复杂地形地区WRF模式四种边界层参数化方案的评估

Evaluation of the four PBL schemes in WRF Model over complex topographic areas

为更加精确地模拟复杂地形地区大气边界层中气象要素,将NASA发布的SRTM3(约90m分辨率)地形高度数据引入中尺度气象模式WRF(weather research and forecasting)中,结合四种边界层参数化方案(YSU、ACM2、MYN2.5level TKE(简称MYN)、Bougeault and Lacarrere TKE(简称BL))及模式自带地形数据GTOPO30(约1km分辨率),模拟了2008年4月24—25日安徽黄山及周边地区大气边界层气象要素场变化特征,并对模式输出的2m气温、2m露点温度、10m风速、湿度廓线与模拟区域内19个气象站及2个探空站数据进行比较。结果表明,无论采用哪种地形数据,四种边界层参数化方案中,YSU方案模拟的2m气温误差最小,ACM2方案模拟的2m露点温度和10m风速误差最小;采用SRTM3数据后,四种边界层参数化方案模拟的2m气温平均均方根误差(root mean squared error,RMSE)分别降低了3.79%(YSU方案)、2.48%(ACM2方案)、3.8%(MYN方案)、0.87%(BL方案);对2m露点温度模拟,除MYN方案模拟平均RMSE降低了0.59%外,其他三种方案模拟误差分别增加了1.39%(YSU方案)、0.49%(BL方案)、0.89%(ACM2方案);而对10m风速的模拟结果,除ACM2方案模拟平均RMSE降低了2.28%外,其他三种方案模拟误差分别增加了0.22%(YSU方案)、2.32%(MYN方案)、2.45%(BL方案);对2个探空站点湿度廓线的模拟显示,各边界层方案均能模拟出水汽的垂直变化趋势,但模拟效果总体表现为偏湿,采用SRTM3地形数据之后,ACM2方案模拟部分时刻的低层水汽廓线有所改善。

In order to simulate meteorological parameters more accurately in the Planetary Boundary Layer （PBL） over complex terrain, the SRTM3 data from NASA was used in WRF model. With configuration of four PBL parameterization schemes （YSU scheme, ACM2 scheme, MYN scheme, and BL scheme） and two geographical data（ SRTM3, GTOPO30） ,meteorological parameters in the PBL of the Mt Huang area during 24-25 April 2008 were evaluated. Temperature and dewpoint temperature of 2 m, wind speed of 10 m and water vapor distribution from simulation were contrasted to the observational data from 19 meteorological stations and 2 sounding stations in the Mt Huang area. Results showthat YSU scheme was best for 2 m temperature simulation and ACM2 scheme was best for 2 m dew- point temperature and 10 m wind speed simulation in the four PBL schemes with both geographical da- ta;when SRTM3 data was used in WRF model, the mean RMSE of 2 m temperature simulated by the four PBL schemes were reduced by 3.79 % （ YSU scheme）, 2. 48 % （ ACM2 scheme ）, 3.8 % （ MYN scheme）, and 0. 87 % （BL scheme）, respectively;for 2 m dewpoint temperature, only the mean RMSE by MYN scheme was reduced by 0. 59% ,while the mean RMSE of YSU,BL and ACM2 schemes increased by 1.39% ,0. 49% ,and 0. 89% ,respectively;as to 10 m wind speed,only the mean RMSE by ACM2 scheme was reduced by 2. 28 %, while the mean RMSE of YSU, MYN, and BL schemes increased by 0. 22% ,2. 32%, and 2. 45% ,respectively; for the vertical distribution of water vapor from sounding report, all of the four PBL schemes can successfully simulate the vertical distribution tendency of water vapor, but all results turned out to be much moister;by using STRM3 data, the vertical distribution of water vapor simulated by ACM2 scheme was improved on low layer during some periods of time.