Weller Robert A.

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Weller

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Robert A.

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0000-0001-8001-6886

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Arabian Sea mixed layer dynamics experiment : mooring deployment cruise report R/V Thomas Thompson cruise number 46, 14 April-29 April 1995

(Woods Hole Oceanographic Institution, 1995-07) Trask, Richard P. ; Weller, Robert A. ; Ostrom, William M.

This report describes in a general manner the work that took place during the R/V Thomas Thompson cruise number 46 which was the mooring turnaround cruise for the moored array program. A detailed description of the WHOI surface mooring and its instrumentation is provided. Information about the XBT and CTD data and near-surface temperature data collected during the cruise is also included.
Intraseasonal variability near 10°N in the eastern tropical Pacific Ocean

(American Geophysical Union, 2006-05-20) Farrar, J. Thomas ; Weller, Robert A.

New in situ observations from 10°N, 125°W during 1997–1998 show strong intraseasonal variability in meridional velocity and sea surface temperature. The 50- to 100-day oscillations in sea surface height (SSH) have long been recognized as a prominent aspect of oceanic variability in the region of 9–13°N in the eastern Pacific Ocean. We use in situ and satellite data to more fully characterize this variability. The oscillations have zonal wavelengths of 550–1650 km and propagate westward in a manner consistent with the dispersion relation for first baroclinic mode, free Rossby waves in the presence of a mean westward flow. Analysis of 9 years of altimetry data shows that the amplitude of the 50- to 100-day SSH variability at 10°N is largest on 90–115°W, with peak amplitudes occurring around April. Some eddies traveling westward at 10–13°N emanate from near the gulfs of Tehuantepec and Papagayo, but eddies sometimes also appear to intensify well away from the coast while in the North Equatorial Current (NEC). The hypothesis that the intraseasonal variability and its annual cycle are associated with baroclinic instability of the NEC is supported by a spatiotemporal correlation between the amplitude of 50- to 100-day variability and the occurrence of westward zonal flows meeting an approximate necessary condition for baroclinic instability. The notion that baroclinic instability may be involved is further corroborated by the tendency of the NEC to weaken while the eddies intensify, even as the wind works to strengthen the current.
Submesoscale processes at shallow salinity fronts in the Bay of Bengal : observations during the winter monsoon

(American Meteorological Society, 2018-02-26) Ramachandran, Sanjiv ; Tandon, Amit ; MacKinnon, Jennifer A. ; Lucas, Andrew J. ; Pinkel, Robert ; Waterhouse, Amy F. ; Nash, Jonathan D. ; Shroyer, Emily L. ; Mahadevan, Amala ; Weller, Robert A. ; Farrar, J. Thomas

Lateral submesoscale processes and their influence on vertical stratification at shallow salinity fronts in the central Bay of Bengal during the winter monsoon are explored using high-resolution data from a cruise in November 2013. The observations are from a radiator survey centered at a salinity-controlled density front, embedded in a zone of moderate mesoscale strain (0.15 times the Coriolis parameter) and forced by winds with a downfront orientation. Below a thin mixed layer, often ≤10 m, the analysis shows several dynamical signatures indicative of submesoscale processes: (i) negative Ertel potential vorticity (PV); (ii) low-PV anomalies with O(1–10) km lateral extent, where the vorticity estimated on isopycnals and the isopycnal thickness are tightly coupled, varying in lockstep to yield low PV; (iii) flow conditions susceptible to forced symmetric instability (FSI) or bearing the imprint of earlier FSI events; (iv) negative lateral gradients in the absolute momentum field (inertial instability); and (v) strong contribution from differential sheared advection at O(1) km scales to the growth rate of the depth-averaged stratification. The findings here show one-dimensional vertical processes alone cannot explain the vertical stratification and its lateral variability over O(1–10) km scales at the radiator survey.
Upper ocean momentum balances in the western equatorial Pacific on the intraseasonal time scale

( 2004-12-15) Feng, Ming ; Lukas, Roger ; Hacker, Peter ; Plueddemann, Albert J. ; Weller, Robert A.

