Hydrological change from space geodetic data and correlation with climate indices in Sudan

Abstract

Terrestrial hydrological data in Sudan are heterogeneous with a limited quantity and quality that hinders reliable monitoring of natural or anthropogenic hydrological change. Thus, alternative data sources such as satellite observations are essential for monitoring hydrological change in Sudan. Moreover, like many other regions around the world, hydrological change in Sudan is strongly related to climate change presenting an opportunity to analyse the correlation of these processes. The aim of this research is to investigate the usefulness of space geodetic data to monitor hydrological change in Sudan and its relation with climate indices.

Temporal variations of equivalent water thickness were determined over the area of Sudan using GLDAS dataset and data from the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow–On (GRACE–FO) satellite missions. Temporal surface water variations at nine river crossings were obtained from satellite altimetry (Sentinel, Jason-2/3). The correlations between temporal variations of equivalent water thickness and sea surface temperature from both the El Niño–Southern Oscillation and the Indian Ocean Dipole climate indices were investigated. The results indicate good agreement between temporal variations of equivalent water thickness from GRACE/GRACE–FO data and GLDAS dataset. These temporal variations of equivalent water thickness were further correlated with the temporal surface water variations from altimetry data. In addition, there exist clear correlations between hydrology change in Sudan and sea surface temperature from El Niño 1 + 2 and El Niño 3 climate indices. In general, the results revealed the usefulness of space geodetic data for determining hydrological change in Sudan.