Mapping high temperature damaged area of paddy rice along the Yangtze River using Moderate Resolution Imaging Spectroradiometer data

The subtropical high temperature anomaly of 2013 in China, adversely affected paddy rice physiology, especially at the heading, flowering and grain filling stages, and left untold damage and significant rice yield reductions in that year. Considering the importance of data on crop failure induced by abnormal meteorological events, in understanding the potential impacts of climate change on agriculture and food security, and in support of crop insurance policies, the current study employs satellite remote sensing data to map and estimate the areal extent of high-temperature-induced damage on paddy rice in 2013, along the Yangtze River, a major rice producing area in China. In this regard, the daily mean and maximum air temperatures were first estimated using the Moderate Resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) products, MODIS Vegetation Indices (VI) products, altitude information from a Digital Elevation Model (DEM), and air temperature measurements at meteorological stations located within the Yangtze River Basin from 2000 to 2016, to derive fully covered mean and maximum daily air temperatures. Paddy rice cultivated areas were then identified based on the seasonal profiles of MODIS Enhanced Vegetation Index (EVI) and Land Surface Water Index (LSWI) in 2013, and map errors at provincial scales were no more than 8.7%. Finally, paddy rice growth characteristics were combined with MODIS VI products to identify heading and flowering stages, and the time series of daily mean and maximum air temperatures, paddy rice phenology and cultivated area, were integrated to map and estimate the rice crop area damaged by the anomalous high temperature. Our results show that all provinces along the Yangtze River, this study investigated, recorded a substantial damaged rice crop area, following the 2013 subtropical temperature high, and Anhui Province was the hardest hit with a damaged rice area of 63.6%. For the entire study area, a damage extent of about 5,656,000 ha, accounting for 35.9% of total paddy rice planted area, was recorded. This indicates a significant agro-meteorological disaster, and in an era of increasing climate variability and weather extremes, studies of this nature would greatly benefit global food security planning and management policies.