Assessing the Effect of Paddy on Ambient Air Temperature
Date Issued
2005
Date
2005
Author(s)
Kuo, Fang-Tzu
DOI
zh-TW
Abstract
Because of deep water, the vigorous evapotranspiration and the higher heat capacity are the major characteristics of paddy fields which definitely have the functions of regulating thermal current, easing air and surface temperature, and adjusting humidity and other variations, such as cooling effect of daytime and shortening diurnal difference of temperature. The predecessors assessed the cooling effect of paddy field on ambient environment by remote sensing, it only use surface temperature without considering the change of air temperature. By selecting Taoyuan as the site of field measurement, the research will shows the transformation of four landcovers by measuring their surface and air temperatures. Otherwise, it is expected to assess the effect of paddy on ambient air temperature by combining the satellite images of multi-time, multi-spectrum and multi-space resolution.
The main research contents are: (1) The process of images: It is going to treat geometric correction and detect cloud in NOAA satellite images. (2) Landcover classification: it is expected to use the maximum likelihood classifier to classify by multi-spectrum SPOT images. (3) Field measurement: it is expected to set a transformation between surface and air temperature. (4) Estimating surface temperature of four landcovers: the major method is least square regression.
The result of the research shows the value of in the transformation between surface and air temperature by field measurement is near 0.91. With the increasing percentages of paddy fields, air temperature and diurnal difference of surface temperature will decrease. Otherwise, comparing the most and the least percentages of paddy fields, the difference of air temperature could be 2.83℃; the diurnal difference of surface temperature could be 4.03℃. However, the increasing percentages of buildings will show a contrast result since the difference of air temperature could be 2.04℃ and the diurnal difference of surface temperature could be 6.27℃ by comparing the most and the least percentages of buildings. In other words, the cooling effect and shortening the diurnal difference of temperature would be significant with the increasing percentages of paddy fields.
Subjects
水田
遙測影像
涼化作用
日夜溫差
NOAA影像
paddy field
satellite image
cooling effect
diurnal difference of temperature
NOAA image
Type
thesis