摘要：Urban settlements are rapidly growing outward and upward, with consequences for resource use, greenhouse gas emissions, and ecosystem and public health, but rates of change are uneven around the world . Understanding trajectories and predicting consequences of global urban expansion requires quantifying rates of change with consistent, well-calibrated data . Microwave backscatter data provides important information on upward urban growth – essentially the vertical built-up area . We developed a multi-sensor, multi-decadal, gridded (0 .05° lat/lon) data set of global urban microwave backscatter, 1993–2020 . Comparison of backscatter from two C-band sensors (ERS and ASCAT) and one Ku-band sensor (QuikSCAT) are made at four invariant non-urban sites (~3500 km2) to evaluate instrument stability and multi-decadal pattern . For urban areas, there was a strong linear correlation (overall R2 = 0 .69) between 2015 ASCAT urban backscatter and a continental-scale gridded product of building volume, across 8450 urban grid cells (0 .05° × 0 .05°) in Europe, China, and the USA . This urban backscatter data set provides a time series characterizing global urban change over the past three decades .
