2014 Aquarius/SAC-D Science Team Meeting
In November 2014, the Aquarius/SAC-D satellite mission convened the 9th Science Meeting in Seattle, WA, USA. This was the 3rd science meeting since the mission was launched on 10 June 2011. This meeting was scheduled to coincide with the completion of NASA's Aquarius 3-year prime salinity measurement mission in November. The agenda emphasized the scientific achievements of these three years, validating the NASA mission science requirements, and to form future plans for Aquarius extended mission science (NASA Senior Review in 2015). The meeting focused on the Aquarius/SAC-D science team and the NASA Ocean Salinity Science Team (OSST) activities.
A Fully Internally Calibrated Aquarius Brightness Temperature Measurement Using Instrument-Only CorrectionsMisra, S. and Brown, S. (13-Nov-14). The following talk will present an instrument-only calibration algorithm that does not use the ocean salinity model for calibration correction. The talk is divided into three portions. The first part will discuss the potential root-cause for the offset and gain drifts observed. The second portion of the talk details the wiggle correction algorithm applied. The last portion of the talk will discuss the drift correction algorithm.
A MWR Ocean Roughness Correction Algorithm for the Aquarius SSS RetrievalJones, L., Hejazin, Y., and Jones, L. (13-Nov-14). In this poster, a microwave radiometer derived sea surface roughness correction algorithm is presented that uses a new semi-empirical microwave Radiative Transfer Model (RTM) to estimate the excess ocean emissivity using ancillary data such as sea surface temperature (SST) and ocean surface wind vector.
A Wide-Spread Freshening During Passage of a Typhoon Captured By Aquarius: A Case StudyAbe, H. and Ebuchi, N. (11-Nov-14). The present study examined ocean salinity responses tothea passage of a typhoon using Aquarius Level-2 swath sea surface salinity (SSS) data and Level-3 weekly-averaged SSS data. We targeted one typhoon generated in the east of the Philippines in 2012; after the formation, it moved to the north-east direction by crossing the western North Pacific basin, then passed through the south of Japan, and on into the central North Pacific. Analyses of the Aquarius data were conducted by focusing on a region near Japan.
Application of the AQ Rain Accumulation Product for Investigation of Rain Effects on AQ Sea Surface Salinity MeasurementsSantos-Garcia, A., Jacob, M., Jones, L. and Asher, W. (11-Nov-14). This poster presents results of a recent empirical investigation into the impact of rain on the Aquarius (AQ) sea surface salinity measurements.
Aquarius Mission and Science OverviewLagerloef, G. (14-Nov-14). In this presentation, the author provides a broad overview of the statuts of the Aquarius mission, including an update on the latest data versions available, instrument health, and current mission status.
Aquarius Radiometers Cold Sky CalibrationLe Vine, D. (11-Nov-14). Aquarius is a NASA instrument comprising three L-band (1.4 GHz) radiometers dedicated to the remote sensing of global sea surface salinity. During the nominal operation, Aquarius' radiometers are calibrated using an internal hot target. An additional empirical adjustment is performed by comparing measured and simulated antenna temperatures over oceans.
Aquarius Satellite Salinity Measurement Mission Status, and Science Results from the Initial 3-Year Prime MissionLagerloef, G. and Kao, H. (11-Nov-14). The Aquarius measurement objectives are to describe unknown features in the sea surface salinity field and document seasonal and interannual variations on regional and basin scales. This presentation will first describe the structure of the mean annual global salinity field compared with the previous in situ climatology and contemporary in situ measurements , including small persistent biases of opposite sign in high latitudes versus low latitudes, currently under intense investigation, as well as global and regional error statistics.
Aquarius Scatterometer Calibration and Bias Drift CorrectionFore, A., Tang, W., Hayashi, A., and Yueh, S. (13-Nov-14). In this talk, we show that Aquarius scatterometer calibration has provided stable L-band backscatter observations over the entire mission duration of more than three years. We analyze the calibration using the ocean as a reference, and we track the calibration stability using a numerical weather product coupled with an ocean geophysical model function.
Aquarius Sea Surface Salinity Measurements Bring New Understanding to Intraseasonal Variability in Tropical OceansLee, T. (11-Nov-14). This presentation highlights the new understanding of tropical instability waves (TIWs) and Madden-Julian Oscillation enabled by the applications of Aquarius data. For the Pacific, Aquarius data provided a better view of TIW at the equator because of the large meridional gradient of sea surface salinity there, and revealed a shorter dominant period and faster propagation of TIWs at the equator than those at off-equatorial latitudes.
