Abstract:
The observation error of satellite radiation data that assimilated into the Korean Integrated Model (KIM) was diagnosed by applying the Hollingsworth and Lönnberg and Desrozier techniques commonly used. The magnitude and correlation of the observation error, and the degree of contribution for the satellite radiance data were calculated. The observation errors of the similar device, such as Advanced Technology Microwave Sounder (ATMS) and Advanced Microwave Sounding Unit-A shows different characteristics. The model resolution accounts for only 1% of the observation error, and seasonal variation is not significant factor, either. The observation error used in the KIM is amplified by 3–8 times compared to the diag- nosed value or standard deviation of first-guess departures. The new inflation value was calculated based on the correlation between channels and the ratio of background error and ob- servation error. As a result of performing the model sensitivity evaluation by applying the newly inflated observation error of ATMS, the error of temperature and water vapor analysis field were decreased. And temperature and water vapor forecast field have been significantly im- proved, so the accuracy of precipitation prediction has also been increased by 1.7% on average in Asia especially.

Keywords:
Data assimilation, Observation error covariance, Advanced technology microwave sounder (ATMS), Desroziers technique, Hollingsworth and Lönnberg

Citation:
Kim, H., Kang, J.-H., & Kwon, I.-H. (2022). Diagnostics of Observation Error of Satellite Radiance Data in Korean Integrated Model (KIM) Data Assimilation System. Atmosphere, 32(4), 263–276.