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SPURS

The SPURS (Salinity Processes in the Upper Ocean Regional Study) project is a series of science process studies and associated oceanographic field campaigns that aim to elucidate key mechanisms responsible for near-surface salinity variations in the oceans. In particular, SPURS seeks to quantify the relative significance of circulation, evaporation, precipitation over a range of scales for representative areas of the open ocean. In so doing, it addresses the fundamental role the ocean plays in global water cycle budgets and its relationship to climate.  Funded principally by NASA with support from other US agencies and European partners, the project involves two field campaigns and a series of cruises in regions of the Atlantic and Pacific Oceans exhibiting salinity and precipitation extremes (Figure 1).  SPURS employs a suite of state-of-the-art in-situ sampling technologies that, combined with remotely sensed salinity fields from the Aquarius/SAC-D and SMOS satellites, provide a detailed characterization of salinity structure over a continuum of spatio-temporal scales.  Coupling of resulting data with physical oceanographic models is a further distinguishing feature of SPURS synthesis activities which aim to understand underlying physical processes at work.

Figure1.jpg


Figure 1: (Left) Global annual map of surface ocean salinity from Aquarius indicating SPURS-1 and 2 campaign sampling areas within salinity maximum and minimum regions of the subtropical N. Atlantic and Eastern Tropical Pacific respectively.(Middle) Global precipitation patterns showing the location of the SPURS-1 and 2 campaigns in low and high rainfall regions respectively.(Right) The SPURS sensor-web illustrating the integrated use of diverse sampling platforms and instrumentation to provide coverage over a continuum of scales.

Figure 2

Figure 2.  Location of the SPURS-1 study site.

The SPURS-1 campaign involved a series of 5 cruises during 2012 - 2013 seeking to resolve the salinity structure and balance in a high salinity, high evaporation, and low rainfall region of the subtropical North Atlantic.  The specific purpose of the experiment was to examine the processes responsible for maintaining the subtropical surface salinity maximum in this region. An array of advanced sampling technologies were employed providing a detailed understanding of salinity structure within a 900 x 800-mile square study area centered at 25N, 38W. Figure 2 adjacent shows the location of the SPURS-1 study site in the salinity maximum region of the subtropical N. Atlantic with tracks for the R/V Knorr, Endeavor and Sarmiento cruises overlaid on a map of remotely sensed salinity data from Aquarius (salinity high values of 37 PSU represented in deeper orange).

Cruises

The table below summarizes the dates of the SPURS-1 cruises and research vessels involved.  Full cruise reports have been issued for the US cruises and the Sarmiento cruise.  These are available from here.

Sampling Platforms & Technologies

A suite of sampling platforms and sensors were deployed during SPURS-1 providing multivariate observations, both ship-based and autonomous, Eulerian (point) and Lagrangian (trajectory), over a range of spatio-temporal scales within the campaign’s domain.  Figure 3 illustrates the SPURS nested survey design and locations of  some of the deployed sampling assets described below.

 

Figure3

Figure 3.  SPURS-1 domain with nested survey design and sensor deployment.

1. Research Vessels

RV Knorr (US) RV Knorr (US) RV Knorr (US) Thalassa
RV Knorr (US) RV Endeavor (US) RV Sarmiento (Spain) RV Thalassa (France)

 

2. Sensor Platforms

Moorings

Device Description Device Description
RV Knorr (US) The SPURS central mooring consisted of a surface meteorological package, surface oceanographic instruments, and subsurface, non-realtime oceanographic instruments including CTD, ADCP sensors and current meters providing continuous series of temperature, salinity and current profile data. Meteorological observations included wind speed, air temperature, precipitation, and radiative flux. The mooring was deployed in 5,535 meters of water at 24° 34.867'N, 38°W on 14 September 2012, was serviced on 25 March 2013 and recovered on 30 September 2013. PICO Two PICO moorings (PICO-1000 & 3000) were deployed on the Knorr cruise in September 2012 in northern and eastern domain quadrants at 24.74°N, 37.95°W and 24.51°N,37.81°W respectively. These moorings contained a surface meteorological package and a "prawler", a CTD that crawls up and down the mooring line from the near-surface down to about 500m, yielding time series of salinity and temperature profile data at fixed locations. The moorings were recovered on the Endeavor-2 cruise.
SPURS Mooring Contributor: T.Farrarr (WHOI)
Data Access
PICO Moorings Contributors: WS.Kessler (NOAA/PMEL)
Data Access