Surface Meteorology, upper ocean current, and hydrographic measurements, collected along a repeated survey pattern and from a central mooring in the western equatorial Pacific during late 1992 to early 1993, were used to analyse upper ocean momentum balances on the intraseasonal time scale. Wind stresses derived from meteorological measurements were compared with numerical weather prediction products. Advection terms in the momentum equations were estimated by planar fits to the current and hydrographic data. Pressure gradient terms were derived from planar fits to the dynamic heights calculated from the hydrographic data, referenced by balancing the momentum equation in a selected layer below the mixed layer. Under prevailing westerly winds, westward pressure gradient forcings of 2x10-7 m s-2 were set up in the western equatorial Pacific, countering the surface wind, while the total advection tended to accelerate the eastward momentum in the surface layer. During both calm wind and westerly wind burst periods, zonal turbulent momentum fluxes estimated from the ocean budgets were comparable with those estimated from microstructure dissipation rate measurements and with zonal wind stresses, so that the zonal momentum could be balanced within error bars. The meridional momentum balances were noisier, which might be due to the fact that the short meridional length scale of the equatorial inertial-gravity waves could contaminate the dynamic signals in the mixed temporal/spatial sampling data, so that the meridional gradient estimates from the planar fits could be biased.
Improved meteorological measurements from buoys and ships (IMET) : preliminary comparison of pyranometers

(Woods Hole Oceanographic Institution, 1989-10) Crescenti, Gennaro H. ; Payne, Richard E. ; Weller, Robert A.

Three different types of pyranometers (two of each) are tested and evaluated. The sensors include the Eppley Precision Spectral Pyranometer (PSP) which meets the World Meteorological Organization (1965) criteria for a first class pyranometer, the Eppley 8-48 Black and White Pyranometer (second class) and the Hollis MR-5 Silicon Photovoltaic Pyranometer (third class).
Structure and surface properties of eddies in the southeast Pacific Ocean

(John Wiley & Sons, 2013-05-07) Holte, James W. ; Straneo, Fiamma ; Moffat, Carlos F. ; Weller, Robert A. ; Farrar, J. Thomas

A number of studies have posited that coastally generated eddies could cool the southeast Pacific Ocean (SEP) by advecting cool, upwelled waters offshore. We examine this mechanism by characterizing the upper-ocean properties of mesoscale eddies in the SEP with a variety of observations and by estimating the surface-layer eddy heat flux divergence with satellite data. Cyclonic and anticyclonic eddies observed during two cruises featured deep positive salinity anomalies along the 26.5 kg m−3isopycnal, indicating that the eddies had likely trapped and transported coastal waters offshore. The cyclonic eddies observed during the cruises were characterized by shoaling isopycnals in the upper 200 m and cool near-surface temperature anomalies, whereas the upper-ocean structure of anticyclonic eddies was more variable. Using a variety of large-scale observations, including Argo float profiles, drifter records, and satellite sea surface temperature fields, we show that, relative to mean conditions, cyclonic eddies are associated with cooler surface temperatures and that anticyclonic eddies are associated with warmer surface temperatures. Within each data set, the mean eddy surface temperature anomalies are small and of approximately equal magnitude but opposite sign. Eddy statistics drawn from satellite altimetry data reveal that cyclonic and anticyclonic eddies occur with similar frequency and have similar average radii in the SEP. A satellite-based estimate of the surface-layer eddy heat flux divergence, while large in coastal regions, is small when averaged over the SEP, suggesting that eddies do not substantially contribute to cooling the surface layer of the SEP.
CLIVAR Mode Water Dynamics Experiment (CLIMODE) fall 2005, R/V Oceanus voyage 419, November 9, 2005–November 27, 2005

(Woods Hole Oceanographic Institution, 2006-02) Hutto, Lara ; Weller, Robert A. ; Fratantoni, David M. ; Lord, Jeffrey ; Kemp, John N. ; Lund, John M. ; Brambilla, Elena ; Bigorre, Sebastien P.

