Data from Tsinghua University (http://data.ess.tsinghua.edu.cn.) Based on the long time-series Landsat optical imagery (nearly 1.5 million views) and other auxiliary data (nighttime light data and Sentinel-1 radar data), the rapid mapping of year-by-year impervious surfaces was firstly realized by spatial mask and feature evaluation ( “Exclusion-Inclusion”) algorithm realizes rapid mapping of impervious surfaces from year to year, and then the temporal consistency check (“Temporal Consistency Check”) algorithm is applied to the initial sequence of impervious surfaces. The initial impervious surface sequence is then subjected to temporal domain filtering and transformational logic reasoning by the Temporal Consistency Check (“TCC”) algorithm, which ensures the temporal and spatial rationality of the acquired impervious surface sequence.

  To address the difficulty of impervious surface mapping in the global arid zone, the research group introduced Sentinel-1 radar data and nighttime light data, which significantly improved the mapping accuracy of the product in the arid zone compared with previous studies. By analyzing the accuracy evaluation of typical years, it can be seen that the average overall accuracy of GAIA exceeds 90%. Meanwhile, comparing the major urban data products in the world, GAIA is found to be more reasonable in terms of the magnitude of the urban area and the temporal characteristics.

  Data research collation of impervious surface in the lower reaches of the Yangtze River, the impervious rate in the lower reaches of the Yangtze River rose from 1.2% in 1985 to 17.6% in 2018, the time course change on the general presentation of the characteristics of the first slow and then fast and tend to flatten out, the performance of the pre-2000 slow increase in the rate of growth of 0.27%/a, the growth rate of the impervious rate in the period of 2000-2010 increased markedly to reach 0.44%/a,. And by 2010-2016, the growth rate increased to 0.99%/a, and 2016-2018 entered a relatively flat phase.

  From the perspective of each province, the impervious rate of high and low ranking for Shanghai > Taihu Lake Basin > Jiangsu Province > Zhejiang Province > Anhui Province; in general, Shanghai, Jiangsu Province, Zhejiang Province and Taihu Lake Basin also presents with the lower reaches of the Yangtze River out of a similar time course of change, the rate of imperviousness of Anhui Province in the long term in a slow increase in the status of the rate of growth in 2010, but the rate of growth in the years after an increase in the rate; provinces in 2016 after the impervious rate of growth show a significant slowdown trend, which has a certain relationship with the construction of sponge city low impact development facilities. growth rate slowed down significantly, which is related to the construction of low impact development facilities in sponge cities.