Ship-based Samplers

Device Description Device Description
CTD Shipboard lowered CTD probes provide continuous conductivity, salinity, and temperature vertical profile observations at fixed sampling stations. There were 100, 52, 17, 22 and 94 CTD casts made during the Knorr, Endeavor-1, Endeavor-2, Sarmiento, and Thalassa cruises respectively. All CTD data were calibrated using shipboard salinometers according to IAPSO standard seawater, and processed to 1 meter bin depth intervals. ADCP Acoustic Doppler Current Profilers (ADCP) provide water column current velocity profile observations.  Shipborne ADCP data were collected during the 3 US cruises, using the Knorr and Endeavor 300 kHz Workhorse, 75 khz broadband and 75 khz narrowband instruments, and during the Sarmiento cruise using a 76.8 khz broadband ADCP.  Additionally, lowered ADCP (L-ADCP) measurements were made during the Knorr cruise on every CTD cast and during the Sarmiento cruise.
CTD Contributors: F.Bingham, G.Riverdin, J.Font (UNCW, IFREMER, CSIC)
Data Access
ADCP Contributors: F.Bingham, J.Schanze (UNCW, ESR)
Data Access
U-CTD Underway-CTD (UCTD) is a towed CTD instrument providing salinity and temperature profile observations while underway at up to 20kts. 771 UCTD casts occurred during the Knorr and Endeavor-I cruises utilizing an Oceanscience instrument. profiler Microstructure profilers are lowered probes measuring small-scale (cm) variations in vertical water turbulence, temperature, and salinity. Numerous microstructure profiles were collected on the Knorr and Endeavor-1 cruises.  This work was NSF funded.

Underway-CTD

Contributors: T.Farrar (WHOI)
Data Access
Microstructure Profiler Contributors: R.Schmitt, L.St.Laurent (WHOI)
Data Access
Thermo A thermosalinograph (TSG) is an automated measurement system that is coupled to a research vessel's water intake and GPS systems to provide continuous, along-track surface temperature and salinity measurements. Each SPURS cruise had a TSG instrument, with measurements calibrated against onboard salinometers. Metereology A ship mast meteorological sensor package was set up on all SPURS-1 cruises, with an additional set of sophisticated sensor, including a direct covariance flux package, installed on the Knorr.  These provided georeferenced, along-track atmospheric pressure, temperature, humidity, IR/visible radiation, rain, wind speed and direct covariance flux measurements.
Thermosalinograph Contributors: Multiple
Data Access
Meteorology Contributors: Multiple
Data Access

seasoar.jpg

 

SeaSoar is a towed vehicle equipped with impeller-forced wings that can be rotated on command to allow the vehicle to undulate in the upper ocean. Generally, SeaSoar operates between the surface and about 400 meters depth while being towed on faired cable at about eight knots. A typical dive cycle takes about 12 minutes to complete, providing an up- and down profile every 3 km.  For SPURS-1, a SeaSoar was deployed exclusively during the Sarmiento cruise over the period 22 Mar-8 Apr, 2013 and to a maximum depth of 312m.  The SeaSoar towed sensor system was equipped with dual pumped temperature/conductivity sensors.  The SeaSoar data, in netCDF form here, contains a highly processed 1-meter gridded version of the original source dataset, which is comprised of temperature, conductivity, salinity, pressure observations from 1144 casts during 2013 Spring SPURS Cruise.    
SeaSoar Contributors: J.Busecke   (Columbia U.)
Data Access
   

