WatER:%20The%20proposed%20Water%20Elevation%20Recovery%20satellite%20mission

1
WatER The proposed Water Elevation Recovery
satellite mission
Eric Wood, Princeton University Presentation to
the meeting of the Integrated Global Observing
Strategy Water Cycle Observations, Paris, March
2006
We welcome everyone to join and participate in
WatER!
Doug Alsdorf, U.S. WatER PI, alsdorf.1_at_osu.edu
Nelly Mognard, EU WatER PI, nelly.mognard_at_cnes.fr
Ernesto Rodriguez, JPL Engineer of KaRIN and
over 150 participants from more than 20
countries, world wide
Seed funding from Ohio State University, CNES,
JPL, and the Terrestrial Hydrology Program at
NASA
www.geology.ohio-state.edu/water
www.legos.obs-mip.fr/recherches/missions/water
2
Three Key Points for this Talk

• One
• WatER will answer the question of Where is water
  stored on Earths land surfaces, and how does
  this storage vary in space and time?
• Two
• Opportunities and problems with profiling
  altimeters
• Three
• Other science and societal benefits from WatER

3
from international water programs
Slide courtesy Eric Wood
4
OSTP OMB 2004
OSTP OMB 2005
OSTP 2004
UN 2004
The ability to measure, monitor, and forecast
the U.S. and global supplies of fresh water is
another high-priority concern.
Significant progress on this plan, including
stakeholder input, is expected during the next
two years.
Decides that the goals of the Decade should be a
greater focus on water related issues at all
levels and on the implementation of water-related
programmes and projects
Does the United States have enough water? We do
not know. What should we do? Use modern
science and technology to determine how much
water is currently available
Co-chair R. Hirsch, Director USGS Water Division
http//www.whitehouse.gov/omb/memoranda/fy04/m04-2
3.pdf
http//www.ostp.gov/NSTC/html/swaqreport_2-1-05.pd
f
http//www.un.org/Depts/dhl/resguide/r58.htm
http//www.ostp.gov/html/budget/2007/ostp_omb_guid
ancememo_FY07.pdf
5
The WatER Mission
Submitted to NRC Decadal Review Panel Alsdorf,
D., D. Lettenmaier, J. Famiglietti, and C.
Vörösmarty, GEWEX News, 15, 6-7, August 2005.
Cazenave, A., P.C.D. Milly, H. Douville, J.
Benveniste, P. Kosuth, and D. Lettenmaier, EOS
Transactions AGU, 85, 59-60, 2004. Alsdorf, D.
and D. Lettenmaier, Science, 1485-1488,
2003. Alsdorf, D., D. Lettenmaier, C. Vörösmarty,
the NASA Surface Water Working Group, EOS
Transactions AGU, 269-276, 2003.
6
WatER TechnologyKaRIN Ka-Band Radar
INterferometer
See Talk by Ernesto Rodriguez This Room 1745
Today

• Only method capable of producing images of high
  resolution water surface elevation measurements
• can provide h, dh/dx, and dh/dt
• Strong Heritage Is technology evolution, not
  revolution
• Radar altimetry has already been successfully
  used in space on a number of missions (e.g.,
  Topex/POSEIDON)
• SRTM was a radar interferometer
• Extensive JPL technology investment in WSOA
• Compared to SRTM
• Order of magnitude better vertical resolution
  over water sub-100 m size pixels
• Near nadir look angle, max 4.5º, not SRTMs 30º
  to 60º
• Water surface is highly reflective, thus is
  easily measured at near nadir

7
Storage change from radar altimetry requires
imagery
Buhayrat Reservoir, Iraq Courtesy of LEGOS
Presently, altimeters are configured for
oceanographic applications, thus lacking the
spatial resolution that may be possible for
rivers and wetlands.
Amazon River
Classified SAR Imagery

DS
Note loss of gauge data post 1997
Birkett, C.M., Water Resources Res.,1223-1239,
1998. Birkett, C.M., L.A.K. Mertes, T. Dunne,
M.H. Costa, and M.J. Jasinski,Journal of
Geophysical Research, 107, 2002.
8
Problems With Profiling Altimeters Global
Coverage
Does the United States have enough water? We do
not know. What should we do? Use modern
science and technology to determine how much
water is currently available
USGS Coverage 7000 gauges
0
5
10
15
Two somewhat similar sized areas
Even if multiple altimeters with optimal along
track resolutions are used, how will they answer
the question for the U.S. and the rest of the
world?
0
5
10
15

