纵向岭谷区冬、夏水热条件空间分布研究

RESEARCH ON THE SPATIAL DISTRIBUTION OF RAINFALL AND TEMPERATURE IN WINTER AND SUMMER OVER LONGITUDINAL RANGE-GORGE REGION(LRGR)

利用纵向岭谷区内76个测站降水、温度资料和大气环流资料,研究该区冬、夏两季降水的空间分布规律。结果表明:纵向岭谷区多年平均冬季降水空间上沿河流呈纵向分布;但纵向岭谷独特地形对冬季降水变化的空间分布影响不明显;冬季气候平均温度大致呈东西向带状分布,由低纬到高纬温度逐渐递减;在区域上,纵向岭谷独特地形的“通道—阻隔”作用对冬季温度空间分布的影响不明显;但在怒江和澜沧江流域,这种影响则较为明显。纵向岭谷区多年平均夏季降水空间分布主要由纵向岭谷的“阻隔”效应,以及夏季从孟加拉湾来的气流和从南海来的气流在相应迎风坡面辐合,形成两支较强的上升气流所致;而纵向剖面大气环流的变化则较为均匀,显示了纵向岭谷的“通道”效应。纵向岭谷的这种“通道—阻隔”效应使得西南季风和东南季风在区内交汇,并使区内夏季降水空间上及夏季降水的变化沿河流呈纵向分布。地形对怒江、澜沧江流域夏季温度空间分布的“通道—阻隔”作用较明显;对夏季温度变化的“通道—阻隔”作用则在纵向岭谷西北部地区最明显,但其余地区地形的作用则相对较弱。

The spatial distribution law of rainfall and temperature in winter and summer over LRGR was studied with corresponding rainfall and temperature data and general circulation data. The results indicated that the LRGR mean winter rainfall longitudinally distributed along river, while the unique topography of LRGR did not obviously have impact on the winter rainfall; the winter temperature distribution was like belt, which decreased from low latitude to high latitude; the passing-obstructing effect of LRGR cannot be clearly showed with the winter temperature distribution; but such effect is obvious over Nu-valley and Lancang-valley. The distribution of LRGR summer mean rainfall was determined by the obstructing effect and two stronger ascending airflow that come from Bengal Bay and South Sea and converge around corresponding windward slopes;the general circulation distribution in meridional section is equal, which showed the passing-effect of LRGR. The passing-obstructing effect led the southwest monsoon and the East Asian monsoon meet around LRGR, which forced the rainfall distribution and spatial change present longitudinal features along the river. The passing-obstructing effect of topography was obviously showed in the distribution of summer temperature over Nu-valley and Lancang-valley;such effect was only obvious on the spatial change of summer temperature around northwest part of LRGR, but was not obvious in the other region.