Autonomous Samplers

Device Description Device Description
s/t glider The Tenuse (Slocum) glider is an autonomous undulating profiler measuring salinity and temperature.  It was deployed from the Thalassa on 21-August and recovered by the Knorr on 4-October-2012. It made a total of about 1400 profiles during that period (1-2 profiles/hour), going from the surface to 200 m. seaglider The Seaglider is an autonomous profiler measuring salinity and temperature. Three Seagliders were deployed on the Knorr cruise in September 2012. These were retrieved during the first Endeavor cruise, and then redeployed. The Seagliders typically made loops or butterfly patterns around the central SPURS mooring, diving to 1000 m.

Slocum/Tenuse Gliders

Contributor: G Reverdin (IFREMER)
Data Access

Seaglider

Contributors: C.Eriksen, C Lee (U. Washington)
Data Access
waveglider A Waveglider is an autonomous platform propelled by the conversion of ocean wave energy into forward thrust and employing solar panels to power instrumentation. For SPURS-1, sensors included a CTD at the near-surface and another at 6 m depth, providing continuous salinity and temperature observations. Three wavegliders (ASL2, ASL3 and ASL4) were deployed from the Knorr in September 2012, redeployed in April 2013 (ASL22, ASL32 and ASL42) with final recovery in September. Waveglider trajectories followed a square loop or butterfly pattern around the central SPURS mooring. ecomapper The Ecomapper or IVER is a portable autonomous underwater vehicle (AUV) capable carrying a range of sensor payloads.  For SPURS-1 these included CTD, chlorophyll, oxygen and turbidity sensors. Ecomapper was deployed on two days during the Knorr cruise, 29 and 30 September 2012.

Waveglider

Contributors: D.Fratantoni, B.Hodges (WHOI, Horizon Marine,)
Data Access

Ecomapper

Contributors:  D.Fratantoni, B.Hodges (WHOI, Horizon Marine)
Data Access
argo Part of the Argo global network of autonomous, self-reporting samplers, Argo floats drift horizontally and move vertically through the water column generally on 10 day cycles, collecting high-quality temperature and salinity profiles from the upper 2000m. Approximately 24 floats were deployed during SPURS-1, mainly on the Knorr cruise. These were standard Argo floats with the addition of surface temperature and salinity (STS) sensors and acoustic rain gauges (PAL). Data accessible here only include the standard ARGO profiles, not the STS or PAL data.

n buoyant

Neutrally buoyant floats drift and move through the water column providing continuous temperature and salinity profiles via 2 integrated CTDs and GPS surface position location data. Two floats were deployed during SPURS-1, one during the Knorr cruise in September 2012 another deployed during the April 2013 Endeavor cruise.  Recoveries were in April and September 2013 respectively.

Argo Float

Contributor: S. Riser (U.Washington)
Data Access

Neutrally Buoyant Float

Contributors: E.d'Asaro, A.Shcherbina (U.Washington)
Data Access

drifter

A drifter is passive Lagrangian platform consisting of a surface buoy and tethered subsurface drogue. Buoys contain GPS and satellite data transmitters, with sensors measuring temperature and other properties. Approximately 83 drifters were deployed during SPURS-1. These were standard Surface Velocity Program (SVP) drifters with salinity sensors added (SVP/S).  Drifter data available here in netCDF format include data from both the US and European driifter deployments during the SPURS-1 campaign.    

Drifter

Contributors: L.Centurioni, G.Reverin (USCD, IFREMER)
Data Access
   

Satellite Observations

Complementary, broad-scale measurements of remotely sensed sea surface salinity over the SPURS-1 domain are provided by the AQUARIUS/SAC-D and SMOS satellite missions.

Device Description Device Description

Aquarius

The Aquarius/SAC-D satellite mission launched in June 2011, providing over 3 years of global sea surface salinity   and wind speed observations in  390 km swaths with a 7 day repeat cycle.  The Aquarius instrument has 3 radiometer beams in push-broom alignment with footprint resolutions of 76 km (along-track) x 94 km (cross-track), 84 km x 120 km and 96km x 156 km and a sampling frequency of 1.44sec/block.  SSS accuracy is about 0.2 PSU RMS (1degree Lat/Lon, monthly average).  Both orbital/swath L2 and gridded L3 products are available from the PO.DAAC.

