| Title: | Assessment of satellite rainfall products for streamflow simulation in medium watersheds of the Ethiopian highlands |
| Authors: | Bitew, M.M. and M. Gebremichael |
| Year: | 2011 |
| Journal: | Hydrology and Earth System Sciences |
| Volume (Issue): | 15 |
| Pages: | 1147-1155 |
| Article ID: | |
| DOI: | 10.5194/hess-15-1147-2011 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | climate data effects |
| Secondary Application Category: | hydrologic assessment |
| Watershed Description: | 299 km^2 Koga and 1656 km^2 Gilgel Abay in Ethiopia |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | The objective is to assess the suitability of
commonly used high-resolution satellite rainfall products
(CMORPH, TMPA 3B42RT, TMPA 3B42 and PERSIANN)
as input to the semi-distributed hydrological model SWAT
for daily streamflow simulation in two watersheds (Koga at
299 km^2 and Gilgel Abay at 1656 km^2) of the Ethiopian highlands.
First, the model is calibrated for each watershed with
respect to each rainfall product input for the period 2003–
2004. Then daily streamflow simulations for the validation
period 2006–2007 are made from SWAT using rainfall input
from each source and corresponding model parameters;
comparison of the simulations to the observed streamflow at
the outlet of each watershed forms the basis for the conclusions
of this study. Results reveal that the utility of satellite
rainfall products as input to SWAT for daily streamflow simulation
strongly depends on the product type. The 3B42RT
and CMORPH simulations show consistent and modest skills
in their simulations but underestimate the large flood peaks,
while the 3B42 and PERSIANN simulations have inconsistent
performance with poor or no skills. Not only are
the microwave-based algorithms (3B42RT, CMORPH) better
than the infrared-based algorithm (PERSIANN), but the
infrared-based algorithm PERSIANN also has poor or no
skills for streamflow simulations. The satellite-only product
(3B42RT) performs much better than the satellite-gauge
product (3B42), indicating that the algorithm used to incorporate
rain gauge information with the goal of improving
the accuracy of the satellite rainfall products is actually
making the products worse, pointing to problems in the
algorithm. The effect of watershed area on the suitability
of satellite rainfall products for streamflow simulation also
depends on the rainfall product. Increasing the watershed
area from 299 km^2 to 1656 km^2 improves the simulations
obtained from the 3B42RT and CMORPH (i.e. products that
are more reliable and consistent) rainfall inputs while it deteriorates
the simulations obtained from the 3B42 and PERSIANN
(i.e. products that are unstable and inconsistent) rainfall
inputs. |
| Language: | English |
| Keywords: | |