型;在所调查的 399 个电离层剖面中,神经网络模型预测结果有 44%的平均绝对误差(MAEs)最小,IRI 模型有 32%的平均绝对误差最小,NeQuick 有 24%的平均绝对误差最小。然而,NeQuick 的 MAEs 显示出最佳(最小)方差。总体而言,神经网络模型给出的平均最大误差最小(最佳)(∼73 × 103 cm-3),而 NeQuick 和 IRI 模型给出的平均最大误差都是∼82 × 103 cm-3,这进一步支持了神经网络是当今电离层建模的绝佳工具这一观点。
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引用次数: 0
Aerosol type classification and its temporal distribution in Kanpur using ground-based remote sensing 利用地面遥感技术对坎普尔的气溶胶类型及其时间分布进行分类
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-05 DOI: 10.1016/j.jastp.2024.106366
Based on AERONET version 3 level 2 inversion products, we classify aerosol types and investigate their temporal distribution in the atmosphere using particle linear depolarization ratio (PLDR) and single scattering albedo (SSA) at the wavelength of 1020 nm over Kanpur. It is for the first time over the North Indian region the work has been emphasized. The remarkable findings over Kanpur station indicate that SSA and coarse-mode particles in the atmosphere increased with increasing PLDR at 440, 675, 870, and 1020 nm wavelengths. It is observed in the 2-dimensional histogram that the rate of occurrence of aerosols is high when the fine mode fraction (FMF) is high and the dust ratio (Rd) is low. The atmosphere of Kanpur is partially influenced by dust-dominated mixture (DDM), pollution-dominated mixture (PDM), and pure dust (PD) with 53% whereas, the rest of the dust-free pollution aerosols are 47%. The annual mean occurrence rate for different aerosol types is 5% for Strongly Absorbing (SA), 20% for Moderately Absorbing (MA), 19% for Weakly Absorbing (WA), 3% for Non-Absorbing (NA), 27% for DDM, 22% for PDM, and 4% for PD, ranging from January 2001 to January 2022. There is a variation in the distribution of various types of pollution particles, which is influenced by the changing seasons. The rate of occurrence of dust-free pollution aerosols is 47%, mostly observed throughout the post-monsoon and winter seasons. The PLDR values in the atmosphere of Kanpur are almost balanced equally because it is affected by both (dust and dust-free) pollution aerosols and the changes can be seen due to the frequent occurrence of dust storms and anthropogenic activities.
根据 AERONET 第 3 版第 2 级反演产品,我们对气溶胶类型进行了分类,并利用坎普尔上空波长为 1020 nm 的粒子线性去极化率 (PLDR) 和单散射反照率 (SSA) 研究了气溶胶在大气中的时间分布。这是首次在北印度地区强调这项工作。坎普尔站上空的重要发现表明,在 440、675、870 和 1020 nm 波长处,大气中的 SSA 和粗模粒子随着 PLDR 的增加而增加。从二维直方图中可以观察到,当细模式分数 (FMF) 高、尘埃比 (Rd) 低时,气溶胶的出现率就高。坎普尔的大气部分受到灰尘为主的混合物(DDM)、污染为主的混合物(PDM)和纯灰尘(PD)的影响,占 53%,而其余无尘污染气溶胶占 47%。在 2001 年 1 月至 2022 年 1 月期间,不同气溶胶类型的年平均出现率分别为:强吸收(SA)5%、中度吸收(MA)20%、弱吸收(WA)19%、非吸收(NA)3%、DDM 27%、PDM 22%和 PD 4%。受季节变化的影响,各类污染颗粒的分布存在差异。无尘污染气溶胶的出现率为 47%,主要出现在季风后和冬季。坎普尔大气中的 PLDR 值几乎是均衡的,因为它同时受到(有尘和无尘)污染气溶胶的影响,而且由于沙尘暴和人为活动的频繁发生,其变化也是显而易见的。
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引用次数: 0
Techno-economic analysis of solar, wind and biomass hybrid renewable energy systems in Bhorha village, India 印度 Bhorha 村太阳能、风能和生物质能混合可再生能源系统的技术经济分析
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-02 DOI: 10.1016/j.jastp.2024.106362
The present study investigates the potential use of Hybrid Renewable Energy Systems (Solar photovoltaic, wind, biomass, and diesel), both with and without the inclusion of battery/supercapacitor storage in the Bhorha village, Bihar, India. A comprehensive assessment of different possible system configurations is conducted using hybrid optimization model for electric renewable (HOMER) software to determine the most economically viable and efficient system for the designated place. The current analysis is focused on six distinct cases in the village community, in view of sufficing the daily energy requirement of 615.625 kWh and a peak demand of 86.47 kW, pertaining to major factors viz. system efficiency, financial viability, and ecological consequences. The primary aim of the research is to elucidate the comparative analysis of energy generation for different proposed designs of hybrid renewable energy systems. Detailed techno-commercial assessments are also carried out to examine the energy production, consumption, and financial impacts of each HRES configuration. The research outcome of this study obtained from HOMER software reveals that the optimized hybrid system comprises 86.7 kW solar photovoltaic, 30 kW wind turbine, 5 kW biogas generator, a 50 kW diesel generator, 280 kWh battery bank with nominal capacity, and 38.8 kW converter to sustain the for energy needs of the nominated place. This system has a minimum cost of energy of 0.309 $/kWh with a net present cost of $854894 along with operating cost 51847 $/year and net carbon dioxide emission of 56728 kg/yr. The research offers useful insights for designers, scholars, and policymakers on the existing design constraints and policies of biomass-based hybrid systems for a safe, sustainable and independent green future for the generations to come.
