scholarly journals FEATURES OF SPATIAL-TIME VARIABILITY OF TOTAL TURBULENT HEAT FLUXES AT THE OCEAN-ATMOSPHERE INTERFACE IN THE ATLANTIC

2021 ◽  
pp. 49-55
Author(s):  
Е.А. Averyanova ◽  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
Arctic Sea Ice ◽  
Heat Fluxes ◽  
Total Heat ◽  
Turbulent Heat ◽  
Edge Zone ◽  
The North ◽  
Turbulent Heat Fluxes ◽  
Ice Edge

The features of the spatial distribution of climate values and the coefficients of linear trends of total tur-bulent heat fluxes are revealed, based on NCEP/NCAR reanalysis data for 1950–2020 for the Atlantic Ocean. Variability of total turbulent heat fluxes is investigated on scales of more than 10 and more than 30 years. It is shown that the trends of average annual total heat fluxes significant at 95% level in most part of the Atlantic Ocean area are negative (except for the western parts of anticyclonic gyres and area of arctic sea ice edge). It is confirmed that the maxima of the low-frequency variability of the total heat fluxes correspond to important energy-active zones of the Atlantic, they are North Atlantic deep-water mass formation region, ice edge zone in the north of the North Atlantic and the Atlantic sector of the Arc-tic Ocean.

The signature of mesoscale eddies on the air‐sea turbulent heat fluxes in the South Atlantic Ocean

2015 ◽  
Vol 42 (6) ◽  
pp. 1856-1862 ◽  
Author(s):  
A. B. Villas Bôas ◽  
O. T. Sato ◽  
A. Chaigneau ◽  
G. P. Castelão
Keyword(s):  
Atlantic Ocean ◽  
Mesoscale Eddies ◽  
South Atlantic ◽  
Heat Fluxes ◽  
South Atlantic Ocean ◽  
Turbulent Heat ◽  
The South ◽  
Turbulent Heat Fluxes

scholarly journals Differences between two estimates of air-sea turbulent heat fluxes over the Atlantic Ocean

2011 ◽  
Vol 116 (C9) ◽  
Author(s):  
A. Santorelli ◽  
R. T. Pinker ◽  
A. Bentamy ◽  
K. B. Katsaros ◽  
W. M. Drennan ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Heat Fluxes ◽  
Turbulent Heat ◽  
Turbulent Heat Fluxes

scholarly journals Evaluating and improving modeled turbulent heat fluxes across the North American Great Lakes

2018 ◽  
Vol 22 (10) ◽  
pp. 5559-5578 ◽  
Author(s):  
Umarporn Charusombat ◽  
Ayumi Fujisaki-Manome ◽  
Andrew D. Gronewold ◽  
Brent M. Lofgren ◽  
Eric J. Anderson ◽  
...  
Keyword(s):  
Heat Flux ◽  
Great Lakes ◽  
Eddy Covariance ◽  
North American ◽  
Heat Fluxes ◽  
Turbulent Heat ◽  
The North ◽  
Turbulent Heat Fluxes ◽  
North American Great Lakes ◽  
Eddy Covariance Measurements

Abstract. Turbulent fluxes of latent and sensible heat are important physical processes that influence the energy and water budgets of the North American Great Lakes. These fluxes can be measured in situ using eddy covariance techniques and are regularly included as a component of lake–atmosphere models. To help ensure accurate projections of lake temperature, circulation, and regional meteorology, we validated the output of five algorithms used in three popular models to calculate surface heat fluxes: the Finite Volume Community Ocean Model (FVCOM, with three different options for heat flux algorithm), the Weather Research and Forecasting (WRF) model, and the Large Lake Thermodynamic Model. These models are used in research and operational environments and concentrate on different aspects of the Great Lakes' physical system. We isolated only the code for the heat flux algorithms from each model and drove them using meteorological data from four over-lake stations within the Great Lakes Evaporation Network (GLEN), where eddy covariance measurements were also made, enabling co-located comparison. All algorithms reasonably reproduced the seasonal cycle of the turbulent heat fluxes, but all of the algorithms except for the Coupled Ocean–Atmosphere Response Experiment (COARE) algorithm showed notable overestimation of the fluxes in fall and winter. Overall, COARE had the best agreement with eddy covariance measurements. The four algorithms other than COARE were altered by updating the parameterization of roughness length scales for air temperature and humidity to match those used in COARE, yielding improved agreement between modeled and observed sensible and latent heat fluxes.