Aquarius SSS Optimum Interpolation Analysis for Global and Regional StudiesMelnichenko, O., Hacker, P., Maximenko, N., Lagerloef, G., and Potemra, J. (12-Nov-14). A new high-resolution sea surface salinity (SSS) analysis has been produced at the International Pacific Research Center of the University of Hawaii using Aquarius Level-2 (swath) data from September 2011 to August 2014. The primary product is a weekly SSS analysis on a nearly-global 0.5-degree grid. The analysis method is optimum interpolation that takes into account analyzed errors on the observations, specific to the Aquarius instrument.
Aquarius SSS Space/Time Biases With Respect to Argo DataHacker, P., Melnichenko, O., Maximenko, N., and Potemra, J. (12-Nov-14). The Aquarius/SAC-D satellite provides an opportunity to observe near-global sea surface salinity (SSS) with unprecedented space and time resolution not available by other components of the Global Ocean Observing System. In order to evaluate and quantify the potential utility of the SSS data for global and regional studies of SSS variability, our research group has been using the Level-2, three-beam swath data and Argo data to characterize and quantify systematic space/time biases and random errors on a global grid.
Aquarius SSS-max and SSS-min Views of the SeaGordon, A. (11-Nov-14). For decades oceanographers have had global near synoptic time series views of the sea surface from space, including, in addition to visible images, temperature, height, color, sea ice, wind and marine rainfall patterns, all of which have dramatically expanded our knowledge of the ocean condition, enabling quantitative investigating of ocean processes and their coupling to the atmosphere/climate and marine ecosystems. But only recently have we gathered from orbiting satellites views of the sea surface salinity, with the advent of ESA's Soil Moisture and Ocean Salinity (November 2009 launch) and of NASA/CONAE Aquarius/SAC-D satellite mission (June 2011 launch).
AQUARIUS/SAC-D Soil Moisture Product Using V3.0 ObservationsBindlish, R., Jackson, T., and Cosh, M. (13-Nov-14). Although Aquarius was designed for ocean salinity mapping, our objective in this investigation is to exploit the large amount of land observations that Aquarius acquires and extend the mission scope to include the retrieval of surface soil moisture.
Assessment of Rain Impact on the Aquarius Salinity RetrievalsMeissner, T., Wentz, F., Scott, J., and Hilburn, K. (13-Nov-14). Fresh biases up to 0.4 psu are observed when comparing Aquarius salinities with ARGO or HYCOM in the tropical and subtropical regions. These biases are partly due to inaccuracies in the geophysical model function that correlate with sea surface temperature and partly due to salinity stratification in the upper ocean layer. Aquarius measures salinity within a few centimeters of the surface, which is fresher during and after rain effects than the 5 m depth layer, to which ARGO and HYCOM refer to. In order to make improvements to the salinity retrieval algorithm and avoid overcorrecting it is essential to separate these two effects.
Assessment of SMOS, Aquarius and AMSR2 Soil Moisture Assimilation Into Hydrological Models of a Flatland BasinBianchi, J., Quirno, M., Lozza, H., Thibeault, M., Dadamia, D., and Goniadzki, D. (13-Nov-14). The impact on discharge simulation efficiency of satellite soil moisture data assimilation was assessed. Soil moisture estimation products of the instruments SMOS, Aquarius and AMSR2 were assimilated through Ensemble Kalman Filtering into two previously-calibrated conceptual hydrological models of the Gualeguay basin, located in the Argentinian temperate sub-humid flatlands.
Basin-Scale Exchange of Salt and Fresh Water Between the Araban Sea and the Bay of Bengal During MonsoonsD'Addezio, J., Bulusu, S., Nyadjro, E., and Murty, V. (11-Nov-14). The Northern Indian Ocean presents a unique dipolar sea surface salinity structure with the salty Arabian Sea on the west and the fresher Bay of Bengal on the east. At the surface, the largest driver of seasonal salinity variability is the monsoonal riverine runoff and winds and their ability to transport volume between the two basins.
