An Analysis of Near-Surface Winds, Air Temperature, and Cyclone Activity in Terra Nova Bay, Antarctica, from 1993 to 2009

Abstract In September 2009, the first unmanned aerial vehicles were flown over Terra Nova Bay, Antarctica, to collect information regarding air–sea interactions. Prior to the field season, wind and temperature data from a local automatic weather station (AWS) were collected from 1993 to 2007 and compared with an August–October 2006–08 satellite cyclone analysis to place the September 2009 observations into a broader context. AWS wind data revealed a strong tendency toward downslope flow in the region regardless of season, as the majority (55%) of winds were from the west to northwesterly directions. Most winds observed at the site were less than 20 m s−1, but 83% of the stronger winds were associated with downslope flow. Of 15 strong wind events (greater than 20 m s−1 for more than 10 h) evaluated during the cyclone analysis period, 100% occurred in the presence of a cyclone in the adjacent Ross Sea. Winter experienced the greatest number of strong wind events (68%), and summer had the least (4%). Most temperatures were between −15° and −25°C, with temperatures influenced by wind fluctuations. The cyclone analysis revealed that 64% of systems were comma shaped, and most cyclones (84%) within the Ross Sea were mesocyclones. A comparison of AWS data for Septembers 1993–2007 and September 2009 showed more strong wind events during 2009, while the cyclone analysis revealed a shift in cyclonic activity eastward. Reanalysis data comparing September 1993–2007 and September 2009 show an eastward shift in a deeper upper-level trough, indicating that September 2009 was an anomalous year.

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Thermohaline structure and variability in the Terra Nova Bay polynya, Ross Sea

Antarctic Science ◽

10.1017/s0954102000000572 ◽

2000 ◽

Vol 12 (4) ◽

pp. 493-508 ◽

Cited By ~ 42

Author(s):

G. Budillon ◽

G. Spezie

Keyword(s):

Surface Layer ◽

Cold Water ◽

Ross Sea ◽

Heat Budget ◽

Salt Content ◽

Heat Fluxes ◽

Local Source ◽

Near Surface ◽

Terra Nova Bay ◽

Terra Nova

Hydrological measurements from three cruises during the summers 1994/95, 1995/96 and 1997/98 in the western sector of the Ross Sea allow summer and year to year changes in heat and salt content in the Terra Nova Bay polynya to be analysed. Changes in the surface layer (upper pycnocline) followed the expected seasonal pattern of warming and freshening from the beginning to the end of the summer. These near-surface changes, expressed as net heating and salting rate, were about 11 W m−2 and -6 mg salt m−2 s−1. The heating changes were substantially lower than the estimated heat supplied by the atmosphere during the summer, which underlines the importance for this season of the advective component carried by the currents in the total heat budget. The year to year differences were about one or two orders of magnitude smaller than the seasonal changes in the surface layer. In the intermediate and deep layers, the summer heat and salt variability were of the same order as or one order higher than from one summer to the next. The differences in sign and magnitude for the heat change in the upper and in the lower pycnocline indicate a weak connection in the summer period between the surface heat fluxes and the deep waters. A local source of very cold water (with temperatures below the surface freezing point) of about 0.3 Sv has been detected close to the Terra Nova Bay coast. It arose out of the interaction of the shallow–intermediate layers of High Salinity Shelf Water with the coastal glaciers. The presence and the variability of this cold water point to the significant role of the thermohaline properties of Terra Nova Bay waters in controlling the floating glacier by governing the basal melting processes.

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Frazil ice growth and production during katabatic wind events in the Ross Sea, Antarctica

10.5194/tc-2019-213 ◽

2019 ◽

Author(s):

Lisa De Pace ◽

Madison Smith ◽

Jim Thomson ◽

Sharon Stammerjohn ◽

Steve Ackley ◽

...

Keyword(s):

Ross Sea ◽

Vertical Mixing ◽

Katabatic Wind ◽

Frazil Ice ◽

Wind Speeds ◽

Terra Nova Bay ◽

Air Temperatures ◽

Terra Nova ◽

Wind Events ◽

Ice Production

Abstract. During katabatic wind events in the Terra Nova Bay and Ross Sea polynyas, wind speeds exceeded 20 m s−1, air temperatures were below −25 ℃, and the mixed layer extended as deep as 600 meters. Yet, upper ocean temperature and salinity profiles were not perfectly homogeneous, as would be expected with vigorous convective heat loss. Instead, the profiles revealed bulges of warm and salty water directly beneath the ocean surface and extending downwards tens of meters. Considering both the colder air above and colder water below, we suggest the increase in temperature and salinity reflects latent heat and salt release during unconsolidated frazil ice production within the upper water column. We use a simplified salt budget to analyze these anomalies to estimate in-situ frazil ice concentration between 332 × 10−3 and 24.4 × 10−3 kg m−3. Contemporaneous estimates of vertical mixing by turbulent kinetic energy dissipation reveal rapid convection in these unstable density profiles, and mixing lifetimes from 2 to 12 minutes. The corresponding median rate of ice production is 26 cm day−1 and compares well with previous empirical and model estimates. Our individual estimates of ice production up to 378 cm day−1 reveal the intensity of short-term ice production events during the windiest episodes of our occupation of Terra Nova Bay Polynya.

