Analysis of Lake Chany using NOAA images

The temporal analysis of NOAA AVHRR images is effective for observing the Earth´s environment. Especially Siberia has the large influence on the Earth´s environment. The Lake Chany complex is located in the Novosibirsk region between the Ob´ River and the Irtish River. It is effective in investigating an environmental change that there is no river of outflow from the Lake Chany. Our aims of the study in Lake Chany are to measure the seasonal changes in the open water area by using NOAA AVHRR images and to compare NOAA AVHRR images with the data from the ground truth. We developed an analysis system to count pixels for arbitrary area in NOAA AVHRR images. The area is thought to be an underestimate in the neighborhood of the inlet and the channel. It is difficult to measure small inlets or bays exactly because the resolution of NOAA is 1.1 km per pixel. The area of Lake Chany was the largest in spring and decreased until summer. It then became fixed in autumn. We analyzed the results in detail by comparing NOAA AVHRR images with the data from the ground truth including measurements of limnological features. In the waterside of this area, the reed grows gregariously over several km and the reed communities are formed. The vegetations of this area are covered with snow in winter, and the reed remains fallen even when spring comes. So, the reed communities may be recognized as open water on NOAA AVHRR images.