一次天气尺度扰动过程对东海北部大气边界层垂直结构的影响

Influence of Synoptic Scale Disturbance on the Atmospheric Boundary Layer Structure over the Northern East China Sea

利用2013年6月船载GPS探空、云高仪资料,结合ERA-Interim再分析资料、卫星资料,分析一次天气尺度扰动(锋面过境)过程对东海北部海洋大气边界层(MABL)垂直结构的影响。结果表明:受梅雨锋影响,航测区域上空在整个过程中都有低云覆盖,MABL没有呈现日变化特征;当MABL为稳定边界层时,锋面与站位距离越近,站位上空增强的上升运动导致MABL高度越高。梅雨锋过境前后云层之上都覆盖有较为稳定的逆温层,受锋面抬升作用,云底高度和云顶逆温层高度在锋面过境后高度变高;锋面过境导致航测区域上空700hPa以下大气的上升运动增强,水汽上升到更高位置,云底从MBAL中脱离。锋面过境后,3 000m以下整层大气相对湿度较大,大气层结退耦的产生导致云分层形成高度不同的多层云。

This paper studied the influence of synoptic scale disturbance on the atmospheric boundary layer structure over the northern East China Sea based on the shipborne GPS sounding system,ceilometer during the cruise in June 2013.It is shown that there is no diurnal variation of the MABL height covered with clouds along the cruise under the influence of the baiu front.The height of the stable MABL increases when the front is nearby.There are stable inversion layer capping above the clouds.The heights of cloud-base and the inversion layer are both increase under the uplifting effect of the baiu front.The dramatic upward motion below 700 hPa due to the passage of the baiu front facilitate the water vapor reach a higher level and help for the cloud-base separating from the MABL.The relative humidity under 3000 mis larger after the passage of the baiu front.The clouds are broken into multi-layers clouds on different levels when decoupling of the atmospheric stratification occurs.