GOESR3 Periodic Reporting
Project Team: Christopher Hain (PI; U. of Maryland/ESSIC/NOAA); Xiwu Zhan (Co-PI;
NOAA/NESDIS/STAR); Martha Anderson (Co-I; USDA-ARS-HRSL); John Mecikalski (Co-I; UAH);
Mark Svoboda (NDMC); Brian Wardlow (NDMC); Yunyue Yu (NOAA/NESDIS/STAR); Istvan Laszlo
(NOAA/NESDIS/STAR); Felix Kogan (NOAA/NESDIS/STAR).
Reporting Period:
September 2012 - February 2013
Team Lead:
Christopher Hain (PI; U. of Maryland/ESSIC/NOAA)
Xiwu Zhan (Co-PI; NOAA/NESDIS/STAR); Martha Anderson (Co-I; USDAARS-HRSL); John Mecikalski (Co-I; UAH)
Team Members:
Project Title: Evapotranspiration and Drought Monitoring Using GOES-R Products for NIDIS
Project Number:
63
Executive Summary
Monitoring evapotranspiration (ET) and the extent and severity of agricultural drought is an important
component of food and water security and world crop market assessment. Agricultural systems are
climate-sensitive, and conventional surface instrument networks are sparse and report with delays,
therefore, satellite remote sensing and modeling play a vital role in monitoring regional water use and
providing early warning of impending moisture deficits, and can be used to supplement coarser
resolution data from weather and precipitation networks to assess drought conditions. Because landsurface temperature (LST) is strongly modulated by evaporation, thermal infrared (TIR) remote sensing
data carry valuable information regarding surface moisture availability and therefore have been widely
used to map ET, drought, and vegetation stress. Signatures of vegetation stress are manifested in the
LST signal before any deterioration of vegetation cover occurs, for example as indicated in the
Normalized Difference Vegetation Index (NDVI), so TIR-based drought indices can provide an
effective early warning of impending agricultural drought. Evapotranspiration deficits in comparison
with potential ET (PET) rates provide proxy information regarding soil moisture availability, without
any need for knowledge of antecedent precipitation. In regions of dense vegetation, ET probes moisture
conditions in the plant root zone, down to meter depths. Our group has spearheaded use of anomalies in
the remotely sensed ET/PET fraction (fPET) generated with ALEXI as a drought monitoring tool that
samples variability in water use, and demonstrating complementary value in combination with standard
drought indices that reflect water supply.
Fully automated ALEXI ET and drought monitoring systems have been implemented at 10-km
resolution over the continental U.S. using TIR and shortwave information from current GOES
instruments. With the launch of GOES-R, our capabilities for ET and drought monitoring will be
significantly enhanced due to substantial improvements in spatiotemporal resolution, radiometric
accuracy, and cloud-clearing capabilities. With GOES-R, the resolution of ALEXI ESI and ET products
can be improved to 2-km. This will significantly improve utility to the drought community and action
agencies served by NIDIS, who are demanding drought information at increasingly higher spatial
resolution to support decision making at the sub-county scale.
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Milestones
The following Year 2 tasks have been completed (or are in progress):

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ALEXI evapotranspiration fields are being validated against available ground-based surface flux
observation over Europe.
All available European drought indices are being collected and archived including standardized
precipitation index (SPI), vegetation health index (VHI), European Drought Observatory drought
classifications, GLDAS soil moisture fields.
ALEXI Evaporative Stress Index (ESI) fields are being validated against all available drought
indices over Europe.
Accomplishments & Plans
During the past year, our research group has collected and archived all necessary MSG-SEVIRI (a
GOES-R proxy) input products (e.g., land surface temperature; incoming shortwave radiation; surface
albedo; leaf area index) from the Land Surface Analysis Satellite Applications Facility (LSA-SAF) for
the year 2012, extending our current climatology to a period of 2007-2012.
