마이크로파 위성관측과 모델 재분석에서 조사된 전지구에 대한 하부 성층권 온도의 추세 = Lower Stratospheric Temperature Trends Derived from the MSUs and GCM reanalyses, and its Temporal and Spatial Variability

다국어 초록 (Multilingual Abstract)

In order to examine the relative accuracy of satellite observations and model reanalyses about lower stratospheric temperature trends, two satellite-observed Microwave Sounding Unit (MSU) channel 4 (Ch 4) brightness temperature data and two GCM (ECMWF and GEOS) reanalyses during 1981-93 have been intercompared with the regression analysis of time series. The satellite data for the period of 1980-99 are MSU4 at nadir direction and SC4 at multiple scans, respectively, derived in this study and Spencer and Christy(1993). The MSU4 temperature over the globe during the above period shows the cooling trend of -0.35 K/decade, and the cooling over the global ocean is 1.2 times as much as that over the land. Lower stratospheric temperatures during the common period (1981-93) globally show the cooling in MSU4 (-0.14 K/decade), SC4 (-0.42 K/decade) and GEOS (-0.15 K/decade) which have strong annual cycles. However, ECMWF shows a little warming and weak annual cycle. The 95% confidence intervals of the lower stratospheric temperature trends are greater than those of midtropospheric (channel 2) trends, indicating less confidence in Ch 4. The lapse rate in the trend between the above two atmospheric layers is largest over the northern hemispheric land. MSU4 has low correlation with ECMWF over the globe, and high value with GEOS near the Korean peninsula. Lower correlations (r<0.6) between MSU4 and SC4 (or ECMWF) occur over 30 N latitude belt, where subtropical jet stream passes. Temporal correlation among them over the globe is generally high (r>0.6). Four kinds of lower stratospheric temperature data near the Korean peninsula commonly show cooling trends, of which the SC4 values (-0.82 K/decade) is the largest.