雲對大氣輻射場影響之數值模擬

The Numerical Study of Cloud Effect on Atmospheric Radiation

柳中明(Chung-Ming Liu) ； 歐思真(Steve S. C. Ou)

《大氣科學》 16卷4期 (1988/12) Pp. 409-434

摘要

本研究採用複雜之三層雲模式，詳細分析單層雲，二層雲與三層雲對太陽短波與行星傳送的影響，及其所造成大氣加熱率與冷卻率之垂直特徵，並同時分析不同氣候區內雲影響特性。在短波傳送方面，單層雲的反射效應能加強行星反射率，同時配合雲之吸收特性減少大氣穿透率，此時除卷雲外，最大增溫區均在雲內。當二層雲存在時，多重反射作用能加強卷雲內之增溫現象，並同時減弱下層雲內增溫。三層雲存在時，中層之高層雲（As）則主宰著垂直大氣加熱率分佈特徵。在長波傳送方面，雲的溫室效應明顯造成雲底下方淨輻射通量減少，雲底增溫與雲頂冷卻。二層雲存在時，下層雲附近之冷卻率則受上層雲之溫室效應而顯著減少。三層雲存在時，As雲仍主宰垂直大氣冷卻率分佈特性。在不同氣候區内，由於雲特徵（如雲高、雲厚），以及大氣溫度及水汽含量等特性不同，因此雲對輻射加熱與冷卻率的影響，及行星反射率，大氣穿透率的改變，均不一致。

關鍵字

雲影響 ； 大氣輻射 ； 數值模擬

並列摘要

This research adopts a complicate three-layered cloud radiative transfer model to detailedly analyze the effect of the single-layered cloud, two-layered cloud and three-layered cloud on the solar short-wave and terrestrial long wave radiative transfer, and on the resulted atmospheric heating and cooling profiles. Meanwhile, the study is also extended to different climatic zones. On the short-wave transfer, the cloud albedo effect intensifies the planetary albedo, whereas the cloud absorption causes a significant heating in cloud and the reduction of the atmospheric transmission. The multiple reflection process in a two-layered could system can enhance the heating in the upper cloud and weaken the lower cloud heating. The altrostratus (As) could plays a major role in a three-layered cloud system in generating a vertical heating profile. On the long-wave transfer, the cloud greenhouse effect reduces the flux below could and results is cloud top cooling and cloud bottom warming. In a two-layered could system, the net fluxes near the lower could are reduced through the greenhouse effect of the upper cloud. Again, as cloud dominates the cooling profile a three-layered cloud system. At different climate zones, significant differences in cloud on radiative transfer are noted, causing by the differences in the cloud characteristics, temperature and water vaper profiles.

並列關鍵字

cloud effect ； Atmospheric Radiation ； numerical modeling