Broadly Sharing the Importance of Ocean SalinitydeCharon, A., Companion, C., Cope, R., and Taylor, L. (11-Nov-14). NASA's Aquarius instrument and Salinity Processes in the Upper Ocean Regional Study (SPURS) have given the scientific community unprecedented insight into salinity's role in the earth system. Synergistic efforts by the University of Maine-based public engagement team have focused on themes of the water cycle, ocean circulation and climate. Resources highlighting salinity's ties to these familiar topics have been disseminated through Aquarius and SPURS webinars and workshops.
Comparison Analysis Between Aquarius Sea Surface Salinity and World Ocean Database In Situ Analyzed Sea Surface SalinityReagan, J., Boyer, T., Antonov, J., and Zweng, M. (12-Nov-14). A new monthly sea surface salinity (SSS) product calculated from profile data within the World Ocean Database is compared and contrasted with Aquarius SSS, both standard and Combined Active-Passive products, from September 2011 through September 2013.
Comparison of Argo and Aquarius Sea Surface Salinity Probability DistributionsMannshardt, E., Sucic, K., Fuentes, M., and Bingham, F. (11-Nov-14). Using Argo in situ and Aquarius version 3.0 sea surface salinity, we compare measured salinity across metric distributions.
Comparison of L-band Radio Frequency Interferences from Aquarius and SMOS ObservationsSoldo, Y., de Matthaeis, P., Le Vine, D., and Richaume, P. (11-Nov-14). The ESA (European Space Agency) SMOS (Soil Moisture and Ocean Salinity) satellite and the NASA (National Aeronautics and Space Administration) Aquarius instrument have been measuring Earth's natural emissions in the protected part of the L-band (1400-1427 MHz) since January 2010 and August 2011, respectively. In this work, the regulations, both instruments see the quality of their observations degraded by significant Radio (RFI) contamination in both instruments have been compared through the "RFI probability" associated to points on Earth's surface, i.e. the ratio between the number of times RFI were detected on a certain point and the number of times the same point was observed.
Comparison of Level-2 Aquarius SSS With Argo Near-Surface SalinityRen, L. and Bayler, E. (11-Nov-14). Comparing sea-surface salinity observations from the U.S. National Aeronautics and Space Agency's (NASA) Aquarius mission and in-situ Argo float data at global, zonal and regional scales reveals interesting and unexpected insights on data quality and uncertainty.
CONAE Microwave Radiometer (MWR) Counts to Tb Algorithm and On Orbit ValidationJones, L., Ghazi, Z., Jacob, M., and Santos-Garcia, A. (11-Nov-14). The Central Florida Remote Sensing Lab, in collaboration with CONAE, have developed two improved algorithms to convert the radiometric counts to brightness temperature for production of MWR level-1 science data. This poster presents a description of these algorithms and shows results for MWR Cal/Val activities during the past 15 months.
Diurnal Sea Surface Salinity Variation Detection in Aquarius DataFine, E., Bryan, F., and Large, W. (11-Nov-14). In this study we quantify the expected range of diurnal salinity variations on a global scale using an extension of a model developed for predicting diurnal sea surface temperature variations. Based on this guidance, we search for regions where Aquarius may be detecting a true diurnal SSS signal. We also use an independent approach based on the near surface salinity balance and observed precipitation by isolating regions where the surface buoyancy input is such as to suppress vertical mixing. This study should help shed light on the processes contributing to upper ocean salinity variations, as well as provide a better target for assessing remaining errors in the Aquarius processing algorithms.
Effect of Sea Water Dielectric Constant Model and Sea Surface Temperature Ancillary Data on Remote Sensing of Sea Surface SalinityDinnat, E., Boutin, J., Xiaobin, Y., and Le Vine, D. (13-Nov-14). ESA's Soil Moisture and Ocean Salinity (SMOS) and NASA's Aquarius use L-band (1.4 GHz) radiometers to measure emission from the sea surface and retrieve sea surface salinity (SSS). Significant differences in SSS retrieved by both sensors are observed, with SMOS SSS being generally lower than Aquarius SSS, except for very cold waters where SMOS SSS is the highest overall. Differences are mostly between -1 psu and +1 psu (psu, practical salinity unit), with a significant regional and latitudinal dependence. We investigate the impact of the vicarious calibration and retrieval algorithm used by both missions on these differences.
