GDAPS(UM)를 이용한 태풍진로예보오차 원인 평가

Abstract

After the Joint Typhoon Warning Center (JTWC) began issuing official five-day tropical cyclone (TC) forecasts in 2003, the Korea Meteorological Administration (KMA) started issuing official five-day forecasts of TCs in May 2012 after 2 year of beta test. Forming a selective consensus (SCON) by proper removal of a likely erroneous track forecast is hypothesized to be more accurate than the non-selective consensus (NCON) of all model tracks that are used for the five-day forecasts. Conceptual models describing large track error mechanisms, which are related to known tropical cyclone motion processes being misrepresented in the dynamical models, are applied to forecasts during the 2012 western North Pacific typhoon season by the Global Data Assimilation and Prediction System (GDAPS (UM N512 L70)). This model tracks are consensus members used in making KMA's five-day forecasts and thus knowledge of its track error tendencies would be useful in forming a SCON forecast. All 72-h track errors greater than 320 km are examined following the approach developed by Carr and Elsberry (2000a, b). Tropical influences caused 37% (47 times / 126 erroneous forecasts) of the GDAPS (UM N512 L70) large track forecast errors primarily because an incorrect beta effect-related process depicted by the model contributed to the erroneous forecasts. Midlatitude influences accounted for 63% (79 times / 126 error cases) in the GDAPS (UM N512 L70) erroneous forecasts mainly due to an incorrect forecast of the midlatitude system evolutions. It is proposed that KMA will be able to issue more reliable TC track information if a likely model track error is recognized by optimum use of conceptual models by Carr and Elsberry (2000a, b) and a selective consensus track is then the basis for an improved warning.