02 February 2005 02 February 2005 Goddard Space Flight Cent Goddard Space Flight Cent er er 1 Goddard Role in Understanding Goddard Role in Understanding the Global Water Budget the Global Water Budget Water Cycle Components Water Cycle Components Present Observational Capabilities and Future plans Present Observational Capabilities and Future plans The Potential for a Global Observational System The Potential for a Global Observational System
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02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 11
Goddard Role in Understanding Goddard Role in Understanding the Global Water Budget the Global Water Budget
Water Cycle ComponentsWater Cycle Components
Present Observational Capabilities and Future plansPresent Observational Capabilities and Future plans
The Potential for a Global Observational SystemThe Potential for a Global Observational System
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 22
Observing the Global Water CycleObserving the Global Water CycleImportance to Human HealthImportance to Human Health
• Water cycle variability:Water cycle variability:– resolve a few percent per yearresolve a few percent per year– Measurements stable over Measurements stable over
decadesdecades– All components measuredAll components measured
• Must evaluate:Must evaluate:– Human uses of waterHuman uses of water– Impacts on availabilityImpacts on availability
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Observing the Global Water CycleObserving the Global Water CycleImportance to Human HealthImportance to Human Health
• Human health:Human health:– Education concerning healthEducation concerning health– Environmental pollution Environmental pollution – Availability of clean waterAvailability of clean water
• As NASA goal:As NASA goal:– As long term vision for As long term vision for
NASA Earth science NASA Earth science – Supports weather & Supports weather &
climate needsclimate needs
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 44
The Global Water Cycle The Global Water Cycle
• Global water budget:Global water budget:– ~ 2.5% of global water is fresh ~ 2.5% of global water is fresh
waterwater– Of the fresh water,Of the fresh water,
• ~ 69% is permanent ice / snow~ 69% is permanent ice / snow• ~ 30% is ground water~ 30% is ground water• the balance is available in soil, the balance is available in soil,
lakes, rivers, etc. lakes, rivers, etc.
• ~ 1% of the fresh water ~ 1% of the fresh water fuels life on Earthfuels life on Earth
• Large variability in fresh water Large variability in fresh water availability due to:availability due to:– latitude and topographylatitude and topography– weather and climate weather and climate – human influenceshuman influences
• How will the availability of fresh How will the availability of fresh water change as climate water change as climate changes?changes?
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 55
The Global Water Cycle The Global Water Cycle
• Global fresh water budget:Global fresh water budget:– Balance between evaporation, precipitation and runoff:Balance between evaporation, precipitation and runoff:– Small available fresh water volume, Small available fresh water volume, – + large fresh water fluxes+ large fresh water fluxes– = Short residence times:= Short residence times:
• Need observations of:Need observations of:– Fresh water fluxesFresh water fluxes– Fresh water storageFresh water storage
• Observations must meet predictive requirements:Observations must meet predictive requirements:– global coverage, sampling and accuracy global coverage, sampling and accuracy
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Water Cycle Components
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• Measure and forecast all water cycle componentsMeasure and forecast all water cycle components• Precipitation, evaporation, atmospheric transport, runoff, Precipitation, evaporation, atmospheric transport, runoff,
storage (ice and snow, rivers and lakes, soil, ground water)storage (ice and snow, rivers and lakes, soil, ground water)• Related radiative issues (aerosols, effects of clouds, …)Related radiative issues (aerosols, effects of clouds, …)• Measurement requirements (spatial, temporal, precision, Measurement requirements (spatial, temporal, precision,
accuracy)accuracy)
• Water cycle variability with climate changeWater cycle variability with climate change• Speed up of water cycle?Speed up of water cycle?• Change in intensity of events?Change in intensity of events?• Sea level changes?Sea level changes?
• Availability of clean fresh water Availability of clean fresh water • Available water resourcesAvailable water resources• Effects of climate variability and changeEffects of climate variability and change• Ability to forecastAbility to forecast
Observing the Global Water BudgetObserving the Global Water Budgetthe Major Issuesthe Major Issues
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 88
Observing the Global Water Cycle Observing the Global Water Cycle Why Satellite Observations?Why Satellite Observations?
Only space provides a systematic Earth Only space provides a systematic Earth view:view:
Sea Surface SalinitySea Surface Salinity
100 Years of Ship Observations
One Month of Aquarius
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Observing the Global Water Cycle:Observing the Global Water Cycle:What are we doing at Goddard?What are we doing at Goddard?
