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2. Regional Water Cycle Analysis

(1) Effect on rainfall by greening desert area near Red Sea

The most high-speed computer in the world, called the “Earth Simulator” in FRSGC provides us a scope to resolve complicated terrains and complex surface conditions in supper-high resolution (1km×1km) in Arabian Peninsula. We are now undertaking numerical simulations of rainfall and meteorology using a regional atmospheric model (RAMS and MM5) during one year of 2000, under several kinds of soil and vegetation conditions; the results of preliminary simulation indicate that there is a possibility of rain enhancement by greening the desert area of 5,625 square kilometers with low grass.

		a) Desert	b) Low Grass
		c) Desert	d) Low Grass
Fig. 4 Calculation domain		Fig. 5 Rainfall amount in horizontal plane(upper) 　　and cloud mixing ratio in vertical plane (lower)

(2) Rain enhancement plan
In order to improve the safety and economic performance of airplanes, which are considered problems in spraying condensation nuclei, a cylinder containing a condensation nucleus will be attached to meteoro-logical observation balloons (pilot balloons) to be released. A meso-scale model will be used for prediction calculation by inverse analysis of balloon trajectory to determine the point and timing of release and their buoyancy for the purpose of bringing the meteoro-logical balloons up to cloud base, as shown in Fig. 6.
	Fig. 6 Image picture of rain enhancement plan