DOCSLIB.ORG

Coupled Ocean–Atmosphere Dynamics in a Simple Midlatitude

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Coupled Ocean–Atmosphere Dynamics in a Simple Midlatitude 3704 JOURNAL OF CLIMATE VOLUME 14 Coupled Ocean±Atmosphere Dynamics in a Simple Midlatitude Climate Model DAVID FERREIRA AND CLAUDE FRANKIGNOUL Laboratoire d'OceÂanographie Dynamique et de Climatologie, Unite mixte de recherche CNRS-ORSTOM-UPMC, Universite Pierre et Marie Curie, Paris, France JOHN MARSHALL Program in Atmospheres, Oceans, and Climate, Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts (Manuscript received 22 February 2000, in ®nal form 16 January 2001) ABSTRACT Midlatitude air±sea interactions are investigated by coupling a stochastically forced two-layer quasigeostrophic channel atmosphere to a simple ocean model. The stochastic forcing has a large-scale standing pattern to simulate the main modes of low-frequency atmospheric variability. When the atmosphere interacts with an oceanic mixed layer via surface heat exchanges, the white noise forcing generates an approximately red noise sea surface temperature (SST) response. As the SST adjusts to the air temperature changes at low frequency, thus decreasing the heat ¯ux damping, the atmospheric spectra are slightly reddened, the power enhancement increasing with the zonal scale because of atmospheric dynamics. Decadal variability is enhanced by considering a ®rst baroclinic oceanic mode that is forced by Ekman pumping and modulates the SST by entrainment and horizontal advection. The ocean interior is bounded at its eastern edge, and a radiation condition is used in the west. Primarily in wintertime conditions, a positive feedback takes place between the atmosphere and the ocean when the atmo- spheric response to the SST is equivalent barotropic. Then, the ocean interior modulates the SST in a way that leads to a reinforcement of its forcing by the wind stress, although the heat ¯ux feedback is negative. The coupled mode propagates slowly westward with exponentially increasing amplitude, and it is fetch limited. The atmospheric and SST spectral power increase at all periods longer than 10 yr when the coupling with the ocean interior occurs by entrainment. When it occurs by advection, the power increase is primarily found at near- decadal periods, resulting in a slightly oscillatory behavior of the coupled system. Ocean dynamics thus leads to a small, but signi®cant, long-term climate predictability, up to about 6 yr in advance in the entrainment case. 1. Introduction and Deser 1995). As discussed by Deser and Blackmon There has been growing interest in understanding the (1993), the decadal SST ¯uctuations in the North At- nature of the air±sea interactions controlling extratrop- lantic are related to the wintertime atmospheric anom- ical sea surface temperature (SST) variability on cli- alies in broadly the same way as on shorter timescales, matic timescales. As reviewed by Frankignoul (1985), with stronger winds overlying cooler SSTs, while dif- the interannual SST anomalies mainly re¯ect the re- ferent relations are seen on interdecadal and longer time- sponse of the oceanic surface mixed layer to the day- scales. Halliwell and Mayer (1996) showed that in the to-day changes in the local air±sea ¯uxes, which act as westerlies local anomalous turbulent heat ¯ux is effec- a stochastic forcing. Away from frontal zones, the main tive in forcing the wintertime SST anomalies down to SST anomaly forcing is by surface heat exchanges and the decadal period, although in the western North At- vertical entrainment, and turbulent heat ¯uxes also con- lantic, the geostrophic variability strongly modulates the tribute to SST anomaly damping (Frankignoul et al. SST ¯uctuations (Halliwell 1998). The decadal signal 1998). Although the decay time of the SST anomalies may have an enhanced variance around periods of about is typically 3 months, that of the heat content in the 