제목: Effects of assimilating additional observations on weather forecasts over polar regions​​​​​

장소: 과학관 B102호 

Abstract:

In polar regions, the number of conventional observations (e.g., radiosonde observations) is limited compared to midlatitudes, and satellite radiance observations are not fully assimilated due to unique surface conditions (e.g., snow and sea-ice). Therefore, it is very important to enhance observational platforms of any type over polar regions in order to improve forecast skills not only in polar regions but also in midlatitude regions. Observing system experiments (OSEs) are widely used in data-impact studies; for example, a certain type of observation is excluded in data denial experiment and it is compared to control experiment that assimilates all observations. Radiosonde observations from the Year of Polar Prediction in the Southern Hemisphere (YOPP-SH) and ship-borne radiosonde observations from the Korean ice breaking research vessel, Araon provide opportunities to investigate effects of assimilating additional observations on weather forecasts over Antarctica and the Arctic, respectively. Using the polar-optimized Weather Research and Forecasting model (Polar WRF) and its data assimilation system (WRFDA), data assimilation cycling experiments were conducted. Effects of additional observations on analyses and forecasts were examined by verifying them against reanalysis data and independent observations. Furthermore, spread of the assimilation effects in horizontal and vertical directions was explored by defining a new metric (i.e., total energy of error), and physical linkage between improved analyses and subsequent forecasts was revealed by doing case studies.​