TITLE:
Radar Rainfall Estimation of a Severe Thunderstorm over Jeddah
AUTHORS:
Ayman Mohammed Hashem Albar, Abdulrahman Khalaf AL-Khalaf, Heshmat Abdel-Basset Mohamed
KEYWORDS:
Rainfall, Radar Reflectivity, Z-R relationship, Buffer, Spatial, GIS, Jeddah, Flood, Saudi Arabia
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.5 No.3,
July
17,
2015
ABSTRACT: The
regular occurrence of flash floods over the region of Jeddah, Saudi Arabia in
the past decade has highlighted the serious need for the development of early
warning systems. Radar stations have been installed in Jeddah in the last
decade whose active radius covers the Middle Western area of the country.
Therefore, radar information and the associated the rainfall estimates are
potentially useful components of an effective early warning system. Weather
radar can potentially provide high-resolution spatial and temporal rainfall
estimates that bring more accuracy to flood warnings as well as having
applications in areas with insufficient rainfall stations coverage. Weather
radar does not measure rainfall depth directly. An empirical relationship
between reflectivity (Z) and rainfall rate (R), called the Z-R relationship (Z
= ARb), is generally used to assess the rainfall depth. In this
study, the rainfall events during August-September 2007 were analyzed to
develop a Z-R relationship using the Spatial Probability Technique (SPT). This
technique is based on a basic GIS function and the probability matching method.
Using this technique, the Z-R pairs can be analyzed for both linear and
empirical power relationships. It is found that the empirical power function is
more appropriate to describe Z-R relationship than a linear function for the
studied area. The method is applied with some success to the flooding event of
November 25, 2009. However, the investigation of the Z-R relationship is only
one step in the development of a warning system; further study of other
parameters relevant to rainfall and flash flood occurrence is needed.