Tropical Plume에 대한 TOVS 추정 가강수량의 평가와 상호비교 = Evaluation and Intercomparisons of the Estimated TOVS Precipitable Waters for the Tropical Plume

국문 초록 (Abstract)

열대 및 아열대 태평양상에서 TOVS(Tiros Operational Vertical Sounder) 가강수량의 추정을 위한 모형을 사용하여 열대 기상 중 하나인 TP(Tropical Plume) 또는 Flare-up 현상의 수증기장을 분석하였다. 전가강수량 모형 (71.1%의 변량과 0.62 g cm-2의 표준편차)와 중대류고도 모형(71.7의 변량과 0.17 g cm-2의 표준편차)을 선택하여 Tropical Plume 현상에 대한 TOVS 가강수량, ECMWF(European Centre of Medium Range Weather Forecasts) 가강수량, SMMR(Scanning Multichannel Microwave Radiometer) 가강수량과 OLR(Outgoing Longwave Radiation)을 상호비교하고 평가하였다. TOVS 가강수량 모형으로는 Tropical Plume이 단지 초기단계인 상층운과 얇은 중층운으로 이루어졌을 때는 이 현상을 식별하기 어려웠으나 발달단계인 상층운과 짙은 중층운이 존재할 때는 이 현상이 뚜렷하였다. ECMWF 가강수량은 종관 기상현상은 잘 설명하였으나 Tropical Plume은 뚜렷하지 않았으며, 열대 수렴대와 남태평양 수렴대에서는 대체로 TOVS 가강수량보다 과습하였다. SMMR 가강수량도 TOVS 가강수량과 비슷한 현상을 보였으나 특히, OLR은 Tropical Plume 현상이 가장 뚜렷이 나타났다.

다국어 초록 (Multilingual Abstract)

Precipitable Waters(PW) are retrieved over the tropical and subtropical Pacific Ocean from TOVS infrared and microwave channel brightness temperature and OLR observations by means of stepwise linear regression. The retrieved TOVS PW fields generated by PWsfc(71.1% of the variance and 0.62 g cm-2 standard error over the surface) and PW7005l0(71.7% and 0.17 g cm-2 over the 700-500 hPa layer) revealed more evolving synoptic signals over the tropical and subtropical Pacific Ocean. The PWsfc does not show significantly the TP feature because of the representation of the lower PW for high-level clouds not associated with deep convection. There exists some elusion to trace the TP on the PWsfc field if any supplementary information does not provide. But ECMWF analysis has a general tendency of drying the subtropics and moistening the ITCZ (InterTropical Convergence Zone) and SPCZ(South Pacific Convergence Zone). However, although ECMWF analysis is fairly successful in capturing mean patterns, it is unsuccessful in following active synoptic signal like a tropical plume. Similarly, SMMR-PW does not represent the TP well Which consists of the high- and middle-level clouds, but PWsfc shows underestimated moistness of TP and does not depict significant signal of TP. In the PW field derived from microwave observations, the TP can not be recognized well. Furthermore, the signature of PWsfc was different from OLR for the TP, which implies the presence of high- and middle-layer thin clouds, but in a closer agreement for deep and active convection areas which contain thick middle- and lower-layer clouds; though OLR represented the cloudiness in the tropics well. In synoptically active regions, it differed from OLR analysis, primarily because of actual differences in water vapor and cloud features. The signature of PWsfc was different from OLR for the TP.