The Aquarius/SAC-D Satellite Mission

The Aquarius/SAC-D Satellite Mission

Gary LagerloefAquarius Principal Investigator

South Atlantic WorkshopBuenos Aires 7-10 May 2007

F. Raúl Colomb SAC-D Principal Investigator

South Atlantic Workshop 28-10 May 2007, San Ceferino, Buenos Aires

G. Lagerloef, Raul Colomb

Salinity Mapping Satellite Mission

• Aquarius Salinity Microwave Instrument

• Launch Vehicle

• Service Platform and SAC-D Science Instruments

• Mission Operations & Ground System

International Partnership between United States – Argentina

Mission Partnership




NASA’s Mission Objective

A Key to Studying the Global Hydrologic Cycle and Global Change

Aquarius Mission is About Understanding the Interactions Between the Global Water Cycle, Ocean Circulation and Climate Through the Measurement of SSS

Aquarius Mission is About Understanding the Interactions Between the Global Water Cycle, Ocean Circulation and Climate Through the Measurement of SSS

Investigate the links between the global water cycle, ocean circulation and climate

Make global, space-based measurements of Sea Surface Salinity (SSS) with high accuracy

Observe and model seasonal and year-to-year variations of SSS , and how these relate to changes in the water cycle and ocean circulation

Aquarius will yield an unprecedented view of ocean’s role in climate and weather

A Critical Climate Parameter Missing from the Present Satellite Observing Network




CONAE’s Mission Objective

The SAC-D Science Mission is About Conducting Local Measurements Over Argentina and Contributing to Global Investigations of the Atmosphere, the

Oceans and the Effects of Human and Natural Processes on the Environment as Defined in the Strategic Plan of the Argentine National Space Program

The SAC-D Science Mission is About Conducting Local Measurements Over Argentina and Contributing to Global Investigations of the Atmosphere, the

Oceans and the Effects of Human and Natural Processes on the Environment as Defined in the Strategic Plan of the Argentine National Space Program

Validate technology for future CONAE missions

Monitoring atmospheric parameters

Understanding ocean circulation, global water cycle and climate interaction

Monitoring environmental changes, natural hazards and sea ice

Studying effect of cosmic radiation on electronic devices and characteristics of space debris

SAC-D Science Mission is About Conducting Local Measurements Over Argentina




Instruments + S/P Observatory

DCS

NIRST

Aquarius(primary instrument)

TDP

SAC-D S/P

CARMEN-1(ICARE-NG & SODAD) ROSA

HSC

Aquarius/SAC-D Observatory

MWRMicrowave Radiometer

New InfraRed Sensor Technology

Data Collection SystemRadio Occultation Sounder for the Atmosphere

High Sensitivity Camera

Technology Demonstration Package

Service Platform

Mass: 1675 KgPower:1443 WOper. Life: 5 yrs

Mass: 1675 KgPower:1443 WOper. Life: 5 yrs

Satélite de Aplicaciones Científicas-D




Instrument Objectives Specifications Resolution Owner

Aquarius Understanding ocean circulation, global water cycle and climate interaction. Soil Measures over

Argentina

Integrated L-band radiometers (1.413Ghz) and scatterometer

(1.26Ghz)

Three beams: 76 x 94, 84 x 120, 96 x

156 km

NASA

MWR Precipitation rate, winds peed, sea ice concentration, water vapour, clouds

23.8 and 36.5 GHzH and V pol.

Bandwidth: 0.5 and 1 GHzSwath:380 km

54 km CONAE

NIRST Hot spots events, sea surface temperature measurement

3.8, 10.85 and 11.85 Swath: 180 kmTilt: +/-30 deg.

350 meters CONAE

HSC Urban lights, electric storms, Polar regions, snow cover

450-900 nmswath: greater than 700 km

200-300 meters CONAE

DCS Data Collection System 401.55 Mhz uplink 2 contacts per day with 200 platforms

CONAE

ROSA Atmospheric properties GPS Occultation Techniques Horiz: 300 kmVert: 300 m

ASI

Carmen 1ICARE and

SODAD

I: Effect of cosmic radiation on electronic devices

S: distribution of microparticles and space debris

I: three fully depleted Si and Si/Li detectors

S: four SMOS sensors

I: 256 channels S: Sensitivity 5 μm part at 10

km/sec

CNES

TDP Position, velocity and time determination

Inertial angular velocity

GPS receiver

Inertial reference unit

20 m, 1 m/sec, .2µsec

ARW: 8* 10-3

deg/sqrt h

CONAE

Level 1 Science Objectives




Aquarius Instrument

76 x 94 km 96 x 156 km

84 x 120 km

3 Beams, 390 km swath, full coverage between adjacent orbit tracks.

3 Beams, 390 km swath, full coverage between adjacent orbit tracks.

Primary Objective: Understand Ocean Circulation; Global water cycle and climate

interaction Measure global SSS from space (0.2 psu rms on 150x150 km

scale over ice free oceans, monthly)

