A Comparison of Different Ground-based Radiative Temperature Measurement Methods on the Field Patch Scale
Received date: 2009-02-04
Revised date: 2009-06-05
Online published: 2009-07-10
Thermal camera，widely used in situ measurement of land surface temperature(LST), has an advantage of obtaining component brightness temperature. A simultaneous airborne, satellite-borne, and ground-based remote sensing field campaign was carried out in the Heihe River Basin of northwest China from May to July, 2008. The radiative temperatures were obtained by two portable infrared radiometers and one thermal camera at the maize field patches around the weather station in Yingke Oasis Area with three different sampling schemes. Average temperatures of the field patches were extracted with those data. The thermal camera′s data was processed as: Firstly, maize and the soil were separated by statistical threshold of radiative temperatures in thermal images, and then their mean radiative temperatures were calculated, respectively. Secondly, with the LAB color space transform technique, the vegetation fraction of each field patch is estimated from visible photos taken simultaneously. Finally, each patch′s mean radiative temperature was obtained by the sum of the component temperatures of maize and soil weighted by vegetation fraction cover. By comparing of the mean radiative temperatures obtained by the thermal camera and portable radiometers sampling in cross-row and along-row direction, we found that their differences are small, and between -1 and +1 . But, both maximum and minimum temperatures of the three methods differ a lot. By simulation on different reliability levels, we also obtained the numbers of randomly sampled points on different pixel scales. Our result indicates that it is difficult to obtain an accurate mean brightness temperature of filed patch with just only 1-2 portable radiometers based on the general point-based measure scheme. To get more accurate data for the validation of LST retrieved in different remote sensing pixel scales, new methods and instruments with high temporal and spatial sampling frequencies are required.
YAN An-Jian , LIN Hua-Zhong , WANG Hao-Xing , JIAN Yong-Gang , KANG Guo-Ting . A Comparison of Different Ground-based Radiative Temperature Measurement Methods on the Field Patch Scale[J]. Advances in Earth Science, 2009 , 24(7) : 784 -792 . DOI: 10.11867/j.issn.1001-8166.2009.07.0784
[1] Zhu Huaisong, Liu Xiaomeng, Pei Huan. Summary on retrieval of land surface temperature using thermal infrared remote sensing[J].Arid Meteorology, 2007,25(2):17-21.[朱怀松, 刘晓锰, 裴欢. 热红外遥感反演地表温度研究现状[J].干旱气象, 2007,25(2):17-21.]
[2] Zhang Renhua.Experimental Remote Sensing Model and Its Land Surface Process[M]. Beijing: Science Press,1996.[张仁华. 实验遥感模型及地面基础[M]. 北京：科学出版社,1996.]
[3] Wan Z M, Dozier J. A generalized split-window algorithm for retrieving land surface temperature from space[J].IEEE Transactions on Geoscience and Remote Sensing,1996, 34(4): 892-905.
[4] Xu Xiru, Liu Qinhuo, Chen Jiayi. The remote sensing of land surface temperature[J].Acta Scientiarum Naturalium Universitatis Pekinensis,1998,34(2):248-253.[徐希孺,柳钦火,陈家宜. 遥感陆面温度[J]. 北京大学学报,1998,34(2):248-253.]
[5] Yu Shanshan, Yu Tao, Gu Xingfa, et al. Investigating the gap frequency of a maize canopy using night TIR fata[J].Journal of Remote Sensing,2006,10(5):683-689.[余珊珊,余涛,顾行发,等.利用夜间热红外数据求取玉米冠层孔隙率[J].遥感学报, 2006,10(5):683-689.]
[6] Francois C, Ottlé C, Prévot L. Analytical parameterization of canopy directional emissivity and directional radiance in the thermal infrared. Application on the retrieval of soil and foliage temperature using two directional measurements[J].International Journal of Remote Sensing,1997,18(12):2 587-2 621.
[7] Purevdorj T, Tateishi R, Ishiyama T,et al.Relationships between percent vegetation cover and vegetation indices[J].International Journal of Remote Sensing,1998, 19(18): 3 5193 535.[ZK)]
[8] Gitelson A A, Kaufman Y J, Stark R,et al.Novel algorithms for remote estimation of vegetation fraction[J]. Remote Sensing of Environment,2002, 80(1): 76-87.
[9] Zhang Wenbo,Fu Suhua, Liu Baoyuan. Error assessment of visual estimation plant coverage[J].Journal of Beijing Normal University (Natural Science), 2001, 37(3): 402-408.[章文波, 符素华, 刘宝元.目估法测量植被盖度的精度分析[J].北京师范大学学报:自然科学版, 2001, 37(3): 402-408.]
[10] Zhang Yunxia,Li Xiaobing, Chen Yunhao. Overview of field and multi-scale remote sensing measurement approaches to grassland vegetation coverage[J].Advances in Earth Science,2003,18(1): 85-93.[张云霞, 李晓兵, 陈云浩.草地植被覆盖度的多尺度遥感与实地测量方法综述[J].地球科学进展, 2003, 18(1): 85-93.]
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