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A study of mapping evapotranspiration at a forested watershed using ballon remote sensing.

使用气球遥感绘制森林流域蒸散发图的研究。

基本信息

批准号：
08456082
负责人：
EBISU Nobuhiro
金额：
$ 4.93万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

The purpose of this study is to estimate the mapping of evapotrans piration at forested areas using Surface Temperature method (S.T.method) which is applied to estimate evapotranspiration using the image data of surface temperature by an infrared radiation thermometer and the energy balance data. The images of surface temperature are obtained using balloon remote sensing of about 100-200 meters height above the ground.The results of this study are listed below :1.The study area is located at Japanese cypress stands in Ehime University forest in 1996. A small balloon was equipped with an infrared radiation thermometer sensor, a control system, a battery and a micro wireless video camera. The measurement of surface temperature by this remote sensing system was carried out for each 15 seconds. The angle of sensor was controlled by an operator who checks the pictures sent through this system. There were obvious differences between the surface temperature of the stands measured from the balloon and from the ground. The evapotranspiration estimated from the balloon is smaller than from the ground. It is considered that surface temperature is more accurate using balloon remote sensing than using the infrared radiation thermometer on the ground.2.The observation was carried out at two study areas of Japanese cypress stands in 1997. These stands were different in aspect and slope angle. The difference of surface temperature at the two plots was 1.8ﾟC on the average. Evapotranspiration using S.T.method at the plot where surface temperature was lower was about 0.28mm/4hr higher than the other plot and evapotranspiration using Bowen ratio method was showed similar values. The balloon remote sensing by S.T.method is a good method for estimating evapotarspiration at wide forested areas with different aspects and slope angles and requires measurement of air temperature, wind speed and net radiation at these plots.

本研究的目的是利用红外辐射测温仪获取的地表温度图像数据和能量平衡数据，利用地表温度法(S.T.法)估算林区蒸散量。利用气球遥感技术在距地面约100-200米的高度获取地表温度图像。研究结果如下：1.研究区域位于1996年爱慕大学森林中的日本柏林中。一个小气球配备了红外辐射温度计传感器、控制系统、电池和微型无线摄像机。该遥感系统每15秒测量一次地表温度。传感器的角度由操作员控制，操作员检查通过该系统发送的图片。气球测得的林分表面温度与地面测得的温度有明显差异。从气球估算的蒸散量比从地面估算的蒸散量小。认为使用气球遥感比地面使用红外辐射温度计更准确。2.1997年在日本柏木林的两个研究区进行了观测。这些林分在坡向和坡度上存在差异。两个地块的地表温度差平均为1.8ﾟC。在地表温度较低的地块，用S.T.法计算的蒸散量比其他地块高0.28 mm/4hr左右，而用Bowen比法计算的蒸散量与用波文比法计算的蒸散量相近。气球遥感是一种在不同坡向和坡度的大面积林区估算蒸散量的好方法，需要测量这些样地的气温、风速和净辐射。