flawiya/Ethiopia-Agri-Drought-Reanalysis

A geospatial data pipeline for agricultural drought monitoring in Africa. This project calculates standardized indices (SPI, SPEI, SSI) using ERA5-Land and CHIRPS data to model crop stress, seasonal correlations, and parametric insurance triggers for Maize and Teff systems. # Ethiopia Agricultural Drought Reanalysis (2000 - 2025) High-Resolution District-Level Drought Monitoring for Parametric Insurance 📌 Project Objective Agriculture in Ethiopia is 94% rainfed, with production concentrated in the Central Highlands. This study provides a high-resolution (ADM2/District level) agricultural drought analysis focusing on the Kiremt rains (June–September) which support the critical Meher harvest. The goal is to develop and validate the Agricultural Reanalysis Index (ARI) a multi-indicator tool designed to reduce "Basis Risk" in parametric insurance by integrating atmospheric demand, soil moisture supply, and thermal stress. 🛠 Methodology & Indices The analysis processes 25 years of climate and satellite data to calculate five distinct drought dimensions: 1. Standardized Precipitation Index (SPI-3) Data: CHIRPS (5km resolution). Method: Fits 3-month rolling rainfall to a Gamma Distribution. Key Feature: Includes the Thom Adjustment to handle "Zero-Rain" months in arid regions like Afar, ensuring mathematical validity in probability scores. 2. Standardized Precipitation Evapotranspiration Index (SPEI-3) Data: CHIRPS (Rainfall) - ERA5-Land (PET). Method: Measures Climatic Water Balance (D=P−PET) fitted to a Log-Logistic (Fisk) Distribution. Significance: Identifies "Flash Droughts" driven by extreme heat rather than just rainfall deficits. 3. Standardized Soil Index (SSI-3) Data: ERA5-Land Root-zone soil moisture (7–28 cm). Method: Standardizes the actual water available to plant roots against historical baselines. Insight: Used to identify the 1-2 month lag between atmospheric drought and physical agricultural impact. 4. Satellite Health Indices (VCI, TCI, VHI) VCI (Vegetation Condition Index): Normalizes NDVI greenness. TCI (Thermal Condition Index): Measures Land Surface Temperature (LST) stress. VHI (Vegetation Health Index): A 50/50 blend of moisture and temperature stress. 5. Agricultural Reanalysis Index (ARI) - The "Master" Trig …