Measurement of components of the water cycleMeasurement of components of the water cycle::
Plus Plus data assimilationdata assimilation of all components into NWP of all components into NWP
Plus an active program of Plus an active program of supporting national needs through supporting national needs through applicationsapplications
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 1010
Global Precipitation Measurement Global Precipitation Measurement TRMMTRMM
• Global precipitation measurement with Global precipitation measurement with TRMM: TRMM: a great leap forward!a great leap forward!
• Quasi-operational measurement of Quasi-operational measurement of globalglobal precipitation precipitation (with other satellites)(with other satellites)
– 10 10 85 GHz radiometers 85 GHz radiometers (with other (with other satellites)satellites)
– 13.6 precipitation radar13.6 precipitation radar– Global coverage Global coverage (with other satellites)(with other satellites)
• a few percent precision for annual precipitationa few percent precision for annual precipitation• dependence on ancillary measurements:dependence on ancillary measurements:
• surface radars & gagessurface radars & gages• high latitude precipitationhigh latitude precipitation
• Microwave radarMicrowave radarss•Multi-frequency for cloud and precipitationMulti-frequency for cloud and precipitation
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Global Precipitation Measurement: GPM Global Precipitation Measurement: GPM
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Observing the Global Water CycleObserving the Global Water Cycle Global Evaporation, Evapotranspiration and Latent Heat FluxGlobal Evaporation, Evapotranspiration and Latent Heat Flux
• Calculated using bulk formula:Calculated using bulk formula: ________
EELL = = ρρLLeew’q’ w’q’ - -ρρLLeeKKee((q/q/z)z)
= -= -ρρLLeeu (qu (qaa – q – qss))
• Resulting quality limited by:Resulting quality limited by:– Use of bulk formulasUse of bulk formulas– Validating measurements Validating measurements
Global Monthly Latent Heat Global Monthly Latent Heat Flux Flux
Comparison of Comparison of satellite and in-situ satellite and in-situ latent heat flux latent heat flux ((σσ=20 W m=20 W m-2-2))
Comparison of model Comparison of model analyses analyses
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 1414
Observing the Global Water Cycle Observing the Global Water Cycle Water Vapor TransportWater Vapor Transport
• Global water vapor Global water vapor measurements:measurements:– Atmospheric water Atmospheric water
vapor measurement vapor measurement precision good (~10%)precision good (~10%)
– Assimilation of water Assimilation of water vapor in weather vapor in weather prediction modelsprediction models
• Improvements needed:Improvements needed:– Vertical sampling poorVertical sampling poor– Global tropospheric Global tropospheric
winds needed for winds needed for transporttransport
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Observing the Global Water Cycle Observing the Global Water Cycle RunoffRunoff
• Measurements of global Measurements of global runoff:runoff:– Highly inconsistent Highly inconsistent
globallyglobally– Comparisons with Comparisons with
models and models and precipitation is variableprecipitation is variable
– Current proposals for Current proposals for ESSP runoff mission ESSP runoff mission
– Significant continental Significant continental discharge problemdischarge problem
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 1616
Runoff / Surface Water MissionRunoff / Surface Water MissionStream Discharge and Surface Water Height from Stream Discharge and Surface Water Height from
Radar Altimetry ConceptRadar Altimetry Concepte.g. Topex/Poseidon over Amazon R.e.g. Topex/Poseidon over Amazon R.
Motivation:Motivation:• critical water cycle componentcritical water cycle component• essential for water resource planning.essential for water resource planning.• stream discharge and water height data stream discharge and water height data are difficult to obtain outside USare difficult to obtain outside US• find the missing continental discharge find the missing continental discharge componentcomponent
Mission Mission Concepts:Concepts:
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ICESat Goal is to measure ice sheet mass balance: ICESat Goal is to measure ice sheet mass balance: • detect average ice changes of ~ 1 cm/year detect average ice changes of ~ 1 cm/year
• 1 cm = ~5% of annual mass input = ~ 0.001% of total ice mass1 cm = ~5% of annual mass input = ~ 0.001% of total ice mass• annual ice sheet mass changes = ~ annual ice sheet mass changes = ~ ±± 25 cm/yr = ~ 25 cm/yr = ~ ±± 1 cm/yr sea 1 cm/yr sea
levellevel• current sea level rise totals approximately 2 mm/year due to:current sea level rise totals approximately 2 mm/year due to:
• melting of small glaciers, ocean thermal expansion, and ? ? ? ? melting of small glaciers, ocean thermal expansion, and ? ? ? ?
