ISSN 1058-3912
Electronic journal of the International Association
for Environmental Hydrology
On the World Wide Web at http://www.hydroweb.com
JEH Volume 5 (1997), Paper 7, December 1997 Posted
December 7, 1997
REMOTE SENSING APPLICATIONS FOR FORECASTING THE AMOUNT OF RAINFALL
OVER THE BLUE NILE BASIN
Ibrahim H. El-Sebaie
Ministry of Public Works and Water Resources, Cairo, Egypt
Osman El-Nawawi and Ibrahim Shaker
Ain Shams University, Cairo, Egypt
ABSTRACT
The main objective of this study is to forecast the amount of rainfall
over the Blue Nile Basin using meteosat satellite images and to establish
the reliability of these estimates when compared to observations. The Blue
Nile Basin has been selected as a study area because it supplies 85% of
the water to Aswan (Up Stream Egypt). Most of the current techniques for
estimating rainfall from temperature of the cloud tops associate rainfall
with cold (high) clouds, assuming that these are the tops of active storms.
Four techniques are applied here for estimating the amount of rainfall
over the Blue Nile Basin on daily basis. These techniques have been tested
and calibrated with raingage data and the results show that there are some
differences between the raingage data and the satellite estimates. Two
techniques (Nfs-clim and GPI) gave better results, but some differences
vary from month to month and year to year. The correlation coefficient
between the satellite estimate and raingage observed mean areal precipitation
over the Blue Nile Basin is found to be 0.65. One of these techniques (Nfs-clim)
is applied here to forecast the amount of rainfall over the Blue Nile Basin.
Work is currently underway to improve rainfall forecasts by collecting
more data and including other satellite images.
Reference: El-Sebaie, I.H., O. El-Nawawi and I. Shaker, Remote
Sensing Applications for Forecasting the Amount of Rainfall Over the Blue
Nile Basin, Journal of Environmental Hydrology, Vol. 5, Paper
7, December 1997.