基于可见光红外成像辐射仪数据的地表温度反演

    Retrieval land surface temperature from visible infrared imager radiometer suite data

    • 摘要: 地表温度是农业旱灾和作物估产模型的重要参数。该文针对可见光红外成像辐射仪(visible infrared imager radiometer suite,VIIRS)传感器缺乏水汽通道的特点,联合Aqua卫星搭载的中分辨率成像光谱仪(moderate-resolution imaging spectroradiometer,MODIS)数据提出了基于分裂窗算法的VIIRS地表温度反演方法。对地表发射率和大气透过率这2个关键参数的获取进行了详细分析,选取了处于作物生长期的2013年6月4日VIIRS数据进行实例验证分析。结果表明,与全国气象数据比较该文算法在大尺度上能够较好地获取中国地表温度;与MODIS数据温度产品在高温产粮区比较,该文算法与MODIS温度产品精度较一致,两者差值小于1 K。使用MODTRAN(moderate resolution transmission)软件对算法的精度进行了模拟评价验证,分析表明:在一定的水汽和地表发射率条件下,算法反演精度一般保持在1 K内,平均误差为0.431 K,误差标准偏差为0.247 K。能够为农业干旱、作物长势等农情信息监测提供所需的地表温度数据。

       

      Abstract: Abstract: The land surface temperature is a basic parameter which had been widely used in agriculture drought monitoring, crop monitoring and the yield forecasting model. In this study, we developed a split-window algorithm to retrieve land surface temperature from VIIRS (visible infrared imager radiometer suite) data which can overcome the lack of the water channel. The key parameter of water vapor content required by algorithm is obtained from MODIS data which is board on an Aqua satellite, and the emissivity computed from international geosphere biosphere program (IGBP) global vegetation classification. The character of the VIIRS data was briefly introduced and the method of estimation of the transmittance of atmosphere and emissivity of the VIIRS M15 and M16 channels also been discussed. Then, a VIIRS data imaging on June 4, 2013 has been chosen to verify the accuracy of the algorithm. By comparison with the global surface summary of day (GSOD) data, the result indicates that the method we proposed can retrieve the land surface temperature in china very well. Comparison with the MODIS LST data in the grain producing area with a surface temperature greater than 45℃ shows that the precision of the algorithm is high and the retrieval error is less than 1 K. Finally, the accuracy assessment of the method was performed with the moderate resolution transmission 4 (MODTRAN4) program. The water vapor content is set to 1.0 g/cm2, 2.2 g/cm2, 3.4 g/cm2, the surface temperature is 295 K, 310 K, 325 K, and the land type of dry soil and green vegetation with the emissivity of 0.963, 0.984 (VIIRS M15) and 0.974, 0.992 (VIIRS M16), respectively. The simulation analysis indicates the accuracy of this algorithm is greater than 1 K with the root mean square (RMS) errors 0.516 K and the average error 0.447 K. The much higher accuracy of the method confirms the application of the algorithm in agricultural information from VIIRS data is available.

       

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