scholarly journals A Climatology of Wintertime Barrier Winds off Southeast Greenland

2011 ◽  
Vol 24 (17) ◽  
pp. 4701-4717 ◽  
Author(s):  
B. E. Harden ◽  
I. A. Renfrew ◽  
G. N. Petersen
Keyword(s):  
North Atlantic ◽  
Large Range ◽  
Heat Fluxes ◽  
Turbulent Heat ◽  
Synoptic Scale ◽  
Blocking High ◽  
Nao Index ◽  
Denmark Strait ◽  
Turbulent Heat Fluxes ◽  
Wind Events

A climatology of barrier winds along the southeastern coast of Greenland is presented based on 20 yr of winter months (1989–2008) from the ECMWF Interim Reanalysis (ERA-Interim). Barrier wind events occur predominantly at two locations: Denmark Strait North (DSN; 67.7°N, 25.3°W) and Denmark Strait South (DSS; 64.9°N, 35.9°W). Events stronger than 20 m s−1 occur on average once per week during winter with considerable interannual variability—from 7 to 20 events per winter. The monthly frequency of barrier wind events correlates with the monthly North Atlantic oscillation (NAO) index with a correlation coefficient of 0.57 (0.31) at DSN (DSS). The associated total turbulent heat fluxes for barrier wind events (area averaged) were typically about 200 W m−2 with peak values of 400 W m−2 common in smaller regions. Area-averaged surface stresses were typically between 0.5 and 1 N m−2. Total precipitation rates were larger at DSS than DSN, both typically less than 1 mm h−1. The total turbulent heat fluxes were shown to have a large range as a result of a large range in 2-m air temperature. Two classes of barrier winds—warm and cold—were investigated and found to develop in different synoptic-scale situations. Warm barrier winds developed when there was a blocking high pressure over the Nordic seas, while cold barrier winds owed their presence to a train of cyclones channeling through the region.

scholarly journals Roles of SST Anomalies on the Wintertime Turbulent Heat Fluxes in the Kuroshio–Oyashio Confluence Region: Influences of Warm Eddies Detached from the Kuroshio Extension

2011 ◽  
Vol 24 (24) ◽  
pp. 6551-6561 ◽  
Author(s):  
Shusaku Sugimoto ◽  
Kimio Hanawa
Keyword(s):  
Kuroshio Extension ◽  
Surface Wind ◽  
Surface Air Temperature ◽  
Surface Wind Speed ◽  
Turbulent Heat Flux ◽  
Heat Fluxes ◽  
Turbulent Heat ◽  
The North ◽  
Turbulent Heat Fluxes ◽  
The Kuroshio

Abstract Variations of turbulent heat fluxes (sum of sensible and latent heat fluxes) in the North Pacific during 16 winters from December 1992/February 1993 to December 2007/February 2008 are investigated because the months from December to February correspond to the period having peak winter conditions in the atmosphere field. Turbulent heat fluxes are calculated from the bulk formula using daily variables [surface wind speed, surface air specific humidity, surface air temperature, and sea surface temperature (SST)] of the objectively analyzed air–sea flux (OAFlux) dataset and bulk coefficients based on the Tropical Ocean and Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE) bulk flux algorithm 3.0. The winter turbulent heat fluxes over the Kuroshio–Oyashio Confluence Region (KOCR; 142°–150°E, 35°–40°N) have the largest temporal variances in the North Pacific. The relative contributions among observed variables in SST, surface air temperature, and surface wind speed causing turbulent heat flux variations in the KOCR are assessed quantitatively by performing simple experiments using combinations of two types of variables: raw daily data and daily climatological data. Results show that SST is primarily responsible for the turbulent heat flux variations—a huge amount of heat is released in the state of the positive SST anomaly. Using the datasets of satellite-derived SST and sea surface height with high spatial and temporal resolutions, it is found that the SST anomalies in the KOCR are formed through activities of the anticyclonic (warm) eddies detached northward from the Kuroshio Extension; SSTs take positive (negative) anomalies when more (less) anticyclonic eddies are distributed there, associated with a more convoluted (straight) Kuroshio Extension path.

scholarly journals Supplementary material to "Evaluating and improving modeled turbulent heat fluxes across the North American Great Lakes"

