夏季半島寬度對於對流雲生長的影響

The Effect of the Width of a Peninsula on the Growth of Convective Clouds in Summer

簡長祿(Charng-Lue Jean) ； 陳景森(Ching-Sen Chen)

《大氣科學》 14卷1期 (1986/09) Pp. 53-62

摘要

利用二維雲模式，研究夏季沿海地區對流雲的產生與發展。並檢討對稱性半島寬度所產生的輻合作用，對於對流雲生成的影響。結果顯示半島寬30～50公里間兩岸的海風，在半島中心所產生的輻合，比10、20公里的半島更有利於對流雲的生成。更寬的半島在海風尚未到達半島中心之前，就已經發展出對流雲系，但成雲的時間卻比較晚。一旦海風移進半島中心，卻能夠產生更強的對流雲。而更窄的半島，海風很早移進半島中心。因而減低地面熱量的往上擴散，進而減弱對流的發展。因此在10公里的窄半島上，較少觀測到積雲的生成。

並列摘要

Using a two-dimensional cloud model, we study the generation and development of convective clouds over the coastal area in summer. We emphasize on the convergent effect of the width of a symmetric peninsula on the genesis of convective clouds in dry seabreeze day. Results show that the convergence of seabreeze at the center of a peninsula between 30 and 50 km is more effective to the growth of convective clouds than that of 10 or 20 km. For more wide peninsula before the seabreeze arrive at the center of a peninsula, the convective clouds have already developed. However the time for the formation of clouds is longer. When seabreeze reaches the center of a peninsula, it can strengthen the intensity of convective clouds. For a narrow peninsula, seabreeze moves to the center very quickly to slow down the upword diffusion of surface heat thro ugh our parameterization scheme. Therefore the development of convections is inhibited. This is the reason why the clouds is rare to be observed in a narrow peninsula like 10 km width.