Abstract: Lake ice phenology is considered a sensitive indicator of regional climate change. Qinghai Lake is the largest saltwater lake in China. Its lake ice phenological characters and changes have attracted much attention. Based on remote sensing datasets including the MOD09GQ surface reflectance product and Landsat TM/ETM+/OLI images, a dataset of lake ice phenology in Qinghai Lake from 2000 to 2018 was built by using RS and GIS technologies. Due to spectral differences between lake ice and lake water, the method of threshold segmentation was adopted to extract the ice area of Qinghai Lake based on MOD09GQ product, which was achieved by setting a reflectance threshold for red band and a reflectance difference threshold between red and near-infrared bands. The extracted ice area was then validated against the visually interpreted ice area based on Landsat TM/ETM+/OLI images, which showed a relative error of 0.8％ only. This dataset includes ice-water vector boundary data, area ratio, and phenological characters in Qinghai Lake from 2000 to 2018. Specifically, phenological information records the start and end dates of lake freeze-up and break-up, freeze-up periods, etc. This dataset provides an important reference for exploring the spatio-temporal characteristics of lake ice in Qinghai Lake, as well as for formulating responses of lake ice-based climate changes in the region.
Keywords: Qinghai Lake; MODIS; lake ice phenology; threshold method