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2011 Aquarius Calibration/Validation Workshop

2011 Aquarius Calibration/Validation Workshop
November 15-17, 2011
Jet Propulsion Laboratory, Pasadena, CA

The objective of the 2011 Aquarius Calibration/Validation Workshop was to discuss post-launch plans for the Calibration and Validation of the Aquarius/SAC-D satellite. The three day workshop's objectives were to: (1) review the radio frequency interference (RFI) mitigation algorithms, review the (2) radiometer and (3) scatterometer calibration performance, (4) assess the performance of geophysical correction algorithms, and (5) make decisions that would lead to the processing of data Version 1.3.

Agenda
Documents (36)
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Aquarius Calibration Analysis
Brown, S. and Misra, S. (15-Nov-11). An analysis of several aspects of the radiometer calibration, including the linearity correction, reflector emissivity, 3rd Stokes calibration and gain and offset drift.

Aquarius Calibration Sub-Group Summary Report
Aquarius Calibration Sub-Group (15-Nov-11). A summary report provided by the Aquarius Calibration Sub-Group.

Aquarius Data Processing System
Feldman, G.C., Gales, J., Hong, L., Kuring, N., Patt, F., Scott, A., and Wilding, J. (15-Nov-11). The Aquarius Ground System at NASA/GSFC consists of the Aquarius Data Processing System (ADPS) and the Aquarius Command and Control System (ACCS). This talk outlines the software development and distribution process, and the required documentation resulting from this process.

Aquarius L-2 Data Moderate-scale Salinity Features: Calibration Issues, Resolution, Noise
Melnichenko, O., Hacker, P., Maximenko, N., and Potemra, J. (16-Nov-11). Between 40-60 degrees south and 15-50 degrees north, there are large differences between beams. The noise in the records varies with latitude. A tentative conclusion from this analysis is that along-track calibration may be required for each beam seperately.

Aquarius Pointing Assessment
Fore, A. (15-Nov-11). An assessment of the pointing error for aquarius is shown to be stable over time, to ~0.1 degrees. The pointing errors can be represented well by biases on the individual beams. Additionally, consistent results were found with both radar and radiometer data.

Aquarius Post Launch Cal/Val Workshop Welcome and Overview
Yueh, S. (15-Nov-11). An overview of the objectives and logistics for the 2011 Calibration/Validation Workshop.

Aquarius Roughness Correction
Brown, S. (16-Nov-11). Ocean roughness has been found to have an affect on the SSS signal, and thus a roughness correction is needed. This talk outlines the roughness corrections approaches for SSS retrieval.

Aquarius Soil Moisture Retrieval
Jackson, T., Bindlish, R., and Zhao, T. (16-Nov-11). The baseline soil moisture algorithm uses the radiative transfer equation (t-w model) and H pol observations along with ancillary data to estimate soil moisture. A difference between the Aquarius and SMAP implementation is the need to incorporate incidence angle effects.

Aquarius Status
Sen, A. (15-Nov-11). The current status and overview of Aquarius since launch. Includes a review of the commissioning and orbit checkout timeline, and the status of the observatory. The observatory remains healthy, and the SAC-D instrument have been commissioned. The Aquarius instrument has met all success criteria n the PLAR and is ready for operations.

Ascending and Descending Differences of Salinity Retrieval
Yueh, S., Tang, W., and Hayashi, A. (17-Nov-11). The ascending and descending passes of salinity retrieval are different, and show a systematic regional bias between ascending and descending passes. There does not appear to be an obvious connection with the salinity bias.

Beacon Overpass
Ruff, C., and Chen, D. (15-Nov-11). The results of a ground-based beacon overpass, positioned at the inner and outer beam edges.

Brightness Temperature Calibration of SAC-D/Aquarius Microwave Radiometer
Biswas, S.K., Jones, L., Gallo, J-C., and Rocca, D. (17-Nov-11). The calibration performed on the Aquarius/SAC-D microwave radiometer for the brightness temperature.

Combined Active-Passive (CAP) Algorithm for SSS and Wind Vector Retrieval
Yueh, S., Tang, W., Fore, A., Chaubell, J., and Hayashi, A. (17-Nov-11). The Combined Active-Passive (CAP) algorithm to retrieve wind vectors is analyzed. It is found that CAP can produce consistent SSS and wind retrievals, and it is more accurate by about 25% on average and 50-100% more accurate for high winds.

Comparison of Aquarius Measurements and Simulations
Dinnat, E. (15-Nov-11). Comparisons of measured antenna temperatures and simulated ones to assess calibration bias over ocean scenes, calibration drift over ocean scenes, and calibration over cold sky.

Error Reduction in the Measurement of the Dielectric Constant of Seawater at 1.413 GHz
Lang, R.H., Zhou, Y., Utku, C., and Le Vine, D. (17-Nov-11). The purpose of this research is to develop an accurate model for the dependence of the dielectric constant of seawater on temperature and salinity. The dielectric measurements should have an accuracy of 02% to meet the Aquarius goal of measuring salinity to an accuracy of 0.2 PSU.

Evaluation of Radiometer RFI Flagging Algorithm
de Matthaeis, P., and Le Vine, D. (15-Nov-11). The goal of this research is to identify regions adversely affected by radio frequency interference (RFI) and provide an analysis of the RFI flagging algorithm.

GMF Radiometer Ascending/Descending (Day 1)
Tang, W. (16-Nov-11). Results for the geophysical model function (GMF) for the radiometer, for both ascending and descending passes.

GMF Radiometer Ascending/Descending (Follow-up)
Tang, W. (17-Dec-17). An analysis of additional results for the geophysical model function on ascending and descending passes.

