Precipitation Evaluation of Cloud Seeding Programs in Saudi Arabia and West Africa

During the past two years, cloud seeding feasibility studies have been conducted in Saudi Arabia and West Africa. In Saudi Arabia, an initial study was held during the period from November 2006 – May 2007 in the central regions of the country. A follow on study for the 2007-2008 rainy season (November-May) is currently ongoing in Saudi Arabia. In West Africa, there are two operational seeding programs being evaluated. One operational program is being conducted in Mali. Cloud characteristics have been observed and studied for two rainy seasons (June-October). A second operational seeding program has been ongoing in Burkina Faso under the support of Programme SAAGA. An evaluation of the program and a study of the observed cloud characteristics have recently been initiated. For both seeding regions, the goal of the study is to conduct research to determine if cloud seeding can increase rainfall and if so, by how much. These feasibility studies will examine cloud and aerosol properties in the two regions to determine if the environmental conditions are favorable for cloud seeding.

A component of any feasibility study, and the focus of this paper, is the evaluation of precipitation characteristics. This objective of this study is to examine precipitation characteristics observed by weather radar in Saudi Arabia and in West Africa. A variety of radar derived precipitation parameters will be examined which include: time of storm initiation, the number of storms expected, precipitation flux, storm intensity, storm duration, storm speed and direction and distribution of rainfall over each region. The presentation will give an overview of the evaluation techniques along with a summary of storm characteristics observed in these two regions.