NASA RESEARCH PRIORITIESNASA RESEARCH PRIORITIES SCIENTIFIC RETURNSCIENTIFIC RETURN

Aquarius Science Goal – To understand the regional and global processesthat couple changes in the water cycle and ocean circulation and influence

present and future climate.

Aquarius Science Goal – To understand the regional and global processesthat couple changes in the water cycle and ocean circulation and influence

present and future climate.

Science Objectives:Seasonal cycle & year-to-yearvariabilityDiscovery & Exploration Salinity mapping of unmeasuredregions & features unknown to scienceWater CycleSalinity response to surface water fluxesOcean Circulation & Climate• Tropics Climate feedback processes,El Niño, La Niña• Mid-Latitudes Subduction andmode water formation• High-Latitudes Deep waterformation processes

Science Objectives:Seasonal cycle & year-to-yearvariabilityDiscovery & Exploration Salinity mapping of unmeasuredregions & features unknown to scienceWater CycleSalinity response to surface water fluxesOcean Circulation & Climate• Tropics Climate feedback processes,El Niño, La Niña• Mid-Latitudes Subduction andmode water formation• High-Latitudes Deep waterformation processes

Aquarius Measurement Objectives:Resolve key ocean and climate

phenomena at 100 km and larger spatialscales, monthly and longer time scales.

Aquarius Measurement Objectives:Resolve key ocean and climate

phenomena at 100 km and larger spatialscales, monthly and longer time scales.

Earth System Variability &Trends: How are global

precipitation, evaporation, and thecycling of water changing?

Earth System Variability &Trends: How are global

precipitation, evaporation, and thecycling of water changing?

Earth System Responses & FeedbackProcesses: How can climate variations

induce changes in the global oceancirculation?

Earth System Responses & FeedbackProcesses: How can climate variations

induce changes in the global oceancirculation?

Global Water CyclePrecipitationEvaporation

Ice Freeze/MeltLand Runoff

Global Water CyclePrecipitationEvaporation

Ice Freeze/MeltLand Runoff

ChangeChange

Water FluxWater Flux SeawaterDensity

SeawaterDensity

ImpactImpact

Ocean CirculationSurface HeightBarrier Layers

El Niño/La NiñaThermohaline Flow

Ocean CirculationSurface HeightBarrier Layers

El Niño/La NiñaThermohaline Flow

Changes in global oceancirculation and heat transporthave lasting climate impact

Changes in global oceancirculation and heat transporthave lasting climate impact

86% of evaporation & 78% of precipitation occurover the ocean, dominating

the water cycle

86% of evaporation & 78% of precipitation occurover the ocean, dominating

the water cycle

Aquarius Salinity Measurements Will Provide the Missing Parameter thatLinks Two Major Climate System Components:

Aquarius Salinity Measurements Will Provide the Missing Parameter thatLinks Two Major Climate System Components:

AquariusSea Surface

Salinity (SSS)

• Salinity responds to changes in the surface water fluxes and, in turn, alters thesurface density field that drives ocean currents• Observing ocean salinity is the only way to measure how water cycle changeseffect the ocean & its circulation

• Salinity responds to changes in the surface water fluxes and, in turn, alters thesurface density field that drives ocean currents• Observing ocean salinity is the only way to measure how water cycle changeseffect the ocean & its circulation

Measured in practical salinity units (PSU)

Aquarius will show details ofglobal SSS variability, shown withthis March-April-May map froman ocean model. Compare with

lower map that shows allhistorical data for March-April-

May.

Aquarius will show details ofglobal SSS variability, shown withthis March-April-May map froman ocean model. Compare with

lower map that shows allhistorical data for March-April-

May.

Aquarius will aidunderstanding of:

•Seasonal cycle & mixing inclimate models

•Salinity transport by currents•Ocean state & freshwaterbudget

•SSS impact on tropical climatemodels & El Niño

•SSS impact on oceansubsurface dynamics

•Ice-ocean interaction•Processes that keep theAtlantic relatively salty

Aquarius will aidunderstanding of:

•Seasonal cycle & mixing inclimate models

•Salinity transport by currents•Ocean state & freshwaterbudget

•SSS impact on tropical climatemodels & El Niño

•SSS impact on oceansubsurface dynamics

•Ice-ocean interaction•Processes that keep theAtlantic relatively salty

Surface salinity is linked tothe water cycle: Mean SSS is

highest where evaporationexceeds precipitation (E-P >0),

and is lowest where there isexcess precipitation, especially

in the tropics

Surface salinity is linked tothe water cycle: Mean SSS is

highest where evaporationexceeds precipitation (E-P >0),

and is lowest where there isexcess precipitation, especially

in the tropics

(PSU)

It’s the right time forAquarius:

•Global array of profilingfloats will follow surfacesalinity and densityresponse at depth

•Aquarius will complete asatellite-based climateobserving system (i.e.,rain, wind, sea level, seasurface temperature)

It’s the right time forAquarius:

•Global array of profilingfloats will follow surfacesalinity and densityresponse at depth

•Aquarius will complete asatellite-based climateobserving system (i.e.,rain, wind, sea level, seasurface temperature)

SSS (PSU)

E - P (m/yr)