High-resolution mapping of China's flooded croplands

Climate change and the increasing frequency of floods have undermined China's food security. Creating detailed maps of flooded croplands is essential to improve prevention and adopt effective adaptation initiatives. Previous large-scale flood mapping efforts were hampered by limited meteorological and hydrological data, and the susceptibility of optical satellite images to cloud cover, leading to high uncertainty when downscaled to the cropland-scale. Here, using 4968 near-real-time (NRT) Sentinel-1 SAR (S1) images (spatial resolution: 10 m), we generated China's first set of high-resolution flooded cropland maps covering the period from 2017 to 2021. Our results demonstrate that croplands accounted for 43.8% to 49.8% of China's total flooded areas (ranging from 82,175 km2 to 122,037 km2). We also created high-resolution flood maps specifically for rice and maize crops. The inundated rice areas ranged from 8428 km2 to 22,123 km2, accounting for 22.34% to 41.91% of the annual flooded cr...