Derivation of Value Added Products Using the High Performance Geostationary Imagery Data for the Short-Range Weather Forecasting

For a better utilization of the 16-channel Advanced Meteorological Imager (AMI) that will be flying with Korea’s second generation geostationary meteorological satellite GEO-KOMPSAT 2A that is scheduled to launch in 2018, an Optimal Estimation (OE) approach to  obtain information on the vertical profiles of temperature (T) and moisture (Q) and to derive related thermodynamic stability information such as total precipitable water and 5 kinds of instability indices (i.e., K-index, Lifted index, Total totals, Showalter index, and CAPE) has been developed. The approach finds a best estimate of the atmospheric state that minimizes a cost function, which combines the observation and background information with their associated errors assumed to follow the normal distribution, using the Gauss Newton iteration method. For the calculation of forward model and Jacobians, the Radiative Transfer for TOVs (RTTOV) version 11.2 is used and a first-guess profile driven by the Unified Model (UM) forecast fields is fed to the algorithm. Background error covariance for T and Q are from the B-matrices used for the Numerical Weather Prediction Satellite Application Facility (NWPSAF) 1DVAR system and ozone B-matrix from the European Center for Medium-range Weather Forecasts (ECMWF) model. Algorithm performance statistics shows that about 50% of the total retrievals are the updated first-guess profiles with the iterative OE. Departure analyses reveal that the better improvements are made in the window channels (particularly 10.4 and 11.2 um).

To characterize the approach, we use the bias corrected radiance from the infrared channels of the Advanced Himawari Imager (AHI) on board Himawari-8, as proxy to AMI. The preliminary results of the algorithm performance from the comparison with the radiosonde, other satellite data and other available reference along with a detailed analysis on the algorithm characteristics will be presented during the conference. Furthermore, to evaluate the possibility of utilizing products from a high-performance imaging system such as AMI for the short-range weather forecasts, typical cases of sever-weather events such as events associated with the synoptic-scale frontal system, thermally unstable atmosphere, and events accompanied by tornadoes occurred in East Asia between 2015 and 2016 are going to be introduced.