All necessary meteorological inputs for ALEXI have also been processed and archived, mainly in the
form of daily WRF simulations for each day during the study period. The ALEXI evapotranspiration
climatological database (2007-2012) has been processed and archived at 3 km over Europe using the
aforementioned input fields. The six-year climatology now serves as the initial period for the
computation of the Evaporative Stress Index (ESI) which has been shown to be an effective drought
monitoring tool over the United States. Figure 1 shows the August ESI map, a period where severe
drought conditions were observed in the Catalonia Region of Spain (eastern Spain). ESI shows
anomalously dry conditions (evident by negative anomalies in ESI [red shading] over this region. Dry
conditions are also observed in ESI in Northern Africa and central Turkey (consistent with documented
drought conditions). A significant drought which occurred in Russia during the summer months of 2010
was also captured in this newly developed ESI dataset (Figure 2). This drought largely affected the
agricultural portions of Russia and lead to significantly decreased yields in Russia.
Assessments of the ESI dataset are currently underway to examine the relationships in ESI with other
standard drought metrics such as the Standard Precipitation Index, GLDAS ET and SM products,
vegetation indices (e.g., Vegetation Health Index, NDVI), and passive microwave soil moisture
products. Also, ESI maps are being compared to drought classification maps produced by the European
Drought Observatory. A manuscript is currently in draft form and will be submitted based on these
findings.
While ESI (anomalies in actual to potential ET) has been shown to be an important drought indicator,
actual evapotranspiration estimates from ALEXI provide a unique opportunity for monitoring actual
water use from space. A six-year climatology (coincident with the current ESI climatology) of daily
ALEXI ET estimates has also been produced. Estimates of daily ET from ALEXI is only possible when
cloud-free conditions are observed during the morning periods, however, our research group have
developed gap-filling methods to estimate ET during cloudy periods. We are currently testing two
methods: (a) one that assumes constant evaporative fraction (ET divided by available energy) during
cloudy intervals and (b) one that attempts to fit a spline interpolate to the time series of clear-sky
evaporative fraction. Assessments of the ALEXI ET dataset are also currently underway using all
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available eddy covariance flux observations from the FLUXNET database. ALEXI ET is also being
compared to model-based ET from the GLDAS project.
Additional Information
1. Interaction with operational partners – PI Hain and Co-I Anderson are both active participants on the
NOAA MAPP Drought Task Force where we interact with drought product end-users.
2. Conference/workshop participation –
Hain, C. R., M. C. Anderson, X. Zhan and M. T. Yilmaz. “Monitoring evapotranspiration and water
resources with thermal infrared geostationary sensors: An intercomparison with model-based ET
predictions and tower observations”, 93nd Annual Meeting of the American Meteorological
Society in Austin, TX 6-10 January 2013 [INVITED].
Hain, C. R., M. C. Anderson, X. Zhan and M. T. Yilmaz. “Monitoring evapotranspiration and water
resources with thermal infrared geostationary sensors: An intercomparison with model-based ET
predictions and tower observations”, American Geophysical Fall Meeting in San Francisco, CA
3-7 December 2012 [INVITED].
Hain, C. R., M. C. Anderson, X. Zhan and W. P. Kustas. "Monitoring evapotranspiration from space:
Methodology and Applications", Urban and Rural Meteorology Workshop in Jeju, South Korea
27-29 August 2012 [INVITED].
Hain, C. R., X. Zhan, M. C. Anderson, and J. R. Mecikalski. "Evapotranspiration and drought
monitoring using GOES-R proxy data", 2012 NOAA Satellite Science Week in Kansas City, MO
30 April - 4 May 2011.
3. Funding concerns –
4. Outside project publicity –
5. Journal articles –
Plans for the next Reporting Period:
Ongoing and future work will focus on:

A quantitative evaluation of 3-km evapotranspiration and drought products over Europe for
2007-present using ground-based flux observations, other satellite and model-based ET estimates
and all available standard drought metrics
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Key Graphics
Figure 1. ALEXI Evaporative Stress Index for August 2008 (top) and August 2010(bottom).
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