SMOS

ESA’s SMOS (Soil Moisture & Ocean Salinity) satellite mission launched November 2009, providing over 5 years of global sea surface salinity observations. The SMOS MIRAS radiometer is an L-band passive microwave 2D-interferometer, with a, spatial resolution of 35 km (at center of the 1000km field of view) and a 3 day Equatorial temporal repeat cycle. SMOS salinity L2, L3 and L4 products are available.

Aquarius/SAC-D

Agency: NASA/CONAE
Data Access

SMOS

Agency: ESA
Data Access

 

Figure 4. Location of the SPURS-2study area in the low salinity, high precipitation area of the ETP within the ITCZ.

Figure 1. Location of the SPURS-2 study area in the eastern tropical Pacific. Colors represent the mean surface salinity.

SPURS-2 was a follow-on field campaign over the period August 2016 to November 2017 aiming to better understand physical processes influencing upper-ocean salinity over the seasonal cycle in a low-salinity region of the eastern tropical Pacific (ETP) centered at 10N, 125W (Figure 1). This is a dynamic, rainfall-dominated area associated with western edge of the eastern Pacific fresh pool and intertropical convergence zone (ITCZ). It exhibits a shallow thermocline and is subject to high seasonal variability and strong zonal flows associated with the North Equatorial Current and Countercurrent. Processes operating on a continuum of scales and the challenges of sampling such a spatially heterogeneous and temporally variable region necessitated a nested survey design involving a suite of in-situ measurements from diverse sampling platforms, guided by a data-assimilating ROMS regional ocean circulation model and satellite observations from SMAP and SMOS. Instrument deployments occurred during two month-long cruises by the R/V Roger Revelle (the “Revelle”, Scripps Institution of Oceanography, University of California, San Diego). The R/V Lady Amber visited the site on a more frequent basis for light sampling and deployment and recovery of instrumentation. This approach facilitated the examination of processes influencing surface salinity variability operative at three different scales:

  • Large Scale: The purpose here is to characterize processes that freshen and salinity the upper ocean in the ITCZ region and connect it to the eastern Pacific fresh pool.
  • Mesoscale: A smaller observational region surrounding the central SPURS-2 site was sampled to resolve scales from 10-300 km. This scale includes eddies which act to stir the salinity field. Numerical modeling studies were especially important at this scale.
  • Small-scale: The smallest scales observed are less than 10 km. Precipitation is expected to be patchy at this scale. SPURS-2 especially focuses on how intense rainfall bursts are dispersed vertically and horizontally.

 

Cruises

The table below summarizes the dates of the SPURS-2 cruises and research vessels involved. Full cruise reports have been issued for the Revelle cruises.  These are available here.

TableCruises.png

 

Sampling Platforms & Technologies
A suite of sampling platforms and sensors were deployed during SPURS-2 providing multivariate observations, both ship-based and mobile, Eulerian (point) and Lagrangian (trajectory), over a range of spatio-temporal scales within the campaign’s domain.  Figure 2 illustrates the Revelle cruise tracks and SPURS-2 domain focused on the central mooring at 10N, 125W and bounded latitudinally by two PICO (Platform Instrumentation for Continuous Observations) / Prawler moorings.

Spurs2_CruiseDomains

Figure 2. Tracks of the Revelle for cruise 1 (blue) and cruise 2 (red). Boundaries for panel B are shown in panel A by a dotted line. Black “X” marker in panel B is the nominal location of the central mooring and red “X”s are the locations of the north and south PICO moorings.

