GRACE and TRMM mission: The role of remote sensing techniques for monitoring spatio-temporal change in total water mass, Nile basin

Abstract

Understanding the spatio-temporal changes of the terrestrial water mass behavior together with Enhanced models of natural water storage variation are imperative for better assessing, adapting better evaluable quantified hydrologic catchments. This study provides a reliable impact of the GRACE “gravity recovery and climate experiment” data to gain an independent water mass change on large regional scale. Using GRACE data sets, Terrestrial total Water Storage (TWS) are alternative index to investigate spatio-temporal water variation responses. This study focuses on the Nile basin and utilizes the integration of TWS extracted from GRACE data solutions and Tropical Rainfall Measuring Mission (TRMM) data sets to interpret the average annual/seasonal variation of Terrestrial Total Water Mass. Terrestrial total Water Storage (TWS) was obtained from GRACE data on monthly basis over the period of January 2003–Jul 2016.156 gravity field solutions (RL06 unconstrained solutions) were analyzed and processed as follows: (1) Removing of temporal mean, destriping, smoothing with 250 km radius, (2) Generation of Trend and Standard deviation (SD) images over the entire period, (3) All mass anomalies derived from GRACE data were explicated as an indicator for water mass changes, (4) Topographic, geological and hydrological data were compared to the preformed SDGRACE spatial distribution anomalies utilizing GIS workspace data pool to recognize areas addressing major and significant temporal variations in mass considering the affecting parameters that lead to such observed rise in those variations. Generally, both the analyzed, processed GRACE and TRMM data sets as well as the resulted TWS, SD and trend images displayed a statistically increasing trend in the seasonal water mass over the entire Nile basin as an average in the investigated period (2003–2016). The results show a significant increasing trend during 2013–2016-time segment especially over the northern region.