12±14 yr (Deser and Blackmon 1993; Sutton and Allen mixed layer is longer and wintertime SST anomalies 1997), but a dominant SST timescale does not require generally recur during the following autumn (Alexander an active ocean±atmospheric coupling; it could arise through the interplay between stochastic atmospheric forcing with a ®xed spatial pattern and oceanic advec- Corresponding author address: Claude Frankignoul, Laboratoire tion (Saravanan and McWilliams 1998), or re¯ect SST d'OceÂanographie Dynamique et de Climatologie, Unite mixte de re- cherche CNRS-ORSTOM-UPMC, Case 100, Universite Pierre et Ma- modulation by stochastically forced geostrophic ¯uc- rie Curie, 4 place Jussieu, 75252 Paris, France. tuations (Frankignoul et al. 1997; Jin 1997). E-mail: [email protected] General circulation model (GCM) experiments with q 2001 American Meteorological Society 1SEPTEMBER 2001 FERREIRA ET AL. 3705 Decadal oscillations sustained by a positive midlati- tude ocean±atmosphere feedback were invoked by Latif and Barnett (1994) to explain decadal variability in the North Paci®c in the ECHO coupled general circulation model. In their scenario, in an anomalously strong sub- tropical gyre, the Kuroshio transports more warm water northward and increases the SST in the western and central Paci®c. The atmospheric response to the SST anomaly is such that it sustains the latter via a positive heat ¯ux feedback while decreasing the wind stress curl, which after some delay spins down the subtropical gyre and eventually yields a SST anomaly of the reversed sign. GroÈtzner et al. (1998) have suggested that a similar coupling is at play in the North Atlantic. However, the midlatitude ocean is less active in ECHAM1/LSG and the heat ¯ux feedback negative (Zorita and Frankignoul 1997; Frankignoul et al. 2000), and the ocean is pri- marily passive in the Geophysical Fluid Dynamics Lab- oratory model (Delworth 1996). Since cause and effect are dif®cult to distinguish in coupled simulations, more studies are needed to understand the nature of the air± sea coupling and establish statistical signatures that could be tested with observed or coupled model data. Early basic studies of the midlatitude coupling have been reviewed by Frankignoul (1985) and Barsugli and FIG. 1. (top) NAO pattern obtained as the leading mode (47% of Battisti (1998). The latter coupled a stochastically the variance) of wintertime sea level pressure over the North Atlantic forced slab (or energy balance) atmosphere to a slab from an EOF analysis. Monthly anomalies were computed from the ocean via surface heat exchanges. The coupling allowed NCEP reanalysis for the period 1948±99 and then averaged to form for an adjustment between air temperature and SST that wintertime (Dec±Mar) anomalies. (bottom) The power spectrum (ar- bitrary units) of the ®rst principal component was computed using reduced the heat ¯ux feedback at low frequencies, en- the multitaper method. The power law in dashed line was obtained hancing the oceanic and atmospheric variability (see by a least squares ®t for periods between 2 and 20 yr. also Saravanan and McWilliams 1998). Longer time- scales are introduced in the coupled system by the ocean dynamics. Frankignoul et al. (1997, hereafter FMZ) prescribed SST anomalies generally suggest that there showed that the baroclinic response of the ocean to sto- is some atmospheric response in fall and winter, but it chastic wind stress forcing was red with a decadal dom- is model dependent. For example, in Kushnir and Held inant timescale, and Jin (1997) that the geostrophic cur- (1996), the response to a North Atlantic SST anomaly rents distorted the climatological SST gradient, leading is very weak and baroclinic, while in Palmer and Sun (for realistic SST damping time) to a very weak decadal (1985), Ferranti et al. (1994), and Peng et al. (1995), it peak under a spatially organized wind stress forcing, is stronger and equivalent barotropic, the