Observing the Global Water CycleObserving the Global Water CycleICESat Measurements of Polar IceICESat Measurements of Polar Ice
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Observing the Global Water CycleObserving the Global Water CycleICESat Measurements of Polar IceICESat Measurements of Polar Ice
• Science Objectives:Science Objectives:– Polar Ice Sheet Mass BalancePolar Ice Sheet Mass Balance– Cloud heights and aerosolsCloud heights and aerosols– Land topography Land topography surface water surface water
• Instrument: Instrument: – Geoscience Laser Altimeter System Geoscience Laser Altimeter System
(GLAS) (GLAS) – Weekly global updateWeekly global update– ~ 3 cm precision (over 100 km~ 3 cm precision (over 100 km22))– ~ 20 cm accuracy = ~ 1 cm sea level~ 20 cm accuracy = ~ 1 cm sea level
• Future Goals:Future Goals:– Improved (denser) spatial coverageImproved (denser) spatial coverage– Improved precision => mass balanceImproved precision => mass balance
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Observing the Global Water CycleObserving the Global Water CycleSnow Cover and Water ContentSnow Cover and Water Content
• Need: Need: – Major annual water Major annual water
resource comes from snow resource comes from snow meltmelt
– Biosphere turns on/off at Biosphere turns on/off at 0°C0°C
• Goal: Goal: – Measure Global Snow Measure Global Snow
Cover and Water Cover and Water Equivalent on ecological Equivalent on ecological and seasonal scalesand seasonal scales
MODIS global snow cover map
• Present and proposed measurements:Present and proposed measurements:– snow cover: color measurements snow cover: color measurements – surface temperature: IR & microwave radiometry surface temperature: IR & microwave radiometry – snow water content: Ku and Ka band Radiometersnow water content: Ku and Ka band Radiometer– surface characteristics & vegetation: C and Ku band SAR; surface characteristics & vegetation: C and Ku band SAR;
hyperspectralhyperspectral
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 2020
Observing the Global Water CycleObserving the Global Water CycleCold Lands MissionCold Lands Mission
• Goals: Goals: – Vastly improved measurement precision and accuracyVastly improved measurement precision and accuracy– Measure global snow cover and water equivalentMeasure global snow cover and water equivalent
• on ecological and seasonal scaleson ecological and seasonal scales• account for the effects of vegetation account for the effects of vegetation
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 2121
Cold Land Processes Hydrology Experiment (CLPX)Colorado, 2002-2003
NASA/JPL/GSFC, NOHRSC, CRREL, USFC, BLM, etc.
Cold Land Processes Pathfinder Mission (CLPM)Synergistic dual-frequency Synthetic Aperture Radar (C- and Ku-band)
and radiometers (18- and 37-GHz). Shared ~2-m antenna with 100m SAR and 5 km radiometer (25km swath).
Mission concept:Mission concept:• Active microwave (C & KU band radar) Active microwave (C & KU band radar) • Passive microwave (19, 37 GHz)Passive microwave (19, 37 GHz)• Capable of full global twice daily coverage (wide swath)Capable of full global twice daily coverage (wide swath)• High spatial resolution (passive to 3-5km)High spatial resolution (passive to 3-5km)• Address global cryospheric monitoring needsAddress global cryospheric monitoring needs
Observing the Global Water CycleObserving the Global Water Cycle
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Observing the Global Water CycleObserving the Global Water Cycle Aquarius Ocean Salinity MissionAquarius Ocean Salinity Mission
• Ocean Salinity:Ocean Salinity: – Drives thermo-haline circulation Drives thermo-haline circulation – Investigate changes with climate Investigate changes with climate
variabilityvariabilityCool, saline water sinks, forms Cool, saline water sinks, forms the ocean deep-water sourcethe ocean deep-water source
Increased salinity due to Increased salinity due to mid-latitudemid-latitude evaporationevaporation
Reduced salinity due to rainfall in inter-tropical convergence zone
Increased salinity in Atlantic ocean … Why?
