Update From Aquarius PI Gary Lagerloef: Our One Year Anniversary
Today, 25 June 2012, marks 10 months since the start of routine data collection on 25 August 2011. Sunday, June 10, marked the one year anniversary of the launch of Aquarius/SAC-D from Vandenberg Air Force Base, California, 14:20:13 UTC. If you are as nostalgic as I am, you can view the launch sequence again here.
Aquarius Science Cal/Val Workshop: 29 October - 2 November 2012
NASA Goddard Space Flight Center, Greenbelt, Maryland
This gathering is primarily a project calibration/validation workshop to review the results of the algorithm updates taking place over the summer (see below). The main agenda is to assess the progress of the calibration/validation working group and the current state of the data processing and measurement uncertainties, prior to the release of validated data in December 2012. There will be a day included for science sessions on data analysis and research results in addition to the calibration/validation. Members of the broader international SAC-D/Aquarius, Soil Moisture and Ocean Salinity (SMOS) mission, and NOAA science teams will also be welcome. More logistic details will be provided during the summer.
Fall American Geophysical Union (AGU) Meeting Special Session
OS034: Science Results from the Aquarius and SMOS Ocean Salinity Missions
Please make plans for presenting your early results from Aquarius or SMOS measurements at this session. We expect this session to be well attended. Abstract deadline is 8 August 2012.
Other related sessions include:
  • OS028: Ocean Surface Emissivity for Passive Remote Sensing Observations
  • OS024: Observations and Modeling of Regional and Global Freshwater and Saltwater Budgets and Transport
  • H045: SMOS - ESA's Water Mission
  • H033: Using Field Measurements and Experiments to Advance Science
Special sessions for salinity remote sensing are also planned for IGARSS (IEEE Geoscience and Remote Sensing Society), 23-27 July, in Munich.
Journal of Geophysical Research (Oceans)
As announced in the last bulletin, a special section has been approved by the editorial board, titled "Early scientific results from the salinity measuring satellites Aquarius/SAC-D and SMOS". The submission window has now been postponed a few months and will be open next year from February 1st to May 30th, 2013. The topics will cover new science results, data validation, modeling and analysis, and related topics. More will be posted on this in the months ahead, including submission details. Please start thinking now about research topics relevant to your studies that would be suitable for this landmark Journal of Geophysical Research collection.
Recent Science Team Meeting
The Aquarius/SAC-D Science Team Meeting was held 11-13 April 2012 in Buenos Aires. The meeting website is here. This was the first joint Aquarius/SAC-D Science Team meeting after the launch, and its central purpose was to assess the status and science progress for both the Aquarius and SAC-D sides of the mission. The agenda included mission operations, algorithm, data processing, calibration and data validation updates. Science presentations covered various comparisons with in situ data, SMOS data and models. Other important breakout discussions addressed the effect of near surface salinity stratification on the validating the satellite salinity with in situ platforms, and relation to accumulated rainfall, diurnal cycles, ascending-descending differences, and understanding 'skin' versus 'bulk' surface salinity in general. There was a general consensus to foster more collaboration between Aquarius and SMOS on many of these common problems. Breakout sessions also covered status and results from the SAC-D instruments: Microwave Radiometer (MWR), New Infrared Sensor Technology (NIRST), High Sensitivity Camera (HSC) and Data Collection System (DCS).
Aquarius Science Algorithm and Data Products
At the start of the April science meeting, the Aquarius project released Version 1.3 (V1.3) reprocessed data. Since that time, V1.3 is the baseline algorithm in the Aquarius data processing stream. The data files appear at the Physical Oceanography Distributed Active Archive Center (PO.DAAC) with about 2 or 3-day latency. Previous versions (V1.1, V1.2DR, V1.2.2 and V1.2.3) will remain at the PO.DAAC as an archive, but are no longer being processed.
The PO.DAAC link to Aquarius data is here.
Two key features of V1.3 are:
  • The scatterometer data are included with National Centers for Environmental Prediction (NCEP) vector wind in a hybrid roughness correction; and
  • The deflection ratio (DR) calibration drift correction is applied in the processing stream. This uses internal noise diode temperatures to effectively remove the secular long-term calibration drift and a portion of shorter-term variations, although small residual errors (informally called "wiggles") on quasi-monthly timescale remain in the data.
The Discussion Forum. This tool has been available for some time, and now I am advocating the use of it for an open Sea Surface Salinity Users Working Group. The page is called the "SEA SURFACE SALINITY SCIENCE TEAM FORUMS". There is a one-time registration. Go here and click on create new account. You will then receive an email confirming your addition to the forum. A few subgroups are listed, and we will start with a subgroup called SSS Products and Algorithms, which (perhaps by the time you read this) will be renamed the SSS Users Working Group. Please use this forum to share your findings, particularly regarding surface validation, ask questions and make comments. If issues arise with the forum site, please contact:
Mission Status. The Aquarius sensor and the SAC-D observatory continue to perform well. There are a few brief interruptions in the precise geodetic pointing during the first and last quarters of the lunar cycle as the moonlight sometimes interferes with the star tracker. Two cold-sky calibration maneuvers have been done in recent months, and the next one is planned for 30-Jun-12. This maneuver lets the radiometers measure the cosmic background for calibration. A chronology of SAC-D/Aquarius maneuvers, anomalies and events is located here, and can also be accessed from the main Aquarius webpage via the "Data" link. Below is the 9-month composite global image for the time period 25-Aug-11 through 04-Jun-12 using the V1.3 data.