CLIMODE (CLIVAR Mode Water Dynamic Experiment) is a program designed to understand and quantify the processes responsible for the formation and dissipation of North Atlantic subtropical mode water, also called Eighteen Degree Water (EDW). Among these processes, the amount of buoyancy loss at the ocean-atmosphere interface is still uncertain and needs to be accurately quantified. In November 2005, a cruise was made aboard R/V Oceanus in the region of the separated Gulf Stream, where intense oceanic heat loss to the atmosphere is believed to trigger the formation of EDW. During that cruise, one surface mooring with IMET meteorological instruments was anchored in the core of the Gulf Stream as well as two moored profilers on its southeastern edge. Surface drifters, APEX floats and bobby RAFOS floats were also deployed along with two other moorings with sound sources. CTD profiles and water samples were also carried out. This array of instruments will permit a characterization of EDW with high spatial and temporal resolutions, and accurate in-situ measurements of air-sea fluxes in the formation region. The present report documents this cruise, the instruments that were deployed and the array of measurements that was set in place.
Sea surface temperature signatures of oceanic internal waves in low winds

(American Geophysical Union, 2007-06-20) Farrar, J. Thomas ; Zappa, Christopher J. ; Weller, Robert A. ; Jessup, Andrew T.

In aerial surveys conducted during the Tropical Ocean–Global Atmosphere Coupled Ocean-Atmosphere Response Experiment and the low-wind component of the Coupled Boundary Layer Air-Sea Transfer (CBLAST-Low) oceanographic field programs, sea surface temperature (SST) variability at relatively short spatial scales (O(50 m) to O(1 km)) was observed to increase with decreasing wind speed. A unique set of coincident surface and subsurface oceanic temperature measurements from CBLAST-Low is used to investigate the subsurface expression of this spatially organized SST variability, and the SST variability is linked to internal waves. The data are used to test two previously hypothesized mechanisms for SST signatures of oceanic internal waves: a modulation of the cool-skin effect and a modulation of vertical mixing within the diurnal warm layer. Under conditions of weak winds and strong insolation (which favor formation of a diurnal warm layer), the data reveal a link between the spatially periodic SST fluctuations and subsurface temperature and velocity fluctuations associated with oceanic internal waves, suggesting that some mechanism involving the diurnal warm layer is responsible for the observed signal. Internal-wave signals in skin temperature very closely resemble temperature signals measured at a depth of about 20 cm, indicating that the observed internal-wave SST signal is not a result of modulation of the cool-skin effect. Numerical experiments using a one-dimensional upper ocean model support the notion that internal-wave heaving of the warm-layer base can produce alternating bands of relatively warm and cool SST through the combined effects of surface heating and modulation of wind-driven vertical shear.
Corrigendum : On the exchange of momentum over the open ocean

(American Meteorological Society, 2014-09) Edson, James B. ; Jampana, Venkata ; Weller, Robert A. ; Bigorre, Sebastien P. ; Plueddemann, Albert J. ; Fairall, Christopher W. ; Miller, Scott D. ; Mahrt, Larry ; Vickers, Dean ; Hersbach, Hans
Moored observations of the surface meteorology and air-sea fluxes in the Northern Bay of Bengal in 2015

(American Meteorological Society, 2018-12-28) Weller, Robert A. ; Farrar, J. Thomas ; Seo, Hyodae ; Prend, Channing ; Sengupta, Debasis ; Lekha, J. Sree ; Ravichandran, M. ; Venkatesan, Ramasamy

Time series of surface meteorology and air–sea fluxes from the northern Bay of Bengal are analyzed, quantifying annual and seasonal means, variability, and the potential for surface fluxes to contribute significantly to variability in surface temperature and salinity. Strong signals were associated with solar insolation and its modulation by cloud cover, and, in the 5- to 50-day range, with intraseasonal oscillations (ISOs). The northeast (NE) monsoon (DJF) was typically cloud free, with strong latent heat loss and several moderate wind events, and had the only seasonal mean ocean heat loss. The spring intermonsoon (MAM) was cloud free and had light winds and the strongest ocean heating. Strong ISOs and Tropical Cyclone Komen were seen in the southwest (SW) monsoon (JJA), when 65% of the 2.2-m total rain fell, and oceanic mean heating was small. The fall intermonsoon (SON) initially had moderate convective systems and mean ocean heating, with a transition to drier winds and mean ocean heat loss in the last month. Observed surface freshwater flux applied to a layer of the observed thickness produced drops in salinity with timing and magnitude similar to the initial drops in salinity in the summer monsoon, but did not reproduce the salinity variability of the fall intermonsoon. Observed surface heat flux has the potential to cause the temperature trends of the different seasons, but uncertainty in how shortwave radiation is absorbed in the upper ocean limits quantifying the role of surface forcing in the evolution of mixed layer temperature.
CBLAST 2003 field work report