SST anomaly and a more pronounced one with active atmospheric primarily displacing the storm track and altering the coupling. However, the coupling was based on ad hoc upper-tropospheric eddy vorticity ¯ux. Rodwell et al. assumptions for the zonally averaged quantities. A bal- (1999) showed that much of the observed low-frequency ance between meridional wind anomalies and low-level variability of the North Atlantic oscillation (NAO) can convergence, plus the assumption that the latter is pro- be reproduced by an atmospheric GCM forced by the portional to the SST perturbation, was used instead by observed changes in SST and sea ice. In addition, Czaja White et al. (1998) to study the wind stress feedback and Frankignoul (1999) showed that North Atlantic SST upon free oceanic Rossby waves. Empirical coupling anomalies have an impact on the observed atmospheric approaches have also been used, as in Weng and Neelin variability in late spring and early winter. These studies (1998) and Neelin and Weng (1999), who used the re- suggest that the ocean could lead to a small predict- sponse of atmospheric GCMs to prescribed SST to spec- ability of the wintertime NAO, consistent with the slight ify the wind stress and heat ¯ux feedback acting on SST redness of its spectrum discussed in Hurrel and van anomaly, or in Xu et al. (1998), who coupled an oceanic Loon (1997) and Wunsch (1999). The NAO redness is GCM to a statistical atmosphere derived from a coupled illustrated in Fig. 1, where the spectral slope is slightly GCM, although this procedure biases air±sea ¯uxes to- steeper than in Wunsch (1999) because the NAO is de- ward positive feedback (Frankignoul 1999). A dynam- ®ned by a large-scale pattern rather than by the tradi- ically more consistent approach, albeit simple enough tional NAO index. to be tractable analytically, was used by Goodman and 3706 JOURNAL OF CLIMATE VOLUME 14 TABLE 1. Standard value of the parameters. b 1.8 3 10211 m21 s21 f 8 3 1025 s21 21 co 22cms La 700 km 23 ra 1.3 kg m 3 23 ro 10 kg m 26 23 21 Cpo 4 3 10 kg m K Ha 10 km Ho 4500 m 23 CD 1.5 3 10 26 21 gr 1.5 3 10 s 26 21 ga 4 3 10 s 27 21 gs 1 3 10 s 28 21 ge 3 3 10 s 21 U1 18ms 21 U2 7ms k 4 3 1027 m21 FIG.
Load more

Recommended publications
  • World Ocean Thermocline Weakening and Isothermal Layer Warming
    applied sciences Article World Ocean Thermocline Weakening and Isothermal Layer Warming Peter C. Chu * and Chenwu Fan Naval Ocean Analysis and Prediction Laboratory, Department of Oceanography, Naval Postgraduate School, Monterey, CA 93943, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-831-656-3688 Received: 30 September 2020; Accepted: 13 November 2020; Published: 19 November 2020 Abstract: This paper identifies world thermocline weakening and provides an improved estimate of upper ocean warming through replacement of the upper layer with the fixed depth range by the isothermal layer, because the upper ocean isothermal layer (as a whole) exchanges heat with the atmosphere and the deep layer. Thermocline gradient, heat flux across the air–ocean interface, and horizontal heat advection determine the heat stored in the isothermal layer. Among the three processes, the effect of the thermocline gradient clearly shows up when we use the isothermal layer heat content, but it is otherwise when we use the heat content with the fixed depth ranges such as 0–300 m, 0–400 m, 0–700 m, 0–750 m, and 0–2000 m. A strong thermocline gradient exhibits the downward heat transfer from the isothermal layer (non-polar regions), makes the isothermal layer thin, and causes less heat to be stored in it. On the other hand, a weak thermocline gradient makes the isothermal layer thick, and causes more heat to be stored in it. In addition, the uncertainty in estimating upper ocean heat content and warming trends using uncertain fixed depth ranges (0–300 m, 0–400 m, 0–700 m, 0–750 m, or 0–2000 m) will be eliminated by using the isothermal layer.