Estimation of the Barrier Layer Thickness in the Indian Ocean Using Satellite Derived SalinityBulusu, S., Felton, C., Murty, V., and Shriver, J. (11-Nov-14). Monthly barrier layer thickness (BLT) estimates are derived from satellite-derived salinity using a multilinear regression model (MRM) within the Indian Ocean. Sea surface salinity from the recently launched Soil Moisture and Ocean Salinity (SMOS) and Aquarius salinity missions are utilized to estimate the BLT. The MRM derived BLT estimates are compared to gridded Argo and Hybrid Coordinate Ocean Model BLTs.
Evaluation of Sea Surface Salinity Observed By AquariusAbe, H. and Ebuchi, N. (11-Nov-14). Sea surface salinity (SSS) fields from three different Aquarius products (Aquarius Official Release version 3.0 (V3.0), Combined Active-Passive (CAP) algorithm version 3.0, Remote Sensing Systems (RSS) test bed algorithm version 3) were evaluated by comparing them to in situ SSS measurements from Argo floats and tropical moored buoys, as well as with global gridded SSS fields produced by JAMSTEC and JMA/MRI. Level-2 Aquarius SSS was collocated with in situ near-surface salinity with spatial and temporal separations of less than 200 km and 12 hours, respectively.
Evaluation of Sea Surface Salinity Variability in the East China Sea Observed by the Aquarius InstrumentKim, S., Lee, J., and de Matthaeis, P. (12-Nov-14). This study demonstrates that the spaceborne Aquarius instrument is able to monitor the sea surface salinity variations in the East China Sea with the spatial resolution of about 150 km at 7-day interval, where routine observations are difficult.
Freshwater Flux from Bay of Bengal, South China Sea and Eastern Indian Ocean and Its Impacts on the Indonesian ThroughflowSusanto, R. and Zheng, Q. (12-Nov-14). The proposed research is a pioneering work to determine the freshwater flux from the Bay of Bengal, the South China Sea, and the Eastern Indian Ocean and its impacts on the Indonesian Throughflow, using in situ observations and satellite data, especially the Aquarius/SAC-D satellite ocean salinity data.
Global Surface Alkalinity from Aquarius SatelliteFine, R., Willey, D., and Millero, F. (11-Nov-14). The unprecedented salinity coverage from the Aquarius satellite (version 3) has provided the opportunity to calculate surface alkalinity globally. In the oceans, total alkalinity (TA) is a gauge on the ability of seawater to neutralize acids. Alkalinity is a major component of seawater, and there is a strong correlation between TA and salinity.
Interannual Caribbean Salinity in Satellite Data and Model SimulationsGrodsky, S., Johnson, B., Carton, J., and Bryan, F. (12-Nov-14). Aquarius sea surface salinity (SSS) reveals the presence of interannual salinity variations in the Caribbean with about 0.5 psu change between salty and fresh events. Anomalous SSS propagates westward across the basin at an average speed of 11 cm/s. Fresh and salty events in the Caribbean are preceded by corresponding SSS anomalies east of the Lesser Antilles.
Isohaline Salinity Budget of the North Atlantic Salinity MaximumBryan, F. and Bachman, S. (11-Nov-14). The choice of control volume influences the processes that dominate budgets of ocean properties. In this study we analyze the salinity budget of the North Atlantic subtropical salinity maximum region for control volumes bounded by isohaline surfaces. We provide closed budgets based on output from a high-resolution numerical simulation, and partial budgets based on climatological analyses of observations.
Linking Information from Sea Surface Salinity to Oceanic Freshwater Fluxes Using Near-Surface Salinity BudgetsVinogradova, N., Ponte, R., and Buckley, M. (11-Nov-14). Characterizing freshwater fluxes (FWF) over the oceans is a key element in advancing our understanding of climate change. One way to improve knowledge of these fluxes is to use variations in sea surface salinity (SSS). However, the problem is challenging because the relationship between SSS and FWF can depend on complex upper-ocean dynamic processes.
Meeting Agenda and ObjectivesLagerloef, G. (11-Nov-14). Opening remarks from Gary Lagerloef, Aquarius Principal Investigator, for the 2014 Aquarius/SAC-D Science Team Meeting in Seattle, WA.