(Woods Hole Oceanographic Institution, 2005-04) Hutto, Lara ; Farrar, J. Thomas ; Weller, Robert A.

The long-range scientific objective of the Coupled Boundary Layer Air Sea Transfer (CBLAST) project is to observe and understand the temporal and spatial variability of the upper ocean, to identify the processes that determine that variability, and to examine its predictability. Air-sea interaction is of particular interest, but attention is also paid to the coupling of the sub-thermocline ocean to the mixed layer and to both the open ocean and littoral regimes. We seek to do this over a wide range of environmental conditions with the intent of improving our understanding of upper ocean dynamics and of the physical processes that determine the vertical and horizontal structure of the upper ocean. Field work for CBLAST was conducted during the summers of 2001, 2002, and 2003 off the south shore of Martha’s Vineyard, Massachusetts. The 2003 field work was conducted from the following platforms: heavy moorings, light moorings, drifters, F/V Nobska, CIRPAS Pelican aircraft, and an IR Cessna Aircraft. This report documents the 2003 field work and includes field notes, platform descriptions, discussion of data returns, and mooring logs. The 2003 Intensive Operating Period (IOP) was very successful and a high data return was seen.
FASINEX Frontal Air-Sea Interaction Experiment (January-June 1986) : cruise summaries for FASINEX phase two; R/V OCEANUS cruise 175, R/V ENDEAVOR cruise 141

(Woods Hole Oceanographic Institution, 1986-10) Pennington, Nancy J. ; Weller, Robert A.

The Frontal Air-Sea Interaction Experiment (FASINEX) was a study of the response of the upper ocean to atmospheric forcing in the vicinity of an oceanic front in the subtropical convergence zone southwest of Bermuda, the response of the lower atmosphere in that vicinity to the oceanic front, and the associated two-way interaction between ocean and atmosphere. FASINEX began in the winter (January 1986) , concluded in the early summer (June 1986) and included an intensive period in February and March. The experiment took place in the vicinity of 27°N, 70°W where sea-surface-temperature fronts are climatologically common. Measurements were made from buoys, ships, aircraft and spacecraft. This report summarizes the shipboard work done on R/V OCEANUS and R/V ENDEAVOR during Phase Two, the dual ship/multi-aircraft measurement period. The two ships worked individually, jointly and as ground truth for the aircraft during the month. Each ship carried specialized instrumentation for measuring oceanographic and meteorological parameters. Information describing the sampling strategy, station positions and times are included. This report contains summaries of the data collected and some preliminary results.
Seasonality and buoyancy suppression of turbulence in the Bay of Bengal

(American Geophysical Union, 2019-04-08) Thakur, Ritabrata ; Shroyer, Emily L. ; Govindarajan, Rama ; Farrar, J. Thomas ; Weller, Robert A. ; Moum, James N.

A yearlong record from moored current, temperature, conductivity, and four mixing meters (χpods) in the northernmost international waters of the Bay of Bengal quantifies upper‐ocean turbulent diffusivity of heat (Kt) and its response to the Indian monsoon. Data indicate (1) pronounced intermittency in turbulence at semidiurnal, diurnal, and near‐inertial timescales, (2) strong turbulence above 25‐m depth during the SW (summer) and NE (winter) monsoon relative to the transition periods (compare Kt > 10−4 m2/s to Kt ∼ 10−5 m2/s, and (3) persistent suppression of turbulence (Kt < 10−5 m2/s) for 3 to 5 months in the latter half of the SW monsoon coincident with enhanced near‐surface stratification postarrival of low‐salinity water from the Brahmaputra‐Ganga‐Meghna delta and monsoonal precipitation. This suppression promotes maintenance of the low‐salinity surface waters within the interior of the bay preconditioning the upper northern Indian Ocean for the next year's monsoon.
A self-contained wind speed, direction and location system for buoys and ships in the World Ocean Circulation Experiment

(Woods Hole Oceanographic Institution, 1994-08) Hosom, David S. ; Weller, Robert A. ; Allsup, Geoffrey P.