 

1. Research Vessels

RvRevelle.jpg

R/V Lady Amber

R/V Roger Revelle (SIO) R/V Lady Amber

 

 

2. Sensor Platforms

Moorings

Device Description Device Description

RV Knorr (US)

The SPURS central mooring consisted of a surface meteorological package, surface oceanographic instruments, and subsurface, non-real time oceanographic instruments including CTD, ADCP sensors and point current meters providing continuous series of temperature, salinity and current profile data. Meteorological observations included wind speed, air temperature, precipitation, and radiative flux. The mooring was deployed in 4769 m depth of water on 24 August 2016, at 10°03.0481'N, 125° 01.939'W, and was recovered on November 11, 2017.

PICO

Two PICO moorings (PMEL 9N and 11N) were deployed on the Revelle cruise in September 2016 in northern and southern domain quadrants at 9° 2.830N, 124° 59.833W and 10° 59.0498N 124° 57.531W respectively. These moorings contained a surface meteorological package and a "prawler", a CTD that crawls up and down the mooring line from 4-450m, yielding time series of salinity and temperature profile data at fixed locations (nominally 8 profiles per day). The moorings were recovered on the second Revelle cruise (Oct. 22 & Nov. 2, 2017).
SPURS Mooring

Contributor: T.Farrarr (WHOI)
Data Access  (Pending)

PICO Moorings Contributors: C. Zhang & W. Kessler (NOAA/PMEL)
Data Access  (Pending)

Ship-based Samplers

Device Description Device Description

CTD

Shipboard lowered CTD probes provide continuous conductivity, temperature and pressure vertical profile observations at fixed sampling stations. There were 50 and 14 CTD casts made during the first and second Revelle cruises respectively. All continuous profile CTD data were calibrated using shipboard salinometers according to IAPSO standard seawater.

ADCP

Acoustic Doppler Current Profilers (ADCP) provide water column current velocity profile observations.  Shipboard ADCP data were collected during the two Revelle cruises, using 150 kHz and 75 khz broadband and narrowband instruments. Additionally, lowered ADCP (L-ADCP) measurements were made on CTD cast  at 0.5 degree intervals during the R/V Revelle cruise.
CTD Contributor: J. Sprintall (UCSD/SIO)
Data Access
ADCP Contributors: J. Sprintall (UCSD/SIO)
Data Access

U-CTD

Underway-CTD (UCTD) is a profiling CTD instrument providing salinity and temperature observations from the surface to 500m while underway at up to 12 kts. A total of 262 and 501 uCTD casts were performed during the first and second Revelle cruises respectively.

xbt

Expendable bathythermographs (XBT) are small, single use probes that are launched over the side of vessels.  They measure water temperature continuously to depths of up to 1100m, providing vertical profile data of water column temperatures at fixed locations.  During SPURS-2, XBTs were deployed during both Revelle cruises, a total of 25 and 11 in the first and second cruises respectively.

Underway-CTD

Contributor: J. Sprintall (UCSD/SIO)
Data Access (Pending)
XBT Contributor: J. Sprintall (UCSD/SIO)
Data Access

Thermo

A thermosalinograph (TSG) and underway surface profiling system (USPS) are automated measurement systems coupled to a research vessel's water intake and GPS systems. They provide continuous, along-track surface temperature and salinity measurements at depths of 2, 3 and 5 m using through-hull ports in the bow of the ship. Each SPURS-2 cruise had a USPS/TSG instrument, with measurements calibrated against onboard salinometers.

SalinityShake.jpg

The Salinity Snake (SS) measures sea surface salinity in the top 1-2 cm of the water column, which is the radiometric depth of L-Band satellite radiometers such as on Aquarius/SAC-D, SMAP and SMOS satellites that measure salinity remotely.  The SS consists of four key components: a 10m boom/mast, a hose, which is deployed from this boom, a powerful self-priming peristaltic pump which transports a constant stream of a seawater/air emulsion, and a shipboard apparatus, which filters, de-bubbles, sterilizes and analyses the salinity of the water.  The SS was deployed during both SPURS-2 Revelle cruises.
Thermosalinograph Contributor: W. Asher (APL/UW)
Data Access  (Pending)
Salinity Snake Contributor: J. Schanze (ESR)
Data Access  (Pending)

meteorology

 

A ship mast meteorological sensor package with an additional set of sophisticated sensors, including a direct covariance flux package was set up on both SPURS-2 Revelle cruises.  These provided georeferenced, along-track atmospheric pressure, temperature, humidity, IR/visible radiation, rain, and wind speed and air-sea flux measurements.

