# Presentation: 284682

## The Aquarius/SAC-D Satellite Mission

**Gary Lagerloef**
***Aquarius***** Principal Investigator**

**South Atlantic Workshop**
**Buenos Aires  7-10 May 2007**

**F. Raúl Colomb **
**SAC-D Principal Investigator**

## International Partnership between United States – Argentina

**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***

**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 ******Ocean******s****** and ******the ******Effect******s****** 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 

- 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**

**MWR**

- Microwave Radiometer

- New InfraRed Sensor Technology

- Data Collection System

- Radio Occultation Sounder for the Atmosphere

- High Sensitivity Camera

- Technology Demonstration Package

- Service Platform

- Mass: 1675 Kg
- Power:1443 W
- Oper. Life: 5 yrs

- Satélite de Aplicaciones Científicas-D

##  Level 1 Science Objectives

** ****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.

_**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

## 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

## Land use Index

- Simple land index derived from SSMIS 22V, 37V, 37H.
- Low resolution.
- Courtesy F. Wentz

**Land use Index**

## Science Measurement Perspective

**Data to Community**

***Beams point toward ***
***the night side to avoid sun glint***

**Launch**
**2010**

***Sun-synchronous exact repeat orbit***
***6pm ascending node***
***Altitude 657 km; 98 deg inclination***
***Earth viewing & Nadir pointing instruments***

**Surface Validation**

*** ******Global Coverage in 7 Days***
*** ******4 Repeat Cycles per Month***

**Ground System**
**& Data Processing**

## Orbit and Swath

## Smoothing Effect of the Aquarius Footprint 

## Science Goal: Net Freshwater Budget

**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)

## 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.

## 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.

***http://www.conae.gov.ar/elespacioyud/ambitoeduc.html***

***http://aquarius.gsfc.nasa.gov/education.html***

## 2010 

- 2010
- A Space Odyssey

**Notes:**
Formulation Phase: 15 months
Implementation Phase: 37 months
Operations Phase: 36 months
Major System Reviews and key milestones
The Key Products are shown below (Phases 2, 3, 4 and 5)