Microwave Radiometer (MWR) Beam-Pointing for the Aquarius/SAC-D MissionClymer, B., May, C., Schneidar, L., Madero, F., Labanda, M., Jacob, M., and Jones, L. (11-Nov-14). This poster concerns the on-orbit validation of the antenna beam pointing and corresponding instantaneous field of view earth location for the CONAE Microwave Radiometer (MWR). The MWR is a three-channel radiometer operating at 23.8 GHz (H-Pol) and 36.5 GHz (V- and H-Pol), which has two multi-beam parabolic reflector antennas in a pushbroom configuration, with eight beams per frequency (36.5 GHz looking forward and 23.8 GHz looking aft producing 24 simultaneous beams).
Mitigation of Large Scale Biases in the Aquarius Salinity RetrievalsMeissner, T., Wentz, F., and Scott, J. (13-Nov-14). The Aquarius Version 3.0 salinity retrievals have salty biases at mid-high latitudes and fresh biases in the tropics and subtropics when compared to ARGO or HYCOM. In addition we observe biases between the three Aquarius beams.
Mixed Layer Salt Balance and the Role of Eddies in a Global Ocean SimulationCarton, J., Grodsky, S., Johnson, B., and Bryan, F. (12-Nov-14). Here we examine the detailed salt balance of the mixed layer in a 0.1 degree resolution multi-decadal simulation of the global ocean/ice system forced by observed historical surface fluxes (1979-2010), with the flux calculations carried out on the original grid every time step. Initial conditions were provided by a simulation forced by Normal Year forcing. The simulation is generally realistic with a slight negative bias in salinity. Here we focus on a comparison of the salt balance as it varies with latitude from the rainy tropics through the dry subtropics and into the humid midlatitudes.
Mixed Layer Variability in the Salinity Processes in the Upper Ocean Regional Study (SPURS) AreaAnderson, J. and Stephen, R. (11-Nov-14). The first Salinity Processes in the Upper Ocean Regional Study (SPURS) I field campaign took place in the approximate center of the north Atlantic surface salinity maximum (~25°N, 38°W). During SPURS I 16 Argo-type profiling floats were deployed in a high-density, 4 by 4 grid surrounding the central mooring with approximate 0.5 degree spacing.
Modeling Skin-Layer Salinity With an Extended Surface-Salinity LayerSong, Y., Lee, T., Moon, J., Qu, T., and Yueh, S. (12-Nov-14). Here, we propose an extended surface-salinity layer (ESSL) within a global ocean circulation model to diagnose skin sea surface salinity without increasing the computational cost, while allowing comparable solutions with both satellite and Argo salinity at the respective depths. Cross-comparisons with Aquarius and Argo data show that the gridded Aquarius surface salinity has a much stronger seasonal variability than the gridded Argo top-level salinity at 5 m or 10 m, particularly in regions of high precipitation variability, suggesting the exist of strong near-surface vertical salinity stratification.
MWR Roughness Correction Algorithm for the Aquarius SSS RetrievalJones, L., Hejazin, Y., Al-Nimri, S. (13-Nov-14). The AQ baseline approach to provide roughness correction uses the AQ scatterometer ocean radar backscatter to infer excess ocean emissivity. In this poster an alternative MWR derived sea surface roughness correction algorithm is presented that uses a new semi-empirical microwave Radiative Transfer Model (RTM) to estimate the excess ocean emissivity using ancillary data such as sea surface temperature and ocean surface wind vector.
NASA Program OverviewLindstrom, E. (14-Nov-14). In this presentation, the author provides an overview of the NASA Earth Science and Physical Oceanography program.
NIRST Ready for ScienceMarraco, H., Labanda, M., Raymondo, H., Colazo, M., and Kalemkarian, M. (13-Nov-14). After considerable work sorting several unforeseen obstacles NIRST is now ready for science. Several examples of the camera's capabilities for revealing land and sea surfaces temperatures distributions with a whole calibrated range are shown. A brief description of the steps leading to this successful goal is also given. This description includes the pitfalls incurred during the camera design, their causes and cures.
Observation and Modeling of Rain-Induced Near Surface Salinity AnomaliesAsher, W., Jessup, A., and Drushka, K. (13-Nov-14). Precipitation on the ocean forms salinity and temperature gradients in the top few meters of the ocean surface. If present, these gradients will complicate comparing salinity measured by ARGO drifters at typical depths of five meters to salinities retrieved using L-band microwave radiometers such as Aquarius and SMOS at depths on the order of 0.01 m.
