| 摘要 |
A method for measuring yellow sand is provided to improve measurement errors generated in detecting yellow by using an infrared ray wavelength region, and to allow easy access to the information about yellow sand. A method for measuring yellow sand comprises the steps of: expressing the data of images taken by a satellite at IR channels of 3.7, 11 and 12 micrometers in any region having yellow sand into the form of brightness temperature data of BT1K, BT2K and BT3K; calculating the difference in brightness temperature between the 11 micrometer channel and 12 micrometer channel, and between the 3.7 micrometer channel and 11 micrometer channel from the data obtained in the preceding step according to the formulae of BTD1= (BT2- BT3) and BTD2= (BT1- BT2); correcting BTD1 and BTD2 by using an atmospheric radiation model considering the factors affecting the IR channel, including the ground surface temperature, energy emission of the ground surface, the spectrometric sensitivity function of each IR channel sensor, and the zenith angles of the satellites; extracting the data belonging to the ranges of -3 K<= BTD1<=0 K and 0 K<= BTD2<=45 K from the corrected BTD1 and BTD2 so as to remove the effect of clouds; converting the data of BTD1 and BTD2 into a magnitude between 0 and 100 and expressing the data as yellow sand indexes for each of the land zones and sea zones.
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