Recognition of satellite images, composition of them and vectorization is used in AARI for ice charts production. There is discussed methodology and results of the ice charts processing by means of computer programs, which were elaborated by Dr. Tretyakov in Python. The paper demonstrates results of analysis of temporal variance of ice navigation circumstances within the buffer zone of the marine transport system from the Sabetta Port (the Yamal Peninsula, Russia) up to the Bering Strait. There are considered the variance for April and May from 1998 up to 2020. This intra-annual interval is the one with the heaviest ice circumstances for shipping. We used conditional length of various age and age and form gradations of the sea ice for the route as a whole, as an integral parameter for estimation of the navigation hardships of ice navigation. The conditional length of an ice age (thickness) diapason is result of multiplication of the diapason partial concentration at the length of the route leg with homogeneous ice characteristics. There were produced series of the conditional lengths for each ten-day periods during April and May. Then statistical homogeneity of the series was tested by various methods.