利用地基微波辐射计资料反演0~10 km大气温湿廓线试验研究

为综合评估地基微波辐射计(以下简称辐射计)温湿探测性能、提高温湿廓线精度，利用2021年3—8月北京辐射计观测、探空和ERA5再分析等资料，分析不同天气条件下(晴天、云天、雨天)辐射计温湿度探测性能，利用探空数据和修正后的ERA5数据对辐射计温湿廓线进行检验，并基于线性偏差订正方法对辐射计温度、相对湿度进行订正。结果表明：(1)辐射计温度在晴天、云天与探空温度具有较好的一致性，而其在降雨天气较探空温度高；辐射计相对湿度在晴天高于探空，云天和雨天低于探空。雨天探空数据对辐射计温、湿度的线性偏差订正效果优于晴天、云天。(2) ERA5相对湿度在4 km以上高度与探空存在明显偏差，其温度与探空温度的相关性高于相对湿度。(3)探空数据修正后的ERA5数据能较好提升辐射计温湿廓线精度，且在雨天效果优于晴云天。垂直方向上，随着高度增加辐射计温、湿度订正效果更明显。(4)采用探空数据和修正后的ERA5数据对订正后的辐射计温湿数据进行误差分析，结果表明晴天和云天条件下辐射计与探空、辐射计与修正后ERA5数据的误差(平均误差BIAS和均方根误差RMSE)廓线垂直分布特征相似。雨天条件下两者在中高层(7—10 km)有明显差异，其中温度RMSE相差4 K，相对湿度RMSE相差20%。

0-10 km Temperature and humidity profiles retrieval from ground-based microwave radiometer

In order to comprehensively evaluate the temperature and humidity detection performance of the ground microwave radiometer (referred to as radiometer, the same below) and improve the accuracy of temperature and relative humidity profiles, by using the ground microwave radiometer data, radiosonde data, and ERA5 reanalysis data of Beijing from March to August 2021, this paper analyzes the temperature and humidity detection performance of the radiometer under sunny, cloudy and rainy days. In the meanwhile, this paper uses radiosonde data and corrected ERA5 data to verify temperature and humidity profiles of radiometer and correct temperature and humidity data of radiometer based on the linear deviation correction method. The results show that: (1) The temperature of microwave radiometer has good consistency with radiosonde temperature under sunny and cloudy days, but it is higher than the radiosonde temperature in rainy days. The relative humidity of microwave radiometer is higher than that of radiosonde in sunny days and lower in cloudy and rainy days. The linear deviation correction effect of radiosonde on ground-based microwave radiometers in rainy days is better than that in sunny and cloudy days. (2) Above 4 km, ERA5 relative humidity data has obvious deviation with radiosonde data, while the temperature correlation between ERA5 and radiosonde is higher than relative humidity correlation. (3) The ERA5 data after radiosonde correction can improve the temperature and humidity profile accuracy of the Microwave radiometer, and the effect is better in rainy days than in sunny days. In vertical direction, with the increase of height, the correction effect of radiometer temperature and humidity data is more obvious. (4) The two true values of radiosonde data and corrected ERA5 data were used to analyze the temperature and humidity data of the ground-based microwave radiometer corrected by ERA5, and the results showed that the vertical distribution characteristics of the error (mean error BIAS and root mean square error RMSE) profiles of radiometer and radiosonde, radiometer and corrected ERA5 data were similar under sunny and cloud conditions. Under rainy conditions, there were obvious differences between the two in the middle and upper height (7-10 km), among which the temperature RMSE differed by 4 K and the relative humidity RMSE differed by 20%.