Floods occur annually and globally, contributing to widespread losses in agriculture, property damage, human suffering, and broader socioeconomic consequence. Risk for individual events is often informed by past experience and hydrometeorological modeling. During and post-event, pilot projects through CGMS and individual countries have demonstrated that Earth observations (EO) from low-Earth orbit (LEO) and geostationary (GEO) platforms accelerate flood monitoring for advisories, warnings, and flood mapping products. Regional GEO and global LEO missions provide valuable mapping capabilities with targeted and higher resolution imaging often provided by collaborations with the International Charter.
Synthetic aperture radar from LEO platforms offer capability to map water extent in views obstructed for other GEO and LEO sensors: through cloud cover, all but the heaviest of rainfall rates, and for some frequencies viewing through dense vegetation canopies. The diverse and growing international constellation of public and private sector SAR resources offers an opportunity to map water extent through means complimentary to current GEO and LEO approaches.
Translating from water extent to inundation requires a reasonable estimate of water depth. Through combination of flood extent mapping and digital elevation models (DEMs), emergency management communities will benefit by translating water extent to improved estimates of damage and impacts.
CEOS-Specific Relevance and Pilot Objectives
With the aforementioned understanding as background, the Pilot will explore and demonstrate best practices for combining diverse optical and SAR flood mapping by:
Objective A: Identify and inventory CEOS and CGMS data sources, partners and critical variables, their metadata, timeliness, spatial/temporal resolution, latency and other factors that contribute to flood mapping, along with mechanisms used to share and acquire said data.
Objective B: Collaborate with CEOS and CGMS flood mapping activities to explore the feasibility of integrating LEO-GEO optical with multi-frequency and multi-temporal SAR flood observations. We expect to use 2-3 regional case studies of long-lasting, impactful, past flood events and up to 1-2 upcoming scenarios during the pilot work period. Team members will develop best practices for integration based upon data availability, expected latency, uncertainty, and other factors.
Objective C: Report on best practices developed through preliminary integration of LEO-GEO and SAR. Engage with product developers and partners to clarify terminology, methods for mapping, and data sharing. Identify gaps to address in training or outreach to support integration of optical and SAR products.
Success in meeting these objectives will demonstrate capabilities to increase resilience to floods for impacted communities, their infrastructure, and local economies, and guide actions for a potential Demonstrator project to extend to a broader range of beneficiaries.