探空温度观测与ERA-interim再分析资料的对比分析

A COMPARISON OF THE RADIOSONDE TEMPERATURE OBSERVATIONS AND THE EC REANALYSIS DATASET

在观测资料同化系统中,探空资料是重要的资料之一。为了解探空温度观测资料的误差特征、合理使用观测,选用欧洲中心再分析场为参照场,针对从国家气象信息中心资料库中检索到的探空资料,按着仪器类型和太阳高度角统计探空温度观测资料的平均偏差和均方差。统计时段分别为夏季(2014年6—8月)和冬季(2014年12月—2015年2月)两个季节。统计结果显示,检索到的全球探空站总数约有680个,使用的探空仪共有三十多种(有仪器标识)。其中约275个探空站使用Vaisala系列探空仪,90个探空站使用中国上海生产的探空仪,约80个探空站使用美国生产的探空仪。不同类型的探空仪器在不同太阳高度角,探空温度观测相对欧洲中心再分析场的偏差差别很大。而有些探空仪器无论是平均偏差(一般低于0.5℃),还是均方差都较小,且随太阳高度角变化不大;有些探空仪器探测温度偏差较大(在高层绝对值大于2℃)。

The quality of the radiosonde temperatures are related to the instrument type and the solar altitude.Radiosonde temperatures are an important data source for assimilation system.In order to describe the representative error of the radiosonde temperatures and carry out the bias correction for radiosonde temperatures,the innovation statistics from the ECMWF re-analysis(ERA interim)are examined.The innovation statistical periods are summer(June to August 2014)and winter(December 2014 to February2015).It is demonstrated that there are about 680 radiosonde stations every day.There are about thirty instrument types with about 275 stations using the Vaisala series instrument,90 stations using the Shanghai radiosonde and about 80 stations using the Sippican MK2 GPS/STAR(USA).The innovation statistics indicate that different instrument type and different solar angle differ greatly.Some instrument types have small bias(less than 0.5℃)while others have big deviation.For example,the Meteorit MARZ2-2’s and the Nanjing GTS1-2/GFE’s temperature bias absolute values are greater than 2℃in the high level,but they need to be put through bias correction.