    [Show full text]
  • Downloaded from the Coriolis Global Data Center in France (Ftp://Ftp.Ifremer.Fr)
    remote sensing Article Impact of Enhanced Wave-Induced Mixing on the Ocean Upper Mixed Layer during Typhoon Nepartak in a Regional Model of the Northwest Pacific Ocean Chengcheng Yu 1 , Yongzeng Yang 2,3,4, Xunqiang Yin 2,3,4,*, Meng Sun 2,3,4 and Yongfang Shi 2,3,4 1 Ocean College, Zhejiang University, Zhoushan 316000, China; [email protected] 2 First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China; yangyz@fio.org.cn (Y.Y.); sunm@fio.org.cn (M.S.); shiyf@fio.org.cn (Y.S.) 3 Laboratory for Regional Oceanography and Numerical Modeling, Pilot National Laboratory for Marine Science and Technology, Qingdao 266071, China 4 Key Laboratory of Marine Science and Numerical Modeling (MASNUM), Ministry of Natural Resources, Qingdao 266061, China * Correspondence: yinxq@fio.org.cn Received: 30 July 2020; Accepted: 27 August 2020; Published: 30 August 2020 Abstract: To investigate the effect of wave-induced mixing on the upper ocean structure, especially under typhoon conditions, an ocean-wave coupled model is used in this study. Two physical processes, wave-induced turbulence mixing and wave transport flux residue, are introduced. We select tropical cyclone (TC) Nepartak in the Northwest Pacific ocean as a TC example. The results show that during the TC period, the wave-induced turbulence mixing effectively increases the cooling area and cooling amplitude of the sea surface temperature (SST). The wave transport flux residue plays a positive role in reproducing the distribution of the SST cooling area. From the intercomparisons among experiments, it is also found that the wave-induced turbulence mixing has an important effect on the formation of mixed layer depth (MLD).
    [Show full text]
  • Influences of the Ocean Surface Mixed Layer and Thermohaline Stratification on Arctic Sea Ice in the Central Canada Basin J
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115, C10018, doi:10.1029/2009JC005660, 2010 Influences of the ocean surface mixed layer and thermohaline stratification on Arctic Sea ice in the central Canada Basin J. M. Toole,1 M.‐L. Timmermans,2 D. K. Perovich,3 R. A. Krishfield,1 A. Proshutinsky,1 and J. A. Richter‐Menge3 Received 22 July 2009; revised 19 April 2010; accepted 1 June 2010; published 8 October 2010. [1] Variations in the Arctic central Canada Basin mixed layer properties are documented based on a subset of nearly 6500 temperature and salinity profiles acquired by Ice‐ Tethered Profilers during the period summer 2004 to summer 2009 and analyzed in conjunction with sea ice observations from ice mass balance buoys and atmosphere‐ocean heat flux estimates. The July–August mean mixed layer depth based on the Ice‐Tethered Profiler data averaged 16 m (an overestimate due to the Ice‐Tethered Profiler sampling characteristics and present analysis procedures), while the average winter mixed layer depth was only 24 m, with individual observations rarely exceeding 40 m. Guidance interpreting the observations is provided by a 1‐D ocean mixed layer model. The analysis focuses attention on the very strong density stratification at the base of the mixed layer in the Canada Basin that greatly impedes surface layer deepening and thus limits the flux of deep ocean heat to the surface that could influence sea ice growth/ decay. The observations additionally suggest that efficient lateral mixed layer restratification processes are active in the Arctic, also impeding mixed layer deepening. Citation: Toole, J.