Instrument Description & Measurement Technique: Sea surface brightness temperature measured by stable

polarimetric radiometers operating at 1.413 GHz. Salinity is derived by measuring brightness temperature at L-Band

Coincident sea surface backscattering cross-section measured by stable polarimetric scatterometer operating at 1.26 GHz. Roughness is the largest correction and is measured with the integrated L-band Scatterometer

Uses Deployable offset parabolic monolithic 2.5m reflector with three feedhorns provides three beams in a push-broom configuration

Revisit: 7 day repeat cycle Mass: 400 kg; Power: 450 W Operational Life: 3 years

Data Products: Derived Geo-located SSS Time spaced averaged SSS maps

6 8 10 12 14 16 18 20 22 24 26 28 30 32 34118

120

122

124

126

128

130

132

134

Water Temp (C)

Tant

(K

)

25 psu 35 psu 40 psu K&S ModelL-Band Vertical

6 8 10 12 14 16 18 20 22 24 26 28 30 32 34118

120

122

124

126

128

130

132

134

Water Temp (C)

Tant

(K

)

25 psu 35 psu 40 psu K&S ModelL-Band Vertical

Sensitivity vs Radiometer Frequency

1400-1427 MHz Protected Band

Tb=εT

ε = f(S, T, Freq, Incidence)

0 0.5 1 1.5 2 2.5 3

Sigma x1000

123.5

124

124.5

125

125.5

126

126.5

127

127.5

Tb

(

K)

67E67W

70/7377

19JulM214_16

CurveFit 3rdCurveFit 2nd

TbV and Sigma LH

0 0.5 1 1.5 2 2.5 3

Sigma x1000

123.5

124

124.5

125

125.5

126

126.5

127

127.5

Tb

(

K)

67E67W

70/7377

19JulM214_16

CurveFit 3rdCurveFit 2nd

TbV and Sigma LH




MWR Instrument

Primary Objective: Microwave Radiometer (MWR) measure surface brightness temperature in the

frequency range sensitive to geophysical parameters over the ocean to contribute to climate and hydrological forecasting for the La Plata basin, Patagonia and Antarctica

MWR data complements Aquarius SSS measurements by providing 8 overlapping beams

Instrument Description & Measurement Technique: Two continuously operating radiometers at 23.8 GHz (K band; V-pol) and at 36.5

GHz (Ka band, polarimetric H & V) over land and sea (with 8 feeds per frequency)

390 km Swath width (coincident with Aquarius) Resolution of 50 km (across-track) Coverage: Global

Precipitation Wind Speed




Simple land index derived from SSMIS 22V, 37V, 37H.

Low resolution.

Courtesy F. Wentz

Land use Index




Data to CommunityData to Community

Science Measurement Perspective

Beams point toward the night side to avoid sun glint

Beams point toward the night side to avoid sun glint

Launch

2010

Launch

2010

Sun-synchronous exact repeat orbit6pm ascending nodeAltitude 657 km; 98 deg inclinationEarth viewing & Nadir pointing instruments

Surface ValidationSurface Validation

Global Coverage in 7 Days 4 Repeat Cycles per Month

Global Coverage in 7 Days 4 Repeat Cycles per Month

Ground System& Data Processing

Ground System& Data Processing




Orbit and Swath




Smoothing Effect of the Aquarius Footprint




5 March 2007

Science Goal: Net Freshwater Budget

• Examine mean salt (SSS) advection and divergence

• Trial balance with E-P net surface freshwater forcing

U·∇S ~ S(E-P)/H

OSCAR = Geostrophic + Ekman @ 15m




2005-2006 Argo mean SSS




Net Freshwater Flux

Precipitation (GPCP)

&

Evaporation (Lisan Yu,

WHOI)

H




Net flux vs Salinity divergence

S(E-P)/H

psu · year-1

U·∇S

psu · year-

1




Surface forcing minus advection

Preliminary findings:

•Global SSS divergence patterns are of the same magnitude as E-P forcing, and thus SSS advection has a predominant role in the net surface freshwater budget.

•Differences between SSS divergence and (E-P)/H are of similar magnitude and are partly the result of meridional offsets of the peak latitudes.

MeridionalZonalTotal

(E-P)/H




Education & Public Engagement

Education and Public Outreach will increase awareness and understanding of how the earth functions as a system – and technology’s role in enabling

development of the knowledge – through Informal and Formal Education and Professional Development activities.

Education and Public Outreach will increase awareness and understanding of how the earth functions as a system – and technology’s role in enabling

development of the knowledge – through Informal and Formal Education and Professional Development activities.

http://www.conae.gov.ar/elespacioyud/ambitoeduc.html http://aquarius.gsfc.nasa.gov/education.html




2010

A Space Odyssey

Documents

The Aquarius/SAC-D Satellite Mission