On the Seasonal Cycle of Sea Surface Salinity In the Gulf Stream from Aquarius/SAC-D: A Data ComparisonVazquez, J., Tang, W., Hayashi, A., and Tsontos, V. (12-Nov-14). Three different sea surface salinity (SSS) data sets were used for comparing the annual signal of salinity in the Gulf Stream. These were both the Project version 3.0 SST-adjusted and non-adjusted data sets as well as SSS based on the v3.0 Combined Active-Passive algorithm.
On the Use of Observations from the Aquarius/SAC-D Mission to Study the CryosphereDinnat, E. and Brucker, L. (14-Nov-14). The objective of this talk is to present the high-latitude products and to summarize their recent applications over the cryosphere. The effect of the 2012 summer melt event at Summit, Greenland created sudden brightness temperature (TB) drops, larger than 15 and 20 K at vertical and horizontal polarization, respectively. We will also emphasize the impact of snow surface changes on the Aquarius L-band TB observations at Dome C (75S, 123E). Finally, we will show that the scatterometer observations are sensitive to the anisotropy of the Antarctic ice sheet.
Rain Accumulation (RA) Product for AquariusSantos-Garcia, A., Jacob, M., and Jones, L. (11-Nov-14). The purpose of this poster is to describe the rain accumulation product and to present validation results using independent environmental data records (EDR) WindSat rain retrievals. The WindSat EDR's have a large number of rain event collocations (< 30 min) with the AQ observation.
Rain Impact Model (RIM) for AquariusJacob, M., Santos-Garcia, A., Jacob, M., Jones, L., and Asher, W. (13-Nov-14). This paper presents results of a recent empirical investigation into the impact of rain on the Aquarius (AQ) sea surface salinity (SSS) measurements. Results demonstrate that AQ SSS measurements are realistic characterizations of a transient dilution of the surface salinity, but they are NOT representative of the bulk salinity at 5 m depth given by HYCOM.
Regional Rainfall Measurements Using Passive Aquatic Listener During SPURS Field CampaignYang, J., Riser, S., Nystuen, J., Asher, W., and Jessup, A. (12-Nov-14). Knowledge of the intensity and spatial-temporal distribution of rainfall over the ocean is critical in understanding the global hydrological cycle. However, rain has proven to be difficult to measure over the ocean due to problems associated with deploying rain sensors from moving platforms combined with the spatial and temporal variability of rainfall itself. Underwater acoustical rain gauges avoid the issues of surface rain sensors by using the loud and distinctive underwater sound generated by raindrops on the ocean surface to detect and quantify rainfall.
Relating River Discharges to Salinity ChangesXie, X., Liu, W., Clark, E., and Xing, Y. (12-Nov-14). New river discharge data recently produced from terrestrial hydrology models and river gauge measurements, as part of the NASA Energy and Water studies, are brought together with space-based sea surface salinity measurements by Aquarius and SMOS to demonstrate the role of river discharge in salinity changes near three river mouths: the Mississippi, the Ganges, and the Amazon. The characteristics of the seasonal cycle and the year-to-year changes of the river runoff are described.
Rising Above the Noise: Estimating and Removing Low-Level Undetected RFI Contamination in the Aquarius Salinity ProductBrown, S. (14-Nov-14). This presentation focuses on how the RFI maps are generated. The first part is identifying the location of the sources and the second part is identifying their strength. This is done iteratively by minimizing a cost function between the observed ascending-descending TB differences for each horn and a forward model of the Aquarius antenna patterns convolved with the pre-identified RFI source locations.
SAC-D/ Aquarius 3rd YearRabolli, M. and Torrusio, S. (13-Nov-14). After the 3rd year on orbit we are presenting the status of the instruments developed under Argentinian responsibility and of those developed by France and Italy.
Salinity Processes in the Upper Ocean Regional Study (SPURS)Lindstrom, E. (12-Nov-14). In this presentation, the author provides an introduction and overview of the Salinity Processes in the Upper Ocean Regional Study (SPURS).
Salinity Structure of the Indian Ocean Dipole: Perspectives from Aquarius and SMOS Satellite MissionsNyadjro, E. and Bulusu, S. (11-Nov-14). We present results on Aquarius and the Soil Moisture and Ocean Salinity (SMOS) observations of the sea surface salinity (SSS) structure during an Indian Ocean Dipole event. Comparisons with Argo data show that the satellites are able to resolve the observed SSS pattern in the Indian Ocean despite some challenges in the northern Indian Ocean.