Knowledge of the absolute wind velocity near the surface of the ocean is a requirement of the World Ocean Circulation Experiment (WOCE) and other large programs directed towards understanding air-sea interactions and how ocean circulation and climate are interrelated. The measurement is made possible using IMET (Improved METeorology) modules, a next generation meteorological data acquisition system developed as part of the WOCE program. An IMET system consists of a set of intelligent modules for each measurement variable, with data being recorded on a computer, typically PC-based. The IMET wind module includes a propeller for wind speed, a vane and optical encoder for wind direction, a flux gate compass for the north reference, and microprocessor-based electronics for control and data formatting. The IMET Global Positioning System (GPS) module includes a five chanel GPS receiver and microprocessor based electronics for control and data formatting. These modules, as part of the complete measurement suite, result in a self-contained system that can make accurate measurements from research ships, drifting and moored buoys, and volunteer observing ships (VOS).
CLIVAR Mode Water Dynamics Experiment (CLIMODE) fall 2006 R/V Oceanus voyage 434 November 16, 2006–December 3, 2006

(Woods Hole Oceanographic Institution, 2007-12) Bigorre, Sebastien P. ; Weller, Robert A. ; Lord, Jeffrey ; Lund, John M. ; Palter, Jaime B. ; Tupper, George H.

CLIMODE (CLIVAR Mode Water Dynamic Experiment) is a research program designed to understand and quantify the processes responsible for the formation and dissipation of North Atlantic subtropical mode water, also called Eighteen Degree Water (EDW). Among these processes, the amount of buoyancy loss at the ocean-atmosphere interface is still uncertain and needs to be accurately quantified. In November 2006, cruise 434 onboard R/V Oceanus traveled in the region of the separated Gulf Stream and its recirculation, where intense oceanic heat loss to the atmosphere in the winter is believed to trigger the formation of EDW. During this cruise, the surface mooring F that was anchored in the core of the Gulf Stream was replaced by a new one, as well as two subsurface moorings C and D located on the southeastern edge of the stream. Surface drifters, ARGO and bobbers RAFOS floats were deployed, CTD profiles and water samples were also carried out. This array of instruments will permit a characterization of EDW with high spatial and temporal resolutions and accurate in-situ measurements of air-sea fluxes in the EDW formation region. The present report documents this cruise, the methods and locations for the deployments of instruments and some evaluation of the measurements from these instruments.
Stratus 11 : Eleventh Setting of the Stratus Ocean Reference Station Cruise on board RV Moana Wave, March 31 - April 16, 2011, Arica - Arica, Chile

(Woods Hole Oceanographic Institution, 2011-09) Bigorre, Sebastien P. ; Lord, Jeffrey ; Galbraith, Nancy R. ; Whelan, Sean P. ; Otto, William ; Holte, James W. ; Bariteau, Ludovic ; Weller, Robert A.

