Abstract:

In order to timely monitor the cold damage conditions of cotton by remote sensing, arrange disaster relief and assessment, cotton image characteristic parameter and vegetation index change were analyzed. Applied July 25, 2001 and August 10, 2001 ETM+ data, the NDVI of DN values, radiance and planetary reflectance were formed through the geometric correction, radiometric correction and conversion of planetary reflectivity. Then, the cotton field characteristic parameter and spectral signatures change situation were analyzed on July 28, 2001 to August 1, 2001. The results showed that the previous image of the DN value, radiance, mean planetary albedo were higher than that of the subsequent image 29.07%, 30.1%, 3.15%, the previous image physical quantities were larger 67.5%, 40.3%, 33.3% than the subsequent image in the variance, while the values of mean NDVI decreased 21.6%, 19.57%, 12.79%. High-resolution remote sensing data can be indirectly affected by low-temperature injury changes in cotton fields. It is an effective method to monitor the strong low-temperature injury and provide quantitative indexes for disaster assessment.