    [Show full text]
  • Coastal Upwelling Revisited: Ekman, Bakun, and Improved 10.1029/2018JC014187 Upwelling Indices for the U.S
    Journal of Geophysical Research: Oceans RESEARCH ARTICLE Coastal Upwelling Revisited: Ekman, Bakun, and Improved 10.1029/2018JC014187 Upwelling Indices for the U.S. West Coast Key Points: Michael G. Jacox1,2 , Christopher A. Edwards3 , Elliott L. Hazen1 , and Steven J. Bograd1 • New upwelling indices are presented – for the U.S. West Coast (31 47°N) to 1NOAA Southwest Fisheries Science Center, Monterey, CA, USA, 2NOAA Earth System Research Laboratory, Boulder, CO, address shortcomings in historical 3 indices USA, University of California, Santa Cruz, CA, USA • The Coastal Upwelling Transport Index (CUTI) estimates vertical volume transport (i.e., Abstract Coastal upwelling is responsible for thriving marine ecosystems and fisheries that are upwelling/downwelling) disproportionately productive relative to their surface area, particularly in the world’s major eastern • The Biologically Effective Upwelling ’ Transport Index (BEUTI) estimates boundary upwelling systems. Along oceanic eastern boundaries, equatorward wind stress and the Earth s vertical nitrate flux rotation combine to drive a near-surface layer of water offshore, a process called Ekman transport. Similarly, positive wind stress curl drives divergence in the surface Ekman layer and consequently upwelling from Supporting Information: below, a process known as Ekman suction. In both cases, displaced water is replaced by upwelling of relatively • Supporting Information S1 nutrient-rich water from below, which stimulates the growth of microscopic phytoplankton that form the base of the marine food web. Ekman theory is foundational and underlies the calculation of upwelling indices Correspondence to: such as the “Bakun Index” that are ubiquitous in eastern boundary upwelling system studies. While generally M. G. Jacox, fi [email protected] valuable rst-order descriptions, these indices and their underlying theory provide an incomplete picture of coastal upwelling.
    [Show full text]
  • Ocean 423 Vertical Circulation 1 When We Are Thinking About How The
    Ocean 423 Vertical circulation 1 When we are thinking about how the density, temperature and salinity structure is set in the ocean, there are different processes at work depending on where in the water column we are looking. If we are considering the thermocline, then we notice first that north-south distribution of the surface density/temperature/ salinity across the subtropical gyre can be mapped into their structure in the vertical. This suggests that vertical structure originates at the surface. To figure this out, we can look any one particular isopycnal layer, and see that at some point north and south it intersects the sea surface. Poleward of that point, the layer below the mixed layer is a slightly denser layer. Following stratigraphy, we call the point where an isopycnal layer intersects the sea-surface its outcrop. isopycnal outcrop w < 0 (downwelling), v < 0 z w(0)=we z=0 y z=-H(y) vG mixed layer, winter L.I. V. P. permanent thermocline = const Let’s imagine a water parcel starting somewhere at the surface in the northern half of the subtropical gyre. We ignore the Ekman layer, except for the Ekman pumping it produces, which we specify as a boundary condition on vertical velocity at the ocean surface. The geostrophic velocity is southward everywhere (including the mixed layer) in this part of the ocean because of the downward Ekman pumping. Imagine water parcels flowing southward in the mixed layer Ocean 423 Vertical circulation 2 (and no heating or cooling). A water parcel, when it encounters lighter water to the south will tend to follow its own isopycnal down out of the mixed layer.
    [Show full text]
  • Implementation of an Ocean Mixed Layer Model in IFS
    622 Implementation of an ocean mixed layer model in IFS Y. Takaya12, F. Vitart1, G. Balsamo1, M. Balmaseda1, M. Leutbecher1, F. Molteni1 Research Department 1European Centre for Medium-Range Weather Forecasts, Reading, UK 2Japan Meteorological Agency, Tokyo, Japan March 2010 Series: ECMWF Technical Memoranda A full list of ECMWF Publications can be found on our web site under: http://www.ecmwf.int/publications/ Contact: [email protected] c Copyright 2010 European Centre for Medium-Range Weather Forecasts Shinfield Park, Reading, RG2 9AX, England Literary and scientific copyrights belong to ECMWF and are reserved in all countries. This publication is not to be reprinted or translated in whole or in part without the written permission of the Director. Appropriate non-commercial use will normally be granted under the condition that reference is made to ECMWF. The information within this publication is given in good faith and considered to be true, but ECMWF accepts no liability for error, omission and for loss or damage arising from its use. Implementation of an ocean mixed layer model Abstract An ocean mixed layer model has been implemented in the ECMWF Integrated Forecasting System (IFS) in order to have a better representation of the atmosphere-upper ocean coupled processes in the ECMWF medium-range forecasts. The ocean mixed layer model uses a non-local K profile parameterization (KPP; Large et al. 1994). This model is a one-dimensional column model with high vertical resolution near the surface to simulate the diurnal thermal variations in the upper ocean. Its simplified dynamics makes it cheaper than a full ocean general circulation model and its implementation in IFS allows the atmosphere- ocean coupled model to run much more efficiently than using a coupler.
