Monitoring of sea ice in Far East Russia

In Far East Russia, the Sea of Okhotsk is covered by sea ice in winter every year. The Amur River plays an important role of generating sea ice. Sea ice goes south by the monsoon. In this paper, we present a four-dimensional histogram method and a threshold method for detecting the sea ice pixels of NOAA AVHRR images. We used 699 scenes from February to March for five years from 1995 to 1999. We chose 179 scenes to create the four-dimensional histogram. We applied the four-dimensional histogram to detect the sea ice area of the Sakhalin region. As the result of applying the presented method, thin ice was detectable. However, thick ice was undetectable. Thin ice is very important because it is generated along the coast line of the continent, and it has a great affect on the ecosystem. Thick ice is detectable by using the threshold method. We confirmed that clouds and sea ice were distinguishable in our method by comparing the detection results of the presented method with that of the oceanography researcher. We demonstrate the effectiveness of the presented method by monitoring the sea ice area for several years