Dynamic monitoring of rice delayed-type chilling damage using MODIS-based heat index in northeast China

Abstract

Rice chilling damage remains one of the major agricultural meteorological disasters in northeast China. Remote sensing technology can easily monitor the disaster on a relatively large scale compared with traditional methods; this is the development trend for the agro-meteorological service system. Although several studies have focused on freeze injury monitoring using remotely sensed data, few applications exist for chilling damage. In this study, Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature and reflectance data were used to produce mean air temperature time series by employing multiple regression models and to identify the planting areas and key development stages of single rice. A novel index based on relative accumulated growing degree day anomaly (rAGDDa) was accordingly proposed to dynamically monitor the distribution and degree of rice delayed-type chilling damage in northeast China from 2000 to 2012. Results are as below. (1) High correlation is obtained over the 0.01 significant level of accumulated growing degree day derived from MODIS data (MODIS_AGDD) and meteorological data at each 8-day period, with a stable multi-year average difference of approximately 55℃ · day throughout the entire rice growth season, except for early May and late September. (2) Compared with MODIS_AGDD, MODIS_rAGDDa yields a higher R value with a meteorological estimation over the 0.05 significant level in each year and can more effectively eliminate the threshold difference in the temperature index of chilling damage caused by the discrepancy in geographical and heat conditions. (3) Dynamic monitoring based on MODIS_rAGDDa is illustrated for three rice growth stages, such as early (from transplanting to heading), late (from heading to maturation), and whole (from transplanting to maturation) growth stages. Results achieved by MODIS_rAGDDa index during the whole growth stage of rice are broadly consistent in spatial distribution with those produced by meteorological standard index (summation of monthly mean air temperature from May to September anomalies) in several disaster years, especially in 2009 when a wide-range disaster occurred. Meanwhile, the spatial distribution of average reduction rate in rice yield indicates that MODIS_rAGDDa less than-5% can be taken as the indicator for monitoring rice delayed-type chilling damage in northeast China. MODIS_rAGDDa estimation for different rice growth stages can reasonably show the low-temperature accumulation and high-temperature compensation effects. It is considered a suitable index applied to the business service of dynamical monitoring of rice delayed-type chilling damage in northeast China.