    [Show full text]
  • Characterizing Transport Between the Surface Mixed Layer and the Ocean Interior with a Forward and Adjoint Global Ocean Transport Model
    APRIL 2005 P R I M E A U 545 Characterizing Transport between the Surface Mixed Layer and the Ocean Interior with a Forward and Adjoint Global Ocean Transport Model FRANÇOIS PRIMEAU Department of Earth System Science, University of California, Irvine, Irvine, California (Manuscript received 1 July 2003, in final form 7 September 2004) ABSTRACT The theory of first-passage time distribution functions and its extension to last-passage time distribution functions are applied to the problem of tracking the movement of water masses to and from the surface mixed layer in a global ocean general circulation model. The first-passage time distribution function is used to determine in a probabilistic sense when and where a fluid element will make its first contact with the surface as a function of its position in the ocean interior. The last-passage time distribution is used to determine when and where a fluid element made its last contact with the surface. A computationally efficient method is presented for recursively computing the first few moments of the first- and last-passage time distributions by directly inverting the forward and adjoint transport operator. This approach allows integrated transport information to be obtained directly from the differential form of the transport operator without the need to perform lengthy multitracer time integration of the transport equations. The method, which relies on the stationarity of the transport operator, is applied to the time-averaged transport operator obtained from a three-dimensional global ocean simulation performed with an OGCM. With this approach, the author (i) computes surface maps showing the fraction of the total ocean volume per unit area that ventilates at each point on the surface of the ocean, (ii) partitions interior water masses based on their formation region at the surface, and (iii) computes the three-dimensional spatial distribution of the mean and standard deviation of the age distribution of water.
    [Show full text]
  • Lecture 4: OCEANS (Outline)
    LectureLecture 44 :: OCEANSOCEANS (Outline)(Outline) Basic Structures and Dynamics Ekman transport Geostrophic currents Surface Ocean Circulation Subtropicl gyre Boundary current Deep Ocean Circulation Thermohaline conveyor belt ESS200A Prof. Jin -Yi Yu BasicBasic OceanOcean StructuresStructures Warm up by sunlight! Upper Ocean (~100 m) Shallow, warm upper layer where light is abundant and where most marine life can be found. Deep Ocean Cold, dark, deep ocean where plenty supplies of nutrients and carbon exist. ESS200A No sunlight! Prof. Jin -Yi Yu BasicBasic OceanOcean CurrentCurrent SystemsSystems Upper Ocean surface circulation Deep Ocean deep ocean circulation ESS200A (from “Is The Temperature Rising?”) Prof. Jin -Yi Yu TheThe StateState ofof OceansOceans Temperature warm on the upper ocean, cold in the deeper ocean. Salinity variations determined by evaporation, precipitation, sea-ice formation and melt, and river runoff. Density small in the upper ocean, large in the deeper ocean. ESS200A Prof. Jin -Yi Yu PotentialPotential TemperatureTemperature Potential temperature is very close to temperature in the ocean. The average temperature of the world ocean is about 3.6°C. ESS200A (from Global Physical Climatology ) Prof. Jin -Yi Yu SalinitySalinity E < P Sea-ice formation and melting E > P Salinity is the mass of dissolved salts in a kilogram of seawater. Unit: ‰ (part per thousand; per mil). The average salinity of the world ocean is 34.7‰. Four major factors that affect salinity: evaporation, precipitation, inflow of river water, and sea-ice formation and melting. (from Global Physical Climatology ) ESS200A Prof. Jin -Yi Yu Low density due to absorption of solar energy near the surface. DensityDensity Seawater is almost incompressible, so the density of seawater is always very close to 1000 kg/m 3.
