1. Global Surface Water Explorer
Jean-Francois Pekel, Andrew Cottam, Noel Gorelick*
and Alan Belward
EC Joint Research Centre, *Google
European Commission/ Google Earth Engine
Side Event: GEOGLOWS and the Harmonization of GEO Water Activities

2. Global Surface Water Explorer
Mission / Objectives and Goals
Mission
To produce maps and statistics documenting when and where the Earth’s land surface has been covered by water during the past 32 years at 30m resolution
Objectives
Globally consistent set of maps, fully validated, distributed with free-and-open access license and easily accessible through an interactive web interface
Goal
Map all open water surfaces (inland and coastal) at global scale, every month of every year at a spatial resolution of 30m. Produce a set of thematic products documenting different facets of the surface water dynamics.

3. Global Surface Water Explorer
Geographical Scope
Methodology
Expert system applied to global Landsat L1T archive at the pixel scale (1.8 PB data), accompanied by validation protocol
Global
Project Governance Structure
Collaboration between EC Joint Research Centre and Google Earth Engine. Longer-term goal is transition to Copernicus Global Land Service

4. Global Surface Water Explorer
Significant achievements in
Achievement 1
Changes in global surface water at 30m resolution; variations in persistence and location between March 1984 and October 2015; gain, loss and constancy in persistence ( ); recurrence (frequency with which water reappears from year to year); annual seasonality; transitions among permanent water, seasonal water and land classes between first and last year of observation; maximum surface water extent; annual / monthly water history at pixel scale; change measurements at global, continental, and country scale.
Pekel, J-F. et al., (2016) Nature 540, 418–422 doi: /nature20584

5. Global Surface Water Explorer
Plans and Deliverables for
Deliverables
- Annual permanent surface water area and trends by country (with estimate of uncertainty) 1984 – 2015
- Coastal erosion/accretion
- Natural / artificial water body identification
General Plans
- Update time series to end of 2017
- Produce 20m resolution using Sentinel 2 and Landsat
- Move towards operational product generation

6. Global Surface Water Explorer
Plans for cross SBA linkages and SDG support
Links to other SBAs or initiatives
UNFCCC: Global Climate Observing System (2016 Plan), Lake Area essential climate variable
CBD: Ecosystem function (inundation)
Sustainable Development on our Human Planet (GEO)
UNCCD: Part of 14 point land degradation classification (World Atlas of Desertification)
Contributions to SDGs
Indicator Change in the extent of water-related ecosystems over time
Indicator Proportion of land that is degraded over total land area (indirect)
Target 15.5 Take urgent and significant action to reduce the degradation of natural habitats...
Challenges and Issues:
Data handling is still a challenge at petabyte scales, Landsat archive consolidation still needed, global scale Sentinel 2 a and 2 b still to be integrated
GEOGLOWS and the Harmonization of
GEO Water Activities

7. Thank You