夏季青藏高原及周边上对流层水汽质量及其向平流层传输年际异常. II：向平流层的绝热和非绝热传输

夏季7～8月青藏高原及周边地区上对流层水汽质量的年际异常分布为整体异常型和东西偶极异常型所主导。本文基于ERA-Interim再分析资料并利用HYSPLIT（Hybrid Single Particle Lagrangian Integrated Trajectory）轨迹模式，分析了两个主导分布型对应的水汽质量向平流层绝热和非绝热传输的异常特征，结果表明:青藏高原上空水汽质量整体偏多（少）时，对应南亚高压和青藏高原地区垂直向上的水汽质量非绝热输送偏强（弱），青藏高原及周边水汽质量向平流层的绝热和非绝热传输均偏强（弱）。水汽质量整体偏多与偏少年，水汽质量向平流层绝热和非绝热传输的主要区域和层次相近，只是水汽质量整体偏多年，水汽质量向平流层非绝热传输的层次略高。当青藏高原上空水汽质量呈西多/东少分布时，对应南亚高压偏西，青藏高原西北、东北侧水汽质量向中纬度平流层的绝热传输偏强，青藏高原南侧高层水汽质量向热带平流层的经向绝热传输也偏强，而青藏高原北侧水汽质量向中纬度平流层的经向绝热传输明显减弱。同时青藏高原主体上空水汽质量向平流层的非绝热传输偏强，而青藏高原南侧高层和北侧低层水汽质量向平流层的非绝热传输偏弱。水汽质量呈西少/东多分布时有相反的结果。轨迹模式模拟的结果证实了水汽质量整体偏多年，青藏高原及周边地区绝热进入平流层的轨迹频次偏多；也证实了水汽质量呈西多/东少分布时，青藏高原西北、东北和南侧绝热进入平流层的轨迹频次偏多，而青藏高原北侧绝热进入平流层的轨迹频次偏少。

Interannual Anomalies of Upper Tropospheric Water Vapor Mass and Its Transport into the Stratosphere over the Tibetan Plateau Area in Summer. Part II: Adiabatic and Diabatic Transport into the Stratosphere

The interannual geographic patterns of the upper tropospheric water-vapor-mass anomaly are dominated by a uniform abnormal mode and an east–west dipole abnormal mode over the Tibetan Plateau (TP) regions in July–August. In this paper, we analyze the relationship between these two leading modes and the adiabatic and diabatic water-vapor-mass transport from the troposphere to the stratosphere based on the European Centre for Medium-Range Weather Forecasts Interim Re-Analysis (ERA-Interim) datasets and the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) trajectory model. Results show that when the water vapor mass is dominated by the positive (negative) phase of the uniform abnormal mode, i.e., there is more (less) water vapor mass over the entire TP area, the intensity of the South Asian High (SAH) and the upward diabatic water-vapor-mass transport are enhanced (weakened), which means both the adiabatic and diabatic water-vapor-mass transport from the troposphere to the stratosphere are stronger (weaker). The regions and layers where the adiabatic and diabatic water-vapor-mass transported from the troposphere to the stratosphere change very little from the positive to negative phases of the uniform mode, although the layers in which the diabatic water-vapor-mass transported from the troposphere to the stratosphere are slightly higher for the positive phase. When the water vapor mass is dominated by the positive (negative) phase of the west–east dipole abnormal mode, that is, when there is more (less) water vapor mass in the west (east) of the TP, the SAH center shifts westward, enhancing the adiabatic water-vapor-mass transport from the troposphere to the mid-latitude stratosphere in the northwest and northeast flanks of the TP as well as the meridional adiabatic water-vapor-mass transport from the troposphere to the tropical stratosphere in the upper layers in the south flank of the TP. However, the meridional adiabatic water-vapor-mass transport from the troposphere to the mid-latitude stratosphere in the north flank of the TP is weakened. Meanwhile, the diabatic water-vapor-mass transport from the troposphere to the stratosphere is enhanced over the TP, whereas it is weakened in the upper layers in the south flank of the TP and the lower layers in the north flank of the TP. When the opposite occurs, there is less (more) water vapor mass in the west (east) of the TP. Trajectory model simulation experiments for the positive phase of the uniform abnormal mode confirm that higher frequency trajectories enter the stratosphere adiabatically over the TP regions. Trajectory model simulation experiments for the positive phase of the west–east dipole abnormal mode are in agreement with the analyzed results, which show higher (lower) frequency trajectories entering the stratosphere adiabatically in the northwest, south, and northeast flanks (north flank) of the TP.