本研究调查了印度比哈尔邦 Bhorha 村使用混合可再生能源系统(太阳能光伏发电、风能、生物质能和柴油)的潜力,包括使用或不使用电池/超级电容器存储系统。使用可再生能源电力混合优化模型(HOMER)软件对不同的可能系统配置进行了全面评估,以确定指定地点最经济可行和最高效的系统。目前的分析重点是村社区的六个不同案例,以满足每天 615.625 千瓦时的能源需求和 86.47 千瓦的峰值需求,涉及的主要因素包括系统效率、财务可行性和生态后果。研究的主要目的是阐明不同混合可再生能源系统设计方案的发电量比较分析。此外,还进行了详细的技术-商业评估,以检查每种 HRES 配置的能源生产、消耗和财务影响。从 HOMER 软件获得的研究结果显示,优化的混合系统包括 86.7 千瓦太阳能光伏发电、30 千瓦风力涡轮机、5 千瓦沼气发电机、50 千瓦柴油发电机、280 千瓦时标称容量蓄电池组和 38.8 千瓦变流器,可满足指定地点的能源需求。该系统的最低能源成本为 0.309 美元/千瓦时,净成本为 854894 美元/年,运营成本为 51847 美元/年,二氧化碳净排放量为 56728 千克/年。这项研究为设计者、学者和决策者提供了有益的启示,帮助他们了解生物质混合动力系统的现有设计限制和政策,为子孙后代创造一个安全、可持续和独立的绿色未来。
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引用次数: 0
Long-term geomagnetic activities and stratospheric winter temperature 长期地磁活动与平流层冬季温度
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-09-29 DOI: 10.1016/j.jastp.2024.106361
In this research, impact of long term solar forcing on stratospheric winter temperature is checked. The 11- year sunspot activity and geomagnetic indices (AE, Kp, Dst) are used as an indicator for solar forcing, as geomagnetic activity indices show good correlation with solar variability. To understand the impact of solar forcing through high latitude, stratospheric winter (November to March) time North Polar Region (60N–90N) temperature anomalies are considered. The findings showed that temperature changes in the stratosphere are significantly correlated with solar activity, as evidenced by a significant positive correlation between the 11-year moving mean of stratospheric (10 hPa) temperature anomalies and sunspot number. Approximately from 1970 to 2000, the North Polar Region saw positive anomalous stratospheric winter temperatures. During the same time, the geomagnetic activity also showed a substantial increase. The year-to-year correlation between stratospheric pole temperature and geomagnetic activity is significant (about 0.5). The Empirical Mode Decomposition analysis reveals a highly significant correlation (around 0.9) between the long-term component of stratospheric winter temperature (IMF-4) and the long-term component of geomagnetic activity (IMF-3 and IMF-4). One of the reasons for the increase in lower stratospheric temperature is an increase in ozone concentration during the same period when geomagnetic activity is higher. Empirical orthogonal function (EOF) and correlation analysis of stratospheric winter temperature with large-scale circulation patterns are also carried out. The spatial correlation is checked for stratospheric winter temperature at North Pole and lower atmospheric levels (250 hPa and 850 hPa) followed by pre-monsoon and monsoon season. This study includes statistical analysis, however, also highlights the necessity of in-depth dynamical analysis to improve our understanding of how solar activity impacts Earth's atmospheric layers, which may be helpful in predicting the weather and climate.