Rawinsonde

 

A Rawinsonde is a helium balloon carrying meteorological instruments and a radar target, enabling the velocity of atmospheric parameters to be measured.  During the first Revelle cruise, rawinsondes were launched every 6-hours, providing a total of 85 profiles of temperature, humidity, wind speed and direction through the marine atmospheric boundary layer within the SPURS-2 domain. Similarly, during the second Revelle cruise, rawinsondes were deployed four-times daily within the study area over the 3-week period.
Meteorology Contributors: C.A Clayson & J. Edson (WHOI)
Data Access  (Pending)
 Rawinsonde Contributors: C.A Clayson, J. Edson (WHOI; cruise 1) and S. Rutledge (CSU; cruise 2)
Data Access (Pending)

Bioptics

Bio-optics underway and profile measurements from the second SPURS-2 Revelle cruise provide data on phytoplankton diversity and community structure at high spatial resolution. Bio-optical properties of water from the 5m intake port and Salinity Snake were measured using two flow-through systems, a WetLabs BB3 scatterometer run inline with a colored dissolved organic matter (CDOM) fluorometer, and a McLane Imaging FlowCytobot (IFCB).  Additionally, discrete samples for flow cytometric analysis, DNA extraction and pigment determination were collected at the surface and from CTD casts.

asphere

A-Sphere spectrophotometer: Approximately 25 casts of the a-sphere spectrophotometer were performed onboard the Revelle during the second SPURS-2 cruise to measure the optical absorption by seawater.

Bio-optics Contributor: S. Clayton (UW)
Data Access (Pending)

A-sphere

Contributor: C.A Clayson & J. Edson (WHOI)
Data Access (Pending)

DicPhPCO2

Underway pCO2/DIC/pH measurements.  During both Revelle cruises, continuous measurements of the partial pressure of CO2 (pCO2), dissolved inorganic carbon (DIC), pH, and dissolved oxygen (DO) were made on water pumped continuously from the Salinity Snake and the ship’s intake port.  The temporal resolution of the observations range from 3 seconds (pH) to 3 minutes (DIC).

RvLadyAmber

Underway physical data from schooner Lady Amber cruises during the SPURS-2 field campaign include along–track meteorological, salinity snake and fixed-hull CTD measurements at 1m and 2 m intake depths. Comparisons with nearby Revelle data facilitate evaluation of uncertainties arising from collecting data from a sailboat, and the characterization of small-scale spatial variability in the ocean and atmosphere.
pCO2/DIC/pH

Contributor: D. Ho (U. Hawaii)
Data Access (Pending)

Lady Amber Contributor: L. Rainville (APL/UW)
Data Access (Pending)

ROSR

The Remote Ocean Surface Radiometer (ROSR) is a self-calibrating system incorporating a pitch-roll sensor that provides sea-surface skin temperature (SSST) measurements in support of air-sea interaction studies or satellite calibration and validation activities. A measurement cycle completes in 285 seconds and involves the ROSR scan drum pointing at a variety of angles.  This allows for correction of reflected sky radiance in the downward looking view. ROSR was successfully deployed during the first SPURS-2 Revelle cruise, resulting in a 10260 point time series from 2016-08-14 to 2016-09-20.