    [Show full text]
  • NOAA Atlas NESDIS 81 WORLD OCEAN ATLAS 2018 Volume 1
    NOAA Atlas NESDIS 81 WORLD OCEAN ATLAS 2018 Volume 1: Temperature Silver Spring, MD July 2019 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Environmental Satellite, Data, and Information Service National Centers for Environmental Information NOAA National Centers for Environmental Information Additional copies of this publication, as well as information about NCEI data holdings and services, are available upon request directly from NCEI. NOAA/NESDIS National Centers for Environmental Information SSMC3, 4th floor 1315 East-West Highway Silver Spring, MD 20910-3282 Telephone: (301) 713-3277 E-mail: [email protected] WEB: http://www.nodc.noaa.gov/ For updates on the data, documentation, and additional information about the WOA18 please refer to: http://www.nodc.noaa.gov/OC5/indprod.html This document should be cited as: Locarnini, R.A., A.V. Mishonov, O.K. Baranova, T.P. Boyer, M.M. Zweng, H.E. Garcia, J.R. Reagan, D. Seidov, K.W. Weathers, C.R. Paver, and I.V. Smolyar (2019). World Ocean Atlas 2018, Volume 1: Temperature. A. Mishonov, Technical Editor. NOAA Atlas NESDIS 81, 52pp. This document is available on line at http://www.nodc.noaa.gov/OC5/indprod.html . NOAA Atlas NESDIS 81 WORLD OCEAN ATLAS 2018 Volume 1: Temperature Ricardo A. Locarnini, Alexey V. Mishonov, Olga K. Baranova, Timothy P. Boyer, Melissa M. Zweng, Hernan E. Garcia, James R. Reagan, Dan Seidov, Katharine W. Weathers, Christopher R. Paver, Igor V. Smolyar Technical Editor: Alexey Mishonov Ocean Climate Laboratory National Centers for Environmental Information Silver Spring, Maryland July 2019 U.S. DEPARTMENT OF COMMERCE Wilbur L.
    [Show full text]
  • Oxygen, Apparent Oxygen Utilization, and Dissolved Oxygen Saturation
    NOAA Atlas NESDIS 83 WORLD OCEAN ATLAS 2018 Volume 3: Dissolved Oxygen, Apparent Oxygen Utilization, and Dissolved Oxygen Saturation Silver Spring, MD July 2019 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Environmental Satellite, Data, and Information Service National Centers for Environmental Information NOAA National Centers for Environmental Information Additional copies of this publication, as well as information about NCEI data holdings and services, are available upon request directly from NCEI. NOAA/NESDIS National Centers for Environmental Information SSMC3, 4th floor 1315 East-West Highway Silver Spring, MD 20910-3282 Telephone: (301) 713-3277 E-mail: [email protected] WEB: http://www.nodc.noaa.gov/ For updates on the data, documentation, and additional information about the WOA18 please refer to: http://www.nodc.noaa.gov/OC5/indprod.html This document should be cited as: Garcia H. E., K.W. Weathers, C.R. Paver, I. Smolyar, T.P. Boyer, R.A. Locarnini, M.M. Zweng, A.V. Mishonov, O.K. Baranova, D. Seidov, and J.R. Reagan (2019). World Ocean Atlas 2018, Volume 3: Dissolved Oxygen, Apparent Oxygen Utilization, and Dissolved Oxygen Saturation. A. Mishonov Technical Editor. NOAA Atlas NESDIS 83, 38pp. This document is available on-line at https://www.nodc.noaa.gov/OC5/woa18/pubwoa18.html NOAA Atlas NESDIS 83 WORLD OCEAN ATLAS 2018 Volume 3: Dissolved Oxygen, Apparent Oxygen Utilization, and Dissolved Oxygen Saturation Hernan E. Garcia, Katharine W. Weathers, Chris R. Paver, Igor Smolyar, Timothy P. Boyer, Ricardo A. Locarnini, Melissa M. Zweng, Alexey V. Mishonov, Olga K. Baranova, Dan Seidov, James R.
