An OSSE Study on Wind Profiler Radar Observing Layout over China

In recent years, wind profiler radar observation technology has developed rapidly, and its detection data has high temporal and spatial resolution. The observing wind field information plays an important role in the small or meso scale weather system analysis and numerical weather prediction. This study aimed to explore the wind profiler radar observing layout over China form the perspective of numerical weather prediction application. A heavy precipitation processe occurring in Jianghuai region on June 16-17, 2015 was studied using Weather Research and Forecasting (WRF) model and Three Dimensional Variational data assimilation (3D-Var) method with Observing System Simulation Experiments (OSSEs). Two sets of sensitive tests - the different station separations test and the different types (i.e. different detection heights) test were designed to explore the influence on numerical weather prediction of different wind profiler radar layout, compared with the control test with no data assimilation. The different station separations test designed uniform distribution wind profiler radars with station separations of approximate 500km, 200km and 100km over China. The different types test designed to assimilate wind profiler radars totally in 3km or 8km detection height and a mixture layout of this two types. Result: Compared with the control test, assimilation wind profiler radar data decreased the wind prediction error at each forecast time, and most of the improvement occurred below 300hPa (about 9km). It also can be seen that assimilation wind profiler radar had more effect on the forecast improvement of the U component wind than that of the V component wind. In the different station separations test, the forecast results of the experiments assimilating wind profiler radar data at layout densities of 100km and 200km were similar, and were superior to the experiment of 500km. In the different types test, the result of the experiment that assimilated wind profiler radar data totally in 8km detection height was closed to the experiment assimilating the mixture layout of 8km and 3km, whose performance were both better than that of totally in 3km. Considering the results above and economic cost comprehensively, the 200km layout density and the mixture layout of 3km and 8km detection height wind profiler radars are suggested in the observation layout design of wind profiler radars over China.