A new 2-way nested WRF-LETKF system has been developed

Higher resolutions are tempting.

A while ago, we have developed the Local Ensemble Transform Kalman Filter (LETKF) data assimilation system with the Weather Research and Forecasting (WRF) model (Miyoshi and Kunii 2011). We have been using 60-km resolution WRF, which produced good analyses and forecasts of Typhoon Sinlaku (2008) as shown in the left panel of the above figure. Several papers were published or are currently under review using this 60-km system. However, it is difficult to fight with the desire for a higher resolution.

Very recently, we have developed a new two-way nested WRF-LETKF system. The LETKF system was modified so that it can consider multiple resolutions simultaneously. Localization scales can be specified at each grid point separately. The enhanced LETKF and 60/20-km two-way nested WRF model enabled to produce a higher-resolution analysis as shown in the right panel. We start to see filaments of spiral rain bands of the tropical cyclone (color shades showing mm/6h rain rate). The eye is clearer, and the deep structure is more evident. Resolving capability is essential for these smaller-scale phenomena.

It is simply exciting as a scientist to have this better resolving capability. Now that we can see more details, we are going to investigate even more to improve tropical cyclone analyses and forecasts.

Professor Watanabe and Dr. Chikamoto (U of Tokyo) visited NCEP and UMD

On Wednesday, November 16, Professor Watanabe and Dr. Chikamoto of the Atmospheric and Oceanic Research Institute (AORI), University of Tokyo visited the NCEP and UMD.

They gave a seminar at NCEP in the morning on their work on decadal climate prediction using their own global air-sea coupled earth system model MIROC. Professor Watanabe provided an overview of the latest development of MIROC version 5, showing much improvement mainly due to the newly developed physics packages. Dr. Chikamoto talked about decadal ensemble prediction using MIROC, particularly with a new idea of "Anomaly Assimilation" in which the systematic differences between model climatology and observation data are considered to deal with the initial drift problem.

After enjoying conversation over lunch with NCEP folks, they visited my office in College Park and had a very nice Japanese conversation (picture).

A paper on observation impact estimates has been accepted

Kunii, M., T. Miyoshi, and E. Kalnay, 2011: Estimating impact of real observations in regional numerical weather prediction using an ensemble Kalman filter. Mon. Wea. Rev., in press.

A paper on variable localization and CO2 data assimilation has been published

Kang, J.-S., E. Kalnay, J. Liu, I. Fung, T. Miyoshi, and K. Ide, 2011: "Variable localization" in an Ensemble Kalman Filter: application to the carbon cycle data assimilation. J. Geophys. Res., 116, D09110. doi:10.1029/2010JD014673

A paper on adaptive inflation has been published

Miyoshi, T., 2011: The Gaussian Approach to Adaptive Covariance Inflation and Its Implementation with the Local Ensemble Transform Kalman Filter. Mon. Wea. Rev., 139, 1519-1535. doi:10.1175/2010MWR3570.1

A paper on tropical observation impacts estimated by ensemble spread has been published

Moteki, Q., K. Yoneyama, R. Shirooka, H. Kubota, K. Yasunaga, J. Suzuki, A. Seiki, N. Sato, T. Enomoto, T. Miyoshi, S. Yamane, 2011: The influence of observations propagated by convectively coupled equatorial waves. Quart. J. Roy. Meteor. Soc., 137, 641-655. doi:10.1002/qj.779

A paper on GPS-based moisture assimilation has been published

Seko, H., T. Miyoshi, Y. Shoji, and K. Saito, 2011: Data Assimilation Experiments of Precipitable Water Vapor using the LETKF System: Intense Rainfall Event over Japan 28 July 2008. Tellus, 63A, 402-414. doi:10.1111/j.1600-0870.2010.00508.x

A paper on balance and localization has been published

Greybush, S. J., E. Kalnay, T. Miyoshi, K. Ide, and B. R. Hunt, 2011: Balance and Ensemble Kalman Filter Localization Techniques. Mon. Wea. Rev., 139, 511-522. doi:10.1175/2010MWR3328.1

A paper on ozone data assimilation has been published

Sekiyama, T. T., M. Deushi, and T. Miyoshi, 2011: Operation-Oriented Ensemble Data Assimilation of Total Column Ozone. SOLA, 7, 41-44. doi:10.2151/sola.2011-011

A paper on WRF-LETKF has been accepted

Miyoshi, T. and M. Kunii, 2011: The local ensemble transform Kalman filter with the Weather Research and Forecasting model: experiments with real observations. Pure and Appl. Geophys.. doi:10.1007/s00024-011-0373-4