Satellite & In Situ Salinity (SISS) Working Group: Current Status and Future PlansChao, Y. and Boutin, J. (12-Nov-14). The Aquarius and SMOS salinity satellite missions have established the Satellite & In Situ Salinity Working Group. The major goal of this working group is to improve our understanding of the link between L-band satellite (SMOS and Aquarius) remotely sensed salinity (for approximately the top 1 cm of the sea surface) and in situ measured salinity (routinely measured at a few meters depths by ships and ARGO floats but recently accessible to up to few cm depth by new profilers, and by surface drifters) and to develop practical methodologies for relating satellite salinity to other estimates of sea surface salinity.
Sea Surface Salinity in the East China Sea Observed By the Aquarius InstrumentLee, Jae., de Matthaeis, P., Yueh, S., Hong, C., Lee, J., and Lagerloef, G. (11-Nov-14). This study demonstrates that the spaceborne Aquarius instrument is able to monitor the sea surface salinity variations in the East China Sea with the spatial resolution of about 150 km at 7-day interval, where routine observations are difficult.
Sea Surface Salinity Variability and ENSOQu, T. (11-Nov-14). This study investigates the sea surface salinity (SSS) variability in the equatorial Pacific using recently available Aquarius and Argo data. For the period of observation from August 2011 to present, Aquarius nicely resolves the SSS front and its zonal displacement along the equator.
Seasonal to Interannual Variations of the Salinity Fronts Under the Pacific Intertropical Convergence ZoneKao, H. and Lagerloef, G. (11-Nov-14). The Pacific Intertropical Convergence Zone (ITCZ) is a zonal band of atmospheric convective instability, clouds and rainfall near the equator. High-resolution sea surface salinity measurements from the Aquarius satellite reveals more detail in the band of lower salinity and a sharp front that aligns with the strong ITCZ atmospheric convection.
The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-band and its Impact on Salinity Retrievalde Matthaeis, P., Kim, S., Soldo, Y., and Le Vine, D. (14-Nov-14). In this work, some observed changes in regional RFI environments are analyzed with the goal of better understanding the performance of the Aquarius RFI algorithm, in particular situations such as when low-level or non-impulsive interference is present. The effect and implications on the salinity retrieval are presented and discussed.
The Aquarius Salinity Retrieval Algorithm Beyond Version 3.0Wentz, F., Meissner, T., Scott, J., and Hilburn, K. (13-Nov-14). This presentation gives an overview of updates and improvements that we plan to make in the Aquarius salinity retrieval algorithm for the next major release.
The Diurnal Cycle of SalinityDrushka, K., Gille, S., and Sprintall, J. (12-Nov-14). TAO mooring data are used to estimate the diurnal cycle of salinity in the tropics and to assess the drivers of diurnal salinity. A comparison against the Aquarius ascending and descending salinity observations reveals that the ascending/descending bias version 3.0 of Aquarius is generally an order of magnitude larger than the diurnal cycle in salinity at 1-m depth.
The Effect of Rain-Induced Stratification and Surface Roughness on Aquarius SSS RetrievalTang, W., Yueh, S., Fore, A., and Hayashi, A. (13-Nov-14). The objective of this study is to develop a rain roughness correction to reduce the uncertainty of Aquarius sea surface salinity (SSS) retrieved under rainy conditions. The calibration reference chosen by the Aquarius project calibration/validation team is the SSS from HYCOM (SSSHYCOM), with Geophysical Model Function built using rain-free data. Under rainy conditions, surface salinity stratification associated with rain freshwater inputs may cause large discrepancy in salinity measured by Aquarius at 1-2 cm (the penetration depth of L-band radiometer) and SSSHYCOM a few meters below the surface.
The North Atlantic Subtropical Surface Salinity Maximum as Observed by AquariusBingham, F., Busecke, Julius., Giulivi, C., Gordon, A., and Li, Z. (12-Nov-14). Aquarius satellite derived sea surface salinity (SSS) data from August 2011 through September 2013 reveals significant seasonal migration and freshening of the subtropical surface salinity maximum (SSS-max) area in the North Atlantic, in good agreement with in situ observations, including those obtained as part of the SPURS (Salinity Processes in the Upper Ocean Regional Study) field experiment in 2012-2013.
