坡地檳榔園之微氣候特性

Microclimatic Characteristics of Betel Palm Plantation On Slopeland

徐森雄(Sen-Hsiung Hsu) ； 唐琦(Tang Chi)

《中華林學季刊》 37卷2期 (2004/06) Pp. 169-180

https://doi.org/10.30064/QJCF.200406.0005

摘要

本研究由1999年1月至2000年2月止，於南投縣水里鄉上安村內，選取檳榔園設置微氣候觀測塔，觀測項目有氣溫、濕度、地溫、風向、風速、全天日射量、淨輻射量、地中傳導熱量、降雨量共九項，藉以探討坡地檳榔園之微氣候特性，期對坡地檳榔園經營管理及相關研究提供參考。初步獲致結果如後，檳榔冠層與其下空間之氣溫差異並不明顯。園內全天之地表下2 cm 處地溫大於冠層問氣溫有1.9~3.3℃，將使園內空氣不易形成逆溫分布，而有利於園內之空氣流通。檳榔冠層稀疏使園內地面能於日間直接吸收部分太陽輻射，及夜間因冠層遮蔽會減緩地面長波輻射冷卻，致在低溫季節中仍有較高之地溫。冠層下之相對濕度略大於冠層間者約3~4％，而冠層問之相對濕度幾近相同，當較強之陣風出現時，會引發其園內空氣中之相對濕度降低。另氣流於流動時會受地物阻礙及地形崎嶇所產生之摩阻效應影響，會使檳榔園內之日平均風速介於0.2~1.4 m/s，呈現一弱風狀態。檳榔園之地中傳導熱量、顯熱及潛熱分佔淨輻射量之比例為：23. 3、27. 6及49.1％。而檳榔樹冠覆蓋係屬稀疏者，其園內地表將能有較多之地中傳導熱量，經L/Rn比例可知其對於調節氣溫效果應與高大喬木之效果相近，再經ℓE/Rn比例可知檳榔之潛熱應會大於高大喬木。較高的檳榔植被高度下，將使晝間之L及B滯後Rn約0.5~2及2~4小時達到最高值，但ℓE與Rn間卻無滯後情形。

關鍵字

檳榔園 ； 微氣候 ； 坡地

並列摘要

The objective of this study was to understand the microclimate of betel palm plantation on slopeland. The microclimate in the betel palm plantation of Shan-Ann village, located in the Shuli, Nan-Tao Hsien, including air temperature, relative humidity, earth temperature, wind direction, wind speed, global solar radiation, net radiation, soil heat flux and rainfall was recorded from Jan.1999 to Feb. 2000. The primary results could be summarized as follow. There was not apparent temperature difference between canopy and ground surface in betel palm plantation. Earth temperature at 2 cm depth was more than canopy’s by 1.9 to 3.3 t inside betel palm plantation. It means that the radiation inversion would not be occured when the air near the ground surface is warmer than the air higher up, and this is advantageous to air circulation inside betel palm plantation. The sparse canopy of betel palm would be able to increase the ground surface receiving from the solar rays at daytime, and decrease the ground by radiating its energy to outer space at nighttime. Therefore, it would cool slowly at nighttime, and the ground could maintain a higher temperature in cold weather. The relative humidity under canopy was higher than inside canopy itself by 3 to 4%, the relative humidity in canopy was not significantly different. When mountain and valley breezes developed along mountain slopes would not preserve the betel palm plantation’s water vapor content in the air. Wind blowing over the betel palm plantation could result a small eddy of air by friction of geomorphology and ground vegetation, and then the average wind speed was about 0.2 to 1.4 ms’. In terms of heat budget in betel palm plantation, the mean proportion of soil heat flux (B), sensible heat (L) and latent heat (ℓE) to net radiation were 23.3, 27.6 and 49.1%, respectively. The sparse canopy of betel palm had achieved the higher soil heat flux magnitudes found. The regulated effect of air temperature for the betel palm plantation within lower L/Rn ratio was similar to that of tall trees. The latent heat flux of betel palm plantation should be higher than tall trees because the higher ℓE/Rn ratio. The higher canopy of betel palm would make L and B be delayed behind Rn to reach the maximum value, which the lags of time are, respectively, 0.5-2 and 2-4 hours, but ℓE was varied with Rn at the same time

並列關鍵字

Betel palm plantation ； Microclimate ； Slopeland