大气对流层顶热量收支变化的时空结构研究

 利用1948~2006年NCEP/NCAR的温度场、风场和对流层顶气压场的逐日资料,对全球对流层顶热量收支及其方差进行了计算.通过对计算结果的分析发现:①南北两半球对流层顶断裂区附近以及青藏高原是对流层顶热量收支变化的显著区域,南半球纬向平均加热率随纬度的波动比北半球剧烈;②赤道附近对流层顶的热量收支处于相对的准平衡态,而加热率突变性最强的区域位于海陆交界的洋面上空;③全球对流层顶的平均热量收支是处于大气冷却为主的热力学状态结构中,而且平均加热强度的主要年代际演变呈现出整体降低的趋势,年际变化则具有显著的QBO现象;④南北半球对流层顶正负加热率存在着随季节变化的空间波列结构,夏季加热率的经向梯度较弱,而冬季经向梯度增强并具有多样性;⑤对流层顶断裂带所在区域为加热率方差常年显著的带状区域,方差的高值带随着季节的转换存在着南北向的移动和东西向的伸缩现象,冬季是对流层顶空间热量收支变化最活跃的季节.

The variation character of global atmospheric heat budget at tropopause

According to the daily global data sets of pressure,temperature and U-V wind at tropopause during the period from 1948 to 2006,the time-space structure of the global heat budget(Q)and its variance at tropopause were calculated.The results are as follows:① The character of Q is most distinct on the the tropopause breakpoints and on Tibet Plateau,the stronger fluctuation of zonal-average Q presents on the northern hemisphere.② The equatorial heat budget at tropopause is quasi-equilibrium state.The strongest zone of the abrupt change character of Q is above some sea marching with some land.③ The global average atmospheric heat budget is mainly cooling condition.Among 59 years,a most significant inter-decadal character is the descending trend of Q,while the inter-annual character is quasi-biennial oscillation(QBO).④ The positive and negative shows a spatial wave train character vary with the season.The longitudinal gradient of Q is weak in summer,but strong and diversity in winter.⑤ The character of variance of Q is most distinct on the the tropopause breakpoints and its north-south moving and east-west extension vary with the season,the strongest change of Q is in winter.