Earth Observations Requirements for Global Agricultural Monitoring: Evaluating the Revisit Capabilities of Current & Planned Moderate Resolution Optical & Thermal Infrared Earth Observing Missions
Wednesday, 17 December 2014
For several decades, Earth observations (EO) have been employed to monitor agriculture, including crop area, type, condition, and yield forecasting processes. However, the EO data required to consistently derive these informational products at multiple scales had not been well-defined. Responding to this dearth, we have articulated spatially explicit EO requirements with a focus on moderate resolution (10-70m) active and passive remote sensors, and evaluated current and near-term missions’ capabilities to meet these EO requirements. These spatially explicit requirements incorporate cropland location, growing season timing, and cloud cover information, establishing the revisit frequency required to yield reasonably clear views within 8 or 16 days. A comparison of these requirements with hypothetical constellations formed from current/planned moderate resolution optical EO missions shows that to return a scene at least 70% clear within 8 or 16 days, 46-55% or 10-32% of cropped areas, respectively, require a revisit more frequent than 8 days, with is more frequent than Landsat 7 & 8 combined can deliver. Supplementing Landsat 7 & 8 with missions from different space agencies leads to an improved capacity to meet requirements, with Resourcesat-2 providing the largest incremental improvement in requirements met. Globally, no single mission/observatory can consistently meet all 8 or 16 day requirements throughout the year. Meanwhile, the only way to meet a majority of these requirements is through coordination of multiple missions. Gaps exist in persistently cloudy regions and periods, highlighting the need for data coordination and for consideration of active microwave EO for agricultural monitoring.