東亞地面紫外線通量的氣候特徵與相關因子的氣候關聯性探討

The Climatological Characteristics of Surface Ultra-Violet Flux over East Asia and Their Climatological Relationship with Other Physical Factors

尤思喻(S. -Y. Yu) ； 柳中明(C. -M. Liu)

《大氣科學》 36卷1期 (2008/03) Pp. 63-82

摘要

本研究選定東亞(88.125°E~151.875°E、3.5°N~47.5°N)範圍，使用TOMS衛星遙測數據，針對一、四、七、十月的資料進行研究，觀察東亞地區近地面紅斑權重紫外線輻射通量(280nm~400nm)及其影響因子間的空間變化關聯性。整體而言，透過長期平均及經驗正交函數分析，近地面紫外線輻射通量與反射率的特徵分佈相關最爲明顯，與臭氧次之，而與懸浮微粒間的相關無合理的關聯性。同時考慮不同地區的差異，將討論的範圍分成六個區域，各區皆呈現總臭氧量逐年減少趨勢。高空總臭氧量的持續減少，原則上會造成地面紫外線輻射通量的逐年增加。不過，若觀察空間分佈關聯性，則地面紫外線輻射通量與反射率的相關性明顯，在各不同區域內，反射率的變動對地面紫外線輻射通量的影響，會較總臭氧量來得關鍵或是明顯。此外，由於TOMS反演近地面紅斑權重紫外線輻射通量的過程中，是使用反射率來處理地表反射、雲與懸浮微粒的衰減影響，而未使用懸浮微粒指數於計算過程中。所以，目前分析顯示該處理方式可能不利於突顯懸浮微粒的影響，即使是在懸浮微粒濃度較高的四月，懸浮微粒指數的變動與近地面紫外線輻射通量間，無合理的關聯性存在。

關鍵字

地面紫外線輻射通量 ； EOF分析 ； 影響因子探討

並列摘要

This study adopts the remote sensing data released by NASA TOMS over the East Asia region (88.125°E-151.875°E, 3.5°N~47.5°N) and focuses on the climatological characteristics of the surface erythermal-weighted ultra-violet (UV) flux (280-400nm) in January, April, July and October. Through long-term mean and empirical orthogonal function analysis, the results suggest that the characteristics of UV are highly correlated with the distribution of reflectivity, then with the total column ozone. There is negligible relationship between UV and aerosol index. The East Asia region has been sub-divided into six sub-regions. All regions show a clear long-term decreasing trend of total ozone, but no significant increasing trend of UV been detected. The change of UV in each sub-region all correlated well with the change of reflectivity, which suggests the importance of weather system change on affecting the amount of surface UV flux. In the meantime, the retrieved aerosol index was not used in the estimation of UV, hence no recognizable relationship between these two datasets are established, even in April when dust-storm prevails.

並列關鍵字

Surface UV flux ； EOF ； Influencing factor analysis