2015年11月中国南方降水异常定量诊断

利用NCEP/FNL再分析资料和地面月降水量资料，应用局地经向环流诊断方程对2015年11月中国南方地区降水异常进行定量诊断，并结合对应天气形势分析了其形成原因。结果表明： 1) 潜热加热、平均纬向温度平流、平均西风动量经向输送是导致2015年11月中国南方地区持续性降水天气形成的主要物理因子；2) 2015年11月来自热带海洋的水汽输送明显偏强，水汽在中国南方地区辐合抬升，其凝结潜热加热对经向环流上升支的正贡献较大；3) 中国南方地区受孟加拉湾槽前的西南风和西太平洋副热带高压西北侧的西南风控制，以暖平流为主，是平均纬向温度平流对南方地区经向环流上升支起正贡献的主要原因；4) 中国南方地区位于高空西风急流入口区反气旋切变一侧，受高层辐散抽吸影响，激发的上升运动是西风动量纬向平流对南方地区降水异常起正贡献的主要原因。

Quantitative diagnosis on persistent heavy rain in southern China in November 2015

Based on NCEP/FNL reanalysis data and the observation data, a quantitative diagnosis on the persistent heavy rain over southern China in November 2015 was carried out using a local meridional circulation equation, and combined with the corresponding weather conditions, the causes of the persistent heavy rain over southern China were analyzed. The results showed that: 1) The latent heating, average zonal temperature advection and zonal advection of westerly momentum were the main physical factors for the persistent heavy rain in southern China. 2) The water vapor transport from the tropical ocean to the southern China was obviously stronger in November 2015, and the water vapor converge and uplift in the southern China resulted in the latent heat heating providing a greater positive contribution to the ascending branch of meridional circulation. 3) The southern China controlled by the southwest wind and dominated by warm advection were the main reasons for the positive contribution of mean zonal temperature advection to the ascending branch of meridional circulation. 4) The southern China was located at the shear side of anticyclone in the entrance area of upper westerly jet, the impact of the high level divergent suction and the motivated ascending motion were the main reasons for positive contribution of mean westerly momentum zonal advection to the ascending branch of meridional circulation.