The Ocean Reference Station at 20°S, 85°W under the stratus clouds west of northern Chile is being maintained to provide ongoing climate-quality records of surface meteorology, air-sea fluxes of heat, freshwater, and momentum, and of upper ocean temperature, salinity, and velocity variability. The Stratus Ocean Reference Station (ORS Stratus) is supported by the National Oceanic and Atmospheric Administration’s (NOAA) Climate Observation Program. It is recovered and redeployed annually, with past cruises that have come between October and January. A NOAA vessel was not available, so this cruise was conducted on the chartered ship, Moana Wave, belonging to Stabbert Maritime. During the 2011 cruise on the Moana Wave to the ORS Stratus site, the primary activities were the recovery of the subsurface part of the Stratus 10 WHOI surface mooring, deployment of a new (Stratus 11) WHOI surface mooring, in-situ calibration of the buoy meteorological sensors by comparison with instrumentation installed on the ship by staff of the NOAA Earth System Research Laboratory (ESRL), and collection of underway and on station oceanographic data to continue to characterize the upper ocean in the stratus region. The Stratus 10 mooring had parted, and the surface buoy and upper part had been recovered earlier. Underway CTD (UCTD) profiles were collected along the track and during surveys dedicated to investigating eddy variability in the region. Surface drifters and subsurface floats were also launched along the track. The intent was also to visit a buoy for the Pacific tsunami warning system maintained by the Hydrographic and Oceanographic Service of the Chilean Navy (SHOA). This DART (Deep- Ocean Assessment and Reporting of Tsunami) buoy had been deployed in December 2010.
Stratus 10 tenth setting of the Stratus Ocean Reference Station : cruise RB-10-01, January 2 - January 30, 2010 Charleston, South Carolina - Valparaiso, Chile

(Woods Hole Oceanographic Institution, 2010-05) Bigorre, Sebastien P. ; Weller, Robert A. ; Lord, Jeffrey ; Galbraith, Nancy R. ; Whelan, Sean P. ; Zappa, Christopher J. ; Otto, William ; Ram, Jessica ; Vasquez, Raul ; Suhm, Diane

The Ocean Reference Station at 20°S, 85°W under the stratus clouds west of northern Chile is being maintained to provide ongoing climate-quality records of surface meteorology, air-sea fluxes of heat, freshwater, and momentum, and of upper ocean temperature, salinity, and velocity variability. The Stratus Ocean Reference Station (ORS Stratus) is supported by the National Oceanic and Atmospheric Administration’s (NOAA) Climate Observation Program. It is recovered and redeployed annually, with past cruises that have come between October and December. Due to necessary repairs on the electric motors of the ship’s propulsion system, this year the cruise was delayed until January. During the 2009/2010 cruise on the NOAA ship Ronald H. Brown to the ORS Stratus site, the primary activities were the recovery of the Stratus 9 WHOI surface mooring that had been deployed in October 2008, deployment of a new (Stratus 10) WHOI surface mooring at that site, in-situ calibration of the buoy meteorological sensors by comparison with instrumentation installed on the ship by staff of the NOAA Earth System Research Laboratory (ESRL), and collection of underway and on station oceanographic data to continue to characterize the upper ocean in the stratus region. Both underway CTD (UCTD) profiles and Vertical Microstructure Profiles (VMP) were collected along the track and during surveys dedicated to investigating eddy variability in the region. Surface drifters were also launched along the track. The intent was also to visit a buoy for the Pacific tsunami warning system maintained by the Hydrographic and Oceanographic Service of the Chilean Navy (SHOA). This DART (Deep- Ocean Assessment and Reporting of Tsunami) buoy had been equipped with IMET sensors and subsurface oceanographic instruments, and a recovery and replacement of the IMET sensors was planned. However, the DART buoy broke free from its mooring on January 3rd and was recovered by the Chilean navy; the work done at that site during this cruise was the recovery of the bottom pressure unit.
Moored surface buoy observations of the diurnal warm layer

(John Wiley & Sons, 2013-09-13) Prytherch, John ; Farrar, J. Thomas ; Weller, Robert A.