这项研究检验了长期太阳强迫对平流层冬季温度的影响。11 年太阳黑子活动和地磁指数(AE、Kp、Dst)被用作太阳强迫的指标,因为地磁活动指数与太阳变化具有良好的相关性。为了解太阳强迫通过高纬度产生的影响,考虑了平流层冬季(11 月至次年 3 月)北极地区(60N-90N)的温度异常。研究结果表明,平流层的温度变化与太阳活动密切相关,平流层(10 hPa)温度异常的 11 年移动平均值与太阳黑子数之间存在显著的正相关关系就是证明。大约从 1970 年到 2000 年,北极地区的冬季平流层温度出现了正异常。在同一时期,地磁活动也出现了大幅增加。平流层极点温度与地磁活动之间的逐年相关性非常显著(约为 0.5)。经验模式分解分析表明,平流层冬季温度的长期分量(IMF-4)与地磁活动的长期分量(IMF-3 和 IMF-4)之间存在高度显著的相关性(约 0.9)。平流层低层温度上升的原因之一是在地磁活动较强的同一时期臭氧浓度增加。还对平流层冬季温度与大尺度环流模式进行了经验正交函数(EOF)和相关性分析。检查了北极和较低大气层(250 hPa 和 850 hPa)的平流层冬季温度与季风前和季风季节的空间相关性。这项研究包括统计分析,但也强调有必要进行深入的动态分析,以提高我们对太阳活动如何影响地球大气层的认识,这可能有助于预测天气和气候。
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引用次数: 0
Analysis of LST, NDVI, and UHI patterns for urban climate using Landsat-9 satellite data in Delhi 利用 Landsat-9 卫星数据分析德里城市气候的 LST、NDVI 和 UHI 模式
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-09-28 DOI: 10.1016/j.jastp.2024.106359
The present study is based on remote sensing techniques focusing on Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) to investigate their influence on land use and land cover dynamics, and the assessment of the Urban Heat Island (UHI) effect in Delhi, India. The objective of this study is to calculate LST, NDVI, and UHI values to understand the changes in LULC patterns, urbanization, and temperature increase within the city. Unlike previous studies conducted with Landsat-8, the present study employs Landsat-9 data, ensuring a higher level of authenticity in the results. Landsat-9, equipped with state-of-the-art sensors and instrumentation, provides superior data quality, enhanced image resolution, and advanced capabilities for precise monitoring and analysis. The methodology encompasses six steps for LST retrieval, enabling the calculation of UHI values and intensity. Ground data from 32 meteorological stations validate the LST results. Pearson correlation coefficients between LST and NDVI exhibit correlations ranging from −0.58 to −0.68 for three dates. On Dec 8, 2023, there is a weak negative correlation of −0.004. The analysis of changing land cover with variation in NDVI and LST unveils a diverse landscape, primarily characterised by green cover (47.34%), followed by built-up area (44.57%), barren land (7.57%), and water (0.52%). The study identifies the minimum value of UHI intensity for Delhi to be 8.13 °C on 26-Feb 2023 and the maximum value of UHI was estimated 10.29 °C on 2-June 2023. The study of Urban Heat Island (UHI) patterns revealed distinctive seasonal trends. The urban areas exhibited relatively cooler temperatures compared to surrounding rural regions on Dec 8, 2023. The conclusion drawn from this comprehensive analysis is that rapid urbanization in Delhi has significantly contributed to the increase in LST and UHI values. This rise can largely be attributed to the extensive use of concrete in construction activities, which exacerbates the UHI effect. Moreover, this analysis signifies the dynamic nature of UHI and emphasizes the urgency for strategic urban planning and climate-sensitive design approaches. Implementing such measures can create more sustainable and resilient urban environments.
