Crop Acreage and Yield Estimation Using Remote Sensing
摘要
Accurate and timely estimates of crop area and yield are crucial for agricultural planning, food security, and market stability. This chapter presents a comprehensive approach for crop acreage and yield estimation using remote sensing, combining satellite imagery analysis with agronomic modeling. We first outline a methodology for mapping crop acreage using multi-spectral Sentinel-2 imagery, including advanced cloud masking (Cloud Score + algorithm), topographic correction, and Random Forest classification implemented on the Google Earth Engine platform. We then describe a semi-physical crop yield modeling approach that integrates satellite-derived indices with crop physiology, notably a light-use efficiency model driven by the fraction of absorbed photosynthetically active radiation (fAPAR), meteorological inputs (solar radiation, temperature), water stress indices, and crop-specific parameters like Radiation Use Efficiency (RUE) and Harvest Index (HI). Case studies from India, sub-Saharan Africa, and the United States demonstrate the accuracy and scalability of these methods—for example, remote sensing-based estimates of wheat area and production in Gujarat closely matched official statistics (within ~ 5–10%), and a national rice forecasting program achieved < 10% error at state scales. We discuss the challenges (cloud cover, small field sizes, model generalizability) and highlight future directions, including multi-source data fusion, machine learning (deep learning and data assimilation), and crowd-sourced ground truth. The results underscore that combining advanced satellite analytics with agronomic modeling can deliver near-real-time, spatially detailed crop insights, supporting decision-makers in achieving resilient and sustainable food systems.