Plateau Meteorology

24 June 1989, Volume 8 Issue 2

NUMERICAL SIMULATION-OF EFFECT OF LARGE-AND MEDIUM-SCALE OROGRAPHY ON THE FLOW FIELD NEAR SURFACE
Zhong Weiguo;Luo Siwei
1989 Vol. 8 (2): 156-166.
Abstract ( ) PDF (779KB) ( )
In this paper a diagnostic study of effect of orography on large and medium-scale on the near surface wind have been made by using a one-level mesoscale model with some modifications. The main results are: (1) the model can be used to diagnose the orographic dynamic effects on the surface winds and has economic computation cost and quite good ability of simulation; (2) in January an anticyclonic center forms in the region of Shanxi, Gansu and Ningxia to the northeast side of Tibetan Plateau and a convergent zone extends eastwards along 35°N in north part of Plateau and through the northeast edge of the Plateau and then goes southwards to the southeast corner of the Plateau, which may be caused by the dynamic effect of Plateau orography; (3) owing to the effect of Qilian Mountain on the west flow in January, there are some climatic systems of medium-scale formed over the mountain and its neighbourhood. All the above results are in correspondence with observation data.

THE LONG PERIOD OSCILLATION IN LAND ATMOSPHERE COUPLING SYSTEM
Li Chao;Tang Maocang
1989 Vol. 8 (2): 167-173.
Abstract ( ) PDF (398KB) ( )
In this paper, the land-atmosphere coupling action is explored from the atmospheric heat balanc equation and the heat conduction equation on land underlying surface. It is found there are two long period waves in this coupling system: one is the quasi-half year wave with a period about 4-9 months; the other is the quasi-three years wave with a period about 2-5 years. In this paper, the emphasis is put on the discussion about the characteristics of the quasi-three years oscillation.

THE RELATIONSHIP BETWEEN THE SCATTERED RADIATION AND THE AIR MASS OVER THE ARID REGIONS OF THE WEST PART OF CHINA ON FINE DAYS
Wang Yaoqi;Gu Linkang;Wang Wenhua;Wu Lingyan
1989 Vol. 8 (2): 174-180.
Abstract ( ) PDF (447KB) ( )
In this paper,we have analysed the secular observational data of 4 solar radiation stations with different sea level elevation and landscape (Nagqu, Xizang; Golmud, Qinghai; Dunhuang and Minqin, Gansu). and have got the empirical relationship between the flux density of scattered radiation and the air mass on fine days. Finally, we calculated the monthly total amount of scattered radiation over the area with 2° interval from 28°N to 50°N.

THE EFFECTS OF ATTENUATION BY PRECIPITATION AND SAMPLING ERROR ON MEASURING ACCURACY OF 713 TYPE DUAL LINEAR POLARIZATION RADAR
Liu Liping;Xu Baoxiang;Cai Qiming
1989 Vol. 8 (2): 181-188.
Abstract ( ) PDF (510KB) ( )
Aimed at determining the measuring accuracy of 713 type dual linear polarization radar, we have discussed the effects of attenuation by raindrops with the shape of spheroid and different orientations on mesaurable parameters such as reflectivity (Z _H)and differential reflectivity (Z _DR) by using matrix method for electromagnetic wave propagation. We also have calculated the sampling errors of Z _H and Z _DR for the radar by using the statistical theory. This work has provided the base for our remodeling the conventional radar into dual linear polarization one.

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