ISPRS-Archives The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ISPRS-Archives Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. 2194-9034 Copernicus Publications Göttingen, Germany 10.5194/isprs-archives-XLIX-B3-2026-729-2026 Analysing the Impacts of Natural-Factor Variability on Lake Water Volume Using the Generalized Method of Moment Yang Yuxuan 1 Lin Yi 1 2 Yu Jie 1 2 Zhang Tinghui 3 College of Surveying and Geo-Informatics, Tongji University, 200092 Shanghai, China Research Center for Remote Sensing Technology and Application, Tongji University, 200092 Shanghai, China Guangzhou Institute of Geography Guangzhou,510070 Guangdong, China 30 07 2026 XLIX-B3-2026 729 735 Copyright: © 2026 Yuxuan Yang et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://isprs-archives.copernicus.org/articles/XLIX-B3-2026/729/2026/isprs-archives-XLIX-B3-2026-729-2026.html The full text article is available as a PDF file from https://isprs-archives.copernicus.org/articles/XLIX-B3-2026/729/2026/isprs-archives-XLIX-B3-2026-729-2026.pdf

Natural-factor variability strongly influences the hydrological stability of large tropical lakes. As a major freshwater resource in East Africa, Lake Victoria has experienced notable water-volume fluctuations under changing climatic conditions. This study investigated the effects of precipitation, evapotranspiration (ET), El Niño–Southern Oscillation (ENSO), and normalized difference vegetation index (NDVI) on lake water volume using multi-source datasets and the generalized method of moments (GMM). The results show that precipitation is the dominant positive driver of water-volume variation, whereas ET has a negative effect through increased surface-water loss. Quantitatively, the GMM estimates indicate that precipitation has a positive coefficient of 1.291, while ET shows a negative coefficient of −0.137. In addition, NDVI exhibits clear seasonality and reaches a monthly maximum of 0.7293 in December 2015, reflecting the close linkage between hydrological fluctuations and vegetation conditions in the basin. Overall, this study clarifies the main hydroclimatic controls on Lake Victoria water-volume variability and provides empirical support for regional water-resource assessment and climate-adaptation planning.