    [Show full text]
  • Three-Dimensional Model-Observation Intercomparison
    Dynamics of Atmospheres and Oceans 76 (2016) 283–305 Contents lists available at ScienceDirect Dynamics of Atmospheres and Oceans journal homepage: www.elsevier.com/locate/dynatmoce Three-dimensional model-observation comparison in the Loop Current region a,∗ a b K.C. Rosburg , K.A. Donohue , E.P. Chassignet a Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA b Center for Ocean-Atmosphere Prediction Studies, Florida State University, Tallahassee, FL, USA a r t i c l e i n f o a b s t r a c t Article history: Accurate high-resolution ocean models are required for hurricane and oil spill pathway pre- Received 9 October 2015 dictions, and to enhance the dynamical understanding of circulation dynamics. Output from Received in revised form 4 May 2016 ◦ the 1/25 data-assimilating Gulf of Mexico HYbrid Coordinate Ocean Model (HYCOM31.0) Accepted 4 May 2016 is compared to daily full water column observations from a moored array, with a focus on Available online 6 May 2016 Loop Current path variability and upper-deep layer coupling during eddy separation. Array- mean correlation was 0.93 for sea surface height, and 0.93, 0.63, and 0.75 in the thermocline Keywords: for temperature, zonal, and meridional velocity, respectively. Peaks in modeled eddy kinetic Evaluation energy were consistent with observations during Loop Current eddy separation, but with Modelling modeled deep eddy kinetic energy at half the observed amplitude. Modeled and observed Ocean currents LC meander phase speeds agreed within 8% and 2% of each other within the 100 – 40 and 40 Mesoscale eddies Baroclinic instability – 20 day bands, respectively.
    [Show full text]
  • Arabian Sea Mixed Layer Deepening During the Monsoon: Observations and Dynamics
    Arabian Sea Mixed Layer Deepening during the Monsoon: Observations and Dynamics by Albert S. Fischer S.B., Physics (1994) Massachusetts Institute of Technology Submitted to the Massachusetts Institute of Technology / Woods Hole Oceanographic Institution Joint Program in Physical Oceanography in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY and the WOODS HOLE OCEANOGRAPHIC INSTITUTION September 1997 © Albert S. Fischer 1997. All rights reserved. The author hereby grants MIT and WHOI permission to reproduce and to distribute publicly paper and electronic copies of this thesis document in whole or in part. Signature of Author ........./...................................................... Joint Program in Physical Oceanography Massachusetts Institute of Technology Woods Hole Oceanographic Institution 18 June 1997 C ertified by ............=.... ..... .. ..................................................................................... Robert A. Weller Senior Scientist Thesis Supervisor A ccepted by ....................... ......... ... ...... Accepted -............... ........................ ........... by.............Paola Malanotte-Rizzoli Chairman, Joint Committee for Physical Oceanography A , i Massachusetts Institute of Technology a IA ' ,-TIM1"" Woods Hole Oceanographic Institution oil~~~E Arabian Sea Mixed Layer deepening during the Monsoon: Observations and Dynamics by Albert S. Fischer Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution Abstract The unusual twice-yearly cycle of mixed layer deepening and cooling driven by the mon- soon is analyzed using a recently collected (1994-95) dataset of concurrent local air-sea fluxes and upper ocean dynamics from the Arabian Sea. The winter northeast monsoon has moderate wind forcing and a strongly destabilizing surface buoyancy flux, driven by large radiative and latent heat losses at the sea surface.
    [Show full text]