User Needs & Essential Water (Cycle) Variables (EWVs)

(1) Water Strategy Report (WSR)—GEOSS-Water-CoP

(2) GEO Societal Benefits Area (SGA)—Water--Report

Unninayar(NASA/GSFC-GESTAR)

User Needs and Essential Water Cycle Variables (EWVs)

• Developed by (1) GEO-UIC-SBA-Water (2010) & GEOSS Water Strategy Report CoP—(2015)

• Through review process with wide acceptance by the community• EWVs are linked to applications and end-users. They are derived by

reviewing/consolidating user-needs/requirements (for observations of water variables) in all GEO user sectors as defined by the GEO SBA’s

• Community agreement reached by review (process) and consensus• EWVs are linked to international bodies (GEO and collaborating

Member Organizations)• Data base with information on EWVs: Various, as maintained by

national, regional and international organizations and programs.

Broad User Categories• Water Cycle Monitoring• Water Cycle Modeling/Prediction• Decision Support—Agriculture• Decision Support--Climate• Decision Support—Energy• Decision Support—Ecosystems• Decision Support—Biodiversity• Decision Support—Health• Decision Support--Land Management• Decision Support—Oceans (Coastal)• Decision Support—Water/Water Resources (Management)• Decision Support—Weather

Broad User Categories

9 GEO SBA’s• Agriculture• Disasters• Health• Biodiversity• Ecosystems• Water• Climate• Energy• Weather[ EWVs include/incorporate ECV’s (Essential Climate Variables—ECVs--as per GCOS, UNFCCC, IPCC][Each User Category was expanded into functional elements before requirements were consolidated. E.g., WRM includes stream flow forecasting , reservoir management, drought monitoring/forecasting…etc.]

Definitions: Essential Water Variables (EWV) are defined as water variables/parameters that address “user”-defined critical requirements for one or more

of the following:

• (1) Observational “monitoring” of key elements of the global and regional/local water cycle,

• (2) Observations required by diagnostic and/or land surface/hydrological prediction models that are used to generate derived products for the end-user communities, and

• (3) Observational and model-derived variables and parameters required by users of water data/information products as applied to various inter-disciplinary decision support systems and tools.

[Capture Key Elements of the Earth-Climate System—Figure-1]

Figure 1. The water cycle dominates the Earth-climate system, as shown in this schematic of the water cycle

(USGCRP,2003).

EWVs

PRIMARY• Precipitation• ET• Snow Cover (& Depth, Freeze/Thaw Margins..)• Soil Moisture/Temp• Ground Water• Run0ff/Streamflow/River Discharge• Water Quality• Water Use/Demand (Agro, Hydro, Energy, Urban,…)• Glaciers/Ice Sheets

EWVs

SUPPLEMENTARY VARIABLES

• Surface Meteorology• Surface & Atmospheric Radiation Budget• Cloud & Aerosols• Land Cover & Vegetation, Land Use• Permafrost• Elevation/Topography and Geological Stratification

[The above can be expanded into much more detailed sub-parameters/variables. E.g., Water Quality alone could have 10 to 100 or more constituents elements]

Essential Water Cycle Variables (EWC-V’s) [Structured following the Water-SBA analysis as being of approximately equal high priority when averaged across all user sectors. Some variables/parameters have been combined for simplicity]

Water Cycle Monitoring

Water Cycle Modelling/Prediction

Decision Support:--Agriculture

Decision Support--Biodiversity

Decision Support--Climate

Decision Support-- Ecosystems

Decision Support--Energy

Decision Support--Geohazards

Decision Support--Health

Decision Support--Land Management

Decision Support—Oceans (Coastal)

Decision Support--Socio-Economic

Decision Support--Water Management

Decision Support--Weather

Cross-Ref.--ECV’s (Essential Climate Variables as per UNFCCC, IPCC)

PRIMARY Precipitation X X X X X X X X X X X X X XEvaporation & Evapotranspiration X X X X X X X Snow Cover (& Depth, Freeze Thaw Margins)

X X X X X X X X X X X X

Soil Moisture/Temp X X X X X X X X X XGroundwater X X X X X X XRunoff/Streamflow/River Discharge X X X X X X X X X X X XLakes/ Reservoir Levels and Aquifer Volumetric Change

X X X X X X X X

Water Quality X X X X X X X X X Water Use/Demand (Agro, Hydro, Energy, Urban,...)

X X X X X X X X X X

Glaciers/ ice sheets X X X X X X XSUPPLEMENTARY VARIABLES Surface Meteorology X X X X X X XSurface & Atmospheric Radiation Budget

X X X X X

Cloud &Aerosols X X X XLand Cover &Vegetation + Land Use X X X X X X X X X XPermafrost X X X

Elevation/ Topography & Geological Stratification

X X X X X X

EWVs—Obs. Requirements

• Space/time resolution requirements (User Needs) vary substantially between user sectors

• From hours to days, week, month, season, year, decade, century,…

• Space/time resolutions also vary substantially with observing instrument/platform

• Data assimilation models are frequently needed to derive variables that are not measured directly, or measured with insufficient spatial/time density

• Requirements vary with early warning/prediction system and the “observable/variable”

[ Detailed in the Water-SBA Report, and the WSR]