夏季东亚副热带西风急流的季节内变化及其与我国东部降水的关系

利用ERA-interim再分析资料和中国降水观测数据,分析了夏季东亚副热带西风急流的季节内变化以及对我国降水的可能影响,结果表明:亚洲地区夏季200 hPa纬向风在空间上主要表现为南北振荡和东西振荡特征,在时间上具有10～40 d的周期;在低频尺度(10～40 d)上,纬向风异常由西北先向东传播,到达东亚地区后再向南传播;伴随低频纬向风季节内演变,高原以北的急流中心向东和东南移动,急流轴也呈现南北振荡的特征;降水异常对200 hPa风场低频振荡有显著响应,在东亚地区,低频纬向风与低频降水南移,降水在黄淮地区出现,并逐渐移至长江及其以南地区;急流附近的低频西(东)风异常在其南侧形成负(正)切变涡度,对应我国东部地区位势高度的升高(降低),使得南亚高压东伸(西退),从而使我国东部雨带的位置发生显著变化。

Intraseasonal variation of the East Asian subtropical westerly jet in summer and its relation to precipitation in Eastern China

With the development of wind profile radar technology, the parameters of high-altitude wind detection are increasing, as well as the accuracy of data is continuously improved, and the detection capability has been greatly improved. It is an important issue to evaluate the credibility of wind profile radar in wind profile radar applications. This paper proposes a data credibility algorithm, which uses two stages of radial data and wind field synthesis, and introduces noise electrical levels in the wind profile radar data inversion process.The performance of the credibility algorithm is evaluated by matching the data of the Nanjing station wind profiler radar and sounding data for one year. The experimental results show that the credibility algorithm proposed in this paper is feasible. The credibility algorithm is implanted into the wind profiler radar data processing software, and the wind profile radar product data with credibility is output in real-time, and the forecaster uses the high-credibility wind profiler radar product data. Analysis of poorly credible product data can help identify potential failures on the radar.