An extensive data set is used to examine the dynamics of diurnal warming in the upper ocean. The data set comprises more than 4700 days of measurements at five sites in the tropics and subtropics, obtained from surface moorings equipped to make comprehensive meteorological, incoming solar and infrared radiation, and high-resolution subsurface temperature (and, in some cases, velocity) measurements. The observations, which include surface warmings of up to 3.4°C, are compared with a selection of existing models of the diurnal warm layer (DWL). A simple one-layer physical model is shown to give a reasonable estimate of both the magnitude of diurnal surface warming (model-observation correlation 0.88) and the structure and temporal evolution of the DWL. Novel observations of velocity shear obtained during 346 days at one site, incorporating high-resolution (1 m) upper ocean (5–15 m) acoustic Doppler current profile measurements, are also shown to be in reasonable agreement with estimates from the physical model (daily maximum shear model-observation correlation 0.77). Physics-based improvements to the one-layer model (incorporation of rotation and freshwater terms) are discussed, though they do not provide significant improvements against the observations reported here. The simplicity and limitations of the physical model are used to discuss DWL dynamics. The physical model is shown to give better model performance under the range of forcing conditions experienced across the five sites than the more empirical models.
Long-term evolution of the coupled boundary layers (STRATUS) mooring recovery and deployment cruise report NOAA Research Vessel R H Brown • cruise RB-01-08 9 October - 25 October 2001

(Woods Hole Oceanographic Institution, 2002-02) Vallee, Charlotte ; Weller, Robert A. ; Bouchard, Paul R. ; Ostrom, William M. ; Lord, Jeffrey ; Gobat, Jason I. ; Pritchard, Mark ; Westberry, Toby K. ; Hare, Jeffrey E. ; Uttal, Taneil ; Yuter, Sandra ; Rivas, David ; Baumgardner, Darrel ; McCarty, Brandi ; Shannahoff, Jonathan ; Walsh, M. Alexander ; Bahr, Frank B.

This report documents the work done on cruise RB-01-08 of the NOAA R/V Ron Brown. This was Leg 2 of R/V Ron Brown’s participation in Eastern Pacific Investigation of Climate (EPIC) 2001, a study of air-sea interaction, the atmosphere, and the upper ocean in the eastern tropical Pacific. The science party included groups from the Woods Hole Oceanographic Institution (WHOI), NOAA Environmental Technology Laboratory (ETL), the University of Washington (UW), the University of California, Santa Barbara (UCSB), and the University Nacional Autonoma de Mexico (UNAM). The work done by these groups is summarized in this report. In addition, the routine underway data collected while aboard R/V Ron Brown is also summarized here.
Using present-day observations to detect when anthropogenic change forces surface ocean carbonate chemistry outside preindustrial bounds

(Copernicus Publications on behalf of the European Geosciences Union, 2016-09-13) Sutton, Adrienne J. ; Sabine, Chris L. ; Feely, Richard A. ; Cai, Wei-Jun ; Cronin, Meghan F. ; McPhaden, Michael J. ; Morell, Julio M. ; Newton, Jan A. ; Noh, Jae Hoon ; Ólafsdóttir, Sólveig R. ; Salisbury, Joseph E. ; Send, Uwe ; Vandemark, Douglas ; Weller, Robert A.

One of the major challenges to assessing the impact of ocean acidification on marine life is detecting and interpreting long-term change in the context of natural variability. This study addresses this need through a global synthesis of monthly pH and aragonite saturation state (Ωarag) climatologies for 12 open ocean, coastal, and coral reef locations using 3-hourly moored observations of surface seawater partial pressure of CO2 and pH collected together since as early as 2010. Mooring observations suggest open ocean subtropical and subarctic sites experience present-day surface pH and Ωarag conditions outside the bounds of preindustrial variability throughout most, if not all, of the year. In general, coastal mooring sites experience more natural variability and thus, more overlap with preindustrial conditions; however, present-day Ωarag conditions surpass biologically relevant thresholds associated with ocean acidification impacts on Mytilus californianus (Ωarag < 1.8) and Crassostrea gigas (Ωarag < 2.0) larvae in the California Current Ecosystem (CCE) and Mya arenaria larvae in the Gulf of Maine (Ωarag < 1.6). At the most variable mooring locations in coastal systems of the CCE, subseasonal conditions approached Ωarag =  1. Global and regional models and data syntheses of ship-based observations tended to underestimate seasonal variability compared to mooring observations. Efforts such as this to characterize all patterns of pH and Ωarag variability and change at key locations are fundamental to assessing present-day biological impacts of ocean acidification, further improving experimental design to interrogate organism response under real-world conditions, and improving predictive models and vulnerability assessments seeking to quantify the broader impacts of ocean acidification.

Weller Robert A.

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