SSP

The towed Surface Salinity Profiler (SSP) platform is a converted paddleboard with a keel and surfboard outrigger that is tethered to the ship and skims the sea surface beyond the ship’s wake. Below the paddleboard are salinity and temperature sensors at depths of 10, 30, 50 and 100cm, and microstructure sensors that measure turbulence. The SSP was deployed 19 times throughout the first SPURS-2 cruise, totaling over 200 hours of measurements, and a further 15 times during the 2017 cruise.  SSP deployment is most informative when there is a rain event leading to near-surface ocean stratification. The SSP then measures how the ocean changes over the periods before, during, and after rain, and how rainwater mixes into the ocean during recovery.
ROSR Contributor: A. Jessup (APL/UW)
Data Access (Pending)
SSP Contributors: K. Druska, W. Asher (APL/UW)
Data Access (Pending)

WAMOS

WaMoS is a radar-based wave and surface current monitoring system providing wave field imagery and station time series or along track data series for key wave parameter in near near-real time. The WaMoS wave radar instrument was available during the second Revelle cruise of SPURS-2. It provided along track wave measurements over the duration of this cruise for the following essential wave field parameters: wave period, wavelength, and wave direction, as well as surface current speed and direction.

SEAPOL

The SEA-POL (seagoing-polarimetric) radar is a C-band, Doppler polarimetric radar system, first deployed during the second SPURS-2 Revelle cruise. SEA-POL’s 1-degree beam width antenna, antenna mounted receiver and positioning system are set on top of the radar and enclosed in a high performance radome located in the inner-starboard seatainer position on the forward deck. The peak power of 250 kW transmitter covered a 240-degree sector centered on the ship’s bow. SEA-POL was used primarily to map rainfall.

WaMoS Contributor: K. Druska (APL/UW)
Data Access
SEA-POL Contributor: S.A. Rutledge (CSU)
Data Access

The RainMOS X-band radar system aboard the Revelle was used to monitor and quantify rain events during both SPURS-2 cruises.  Resulting data include radar imagery and derived rain intensity products.

CFT

The Controlled Flux Technique (CFT) is a system for measuring the net heat transfer velocity and turbulent kinetic energy (TKE) dissipation at the ocean surface, and is a useful tool for studying the turbulence generated at the ocean surface by the impact of raindrops. CFT was employed during both SPURS-2 Revelle cruises. It involves a laser heating a small patch of water on the ocean surface, and the IR imaging camera then tracking the resulting thermal decay.  This decay is known to be proportional to the dissipation of TKE at the water surface, which in turn can be used to scale the transfer velocity for the net heat flux.
X-band radar Contributor: E. Thompson (APL/UW)
Data Access (Pending)
CFT Contributor: W. Asher (APL/UW)
Data Access (Pending)

Autonomous & Lagrangian Samplers

Device Description Device Description

waveglider

A Waveglider is an autonomous platform propelled by the conversion of ocean wave energy into forward thrust and employing solar panels to power instrumentation. For SPURS-2, sensors included a CTD at the near-surface and another at 6 m depth, providing continuous salinity and temperature observations plus air temperature and wind measurements.  Three wavegliders (ASL22, 32, 42) were deployed from the Revelle in August 2016 and again in November 2017 before final retrieval at the conclusion on the second cruise. Waveglider trajectories followed a 20x20km square loop around the moorings and a butterfly pattern around the neutrally-buoyant float.

seaglider

The Seaglider is an autonomous profiler measuring salinity and temperature. Three Seagliders were deployed on the first Revelle cruise in August 2016, recovered by the Lady Amber after 7 months and redeployed, to be retrieved finally during the second cruise in November 2017. One of the Seagliders deployed alongside and tracked the Lagrangian array across the study region, diving to depths of 1000m.

Waveglider

Contributor: B. Hodges (WHOI)
Data Access  (Pending)

Seaglider

Contributors: L. Rainville (APL/UW)
Data Access  (Pending)

drifter

A drifter is passive Lagrangian platform consisting of a surface buoy and tethered subsurface drogue. Buoys contain GPS and satellite data transmitters, with sensors measuring temperature and other properties. A range of drifters were deployed during both Revelle SPURS-2 cruises. These included: standard Surface Velocity Program (SVP) drifters with salinity sensors added (SVP/S), Surface Contact Salinity drifters, SURPACT drifters, CODE and ADOS drifters. 

ecomapper

The Ecomapper or IVER is a portable autonomous underwater vehicle (AUV) capable carrying a range of sensor payloads.  For SPURS-2 these included CTD, chlorophyll, oxygen and turbidity sensors. Ecomappers were deployed on two occasions during the second Revelle cruise, 30 and 31 October 2017.

