Spatio-temporal Drought Dynamics in theParnaíba River Basin (2000–2024): A Multi-scale Analysis Integrating MODIS-derived Vegetation Anomalies and Climatic Trends

Spatio-temporal Drought Dynamics in theParnaíba River Basin (2000–2024): A Multi-scale Analysis Integrating MODIS-derived Vegetation Anomalies and Climatic Trends | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Spatio-temporal Drought Dynamics in theParnaíba River Basin (2000–2024): A Multi-scale Analysis Integrating MODIS-derived Vegetation Anomalies and Climatic Trends Virgílio Cardozo Silva Neto, Rayane Alves da Paz, Reurysson Chagas de Sousa Morais This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9149405/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Drought represents one of the most severe hydroclimatic hazards affectingthe Brazilian Northeast, yet the spatio-temporal dynamics of vegetation-baseddrought and its relationships with multi-variable climatic trends remain poorlycharacterised at sub-basin scale in the Parna´ıba River Basin (PRB). This studyaddresses this gap by providing a comprehensive multi-scale assessment ofdrought dynamics across the PRB over the 2000–2024 period. The Standard-ized Vegetation Index (SVI) was computed pixel-wise from the MODIS TerraMOD13A1 500 m time series processed in Google Earth Engine, and integratedwith annual hydroclimatic variables (precipitation, air temperature, referenceevapotranspiration, actual evapotranspiration, and soil moisture) derived fromCHIRPS and ERA5-Land reanalysis. Long-term trends were assessed using theMann–Kendall test and Sen’s slope estimator at both basin and pixel scales.Basin-scale and sub-basin-scale climate–vegetation relationships were examinedthrough Spearman rank correlations with temporal lags of 0, 1, and 2 years. Sub-basin drought behaviour was classified using k-means clustering applied to SVItemporal profiles across 12 sub-basins. The SVI accurately captured the 2012–2017 megadrought as the most severe event of the record, with basin-mean SVIreaching −1.02 in 2012 and −1.08 in 2015. A statistically significant basin-widewarming trend of +0.034 °C yr−1 (p = 0.006) was detected, accompaniedby significant negative trends in actual evapotranspiration (−3.33 mm yr−1; p = 0.024) and soil moisture (p = 0.034), despite the absence of a significantprecipitation trend (p = 0.761). Precipitation emerged as the dominant driverof vegetation dynamics (r = 0.65 at lag-0; r = 0.57 at lag-2 years), evidencingmulti-year vegetation memory effects. Clustering identified three ecohydrologi-cal sub-basin groups reflecting distinct drought response regimes associated withthe Caatinga semi-arid interior, the Cerrado–MATOPIBA agricultural frontier,and the coastal lower basin. These results demonstrate that the PRB operatesunder a water-limited regime in which regional warming intensifies atmosphericevaporative demand, driving progressive land-surface drying particularly in thesouthern and central sectors. The spatially explicit framework developed hereprovides a scientific basis for adaptive water resource management and sustain-able land-use planning in large basins facing the synergistic pressures of climatechange and agricultural expansion. Standardized Vegetation Index Mann–Kendall Drought monitoring Remote sensing Semi-arid Google Earth Engine Full Text Additional Declarations No competing interests reported. Supplementary Files supplementarydatascriptgeepython.zip Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 26 Apr, 2026 Reviewers agreed at journal 16 Apr, 2026 Reviewers agreed at journal 01 Apr, 2026 Reviewers invited by journal 31 Mar, 2026 Editor assigned by journal 18 Mar, 2026 Submission checks completed at journal 18 Mar, 2026 First submitted to journal 17 Mar, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9149405","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":616057190,"identity":"ed1e8c73-2f09-47af-a23d-19a924e0cd83","order_by":0,"name":"Virgílio Cardozo Silva Neto","email":"","orcid":"","institution":"Federal Institute of Education, Science and Technology of Piauí","correspondingAuthor":false,"prefix":"","firstName":"Virgílio","middleName":"Cardozo Silva","lastName":"Neto","suffix":""},{"id":616057191,"identity":"3a67ad71-b51b-4b1b-8aaf-c61e9ce07474","order_by":1,"name":"Rayane Alves da 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