11 μm 휘도온도와 11-12 μm 휘도온도차의 상관성 분석을 활용한 해빙탐지 동적임계치 결정

Sea ice which is an important component of the global climate system is being actively detected by satellite because it have been distributed to polar and high-latitude region. and the sea ice detection method using satellite uses reflectance and temperature data. the sea ice detection method of Moderate-Resolution Imaging Spectroradiometer (MODIS), which is a technique utilizing Ice Surface Temperature (IST) have been utilized by many studies. In this study, we propose a simple and effective method of sea ice detection using the dynamic threshold technique with no IST calculation process. In order to specify the dynamic threshold, pixels with freezing point of MODIS IST of 273.0 K or less were extracted. For the extracted pixels, we analyzed the relationship between MODIS IST, MODIS 11 μm channel brightness temperature(T11 μm) and Brightness Temperature Difference (BTD: T11 μm-T12 μm). As a result of the analysis, the relationship between the three values showed a linear characteristic and the threshold value was designated by using this. In the case of sea ice detection, if T11 μm is below the specified threshold value, it is detected as sea ice on clear sky. And in order to estimate the performance of the proposed sea ice detection method, the accuracy was analyzed using MODIS Sea ice extent and then validation accuracy was higher than 99% in Producer Accuracy (PA).