Monitoring freeze-up and break-up dates of Northern Hemisphere big lakes using passive microwave remote sensing data

Historic freeze-up and break-up dates of lake can record the regional climate variability. Observations of lake ice from different regional or country´s stations are inconsistent and their number was declined in past two decades, which makes climate change analysis difficult. This paper proposes a dynamic threshold method to derive the freeze- up and break-up dates of big lakes using passive microwave brightness temperature data. Lake ice information from 35 big lakes in Northern Hemisphere is retrieved in past three decades. These freeze-up and break-up dates were validated from 18 stations´ observations. The linear correlation coefficients between observations and retrievals are 0.926 for freeze-up dates and 0.936, respectively.