Defining the agricultural wet season in Africa using soil moisture from the Soil Moisture Active-Passive satellite

Defining the agricultural wet season in Africa using soil moisture from the Soil Moisture Active-Passive satellite | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 24 July 2025 V1 Latest version Share on Defining the agricultural wet season in Africa using soil moisture from the Soil Moisture Active-Passive satellite Authors : Christopher Chalmers 0009-0000-1028-1879 [email protected] , Yan Zhang 0000-0002-6158-448X , Jingfeng Xiao 0000-0002-0622-6903 , Xing Li 0000-0003-2206-0429 , and Angela J. Rigden 0000-0003-3876-6602 Authors Info & Affiliations https://doi.org/10.22541/au.175338267.73324795/v1 Published Geophysical Research Letters Version of record Peer review timeline 200 views 161 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract The wet season is typically defined based on daily precipitation accumulation, which represents water inputs but does not account for losses from evaporation, infiltration, and runoff. Here, we estimate root-zone soil moisture using observations from the Soil Moisture Active Passive (SMAP) satellite to capture year-to-year variations in seasonal soil moisture availability across Africa from 2016 to 2023 using a cumulative anomaly algorithm. Our analysis shows that seasonal soil moisture timing correlates more strongly (p < 0.01) with seasonal vegetation timing than precipitation across African croplands with over 30% crop cover. Additionally, soil moisture-based onsets capture small early season rainfall events that precipitation-based methods misclassify as false onsets. However, in Southern Hemisphere woodlands, neither soil moisture nor precipitation fully explains vegetation variability, likely due to deep-rooted trees accessing moisture beyond SMAP’s detection limits. These findings highlight soil moisture as a valuable indicator for refining wet season definitions, particularly in agricultural regions. Supplementary Material File (1041439_0_merged_1752791576.pdf) Download 14.24 MB File (chalmers et al. (2025) supplementary materials.pdf) Download 11.32 MB Information & Authors Information Version history V1 Version 1 24 July 2025 Peer review timeline Published Geophysical Research Letters Version of Record 16 Sep 2025 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords agricultural wet season hydrology precipitation seasonality soil moisture seasonality vegetation green-up wet season timing Authors Affiliations Christopher Chalmers 0009-0000-1028-1879 [email protected] University of California Irvine View all articles by this author Yan Zhang 0000-0002-6158-448X University of California Irvine View all articles by this author Jingfeng Xiao 0000-0002-0622-6903 University of New Hampshire View all articles by this author Xing Li 0000-0003-2206-0429 Sun Yat sen University View all articles by this author Angela J. Rigden 0000-0003-3876-6602 University of California, Irvine View all articles by this author Funding Information U.S. Department of Education P200A240042 Christopher Chalmers Metrics & Citations Metrics Article Usage 200 views 161 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Christopher Chalmers, Yan Zhang, Jingfeng Xiao, et al. Defining the agricultural wet season in Africa using soil moisture from the Soil Moisture Active-Passive satellite. Authorea . 24 July 2025. DOI: https://doi.org/10.22541/au.175338267.73324795/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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