2012 Aquarius Calibration/Validation Workshop

2012 Aquarius Calibration/Validation Workshop
March 26-28, 2012
Santa Rosa, CA

The Aquarius Calibration/Validation Workshop took place in Santa Rosa, California in late March 2012. The objectives of the two day workshop were to (1) assess radiometer calibration performance, (2) review tht RFI mitigation algorithms, (3) review scatterometer calibration performance and algorithm, (4)review the geophysical correction algorithms and performance, and to make decisions on the path towards Aquarius data Version 1.4 processing.

Documents (26)
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Aquarius Cal/Val : Zonal and Orbit Position Biases
Meissner, T., Wentz, F. and Lagerloef, G. (26-Mar-12). Ascending and descending biases were found to correlate with S3 and can largely be removed by adjusting x-pol coupling from S3 into Q. Residual ascending/descending biases do not appear to be persistent in time, strictly zonal, due to diurnal SST or diurnal ATM.

Aquarius Cal/Val Workshop Overview
Yueh, S. (26-Mar-12). An introduction to the Aquarius Calibration and Validation workshop, including workshop goals and schedule.

Aquarius Cal/Val: Salinity Retrieval Algorithm V1.3
Meissner, T., and Wentz, F. (27-Mar-12). A walk-through of the salinity retrieval algorithm for Version 1.3., including the differences between the current version and V1.1.

Aquarius Cross-Pol Calibration
Fore, A. (27-Mar-12). Results from Cross-Pol Calibration are presented. Faraday rotation correction seems to be improved when using the radiometer Faraday angle instead of model.

Aquarius Data Application in Freeze/Thaw Detection
Xu, X., and Yueh, S. (28-Mar-12). Land data, binned to the SMAP grid map, was examined to determine whether freeze and thaw conditions could be detected. Maps of freeze/thaw conditions were produced.

Aquarius Drift over Antarctic and Rainforest Regions
Brown, S. and Misra, S. (26-Mar-12). This work uses on-earth calibration targets for stability tracking, namely Antarctica and a location in the rainforest. Antarctic and Rainforest trend estimates consistent with a gain drift in the Aquarius radiometer (e.g. noise diode). The next steps are to continue model development for both regions to increase fidelity as well as continue tracking the Aquarius performance.

Aquarius MWR Part 1: Geolocation
Scott, J. (28-Mar-12). Presented at the 2012 Aquarius Calibration/Validation Workshop in Santa Rosa, CA.

Aquarius Roughness Correction for Sea Surface Salinity Retrieval
Jones, L., and Hejazin, Y. (28-Mar-12). This presentation describes the approach used to derive an ocean roughness correction for Aquarius. This correction involves using the microwave radiometer's brightness temperature to infer Ka-band ocean roughness. This is translated into L-band using an ocean surface emissivity radiative transfer model.

Aquarius Scatterometer Stability
Neumann, G., Yueh, S., Fore, A., Freedman, A., Hayashi, A., and Tang, W. (27-Mar-12). An analyis of the stability of the Aquarius scatterometer. In this analysis, no significant long-term trend was seen in the predicted vs. measured Sigma0.

Aquarius Soil Moisture Retrieval
Bindish, R. (28-Mar-12). 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 Validation Data System
Kao, H-Y., Lagerloef, G. and Carey, D. (26-Mar-12). The trends of Aquarius salinity measurements for all beams were compared between Version 1.2.2 and 1.2.3.

Coastal Correction to Ta & Tb (TOA, surface)
Kim, S-B., Chan, S., Yueh, S., and Lee, J-H. (28-Mar-12). Presented at the 2012 Aquarius Calibration/Validation Workshop in Santa Rosa, CA.

Cold Sky Calibration (CSC)
Freedman, A. (27-Mar-12). Reviewing the results of Cold Sky Calibration (CSC), several scatterometer "bumps" were observed. The origin and impact of these bumps are discussed.

Cold Sky Calibration: Quick Look
Dinnat, E., Le Vine, E. and Abraham, S. (27-Mar-12). A quick look at the Cold Sky Calibration (CSC) efforts, and a comparison of the results to simulations.

Evaluating the Impact of Ocean Gravity Wave Variability on Aquarius Satellite Measurements
Vandemark, D., and Feng, H. (28-Mar-12). Presented at the 2012 Aquarius Calibration/Validation Workshop in Santa Rosa, CA.

Evaluation of Radiometer RFI Flagging Algorithm Performance Using TVAC Data
de Matthaeis, P., Le Vine, D., and Piepmeier, J. (27-Mar-12). The status of the radiometer RFI flagging algorithm performance are presented, as well as a status for what issues have already been addressed. The recently-discovered issue of short accumulations is investigated, and its potential for correction are discussed.

Inter-comparison Between Aquarius and SMOS Observations
Bindish, R. (26-Mar-12). Aquarius observations compare well with SMOS observations. There is some scatter, possibly due to RFI in SMOS and Aquarius, as well as the heterogeneous footprint and different azimuth angles.

L-Band Model Functions
Meissner, T., and Wentz, F. (27-Mar-12). Presented at the 2012 Aquarius Calibration/Validation Workshop in Santa Rosa, CA.

Level 1B Sea-Ice Proxy Analysis
Freedman, A. (27-Mar-12). Proxy measurement datasets are presented for polar sea ice. Two measurements appear to be best for sensing sea-ice cover: Sigma-0 VV / Sigma-0 HH ratio and Noise-equivalent Sigma-0 (HH or VV). Other measurements are significantly influenced by RFI or other geophysical variables.

Miscellaneous Issues
Freedman, A. (26-Mar-12). A variety of remaining observations and issues are presented, including a look at inclination angles, monitoring loopback power, and drift in echo.

Model Function and Rain Impact
Tang, W., Yueh, S., and Hayashi, A. (27-Mar-12). The ascending and descending passes of Aquarius have had an observed difference. The question posed here is whether ocean surface rain could explain some of the ascending/descending asymmetry that has been observed.

Ocean Wave Slope and Galactic Reflection
Yueh, S. (28-Mar-12). Aquarius data collected near the galactic plane allows for the recovery of ocean wave slope. The retrieved wave slope improves sea surface salinity retrieval by about 1 psu near the galactic plane, under light wind conditions.

Radio Frequency Interference (RFI) Assessment
Ruf, C. and Chen, D. (27-Mar-12). An assessment of the state of radio frequency interference (RFI) and its affect on the Aquarius signal.

Reflected Galaxy Radiation and Land Correction
Wentz, F.J., and Meissner, T. (27-Mar-12). This talk concerns the reflected galactic radiation, a large scale signal that is complex and subject to modeling errors. Complete validation of galaxy reflection tables will likely require multiple years of observations to complete.

Space/Time SSS Variability and the Quantification of Regional Inter-Beam Biases
Melnichenko, O., Hacker, P., Maximenko, N., and Potemra, J. (26-Mar-12). Are small scale features real, and to what degree are they a product of ascending/descending and inter-beam biases?

Towards a Physical Explanation of Calibration Drift
Piepmeier, J. (26-Mar-12). The focus of this talk is whether or not signatures of observed deflection ratios can be reproduced. The current calibration model, RF model, and deflection ratios are investigated, and a potential for improvement is presented.