In correspondence with the establishment of the“upper high and lower high”pressure pattern due to the activities of 500 hPa high over the Tibetan Plateau in summer,a series of changes of the East Asia atmospheric ci...In correspondence with the establishment of the“upper high and lower high”pressure pattern due to the activities of 500 hPa high over the Tibetan Plateau in summer,a series of changes of the East Asia atmospheric circulation will take place.In this paper,the distributions of divergence and vertical velocity of 500 hPa high,the evolutions of atmos- pheric heat source,the variations of vorticity and zonal wind at 100 hPa level and vertical meridional cell over the Tibetan Plateau etc.are statistically analyzed.Thus,we can see that the ascending motion and the convective heating over the Tibetan Plateau,the South Asia high and the westerly jet on the north of the Plateau at 100 hPa level are weak- ened.The northern branch and the southern branch of the easterly jet on the south of the Plateau merge into a single whole and situate on the south of the former northern branch.In the meantime,thermodynamic land-sea discrepancy in South Asia and the convective heating over the Bay of Bengal is enhanced.It will play an important role in the mainte- nance of the easterly jet and the South Asia monsoon.展开更多
利用地面气象站和探空观测资料,对2013年8月16日辽宁地区特大暴雨过程数值模式预报的产品进行检验和对比分析,主要包括降水、500 h Pa位势高度场和副热带高压指数等。结果表明:一般性降水预报准确率T639模式整体优于EC模式,暴雨预报平...利用地面气象站和探空观测资料,对2013年8月16日辽宁地区特大暴雨过程数值模式预报的产品进行检验和对比分析,主要包括降水、500 h Pa位势高度场和副热带高压指数等。结果表明:一般性降水预报准确率T639模式整体优于EC模式,暴雨预报平均准确率EC模式略高于T639模式,T639模式和EC模式降水预报正负距平出现位置近似。多个数值模式对清原站主要降水时段(8月16日11—23时)的降水预报明显偏弱,WRF模式预报的全省3 h最大降水量远大于实况,T639模式和EC模式预报的降水量级均明显小于实况。EC模式和多模式集成72 h内降水落区与强降水中心位置的预报相对较稳定,过去15 d的滑动平均检验结果对降水预报具有一定的指示意义,72 h内EC模式的特征线预报一致性明显高于T639模式,对于辽宁省大部地区及上游高空槽附近EC模式降水预报的离散度小于T639模式。展开更多
基金This study is partially supported by the National Natural Science Foundation of China.
文摘In correspondence with the establishment of the“upper high and lower high”pressure pattern due to the activities of 500 hPa high over the Tibetan Plateau in summer,a series of changes of the East Asia atmospheric circulation will take place.In this paper,the distributions of divergence and vertical velocity of 500 hPa high,the evolutions of atmos- pheric heat source,the variations of vorticity and zonal wind at 100 hPa level and vertical meridional cell over the Tibetan Plateau etc.are statistically analyzed.Thus,we can see that the ascending motion and the convective heating over the Tibetan Plateau,the South Asia high and the westerly jet on the north of the Plateau at 100 hPa level are weak- ened.The northern branch and the southern branch of the easterly jet on the south of the Plateau merge into a single whole and situate on the south of the former northern branch.In the meantime,thermodynamic land-sea discrepancy in South Asia and the convective heating over the Bay of Bengal is enhanced.It will play an important role in the mainte- nance of the easterly jet and the South Asia monsoon.
