Amr Elgamal
Dar Al-Handasah Shair and Partners
Egypt
Title: Impact analysis of satellite rainfall products on flow simulations in the Magdalena River Basin, Colombia
Biography
Biography: Amr Elgamal
Abstract
The Magdalena River is the most important river in Colombia in terms of economic activities and is home to about 77% of the country´s population. The river faces water resources allocation challenges, which require reliable hydrological assessments. In this research the reliability of ground-based measurements, different satellite products of rainfall and their combinations are tested for their impact on the discharge simulations of the Magdalena River.
Two different satellite rainfall products from the Tropical Rainfall Measuring Mission (TRMM) namely (TRMM-3B42 & TMPA), have been compared and merged with the ground-based measurements and their impact on the Magdalena river flows were quantified using the Representative Elementary Watershed (REW) distributed hydrological model.
It has been found that the use of TRMM-3B42 satellite product does not produce a reliable estimation of the spatial and temporal rainfall patterns over the study area. The performance of TRMM products had clear dependence on elevation. On the other side, TRMM best performed over areas gently rolling landscape and mild rainy parts. For hydrological modeling purposes the two products did not reproduce reliable estimation for the discharge at the downstream. Both TRMM-3B42 and TMPA tended to suffer from a systematic overestimation of the peak flows.
The impact of merging the rainfall products with ground-based measurements to generate a continuous rainfall field over areas with sparse raingauges, was investigated. Merging the TRMM-3B42 product with ground-based measurements had a negative impact on the model efficiency compared to the case of using ground-based data only. Merging the TMPA product with ground-based measurements, had a marginally positive impact on the simulated discharge. The estimation of the heterogeneous rainfall patterns and the hydrological modeling of the Magdalena River can be improved by using an enhanced assessment of the complex rainfall fields on the basis of merged TMPA satellite rainfall and ground station measurements.