空间加密探空观测资料对西南低涡暴雨天气过程数值模拟的影响

本文基于AREM（Advanced Regional Eta Model）模式，结合中国气象局成都高原气象研究所西南低涡加密观测科学试验得到的探空观测第一手资料，通过对2012年7月3～4日四川区域性暴雨天气过程（20120703过程）进行数值模拟分析，结果表明:（1）降水雨带的分布主要取决于西南低涡移动路径，不同初值会使得低涡路径在磨合协调期产生强摆动，稳定后则在此基础上，随着环境流场继续移动发展。（2）引入4个加密探空站点资料会对整个大气物理量场造成一定影响，最大差值分布在这些站点附近，热力和动力物理量场最大偏差中心并不重合。时间演变直观地说明了初值对局地大气状态的影响时段有限，主要集中在前期，与模式自身调整期相重叠。（3）初始的大气状态必然会随着模式的磨合过程进行调整，不同初值在调整期能对中小尺度低涡系统的位置及强度产生影响，形成各自稳定的低涡系统初态。（4）低涡中心所对应的散度、涡度、垂直速度关系非常密切，但三者强度和发展高度的演变并非完全一致。

The Influence of Spatially Intensive Sounding Observation Data on the Numerical Modeling of Southwest Vortex Rainfall

A regional-scale heavy rainfall process that occurred in the Sichuan area during 3-4 July 2012 was simulated by the Advanced Regional Eta Model, forced by first-hand data obtained from the Intensive Observation Scientific Experiment of the Southwest vortex. Results show that: (1) The distribution of the rain belt was determined by the moving path of the Southwest vortex; different initial conditions lead to a strong shift of the path in the spin-up processes, and then the large-scale circulation becomes important in regulating the movement and development of the vortex. (2) Four newly added sounding stations have impacts on all atmospheric fields; the largest differences occurred around these stations, and the largest deviations of the thermal and dynamical field were not consistent. The time series indicates that the impact of initial conditions is constrained at the beginning of the simulation, related to the model spin-up process. (3) The initial atmospheric circulation adjusted to the model spin-up process. Different initial conditions have impacts on the location and strength of the meso-small-scale vortex and forms a distinct initial state of the stable vortex. (4) The diversion, vorticity and vertical velocity corresponding to the vortex are tightly related; however, the evolutions of strength and height are not consistent.