台湾花东纵谷河床新兴地果园内之风向与风速变化

研究自2007年11月至2010年1月于台湾东部花东纵谷区域之台东县鹿野乡河床新兴地番荔枝栽植区，择定一面积32 000 m²之番荔枝果园为试区（22°56’56.4″N，121°8’56.4″E），果树平均高度为2.2 m，树龄5 a以上。先利用观测铁塔于距离地面2.5 m及6 m处来测定风向及风速，再藉分析以探讨该果园内之气流行进分布特性。结果表明:花东纵谷南部区域河床新兴地于每日出现逐时平均风速趋近静风状态时，可作为区分昼夜间风场特性之依据，而昼夜间之时段分别为7:00—19:00及20:00至翌日6:00。当强盛偏北气流行进至花东纵谷区域河床新兴地之风场内，区域内风速会在1.0 h内激增，且于果园试区内果树冠层上0.3 m高度之风速达3.8 m/s，对于果树之枝干将产生摇曳不止的情形，将造成果实易受磨损及不利果树生长。

The Variation of Wind Direction and Wind Speed in an Orchard Reclaimed on Riverbed Land in the East Rift Valley of Taiwan

This study aimed at the airflow variation of an orchard on reclaimed land from riverbed in the East Rift Valley of Eastern Taiwan.The experimental site was a sugar apple orchard with area of 32 000 m2 and reclaimed from the riverbed of Luye River,located in Luye Hsiang,Taitung Hsien,Taiwan,near to southern East Rift Valley.The anemometers with 2.5 m and 6 m height above ground surface were set on the observational tower which had been set in middle side of the experimental orchard from November,2007 to January,2010.The mean height of sugar apple tree canopy was 2.2 m and the age was over 5 years.The results had summarized as,the hourly mean wind speed was close to zero twice a day,and it could be easily to distinguish the wind field variation of daytime(7:00 am—7 :00 pm) and 8:00 pm—6:00 am).The north strong breeze inlet the southern East Rift valley could result in the wind speed in apparent increasing tendency with one hour,then the wind speed above fruit tree canopy with 0.3 m height was over 3.8 m/s.The strong breeze continually swayed the fruitage would result in the frictional damage and that was harmful for fruit tree growth.