摘要
在SAS(Relaxed Arakawa-schubert Scheme)对流参数化方案中引人对流云和层状云的相互耦合机制,并通过一个台风个例对改进前后两种方案的预报效果进行了比较。试验结果表明:对于台风这种对流云和层状云相互作用非常强烈的天气系统,在对流参数化方案中引人对流云和层状云的耦合机制可以有效地提高模式对台风路径的预报水平,但是对于台风强度的预报效果不明显。考虑对流参数化和微物理过程耦合后模式的参数化降水变弱而格点降水增强,与NCEP再分析资料的对比发现,改进方案对于台风外围的大尺度温度场和湿度场的预报会有所改进,但仍然存在偏干偏冷的现象。对雨和雪的不同处理方式、不同云底条件以及是否考虑雨雪的卷人抬升三个方面进行了敏感性试验,发现72 h内模式预报结果对这些因素的差异不是很敏感。从多个个例的统计结果来看,新方案对台风路径预报的改进效果是比较稳定的。
The two-way interactions between cloud microphysics and cumulus convection are introduced into the Relaxed Araka-wa-schubert Scheme （SAS）convection scheme,the improved scheme is tested with a typhoon case and,the forecasts are com-pared with those of the original SAS scheme.The results show that the track forecast is improved obviously after the inclusion of inter-actions between convection and large-scale environments while the influence on intensity forecast is not so evident.The grid-scale ex-plicit precipitation gets much stronger and the sub-grid scale precipitation is reduced after coupling convection with cloud microphysics, with the impact on large-scale temperature and humidity also revealed based on the NCEP reanalysis data.A series of experiments are implemented to test the sensitivity of the different treatments of the convective snow,the different cloud-base conditions and the en-trainment of snow and rain with the result that 72 h forecast is not sensitive to these factors.The improvement of the revised scheme on typhoon track forecast is reliable as shown by the statistical results from many cases.
出处
《气象学报》
CAS
CSCD
北大核心
2014年第2期337-349,共13页
Acta Meteorologica Sinica
基金
公益性行业(气象)科研专项(GYHY201206010)"热带环流系统的数值天气预报技术研究"
广东省科技计划项目(2011A032100006)"广东省突发灾害性天气应急技术研究中心"
广东省科技计划项目(2012A061400012)
关键词
对流参数化
微物理过程
耦合
台风
Convection parameterization, Microphysical process, Coupling, Typhoon