Inter-Comparison Between Aquarius and SMOS Observations
Bindlish, R., Jackson, T., and Zhao, T. (16-Nov-11). When comparing Aquarius and SMOS observations, it was found that Aquarius observations compare well with SMOS. There are differences in scatter due to RFI, heterogeneous footprint, and different azimuth angles between the two instruments.

MWR Geophysical Retrievals
Jones, L., Hejazin, Y. and Aslebagh, S. (17-Nov-11). An overview of the retrieval algorithms for columnar water vapor, oceanic wind speed, and rain rate. Preliminary radiometer geophysical retrievals are compared with collocated WindSat environmental records.

MWR Tb Anomaly: Antenna Pattern Effects
Jones, L. and Farrar, S. (17-Nov-11). "MWR has a parabolic torus reflector antenna design with 8 component beams. In this talk, examples of the ""smearing"" effect of the radiometer offset, as well as ""worst-case"" examples for land and ocean crossings."

Proposal for TA Bias Correction Using Deflection Ratios
Piepmeier, J. (16-Nov-11). Freely forcing radiometer calibration bias to =0 could potentially mask geophysical modeling errors. The objective of this proposal is to constrain bias correction to instrument behavior. This talk outlines the approach, algorithm, and the convergence of model parameters.

Radiometer Pointing Accuracy Assessment
Dinnat, E. (15-Nov-11). In the assessment of the radiometer pointing accuracy, it was found that there is good agreement of model to observation at full land and full ocean locations. There should be small impact of model uncertainty on relative levels during transitions.

Regional and Global Analysis Using Aquarius Validation Data Segment
Kao, H-Y., Lagerloef, G., and Carey, D. (16-Nov-11). A regional and global analysis of Aquarius data, using the Aquarius Validation Data Segment. The Aquarius L2/V1.2 data are compared between ascending and descending tracks along with other variables.

Roughness Correction for AQ SSS Algorithm using MWR
Jones, L., and Hejazin, Y. (17-Nov-11). This talk outlines a roughness correction from salinity retrieved by the microwave radiometer (MWR).

RSS Aquarius Cal/Val Activities: Overview and Results
Meissner, T., and Wentz, F. (15-Nov-11). This overview provides a summary of Aquarius Cal/Val Activities a review of results.

Salinity Retrieval Algorithm
Wentz, F. and Meissner, T. (16-Nov-11). This talk includes a review of current algorithm updates, a brief description of the reflected galaxy computation, analysis of Sigma-wv and Sigma-hh, a method of removing the TB roughness component. Salinity retrieval results are also shared.

Scatterometer and Radiometer Variations Due to Sea State Using Wave Model Data
Vandemark, D., Feng, H., Ardhuin, F, Chapron, B., and Reul, N. (17-Nov-11). The goal of this work is to develop and refine an empirical SSS correction for long wave impacts that augment winds, Aquarius scatterometer, or other ocean roughness information.

Scatterometer Calibration
Fore, A. (16-Nov-11). The components of the scatterometer calibration were discussed in this talk, including the bias correction factor, antenna pattern correction, and faraday rotation correction.

Scatterometer RFI Detection Algorithm and Mitigation
Freedman, A., Fore, A., Neumann, G., and Huneycutt, B. (15-Nov-11). The topic of this presentation are the Aquarius RFI products that may be of interested to the large community, a discussion of on-board RFI flagging, and an overview of the process of detecting RFI outliers and flagging them.

Scatterometer Stability
Neumann, G., Yueh, S., Fore, A., Freedman, A., Hayashi, A. and Tang, W. (16-Nov-11). To assess the scatterometer stability, measurements were compared to expected over three locations - open ocean, Dome-C and over the Amazon plume. The results demonstrated that the scatterometer is stable to within ~.1db over time. The difference between the ascending and descending Sigma0 over DOME-C is large, especially for Beam 1.

Scatterometer Stability (Follow-up)
Neumann, G., Yueh, S., Fore, A., Freedman, A., Hayashi, A. and Tang, W. (16-Nov-11). To assess the scatterometer stability, measurements were compared to expected over three locations - open ocean, Dome-C and over the Amazon plume. The results demonstrated that the scatterometer is stable to within ~.1db over time. The difference between the ascending and descending Sigma0 over DOME-C is large, especially for Beam 1. This talk contains additional slides covering the DOME-C results.

Scatterometer Temperature Calibration
Freedman, A. (16-Nov-11). An overview of efforts to calibrate the scatterometer temperature. For current benign space environment, it appears to be irrelevant whether temperature calibrations are used. If the environment degrades, the temperature calibration correction may have a more noticeable effect.

Science Data Monitoring and Telemetry Trending
Freedman, A., Piepmeier, J., and Hong, L. (15-Nov-11). Full sets of Aquarius telemetry are monitored at every downloading for red and yellow outliers, which is linked to an automatic alarm system. These telemetry are viewable using web tools. There is a desire to compute and view daily averages of all telemetry items, and to be able to compute and view full sets of daily statistics for selected items.

TA Calibration Bias and Trend Analysis
Ruff, C., Mims, A. and Chen, D. (15-Nov-11). A trend analysis and overview of the antenna temperature (Ta) calibration. Two calibration approaches were used: a global average, and a vicarious cold calibration. This was performed for the full time series available - from August to November 2011.

TA Calibration Bias and Trend Analysis
Ruf, C., Mims, A., and Chen, D. (16-Nov-11). A trend analysis and overview of the antenna temperature (Ta) calibration. Two calibration approaches were used: a global average, and a vicarious cold calibration. This was performed for the full time series available - from August to November 2011.