夏季青藏高原地区水汽向平流层的等熵绝热和非绝热传输的气候学特征及其与落基山地区的对比

夏季亚洲季风区是对流层向平流层物质输送的主要通道，其对平流层水汽的变化有重要贡献。以往的研究表明亚洲季风区向平流层的水汽传输主要在青藏高原及周边地区。本文利用多年平均的逐日ERAi、MERRA再分析数据和微波临边观测仪（Microwave Limb Sounder，MLS）数据，首先对比分析夏季青藏高原周边上空水汽的分布特征，再利用再分析资料分析了对流层—平流层水汽传输的特征。结果表明:青藏高原周边特定的等熵面和对流层顶结构分布有利于水汽向平流层的绝热输送；在南亚高压的东北侧，从青藏高原到中太平洋地区，340~360 K层次存在最为显著的水汽向平流层的纬向等熵绝热输送通道，7~8月平均输送强度可达约7×103 kg s-1。此外，在伊朗高原及南亚高压的西部，350~360 K层次也存在一支水汽向平流层的经向等熵绝热输送通道，但强度相对较弱（约2.5×103 kg s-1）。在青藏高原南侧370~380 K层次存在强的水汽向平流层的非绝热输送，主要由深对流和大尺度上升运动引起，7~8月平均输送强度约0.4×103 kg s-1。落基山以东到大西洋西部，350~360 K层次存在水汽向平流层的纬向等熵绝热输送通道，但强度也弱得多（约2.5×103 kg s-1）。

Characteristic of Adiabatic and Diabatic Water Vapor Transport from the Troposphere to the Stratosphere over the Tibetan Plateau and its Comparison with the Rocky Mountains in the Summer

The Asian summer monsoon regions are mainly atmospheric composition transport pathways from the troposphere to the stratosphere, and have large contribution to the variation of the stratospheric water vapor. Previous research show that the Tibetan Plateau (TP) and its surround regions contribute most water vapor transport from the troposphere to the stratosphere over Asian summer monsoon regions. The multi-year average Aura Microwave Limb Sounder (MLS) satellite observations, and the ERAi and MERRA reanalysis datasets are used to diagnose the water vapor maintenance and quantify the water vapor transport from the troposphere to the stratosphere over the TP and the Rocky Mountains (RM) in July and August. The three-dimensional structure of isentropic surfaces and the tropopause is favorable for adiabatic water vapor transport from the troposphere to the stratosphere over the TP. According to the quantified result from ERAi, there is a significant zonal adiabatic water vapor transport pathway from the northeast of the South Asian high to the central Pacific at 340-360 K, and the averaged water vapor mass flux is nearly 7×10³ kg s^-1 during July and August. Strong diabatic water vapor transport pathway is found in the southern flank of the TP at 370-380 K, which is controlled by deep convection and large-scale ascending motion, and the averaged flux is about 0.4×10³ kg s^-1 during July and August. Besides, at 350-360 K, there is a weak meridional adiabatic water vapor transport pathway from the Iranian Plateau to western flank of the TP, and a weak zonal adiabatic water vapor transport pathway is also found from the eastern flank of the RM to the western Atlantic, where the water vapor mass flux is about 2.5×10³ kg s^-1.