Research Of Local Short-term Forecast And Nowcasting Based On Doppler Radar And Multi-sourced Data

Severe convective weather is one of the most common meteorological disasters, and has the feature of short life history, fast movement, which can often bring inconvenience to the people’s work and life as well as pose a threat to agricultural production, national property, etc. Doppler radar data, with its high space-time resolution, has a unique advantage in nowcasting and disaster warning. Severe convective weather warning basically relies on the real-time monitoring of radar in meteorological operations. Doppler weather radar, which plays an important role in the analysis and prediction of severe convective weather, can also combine with other methods of monitoring. Nowadays, there is an increasing high requirement in research of radar data application due to civil aviation development and the significant international events holding.This article mainly focuses on the application of radar data in nowcasting of certain airport and important international events such as Youth Olympic Games ceremony which have special requirements in high spatial and temporal resolution. A strong convective weather in Guangdong province as the study case, combined with a variety of detection data, using radar data as a main data source in the data fusion and analysis in the LAPS, LAPS outputs analysis fields and the result is compared with the simulation result of WRF, in order to utilize numerical model and data fusion better in airport short-term forecast and nowcasting; In order to study effect of radar data in the analysis and nowcating of local thermal convection weather, taking a thermal convection process as a research case which happened on August15to17,2013around Nanjing Olympic sports center for three days, this article explores the influential factors and the mechanism of this process comprehensively and thoroughly, then comes to the conclusions as follows:(1) Severe weather is a result of the accumulation of unstable energy. Severe convection occurs before the appearance of cold cloud layer structure and ultra-low temperature structure, which can be regarded as a precursor of strong convective weather forecast.(2) LAPS system is applied in airport meteorological forecast for the first time. After fusion of a variety of detection data, the spatial and temporal resolution can meet the requirements of the airport local nowcasting. Moreover, the outputs of multiple parameters have higher reference value. Compared with the WRF model simulation results, the output of the LAPS system accords with the actual data of large scale circulation as well as preciously describes mesoscale factor fields better, and offers basis and references for short-term forecast and nowcating of the airport.(3) If the temperature is favorably high, and the thermal circumstance is beneficial, thermal convective weather will be easy happening near the ground convergence line although in the eastward air flow. Urban heat island effect and the influence of the Yangtze River water contribute in the appearance of surface convergence line. The gust front which appears in the radar echo strengthens the convection development, and prompts the westward moving echo to spread and develop backward.(4) Through the analysis of the wind profiler, microwave radiometer, and GPS/MET information, it is found that these data reveals the precursor information before the convection development, such as:previous clockwise and reverse rotation on the wind profile, low-level moisture and energy changes detected by microwave radiometer, water vapor distribution and short-time increase or decrease in GPS data, which offer significant reference and instruction and can all be used in short-term forecast and nowcasting.