青藏高原及周边地区垂直温度梯度特征及其成因分析

Analysis of Vertical Temperature Gradient Characteristics and Its Causes over Qinghai-Tibetan Plateau and Its Surroundings

利用1980 2015年ERA-Interim全球0.25°×0.25°月平均再分析温度场、风场、垂直速度场资料,分析了青藏高原(下称高原)上空垂直温度梯度(T_G)特征及其成因。结果表明:(1)高原主体地区温度随高度升高而降低的程度要比周边地区大,东西两侧的温度随高度升高而降低得慢;(2)对流层中下层高原边缘陡峭地形区的T_G变化程度比周边地区大,对流层中上层各层T_G呈水平均匀分布;(3)非高原地区温度随高度升高而降低的程度略大于高原地区;在冬春季,两个区域的T_G对外界因素变化的反应都很灵敏;(4)初步成因分析显示,对流层中下层高原边缘地区,非绝热加热(冷却)作用越强时,T_G越小(大),温度随高度升高而降低的程度就越小(大);对流层中上层,高原部分区域非绝热加热(冷却)作用越强,T_G越大(小),温度随高度升高而降低的程度越大(小);在高原整层大气中,非绝热加热(冷却)作用是引起温度随高度升高而降低得慢(快)的主要因素。

Based on the ERA-Interim monthly mean reanalysis data of temperature field, wind filed and vertical velocity field from 1980 to 2015, the characteristics of Qinghai-Tibetan Plateau （QTP） temperature gradient （ TG ） and its causes were studied. The results show： （ 1 ） The decreased degree of the temperature in the major region of QTP decreases faster with the rise of the altitude than that in the surrounding areas, and the temperature on both sides of the plateau decreases lower with the rise of the altitude. （2） The change degree of TG in the low- er troposphere in the steep terrain area at the edge of QTP is greater than that in the surrounding areas, and Tc in the upper-middle troposphere is in horizontal uniform distribution. （3） The decreased degree of the temperature in the non-plateau region decreases with the rise of the altitude, which is slightly higher than that in the plateau region; In winter and spring, TG in the both regions is sensitive to changes in external factors. （4） The initial cause analysis revealed that at the edge of plateau region in the lower troposphere, the stronger the effect of the non-adiabatic heating （ cooling）, the smaller （larger） the To, and the smaller （larger） the reduced degree of the temperature decreased with the rise of the altitude; In the upper-middle troposphere, the stronger the effect of non-adiabatic heating （cooling） in some regions of the plateau, the larger （smaller） the To, and the larger （smaller） the reduced degree of the temperature decreased with the rise of the altitude ; The non-adiabatic heating （cooling） is the main factor that causes the temperature to decrease slowly （quickly） with the rise of the altitude in the whole atmosphere of the plateau.