• Coverage from a pulse limited altimeter severely
  under samples rivers and especially lakes
• 16-day repeat (i.e., Terra) coverage misses 30
  of rivers and 70 of lakes in the data bases
  (CIA-2 UNH UH)
• 120 km swath instrument misses very few lakes or
  rivers
• 1 for 16-day repeat and 7 for 10-day repeat

Topex/POSEIDON 70 points
Birkett, C.M., L.A.K. Mertes, T. Dunne, M.H.
Costa, and M.J. Jasinski,Journal of Geophysical
Research, 107, 2003. Hirsch, R.M., and J.E.
Costa, EOS Transactions AGU, 85, 197-203, 2004.
9
Problems With Profiling Altimeters Local Coverage
cm
SRTM DEM
m
Actual dh/dt
cm
dt 44 days
dt 44 days
dt 44 days
cm
Predicted dh/dt
Predicted dh/dt
10
?S and Floodplain Hydraulics from Repeat Pass
Interferometric SAR
Perspective views of dh/dt. Surface water
mission should be capable of measuring these
hydraulics.
12 Jul 96 15 Apr 96
29 Jun 97 2 Apr 97
Views are 70x70km
Flow hydraulics vary across these images.
Floodplains are not bathtubs. Arrows indicate
that dh/dt changes across floodplain channels.
11 Apr 93 26 Feb 93
DEM
Alsdorf et al., Nature, 404, 174-177, 2000
Alsdorf et al., Geophysical Research Ltrs., 28,
2671-2674, 2001 Alsdorf et al., IEEE TGRS, 39,
423-431, 2001.
11
Targets are Global Russia's vast northern
wetlands are a key player in global change
Lake Water Surface Area North of 45.5N is 589,000
km2 Wetland area North of 45.5N is 4.5M km2
(Larry Smith)
Photo Karen Frey
12
Changes in Arctic lake volumes cannot be
adequately sampled with one-dimensional methods
L. Smith Slide
13
1D Sampling will completely miss this volumetric
change
Disappearing Arctic Lakes The inter-seasonal
and inter-annual variations in surface water
storage volumes as well as their impact on
balancing regional differences between
precipitation, evaporation, infiltration and
runoff are not well known. For example, despite a
slight increase in Arctic precipitation, Siberian
lake area and numbers have decreased a
phenomenon recently identified by Smith et al
2005 and which they attribute to regional
variations in the melting of permafrost.
Smith et al., Science 308, 2005
14
Targets are Global
Congo River Basin 3.7M km2
Matthews, E. and I. Fung, GBC, 1, 61-86, 1987.
Ohio R.
Canada
Floods
Peace-Athabasca Delta 3200 km2
New Orleans
Costa Rica
Braided Rivers
Turkey
Reservoirs
Coastal Zones
New Zealand
15
WatER Science Goals

• Primary
• To determine the spatial and temporal variability
  in freshwater stored in the worlds terrestrial
  water bodies.
• Potential Additional Goals (no particular order)
• Inundation area provides carbon fluxes at
  air-water boundary (e.g., CO2)
• Repeated topographic measurements for
  floodplains, glacial ice, etc.
• Global low-relief topography every 8 days and
  topographic change

Carbon Fluxes
Global Low-Relief DEMs
Floodplain Topography
3 cm s for a given pixel after 250 measurements
over 5 yrs
Vertical Component, Low Relief, Local
Deformation Only
Ice DEMs
16
WatER Science Goals

• Potential Additional Goals (continued)
• High resolution h images allow plume and near
  shore studies
• Calculation of ocean water slopes and sea surface
  topography for bathymetry, ocean circulation, and
  climate.
• Differences between sea ice and water surface
  allow ice-freeboard calculations, thus thickness.

Plume off California
Jason-1
Sea Surface Anomalies
So, our acronym was carefully chosen WatER
Water Elevation Recovery can easily
become. WATER Water And Terrestrial Elevation
Recovery
Arctic Sea Ice Thickness
17
Conclusions
www.geology.ohio-state.edu/water
www.legos.obs-mip.fr/recherches/missions/water
WatER is not a gauge replacement strategy. It is
an altogether new way of understanding water
storage and flow. Water fluxes and volume
changes are more than a 1D process. Profiling
altimeters repeat 1D, in-situ gauge approaches
whereas WatERs KaRIN will provide
two-dimensional h, dh/dt, and dh/dx about once a
week, thus yield ?S and Q globally. Free access
to data will enable all governments to know how
much surface water they have.
We welcome everyone to join and participate in
WatER!