Saudi Arabia - Assessment of Rainfall Augmentation

Objective

The focus of this project is to conduct research to determine if clouds in Saudi Arabia are amenable to cloud seeding. This feasibility study utilizes a suite of instrumentation including instrumented research aircraft, polarimetric and Doppler weather radar, automated weather stations, disdrometers, and high–resolution, high quality rain gauges. The original field program started in November 2006 focusing on aerosol, clouds, precipitation and the atmospheric conditions in the central region (Riyadh, Qassim, Hail) of Saudi Arabia. For the past two summers, the field program has focused on characterizing aerosol, clouds, and precipitation along the mountains in the southwest region (Abha, Al Baha, and Taif) of Saudi Arabia. The current field program is being conducted in July–August 2009.

Description

Scientists from the National Center for Atmospheric Research (NCAR), Texas A&M University (TAMU), University of Witwatersrand in South Africa (WITS), Arizona State University, and Weather Modification Inc. of Fargo, North Dakota (WMI) are working together to study: cloud and rainfall climatology studies; airborne aerosol and cloud microphysics studies, numerical modeling studies, quantitative precipitation analysis, polarimetric radar studies, and training and technology transfer with Saudi Arabian scientists. These efforts build upon the experience obtained in programs in other parts of the world.

Aircraft Observations

The objective is to document the aerosols in the environment, microphysics and dynamics of both natural and seeded clouds through cloud profiling and tracer experiments using two aircraft: an instrumented King Air 200 research aircraft and a Piper Cheyenne II seeding aircraft.

Radar

The characteristics of the rainstorms are monitored by radar to understand:

  1. The large–scale organization of the storms
  2. Their frequency of occurrence and spatial distribution around the area of study
  3. The temporal history, sizes, and intensities of individual storms and rain events

There are five radars located within the study area. Four of the radar systems (located at Abha, Jeddah, Jizan, and Taif) have Doppler capability and one radar system (located at Baha) also had polarimetric capability.

Real-Time Forecast Support

Forecast support for the project is provided by an operational RTFDDA model run at NCAR/RAL.