Abstract
Global agricultural monitoring utilizes a variety of Earth observations (EO) data spanning different spectral, spatial, and temporal resolutions in order to gather information on crop area, type, condition, calendar, and yield, among other applications. Categorical requirements for space-based monitoring of major agricultural production areas have been articulated based on best practices established by the Group on Earth Observation’s (GEO) Global Agricultural Monitoring Community (GEOGLAM) of Practice, in collaboration with the Committee on Earth Observation Satellites (CEOS). We present a method to transform generalized requirements for agricultural monitoring in the context of GEOGLAM into spatially explicit (0.05°) Earth observation (EO) requirements for multiple resolutions of data. This is accomplished through the synthesis of the necessary remote sensing-based datasets concerning where (crop mask, when (growing calendar, and how frequently imagery is required (considering cloud cover impact throughout the agricultural growing season. Beyond this provision of the framework and tools necessary to articulate these requirements, investigated in depth is the requirement for reasonably clear moderate spatial resolution (10–100 m) optical data within 8 days over global within-season croplands of all sizes, a data type prioritized by GEOGLAM and CEOS. Four definitions of “reasonably clear” are investigated: 70%, 80%, 90%, or 95% clear. The revisit frequency required (RFR) for a reasonably clear view varies greatly both geographically and throughout the growing season, as well as with the threshold of acceptable clarity. The global average RFR for a 70% clear view within 8 days is 3.9–4.8 days (depending on the month), 3.0–4.1 days for 80% clear, 2.2–3.3 days for 90% clear, and 1.7–2.6 days for 95% clear. While some areas/times of year require only a single revisit (RFR = 8 days) to meet their reasonably clear requirement, generally the RFR, regardless of clarity threshold, is below to greatly below the 8 day mark, highlighting the need for moderate resolution optical satellite systems or constellations with revisit capabilities more frequent than 8 days. This analysis is providing crucial input for data acquisition planning for agricultural monitoring in the context of GEOGLAM.
Highlights
The coordination of Earth observations (EO) data necessitates first the articulation of spatially explicitEO requirements for monitoring, including where [1], when [2], how frequently [3], over which spectral range, and at what spatial resolution these data are needed
As was shown in Whitcraft et al (2015) [3], the early-to-mid agricultural growing season (AGS) in most areas is more heavily occluded by cloud cover than is the late AGS
The revisit frequency required to yield a view at least 70% clear within 8 days varies throughout the calendar year and the AGS, ranging from < 1 day to exactly 8 days, with a mean ranging between 3.9 and 4.8 days, depending on the month (Figure 2a)
Summary
The coordination of Earth observations (EO) data necessitates first the articulation of spatially explicitEO requirements for monitoring, including where [1], when [2], how frequently [3], over which spectral range, and at what spatial resolution these data are needed. In 2012, the newly formed Committee on Earth Observations Satellites (CEOS) Ad Hoc Team for GEOGLAM (including members of the GEO Agricultural Community of Practice and CEOS space agency representatives) met to articulate the spatial (Table 1 [8,9], Column B), spectral (Table 1, Column C), and “cloud free” temporal resolution (Table 1, Column D) data requirements for a variety of agricultural monitoring applications or “target products” (Table 1, Columns G–M), based on their combined experiences in research and operational agricultural monitoring [8].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
