Towards an Initiative in Evapotranspiration

1. Towards an Initiative in Evapotranspiration NASA/USDA ET Workshop Silver Spring, MD April 5, 2011 Rick Lawford (UMBC)

2. Importance of Evapotranspiration Critical for understanding the water cycle. Critical for evaluating the impacts of Climate change Critical for water management decisions

3. (from Paul Bulock) Statistically Significant Drought Index Correlations by Category AC Barrie Superb Water Supply Indices 0 3 Water Demand Indices 19 24 Water Balance Indices 14 18 Water Use Indices 7 7 Evapotranspiration provides a more accurate estimate of wheat yield and quality than precipitation and should be utilized for assessment of agricultural drought. DRI 2008 Calgary

4. SURFACE TEMPERATURE EVAPOTRANSPIRATION ALEXI (GOES Sounder) Continental ALEXI (GOES Imager) Regional DisALEXI (Landsat) Watershed DisALEXI (USU aircraft) Temperature (C) CORN Field scale Latent Heat (Wm-2) SOY Observational ET Challenges: In-situ measurements: Closure of the water balance at Flux towers is a significant problem. In-situ FLUXNET measurements are not uniformly distributed around the Globe. • Remote Sensing: • High resolution data are needed • to develop information for many • of the agricultural applications. • Thermal IR sensor data are • needed on an on-going basis. • Disruptions in input data • affect the quality of the product

5. Global Climate Observing System • Mission: To ensure that the data required to meet the needs of users for climate information are obtained and made available for: • Climate system monitoring, climate change detection and attribution; • Research, modelling and prediction of the climate system; • Assessing impacts, vulnerability & adaptation; • Application to sustainable economic development. Global, long-term, high-quality, sustainable.

6. ECV Standard Reports ECV Web Portal http://www.fao.org/gtos/topcECV.html • Web pages created for each terrestrial ECV • Contains background, report, references and all other materials gathered. • Allows greater stakeholder participation and review of documentation. • Review of ECVs also in GTOS Biennial report supplement: • River discharge • Water use • Ground water • Glaciers • Permafrost • fAPAR • LAI • Biomass • Fire disturbance • Albedo • Land cover • Lake levels • Snow cover Missing: ET

7. GTN-H is recognized as a major partner in IGWCO especially in areas such as discharge, surface water storage and groundwater.

8. The Primary Framework: GEOSS: A Global, Coordinated, Comprehensive and Sustained System of Observing Systems • Relevant Facts: • The Group on Earth Observations (GEO) consists of • ~85 nations and ~60 international organizations which have • agreed to work together to build the GEOSS. • GEO implements the GEOSS work plan through the best • efforts of its community. Targets Tasks Sub Tasks The Water Target By 2015, produce comprehensive sets of data, information products and services to support decision-making for efficient management of the world's water resources, based on coordinated, sustained observations of the water cycle on multiple scales.

9. Assessment of WA-08-01 Integration Satellite Integration In-situ Good Progress Work underway: Progress anticipated Progress limited by people/ science Evapotranspiration ? Water Vapour ? Skin Temperature ?

10. non-expert user communities need • small data files • subsetting to regions of interest • pre-computed averages over stream basins, political subdivisions • COTS application-specific formats Concepts for Precipitation in 2012-15 GEO Major Issues (1/2) (from George Huffman) IPWG validation studies for observations and models need schemes for useful validation at fine time/space scales Societal Benefit Areas need precipitation information: Fine-scale; Climate-scale (CDR) Societal Benefit Areas end-to-end applications including precipitation Post-processing into “user-friendly” formats User support on appropriate sources, uses Data streams/ archives Similar box structure for other water cycle variables Validation Algorithm development and maintenance Routine provision of observational (and model) data input freely available uniformly processed long data records co-registered time/space grids consistent units consistent periods of record Science concepts for use of existing/new sensor data Model development Sensor development, construction, deployment wider visibility of data sets better documentation for data sets systematic metadata training opportunities Science/engineering concepts for improved/new sensors 10

11. Example for an IP Action that could be applied to ET • ECV: Soil moisture Action T12 Action: Develop Global Terrestrial Network on Soil Moisture Who: Parties’ national services and research programmes, through IGWCO, GEWEX and TOPC in collaboration with space agencies. Time frame: 2014 Performance indicator: Fully functional GTN-SM with a set of in situ observations (possibly co-located with reference network, cf. T3), with standard measurement protocol and data quality and archiving procedures. Annual Cost Implications: 1-10M USD (40% in non-Annex-I Parties). • GCOS looks for: • A commitment by an organizations to archive the variable. • a network of observations. • an operational product that will be available on a continuing basis.

12. SUMMARY: • From the perspective of applications Evapotranspiration is an • essential climate variable although it is not recognized as such • by GCOS. • There are a number of merged products for ET that could serve • as the basis for an integrated GEO water cycle product in the • 2012-2015 work plan. • It is recommended that GEO adopt a data product related to • ET as part of its work package. This product should facilitate • developments in • Science • Technology (e.g., satellite sensors) • Needs (e.g., stronger focus on adaptation and mitigation options) • International coordination (e.g., GEO/GEOSS, etc)