Effects of Channel Selection and Observation Error Allocation on the Assimilation of AIRS Data

Hyper-spectral Atmospheric Infrared Sounder AIRS has many channels. Taking into account the correlation between channels, different detection purposes and the timeliness of assimilation, channel selection is necessary. Principal component-dual-zone-stepwise regression method is proposed in this paper and points the day and night for channel selection. The contribution rate of channel observation brightness temperature to the objective function is controlled by channel observation error, variational data assimilation system is generally given observation error and then in the process of minimization objective function remains unchanged, the paper adopt the observation error re-estimated and then provide observation error information to the variational data assimilation. Study effects of channel selection and the observational error allocation on the assimilation of AIRS data in this paper.