摘要
利用全球通讯系统GTS传输的常规观测资料和卫星资料,用全球与区域同化预报系统GRAPES(global/regional assimilation and prediction system)全球等压面三维变分分析和中期数值预报模式进行为期两个月6 h分析预报循环试验,并对分析结果进行了诊断分析。结果表明,位势高度在中低纬对流层顶及以上区域存在5~20 gpm负偏差,在100 hPa以下的南北极区域存在5~20 gpm正偏差;相对湿度在南极存在较大负偏差,在高层有较大正偏差。风场在赤道中高层有较明显的偏差。在500 hPa上北半球GRAPES位势高度与NCEP资料的均方根误差在10 gpm左右,南半球在15~24 gpm之间。与探空观测相比,经变分分析后,分析的偏差和均方根误差都有所减小,但位势高度背景场存在明显负偏差,而且在100 hPa以上位势高度改进不如低层明显。全球等压面三维变分分析预报循环试验表明,分析预报循环系统能稳定运行,但是分析和6 h预报场还存在系统性偏差。
The assimilation cycle experiments with every 6 h in two months of the GRAPES global 3DVar analysis based on pressure level and prediction system were carried out and diagnosed by using the conventional observations transferred by GTS and satellite observations. The results show that: There are 5 ~ 20 gpm negative geopotential bias above tropopause of middle and low latitude and 5 ~ 20 gpm positive geopotential bias in polar region below 100 hPa. There are bigger negative relative humidity bias in South Pole and positive relative humidity bias at the upper level. It is obvious that there is wind bias at the upper level of equator. The geopotential RMSE difference between GRAPES analysis and NCEP analysis on 500 hPa are about 10 gpm for north hemisphere and15 ~ 24 gpm for south hemisphere. The bias and RMSE between the interpolated values of analysis and observed values have decreased. However,the geopotential height background fields have obvious negative bias in compared with observations,and there is no obvious improvement above 100 hPa. The experiments of global 3DVar analysis and prediction system indicate that the system can be run stably,although there are systemic bias for analysis and 6 h prediction fields.
出处
《高原气象》
CSCD
北大核心
2014年第3期666-674,共9页
Plateau Meteorology
基金
公益性行业(气象)科研专项(GYHY201206007)
国家自然科学基金项目(41305092)
关键词
GRAPES
等压面三维变分
中期数值预报模式
分析预报循环
GRAPES
3DVar based on pressure level
Medium range numerical prediction model
Analysis and prediction cycle