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 2323
radiometer (GSFC)radiometer (GSFC)– Global coverage in 3 daysGlobal coverage in 3 days– 40 km resolution40 km resolution– Stability: 0.5K Stability: 0.5K – MIT-JPL-Goddard MissionMIT-JPL-Goddard Mission
capabilities?capabilities?− 1 km resolution1 km resolution− Root zone penetrationRoot zone penetration
Observing the Global Water CycleObserving the Global Water Cycle HYDROS Soil Moisture MissionHYDROS Soil Moisture Mission
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 2626
Observing the Global Water CycleObserving the Global Water CycleGRACE: GRACE: groundwater, soil moisture, snow, surface groundwater, soil moisture, snow, surface
water water
GRACE senses water storage GRACE senses water storage changes as variations in the changes as variations in the Earth’s gravity fieldEarth’s gravity field
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Terrestrial Water Storage Anomalies in the Mississippi River Basin, April 2002 – December 2003
Bars = GRACE terrestrial water storage (800km smoothing)Dots = Atmospheric-terrestrial water balanceRed line = GLDAS/Noah modeled soil moisture + snowBlue line = Well observations of groundwaterGreen line = Red line + Blue line (Total Water Storage)Green line = Red line + Blue line (Total Water Storage)
GRACE team:GRACE team:• U. of TexasU. of Texas• JPLJPL• GSFCGSFC
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FORCING DATA & FORCING DATA & PARAMETERSPARAMETERS
Land Data Assimilation System (LDAS)Land Data Assimilation System (LDAS) Provides land surface states (snow depth, soil moisture, temperature, etc.) Provides land surface states (snow depth, soil moisture, temperature, etc.) and fluxes (evaporation, etc.) for water resource applications.and fluxes (evaporation, etc.) for water resource applications.
Results used to initialize of weather and Results used to initialize of weather and climate prediction models and surface water climate prediction models and surface water resource applications.resource applications.
APPROACH: Force land surface APPROACH: Force land surface models with data from space-models with data from space-based and ground observing based and ground observing systems.systems.
Root zone soil water content [%]LDASNorth American LDAS
Soil Moisture, Evaporation, Energy Fluxes, River Runoff, Snowpack Characteristics, etc.
Application DSSApplication DSS
Floods/Drought, AgricultureManagement, Water Quality withUSDA, Bureau Reclamation, EPA
Assimilation
Land Surface Model
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Measurement approaches must consider the requirements for:
• frequency of observation
• spatial sampling
• measurement precision
As set by the characteristic scales of the phenomena.
Observing the Global Water CycleObserving the Global Water Cycle
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 2929
Observing the Global Water Cycle:Observing the Global Water Cycle:
• As a 20 year goal, the global water cycle As a 20 year goal, the global water cycle can be measured with sufficient can be measured with sufficient
• temporal and spatial resolution, temporal and spatial resolution, • measurement precision,measurement precision,
to provide needed understandings ofto provide needed understandings of• natural variability in availability of water,natural variability in availability of water,• short term climatic effects, and short term climatic effects, and • changes in cycling of water due to long term climate changes in cycling of water due to long term climate
change.change.
• But:But:– Could this be done operationally?Could this be done operationally?
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Select instruments based on measurement requirements and observational capabilities:
• sampling & precision
Observing the Global Water Cycle: Observing the Global Water Cycle:
Select orbits based Select orbits based on instrument on instrument measurement measurement capabilities and capabilities and orbital sampling orbital sampling characteristicscharacteristics
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Observing the Global Water Cycle: Observing the Global Water Cycle: Satellites and Data AccessSatellites and Data Access
Is it reasonable Is it reasonable to consider to consider observing observing
Earth’s complete Earth’s complete water cycle water cycle
with >20 with >20 satellites?satellites?
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LEO orbits:LEO orbits:8-10 satellites provide:8-10 satellites provide:
• multi-hour to multi-hour to multi-day scalesmulti-day scales• longer longer wavelength wavelength instrumentsinstruments
Special LEO:Special LEO:• ~10 satellites~10 satellites• multi-day to multi-day to weekly samplingweekly sampling• longer longer wavelength wavelength instrumentsinstruments
Observing the Global Water Cycle: Observing the Global Water Cycle: Satellites and Data AccessSatellites and Data Access
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Observing the Global Water Cycle: Observing the Global Water Cycle: Satellites and Data AccessSatellites and Data Access
•Sensor WebSensor Web–links data to links data to computational nodescomputational nodes–synthesizes synthesizes information in data information in data assimilation modelassimilation model
Develop a network of Develop a network of specialized satellites all specialized satellites all working togetherworking together
Data are accessed by Data are accessed by end users.end users.
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 3434
Future Operational Water Cycle Observations & Predictions
Water Table
3-D Cloud & Water Vapor
Global Precipitation
Ocean Salinity
Soil Moisture
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Ice and Snow
02 February 200502 February 2005 Goddard Space Flight CenterGoddard Space Flight Center 3535
Observing the Global Water Cycle:Observing the Global Water Cycle:What are we doing at Goddard?What are we doing at Goddard?
Measurement of components of the water cycleMeasurement of components of the water cycle::
