Asian Rice Calendar Dynamics Detected by Remote Sensing and Their Climate Drivers

Abstract

Detecting crop calendar changes is critically important for crop monitoring and management, but the lack of annual, Asia-wide, and long-term rice calendar datasets limits our understanding of rice phenological changes and their climate drivers. In this study, we retrieved key rice phenological dates from the GLASS AVHRR LAI through combining threshold-based and inflection-based detection methods, analyzed the changes during the period 1995–2015, and identified the key climate drivers of the main rice seasons in Asia. The retrieved phenological dates had a high level of agreement with the referenced observations. All R2 were greater than 0.80. The length of the vegetation growing period (VGP) was mostly shortened (by an average of −4 days per decade), while the length of the reproductive growing period was mostly prolonged (by an average of 2 days per decade). Moreover, solar radiation had the most significant impact on the rice calendar changes, followed by the maximum and minimum temperatures. The VGP in tropical areas is the most sensitive to climate change. Our study extends the annual rice phenology dynamics to a higher spatial–temporal resolution and provides new insights into rice calendar changes and their climate drivers, which will assist governments and researchers regarding food security and agricultural sustainability.

Spatio-Temporal Variability Analysis of Vegetation Dynamics in China from 2000 to 2022 Based on Leaf Area Index: A Multi-Temporal Image Classification Perspective

“…Yang et al [16] and Qiu et al [17] identified different driving patterns of vegetation climate under various altitude gradients of the Qinghai-Tibet Plateau, and vegetation growth in relatively high-altitude areas is determined by growing season precipitation and atmospheric CO 2 concentrations, while relatively low altitudes are dominated by growing precipitation. Climate change has a profound impact on vegetation dynamics, hydrological cycles, and ecosystem productivity globally [18,19].…”