Droughtmap-ASB, a novel online monitoring tool for improved drought management in the Aral Sea Basin

Abstract

Agricultural droughts severely affect people and the environment along the extensive river systems in the desert ecosystems in the Aral Sea Basin that is shared by the five Central Asian countries, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan, and Afghanistan. There, meteorological drought situations upstream and poor water management along the rivers lead to hydrological drought situations that in turn strongly challenge land management and consequently food security as well as rural livelihoods downstream. Knowledge about ongoing droughts can serve for operational decisions, e.g. assessing crop damage, or excluding certain areas from water during drought periods and planning of compensation payments, but also for strategic purposes in land and water management

This presentation introduces a novel drought early detection and monitoring system for all >8 Mio ha land irrigated in the Aral Sea Basin. The tool has been specified and implemented within the Green Central Asia initiative of the German Federal Foreign Office, together with the five Central Asian Hydrometeorological Services.

Using time series of two indicators derived from the freely available MODIS data products, MODIS MOD13 NDVI and MOD16 global evapotranspiration, i.e. the normalized difference vegetation index (NDVI) and the evaporative stress index (ESI), normal conditions of water consumption and vegetation development of the past ten years are automatically derived within 5 km * 5 km grids. Current index development is compared to these normal conditions in accordance with the FAO guidelines. As soon it falls below a specified critical benchmark, drought indications get summarized in terms of drought intensity and drought duration, and classified into different drought levels. The information is aggregated at district, province, and national levels and provided via a dashboard or a pdf bulletin users can order via email.

The drought classifications were found in high congruence with time series of Standardized Soil Moisture Index (SMI) based on FLDAS Soil Moisture from 0-100 cm with a spatial resolution of ~11km and agreed well with water distribution amounts at the province and district levels provided by the Scientific Information Center of the Interstate Commission on Water Coordination in Central Asia (SIC-ICWC) for Uzbekistan across 2001-2022.

Scientific validation also increases the acceptance and application of scientific tools by national institutions that want to decide on land and water management options based on of scientific information. Hence, common validation campaigns using on soil moisture and other indicators derived from in situ stations of the Hydrometeorological Services belong to ongoing activities in Green Central Asia together with a series of workshops and trainings. The presentation will reach from the scientific basis to the ongoing trustbuilding activities and transfer of the online information system into practice.