Application of Encrypted Automatic Weather Station Data in RMAPS-CA Numerical Model

Abstract

The regional numerical forecast system named Rapid-refresh Multi-scale Analysis and Prediction System-Central Asia （RMAPS-CA） is the numerical weather forecast business system of Xinjiang Meteorological Bureau， which provides support for the meteorological forecast and early warning service of Xinjiang province， its predictive performance is closely related to daily travel safety and meteorological guarantee of various industries.Therefore， the different automatic weather station observations are separately added to the RMAPS-CA to carry out a three-dimensional variational assimilation experiment， then compared the results of experiments with the actual situation.More than 8000 regional automatic weather stations （including nearly 600 stations in Xinjiang） and more than 2400 national automatic weather stations that have been included in the routine assessment objectives of China Meteorological Administration are selected as encryption automatic stations.Their application effect in regional numerical prediction system （RMAPS-CA） is analyzed.The purpose is to further improve the assimilation efficiency of encrypted automatic station by improving the quality and assimilation method of encrypted automatic station， so as to improve the contribution of encrypted automatic station observation to the prediction performance of RMAPS-CA service system.At the same time， the different assimilation schemes are used to carry out sensitivity tests， the updated assimilation scheme proposed by Zhang X Y （2021） is used for assimilation test， then the effects of the updated assimilation scheme and the original scheme on ground element prediction are compared and analyzed in order to analyze the contribution of updated assimilation scheme to numerical prediction performance.Through the results of a single case in July 2020 and a batch test of 15 days in July 2020 show that on the premise of ensuring the data quality， compared with only assimilating the national automatic weather station data， assimilating the encrypted automatic weather station data can effectively improve the prediction accuracy of 2-meters temperature， 2-meters humidity and 10-meters wind speed.Based on the use of encrypted automatic weather station data， the assimilation scheme of RMAPS-CA is changed from the original scheme to the updated scheme， which can reduce the root mean square error of 2-meters temperature prediction and 10-meters wind speed prediction， improve the assimilation application effect of encrypted automatic weather station.In conclusion， the reasonable use of encrypted automatic weather station can improve the prediction performance of RMAPS-CA， then， the updated assimilation scheme can further improve the contribution of encrypted automatic weather station data to the numerical prediction system.In a word， the RMAPS-CA has better prediction performance when the encrypted automatic weather station data and the updated assimilation scheme are used at the same time.

Keywords

• regional numerical model
• data assimilation
• encrypted automatic weather station
• update assimilation scheme