Drifter

Contributors: L. Centurioni, V. Hormann, G. Reverdin, A. Hasson, A. Supply (USCD/SIO, IFREMER)
Data Access  (Pending)

Ecomapper

Contributors:  B. Hodges (WHOI)
Data Access  (Pending)

argo

Part of the Argo global network of autonomous, self-reporting samplers, Argo floats drift horizontally and move vertically through the water column generally on 10 day cycles, collecting high-quality temperature and salinity profiles from the upper 2000m.  During the first SPURS-2 Revelle cruise, 15 profiling floats were deployed, 10 of which are regular US Argo floats, with the remaining 5 being US Argo floats equipped with Surface Temperature and Salinity (STS) and Passive Aquatic Listener Sensors (PALS) that measure rainfall and wind speed during times when the float is not profiling.  During the second cruise in the fall of 2017, 11 Argo floats were deployed, 2 of which were a new design built for the Tropical Pacific Observing System (TPOS) pilot program, that additionally carried sensors for dissolved oxygen, chlorophyll fluorescence and particle backscatter, and a hydrophone for ambient acoustic noise measurements used to estimate wind speed and rainfall.

n buoyant

Neutrally buoyant floats (also known as Mixed Layer Floats - MLF) drift and move through the water column providing continuous temperature and salinity profiles via 2 integrated CTDs and GPS surface position location data. One float was deployed in SPURS-2 during the first Revelle cruise in August 2016 and recovered in December 2016 after 3.5 months about 1800 km east of the central mooring.

Argo Float

Contributor: S. Riser, J. Yang (U.Washington)
Data Access  (Pending)

Neutrally Buoyant Float

Contributors: A. Shcherbina (APL/UW)
Data Access  (Pending)

Saildrone

Saildrone is a state-of-the-art, remotely guided, wind and solar powered unmanned surface vehicle (USV) capable of long distance deployments lasting up to 12 months.  It is equipped with a suite of instruments and sensors providing high quality, georeferenced, near real-time, multi-parameter surface ocean and atmospheric observations while transiting at typical speeds of 3-5 knots.  In SPURS-2, two saildrones were deployed over the period of the second Revelle cruise.    

Saildrone

Contributors: D. Zhang (NOAA/PMEL)
Data Access 
   

Satellite Observations

Complementary, broad-scale measurements of remotely sensed sea surface salinity over the SPURS-1 domain are provided by the AQUARIUS/SAC-D and SMOS satellite missions.

Device Description Device Description

SMAP

Launched on January 31, 2015, the NASA Soil Moisture Active Passive (SMAP) mission was designed to principally measure soil moisture and freeze/thaw state from space . The mission is, however, building upon the legacy of Aquarius/SAC-D in also delivering derived sea surface salinity (SSS) observations for the world’s oceans given its highly sensitive radiometer operating at 1.41GHz and ability to provide global coverage in 3 days. The SMAP satellite is in a near-polar orbit at an inclination of 98 degrees and an altitude of 685 km. It has an ascending node time of 6 pm, is sun-synchronous, and has an exact orbit repeat cycle of 8 days.  Both orbital/swath L2 and gridded L3 products are available from the PO.DAAC.

SMOS

ESA’s SMOS (Soil Moisture & Ocean Salinity) satellite mission launched November 2009, providing over 5 years of global sea surface salinity observations. The SMOS MIRAS radiometer is an L-band passive microwave 2D-interferometer, with a, spatial resolution of 35 km (at center of the 1000km field of view) and a 3 day Equatorial temporal repeat cycle. SMOS salinity L2, L3 and L4 products are available.

SMAP

Agency: NASA
Data Access

SMOS

Agency: ESA
Data Access