2018 ◽  
Author(s):  
Umarporn Charusombat ◽  
Ayumi Fujisaki-Manome ◽  
Andrew D. Gronewold ◽  
Brent M. Lofgren ◽  
Eric J. Anderson ◽  
...  
Keyword(s):  
Great Lakes ◽  
North American ◽  
Heat Fluxes ◽  
Turbulent Heat ◽  
The North ◽  
Turbulent Heat Fluxes ◽  
North American Great Lakes ◽  
Supplementary Material

scholarly journals Association of the North Atlantic Surface Turbulent Heat Fluxes with Midlatitude Cyclones

2018 ◽  
Vol 146 (11) ◽  
pp. 3691-3715 ◽  
Author(s):  
Natalia Tilinina ◽  
Alexander Gavrikov ◽  
Sergey K. Gulev
Keyword(s):  
Life Cycle ◽  
North Atlantic ◽  
Critical Role ◽  
Surface Fluxes ◽  
Heat Fluxes ◽  
Turbulent Heat ◽  
Atmospheric Conditions ◽  
The North ◽  
Strong Surface ◽  
The North Atlantic

Abstract Atmospheric mechanisms leading to the formation of very strong turbulent air–sea heat fluxes in the North Atlantic are analyzed using the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR) for the winter periods from 1979 to 2010. Surface turbulent flux extremes were quantified by considering both absolute and relative extremeness of these fluxes. For all cases of very strong surface turbulent fluxes, regional composites of the associated atmospheric conditions were built using reanalysis output. These composites clearly demonstrate a critical role of the cyclone–anticyclone interaction zone in forming very strong surface fluxes. The implied importance of cyclones followed by anticyclones in generation of surface air–sea heat flux extremes was demonstrated by the analysis of case studies. We further used the results of numerical cyclone tracking to identify extratropical cyclones associated with air–sea flux events of different intensities and to quantify the life cycle characteristics of these cyclones. Analysis of frequency distribution of surface heat fluxes has shown that extreme fluxes over the North Atlantic are associated with less than 30% of winter cyclones and that this association occurs mostly during the initial stage of their life cycle. Analysis of life cycle characteristics of these cyclones shows, in turn, that they are considerably more intense than most North Atlantic cyclones and are characterized by rapid deepening and slower propagation. We argue that variability of the North American high is a key factor controlling atmospheric conditions favorable for the occurrence of high turbulent air–sea heat fluxes in the North Atlantic mid- and subpolar latitudes.

scholarly journals Pathways, Volume Transport, and Mixing of Abyssal Water in the Samoan Passage

2015 ◽  
Vol 45 (2) ◽  
pp. 562-588 ◽  
Author(s):  
Gunnar Voet ◽  
James B. Girton ◽  
Matthew H. Alford ◽  
Glenn S. Carter ◽  
Jody M. Klymak ◽  
...  
Keyword(s):  
Volume Transport ◽  
Heat Fluxes ◽  
Meridional Overturning Circulation ◽  
Turbulent Heat ◽  
Turbulent Dissipation ◽  
The North ◽  
The Pacific ◽  
Turbulent Heat Fluxes ◽  
Transport And Mixing ◽  
Heat Budgets

AbstractThe flow of dense water through the Samoan Passage accounts for the major part of the bottom water renewal in the North Pacific and is thus an important element of the Pacific meridional overturning circulation. A recent set of highly resolved measurements used CTD/LADCP, a microstructure profiler, and moorings to constrain the complex pathways and variability of the abyssal flow. Volume transport estimates for the dense northward current at several sections across the passage, calculated using direct velocity measurements from LADCPs, range from 3.9 × 106 to 6.0 × 106 ± 1 × 106 m3 s−1. The deep channel to the east and shallower pathways to the west carried about equal amounts of this volume transport, with the densest water flowing along the main eastern channel. Turbulent dissipation rates estimated from Thorpe scales and direct microstructure agree to within a factor of 2 and provide a region-averaged value of O(10−8) W kg−1 for layers colder than 0.8°C. Associated diapycnal diffusivities and downward turbulent heat fluxes are about 5 × 10−3 m2 s−1 and O(10) W m−2, respectively. However, heat budgets suggest heat fluxes 2–6 times greater. In the vicinity of one of the major sills of the passage, highly resolved Thorpe-inferred diffusivity and heat flux were over 10 times larger than the region-averaged values, suggesting the mismatch is likely due to undersampled mixing hotspots.

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