关键词: 辐射增量, 人工火场, MODIS

Abstract: [Objective] Radiation increment caused by forest fire is a vital parameter in using the remote sensing technique. In this paper, to provide reference for forest fire monitoring and research, the ground and artificial satelite syncharonous observation experiment are carried out, and then, radiation increments of MODIS bands at No.20,21,22,31 and 32 are calculated. [Method] Radiation parameters were acquired through the ground observation experiment of artificial fire scene and satellite synchronous observation. First, surface background data were extracted using TM data of 30 meters resolution. Second, the land around the artificial fire was divided into three categories of vegetation, bare and water which were taken as pixel endmember of MODIS data of 1 kilometers resolution. Finally, according to the linear mixed theory, radiation estimation models of MODIS channel No.20,21,22,31 and 32 were constructed without fire scene influence, then the above channel's radiation increments of artificial fire scene were calculated. [Result] 1) Correlation coefficients of MODIS radiance estimation model samples are all over 0.99; 2) MODIS radiance estimation model is used to calculate bright temperature increment. It shows that MODIS bands No.20, 21 and 22 are highly sensitive to surface thermal radiation with increment of 9.35, 7.49 and 8.00 K respectively while bands No. 31 and 32 are insensitive to high-temperature heat source with increment of 1.13 and 0.83 K respectively.[Conclusion]1) Fire scene area of 200 m² (ratio of fire scene area to pixel size is 1:5000) can be detected, it is of great significance for error identification, fire detection and area estimation in further study; 2) Pixel segmentation phenomenon exists in satellite observation and these phenomenon could easily lead to over-calculated fire points and overestimate its area. In our experiment, artificial fire is mainly within No.13 pixels but No.14 pixel is also influenced by the fire with its radiation increment of 4.08 K. Thus, the artificial fire may be within No.13 and 14 pixel simultaneously. 3)Methods and conclusions of this paper are suitable for mid-resolution remote sensing data, such as FY-3.

Key words: radiation increment, artificial fire, MODIS