Publications

Qiu, JL; Yang, XK; Zheng, ZH; Tarolli, P (2025). High-resolution mapping of China's flooded croplands. SCIENCE BULLETIN, 70(7), 1165-1173.

Abstract
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 croplands, or 2.82% to 7.45% of the annual rice cropland. In comparison, the inundated maize cropland fluctuated from 2619 km2 to 5397 km2, representing 5.38% to 13.56% of the annual flooded croplands. Our findings revealed extensive floods in rural areas, highlighting the urgent need to prioritize flood prevention and mitigation efforts in such regions. In light of China's allocation of an additional 1-trillion-RMB treasury bonds for water infrastructure projects, the high-resolution flood maps can be used to select sites for flood control projects, and evaluate the impact of flooding on crop yields and food security, thus targeting poverty alleviation in rural areas of China. (c) 2025 The Authors. Published by Elsevier B.V. and Science China Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

DOI:
10.1016/j.scib.2025.01.053

ISSN:
2095-9281