关键词: 中国热带东、西部地区, 冬季气候差异, 青藏高原的动力影响, 橡胶树越冬

Abstract: Tropicl China were divided into two parts(sub regions)eastern part and western part by Chinese botanists and geographers∶Huge amount of rubber trees(Brasiliensis Hevea)were cultivated in both parts of above mentioned regions in the beginning of 1950’s or 1960’s Remarkable differences in growing conditions of rubber trees in these two parts were found after planting. The rubber trees in the eastern part suffered heavy cold injury frequently during overwintering period and finally diminished and perished completely or almost completely owing to unfavorable winter climate; but the rubber trees in western part have been growing normally, Even though in some cold winters they suffered cold damage but they recovered very soon after ovcrwintcring. And the yicld of latex incrcases year by year, and it is of benefit to the loeal people. A comparison of overwintering climates in these two parts was made. No significant differences in both minimum and mean temperature were found. But great difference in sunshine durations in these two parts was found, Viz, rich sunshine in the western part and poor sunshine in the eastern part. And also the difference in the pattern of temperature drop for these two parts during cold wave outbreak inter, was found the temperature drop in the eastern part is quite abrupt and the temperature drop in the western part is rather gentle. Besides there appears frequently a long spell (several even more than 10 days) of overcast and chilly days during outhreak of cold wave in the eastern part but there appears only a short spell (1 to 3 days) of overcast and chilly days in the western part. Such a long spell of overcast and chilly weather will usually cast the cold injury of rubber trees. The cause of these differences is due to the dynamic effects of Qinghai Xizang plateau. Two aspects should be considered: (1) The position of jet stream in Asia in winter shifts southwards and it hits the western corner of the Qinghai Xinghai Plateau. And somethin like stationary wave is induced, hence the air in certain area (eastern part) moves upwards and the air in some other area (western part) moves downwards. It is knowh in meteorology that fine (sunny)weather is usully connected with downward motion and cloudy or rainy weather is alwys assocaeted with upward motion. The fommer weather will ususally cause the adveetional cold damage of rubber tree. (2) The retarding or blocking effects of the high and huge mass of the Qinghai Xinghai Plateauee to cold air advection in winter make the temperature drop in western part much gentlier in character. And the effects of Qinghai Xinghai Platean also reduce the front activity in the western part, Hence there are much more sunny days in this part. All these effects are of benfitial to the overwintering of rubber tree. But the weathers in eastern part in winter are quite different from those in the western past due to the blocking of high and huge mountais to the north.

Key words: eastern and western parts of tropical China, difference in winter climate, the dynamic effect of Qinghai Xizang (Tibetan) Plateau, overwintering of rubber tree