The Salinity Signature of the Cross-Shelf Exchanges in the Southwestern Atlantic Ocean: Aquarius Observations and ModelsMatano, R., Combes, V., Piola, A., Guerrero, R., Palma, E., Strub, T., James, C., Fenco, H., Chao, Y., and Saraceno, M. (13-Nov-14). Sea surface salinity data from Aquarius and SMOS and the results of high-resolution numerical model are used to investigate the shelf-deep ocean exchanges in the southwestern Atlantic region, a region characterized by the freshwater discharge from the La Plata River. The satellite data shows strong seasonal variations of the location where the low salinity shelf waters are exported to the deep ocean: to the south of the La Plata River mouth during the summer and to the north during the winter.
The Salinity Signature of the Cross-Shelf Exchanges in the Southwestern Atlantic Ocean: Satellite ObservationsGuerrero, R., Piola, A., Fenco, H., Matano, R., Combes, V., Chao, Y., James, C., Palma, E., Saraceno, M., and Strub, T. (13-Nov-14). We use sea surface salinity (SSS) data from Aquarius and SMOS to describe the shelf-open ocean exchanges in the western South Atlantic near 35°S. The satellite data show a well-defined seasonal pattern. During spring and summer low SSS shelf waters expand offshore and are transferred to the open ocean primarily southeast of the river mouth (from 36 °S to 37°30'S). During fall and winter low SSS waters extend along a coastal plume and the export path to the open ocean distributes along the offshore edge of the plume.
To What Extent Aquarius Surface Salinity Measurements Can Detect Large-Scale, Low-Frequency Climate Signals?Lee, T. (11-Nov-14). This presentation will present results of the analysis of uncertainty of Aquarius sea surface salinity data on scales of 1000 km with a focus on year-to-year changes currently resolved by Aquarius in order to shed light on the extent to which Aquarius can detect climate variability and change signals like these.
Tools, Services and Support of Aquarius/SAC-D Salinity Data Archival and Distribution Through PO.DAACTsontos, V. and Vazquez, J. (11-Nov-14). The Physical Oceanography Distributed Active Center (PO.DAAC) serves as the official NASA repository and distribution node for all Aquarius/SAC-D data products in close collaboration with the project. Here we report on the status of Aquarius data holdings at PO.DAAC, the range of data services and access tools that we provide in support of this mission, and new efforts underway to support in-situ salinity datasets from the SPURS field campaign.
Using Aquarius Radiometer and Scatterometer for Generating New Soil Moisture Products (Active, Passive, Active-Passive)Bruscantini, C. (13-Nov-14). In December 2013, Aquarius official soil moisture maps were released worldwide. Aquarius' co-located radar and radiometer instruments give a unique activity for space-born active/passive fusion retrieval development, of special interest for the forthcoming SMAP mission.
Validation of Aquarius Sea Surface Salinity Data With In Situ Measurements from the SPURS Field ExperimentChao, Y., Zhang, H., Centurioni, L., Farrar, T., Fratantoni, D., and Hodges, B. (12-Nov-14). Using multiple independent in situ measurements, the accuracy for the Aquarius retrieved sea surface salinity in the SPURS region is assessed, and compared to the accuracy assessed by the standard Argo profiling float. Using four independent data types, we can select any three data types to perform triple-point analysis to derive the weekly Aquarius error in the range of 0.13 to 0.14 psu, which is already smaller than the allocated monthly error of 0.16 psu.
Validation of MWR Marine Surface Wind SpeedTauro, C., Hejazin, Y., Jacob, M., and Jones, L. (11-Nov-14). This poster presents a description of the algorithm and results of a comprehensive on-orbit validation using coincident ocean wind speed retrievals provided by Remote Sensing Systems, Inc.
Where Can Ocean Salinity Be Used as a Rain Gauge?Yu, L. (11-Nov-14). The concept of using ocean salinity as a rain gauge to detect the change of the global water cycle has long been proposed but yet materialized. The main obstacle is that ocean salinity and the freshwater flux (namely, the E-P flux) are related through complex upper ocean dynamics, and the ocean advective/mixing processes are often found to have a more influential role than the freshwater flux in explaining the observed sea surface salinity variability on seasonal and longer timescales.