本研究基于遥感技术,重点关注印度德里的地表温度(LST)和归一化植被指数(NDVI),以调查它们对土地利用和土地覆被动态的影响,并评估城市热岛(UHI)效应。本研究的目的是计算 LST、NDVI 和 UHI 值,以了解城市内 LULC 模式、城市化和气温上升的变化。与以往使用 Landsat-8 进行的研究不同,本研究使用了 Landsat-9 数据,以确保研究结果具有更高的真实性。Landsat-9 配备了最先进的传感器和仪器,数据质量上乘,图像分辨率更高,具有精确监测和分析的先进能力。该方法包括六个 LST 检索步骤,可计算出 UHI 值和强度。来自 32 个气象站的地面数据验证了 LST 结果。LST 与 NDVI 之间的皮尔逊相关系数在三个日期显示出 -0.58 至 -0.68 的相关性。在 2023 年 12 月 8 日,两者之间存在-0.004 的微弱负相关。通过对随 NDVI 和 LST 变化而变化的土地覆被进行分析,发现了一个多样化的地貌景观,其主要特征是绿色覆被(47.34%),其次是建筑区(44.57%)、贫瘠土地(7.57%)和水域(0.52%)。研究发现,2023 年 2 月 26 日德里的 UHI 强度最小值为 8.13 °C,2023 年 6 月 2 日的 UHI 最大值估计为 10.29 °C。城市热岛(UHI)模式研究揭示了独特的季节性趋势。与周边农村地区相比,2023 年 12 月 8 日城市地区的气温相对较低。综合分析得出的结论是,德里的快速城市化在很大程度上导致了 LST 和 UHI 值的上升。这种上升在很大程度上归因于建筑活动中大量使用混凝土,从而加剧了 UHI 效应。此外,这项分析表明了 UHI 的动态性质,并强调了战略性城市规划和气候敏感性设计方法的紧迫性。实施这些措施可以创造更可持续和更具弹性的城市环境。
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引用次数: 0
Unveiling the impact of cosmic rays and solar activities on climate through optimized boost algorithms 通过优化助推算法揭示宇宙射线和太阳活动对气候的影响
IF 1.8 4区 地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-09-26 DOI: 10.1016/j.jastp.2024.106360
This investigation explores the enhancement of climate anomaly predictions by incorporating Solar Sunspot Number (SSN) and Cosmic Ray (CR) data into climate models. Leveraging XGBoost and CatBoost regression methodologies enhanced by Atom Search Optimization (ASO) and Nuclear Reaction Optimization (NRO) for predictive analysis. Utilizing a dataset spanning from 1965 to 2020, comprising 672 data points per climate parameter, the study delves into the dynamics between CR flux, SSN variability, and climate parameters. The models aimed to forecast variations in total precipitation anomaly (TPA), total cloud cover anomaly (TCCA), and sea surface temperature anomaly (SSTA) based on decadal solar cycle activities and CR data. Our findings reveal the significant impact of integrating SSN and CR data into environmental prediction models for TCCA, TPA, and SSTA, employing CatBoost and XGBoost machine learning (ML) algorithms. Performance evaluation, centered on root mean square error (RMSE), mean absolute error (MAE), coefficient of determination (R2), and Nash-Sutcliffe efficiency (NSE), illuminated the efficacy of ASO and NRO in model optimization, particularly under scenarios with and without SSN/CR data inclusion. The analytical outcomes underscore the enhanced prediction accuracy for TCCA, TPA, and SSTA when incorporating SSN and CR data, with ASO generally outperforming NRO in optimizing model parameters. Our regression models, optimized using ASO and NRO, showed a marked improvement in SSTA forecasts, with an increase in the R2 value from 0.73 to 0.76 when SSN/CR data were not included. The CatBoost was superior the XGBoost models with results of four error metrics. These results underscore the critical role of solar activity data and optimized algorithms in enhancing the accuracy and reliability of climate modeling. This study underscores the utility of advanced ML techniques and the importance of strategic variable selection in environmental modeling, offering new insights into the complex interactions between solar activity, CR, and climate dynamics.
这项研究探讨了通过将太阳黑子数(SSN)和宇宙射线(CR)数据纳入气候模型来增强气候异常预测的问题。利用原子搜索优化(ASO)和核反应优化(NRO)增强的 XGBoost 和 CatBoost 回归方法进行预测分析。该研究利用从 1965 年到 2020 年的数据集,每个气候参数包含 672 个数据点,深入研究了 CR 通量、SSN 变率和气候参数之间的动态关系。模型旨在根据十年太阳周期活动和CR数据预测总降水异常(TPA)、总云量异常(TCCA)和海面温度异常(SSTA)的变化。我们的研究结果表明,采用 CatBoost 和 XGBoost 机器学习(ML)算法,将 SSN 和 CR 数据整合到 TCCA、TPA 和 SSTA 的环境预测模型中会产生重大影响。以均方根误差 (RMSE)、平均绝对误差 (MAE)、判定系数 (R2) 和纳什-苏特克利夫效率 (NSE) 为核心的性能评估表明了 ASO 和 NRO 在模型优化方面的功效,尤其是在包含和不包含 SSN/CR 数据的情况下。分析结果表明,在纳入 SSN 和 CR 数据时,TCCA、TPA 和 SSTA 的预测准确性得到了提高,ASO 在优化模型参数方面普遍优于 NRO。我们使用 ASO 和 NRO 对回归模型进行了优化,结果表明 SSTA 预测有明显改善,当不包含 SSN/CR 数据时,R2 值从 0.73 增加到 0.76。在四个误差指标上,CatBoost 模型优于 XGBoost 模型。这些结果强调了太阳活动数据和优化算法在提高气候建模的准确性和可靠性方面的关键作用。这项研究强调了先进的 ML 技术的实用性以及在环境建模中战略性变量选择的重要性,为太阳活动、CR 和气候动力学之间复杂的相互作用提供了新的见解。
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引用次数: 0
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