Accumulation Sea Ice Concentration (ASIC) is developed to quantitatively measure the regional difference of Arctic sea ice concentration. During the periods of 1979-1989, 1989-1999 and 1999-2009, the linear trends of ASIC in melt period (April-September) and in ice-formation period (October-March) were obtained from SSMR/SSMI sea ice concentration, respectively. Retrospective analysis reveals that there exits greater areas, where dramatic change happens for ASIC in melt period than in ice-formation period. It is revealed that during 1998-2010, in most areas where sea ice was rapidly melted, sea ice amount did not yet decrease in ice-formation period. These areas of ASIC in melt period decreased and in ice-formation also decreased in Chukchi Sea, northern Nova Zembla, and the east and west coast of Greenland. These areas of ASIC in melt period decreased and in ice-formation did not obviously change in Beaufort Sea, East Siberian Sea, Laptev Sea and eastern Kara Sea, where sea ice was influenced by continental runoff. Continental runoff can accelerate the melt of sea ice in melt period and can accelerate the freeze of sea water in ice-formation period. It is concluded that its action is enough to compensate for the delay due to regional sea water absorbing more radiation in summer, as a result of freezing sea ice on time in these areas. The area of ASIC in melt period decreased and in ice-formation increased only in Bering Sea. Conclusively, ASIC is regarded as a useful parameter presenting low frequency of sea ice change and eliminating the high frequency, and is used to illustrate annual variation characteristics of sea ice. Meanwhile, due to sea ice change consistent with other parameters in sea water, using ASIC can better understand the change of sea water’s properties. There is a negative correlation between ASIC calculated by changeable time-scale and the depth of subsurface chlorophyll maximum layer.