Monitoring of Surface Intraday Frozen Duration Based on Multi-Temporal Passive Microwave Remote Sensing Observations

Xiaokang Kou, Xudong Li, Zhenyi Zu, Bin Zhang, Shuaibing Han, Xinda Liu, Yuzhi Zhang, Tianliang Wang

Abstract: The surface freezing-thawing cycle is an important indicator of global climate change. In current studies, more attention has been paid on the monitoring of daily freezing-thawing changes, but less on the intra-day freezing-thawing changes. While the intraday freeze-thaw cycles are more sensitive to climate change. Thus, in this study, the multi-temporal observations derived from DMSP F15, F16, F17 and F18 in the period of 2015.01.01~2016.12.31 were used to monitoring the intraday freezing and thawing varations. A unified discriminant equation for four kinds of satellites was established. The ground soil temperature measurements from four networks (Naqu, Maqu, Pali and Ali) in the Qinghai-Tibet Plateau were used for the validation. The results show that there is a strong consistency between the intraday frozen duration calculated based on the F/T discrimination results and the in-situ measurements, with a maximum standard error of 12.6 hours in Ali and a minimum standard error of 4.34 hours in Naqu.