Quantifying the Impacts of the 2020 Flood on Crop Production and Food Security in the Middle Reaches of the Yangtze River, China

This study uses satellite imagery and geospatial data to examine the impact of floods over the main planting areas for double-cropping rice and grain crops in the middle reaches of the Yangtze River. During summer 2020, a long-lasting 62-day heavy rainfall caused record-breaking floods over large areas of China, especially the Yangtze basin. Through close examination of Sentinel-1/2 satellite imagery and Copernicus Global Land Cover, between July and August 2020, the inundation area reached 21,941 and 23,063 km2, and the crop-affected area reached 11,649 and 11,346 km2, respectively.

We estimated that approximately 4.66 million metric tons of grain crops were seriously affected in these two months. While the PRC government denied that food security existed, the number of Grains and Feeds imported from the U.S. between January to July 2021 increased by 316%. This study shows that with modern remote sensing techniques, stakeholders can obtain critical estimates of large-scale disaster events much earlier than other indicators, such as disaster field surveys or crop price statistics. Potential use could include but is not limited to monitoring floods and land use coverage changes.

1. Introduction

2. Materials and Methods

2.1. Study Area

2.2. Data Sets

2.2.1. Sentinel-1A/B Data

2.2.2. Sentinel-2 Data

2.2.3. Copernicus Global Land Cover

2.3. Methodology

2.3.1. LULC Map Extracted from Multi-Source Data

2.3.2. Monthly Composite Flooding Map

3. Results

3.1. Spatial and Temporal Variability of Flood Impact Area

3.2. Food Security

4. Discussion

4.1. Rapid Damage Assessment

4.2. Remedial Actions after the Flood

4.3. Apply the Research Results for Other Cases

5. Conclusions

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► See detail:  Quantifying the Impacts of the 2020 Flood on Crop Production and Food Security in the Middle Reaches of the Yangtze River, China

Liang-Chen Wang 1 , Duc Vinh Hoang 2,3 and Yuei-An Liou 2,*
1 Department of Space Science and Engineering, National Central University, 300 Jhongda Road,
Jhongli District, Taoyuan City 320317, Taiwan; 101683006@cc.ncu.edu.tw
2 Center for Space and Remote Sensing Research, National Central University, 300 Jhongda Road,
Jhongli District, Taoyuan City 320317, Taiwan; hoangducvinh@vawr.org.vn
3 The National Key Laboratory of River and Coastal Engineering, Vietnam Academy for Water Resources,
171 Tay Son Street, Dongda District, Hanoi 100000, Vietnam
* Correspondence: yueian@csrsr.ncu.edu.tw; Tel.: +886-3-422-7151 (ext. 57631)

Remote Sens. 2022, 14, 3140. https://doi.org/10.3390/rs14133140         https://www.mdpi.com/journal/remotesensing