Abstract:The rain enhancement operations in May 19, 20, 24, 25, 1987 in the area of huge forest fire in Heilongjiang Province are described in detail. The operation designs, synoptic situations, cloud conditions and the effecs of operations are analysed, and discussed.

Abstract:The OLR data were applied in this study to detect the low-frequency mode which are pronouced in the equatorial Indian Ocean, and the Western Pacific. 40 day OLR oscillations are closely related to the formation of typyoon. There are some cluster characterists of the typhoon formation not only in spacial but also in temporal distribution. The period when the typhoon frequently occurred was consistent with convec-tive phase of low-frequency mode. This result will be useful to the midium range forecast of the typhoon formation.

Abstract:Based on the vessel "Xiangyanghong No. 14, China" and other marine meteorological data,the atmospheric diabatic budget on the West Tropical Pacific has been calculated in this paper. Some components, such as radiative heating, latent heating and sensible heating, are. analyzed. As a result, it has been pointed out that there was a heat source over the West Tropical Pacific during the investigation period.The atmospheric total heating rate is about 0.57℃/day.

Abstract:A detail examination of the truncation errors of the pressure gradient force is shown in a coordinate system when orography was introduced into the numerical weather prediction model. By means of theoretical analysis and numerical calculation, it was found that the accuracys of Corby scheme are differed greatly for different definitions of σ and vertical distributions of variables of the model. In order to suppress the errors, some suggestions about vertical discretization of the model and finite difference formulation of pressure gradient force are given.

Abstract:It is necessary to study cloud parameter retrievals from cloud radiance measurements in order to obtain cloud-top height and temperature,cloud emissivity and thi-ckness, and perhaps cloud water content etc.This paper presents the preliminary results of the numerical test for retrieving two-level cloud height from a radiance ra- tioing method using NOAA satellite radiance measurements in the 15μm carbondioxide hand and 5,5μm oxygen band .(i.e. infrared and microwave channels). The comparison between the calculated and ground-thuth data shows that two-level cloud height can be obtained using a proper combination of two sets of channel measurements, but if middle and low level clouds Simultaneously occur these cloud heights can not be classified.