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Particulate organic matter release below melting sea ice (Terra Nova Bay, Ross Sea, Antarctica): Possible relationships with zooplankton

Journal of Marine Systems ◽

10.1016/j.jmarsys.2021.103510 ◽

2021 ◽

pp. 103510

Author(s):

Alessandro Cau ◽

Claudia Ennas ◽

Davide Moccia ◽

Olga Mangoni ◽

Francesco Bolinesi ◽

...

Keyword(s):

Organic Matter ◽

Sea Ice ◽

Particulate Organic Matter ◽

Ross Sea ◽

Terra Nova Bay ◽

Terra Nova

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A comparison between polynya area and associated ice production with mooring-based measurements of temperature, salinity and currents in the southwestern Ross Sea, Antarctica

Annals of Glaciology ◽

10.3189/172756411795931705 ◽

2011 ◽

Vol 52 (57) ◽

pp. 291-300 ◽

Cited By ~ 3

Author(s):

Stefan Kern ◽

Stefano Aliani

Keyword(s):

Ross Sea ◽

Time Lag ◽

Ice Formation ◽

Terra Nova Bay ◽

In Situ Observations ◽

Satellite Microwave ◽

Terra Nova ◽

Ice Production ◽

The Impact

AbstractWintertime (April–September) area estimates of the Terra Nova Bay polynya (TNBP), Antarctica, based on satellite microwave radiometry are compared with in situ observations of water salinity, temperature and currents at a mooring in Terra Nova Bay in 1996 and 1997. In 1996, polynya area anomalies and associated anomalies in polynya ice production are significantly correlated with salinity anomalies at the mooring. Salinity anomalies lag area and/or ice production anomalies by about 3 days. Up to 50% of the variability in the salinity at the mooring position can be explained by area and/or ice production anomalies in the TNBP for April–September 1996. This value increases to about 70% when considering shorter periods like April–June or May–July, but reduces to 30% later, for example July–September, together with a slight increase in time lag. In 1997, correlations are smaller, less significant and occur at a different time lag. Analysis of ocean currents at the mooring suggests that in 1996 conditions were more favourable than in 1997 for observing the impact of descending plumes of salt-enriched water formed in the polynya during ice formation on the water masses at the mooring depth.

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The Extreme Wind Events in the Ross Island Region of Antarctica

Weather and Forecasting ◽

10.1175/waf-d-15-0125.1 ◽

2016 ◽

Vol 31 (3) ◽

pp. 985-1000 ◽

Cited By ~ 1

Author(s):

Nicholas J. Weber ◽

Matthew A. Lazzara ◽

Linda M. Keller ◽

John J. Cassano

Keyword(s):

Structural Damage ◽

Ross Sea ◽

Enso Event ◽

Central Pacific ◽

Island Region ◽

Back Trajectories ◽

Extreme Wind ◽

Mcmurdo Station ◽

Wind Events ◽

Upper Level

Abstract Numerous incidents of structural damage at the U.S. Antarctic Program’s (USAP) McMurdo Station due to extreme wind events (EWEs) have been reported over the past decade. Utilizing nearly 20 yr (~1992–2013) of University of Wisconsin automatic weather station (AWS) data from three different stations in the Ross Island region (Pegasus North, Pegasus South, and Willie Field), statistical analysis shows no significant trends in EWE frequency, intensity, or duration. EWEs more frequently occur during the transition seasons. To assess the dynamical environment of these EWEs, Antarctic Mesoscale Prediction System (AMPS) forecast back trajectories are computed and analyzed in conjunction with several other AMPS fields for the strongest events at McMurdo Station. The synoptic analysis reveals that McMurdo Station EWEs are nearly always associated with strong southerly flow due to an approaching Ross Sea cyclone and an upper-level trough around Cape Adare. A Ross Ice Shelf air stream (RAS) environment is created with enhanced barrier winds along the Transantarctic Mountains, downslope winds in the lee of the glaciers and local topography, and a tip jet effect around Ross Island. The position and intensity of these Ross Sea cyclones are most influenced by the occurrence of a central Pacific ENSO event, which causes the upper-level trough to move westward. An approaching surface cyclone would then be in position to trigger an event, depending on how the wind direction and speed impinges on the complex topography around McMurdo Station.

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Diesel oil and PCB-degrading psychrotrophic bacteria isolated from Antarctic seawaters (Terra Nova Bay, Ross Sea)

Polar Research ◽

10.3402/polar.v23i2.6275 ◽

2004 ◽

Vol 23 (2) ◽

pp. 141-146 ◽

Cited By ~ 9

Author(s):

Maria De Domenico ◽

Angelina Lo Giudice ◽

Luigi Michaud ◽

Marcello Saitta ◽

Vivia Bruni

Keyword(s):

Ross Sea ◽

Diesel Oil ◽

Psychrotrophic Bacteria ◽

Terra Nova Bay ◽

Terra Nova

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Summer Epiphytic Diatoms from Terra Nova Bay and Cape Evans (Ross Sea, Antarctica) - A Synthesis and Final Conclusions

PLoS ONE ◽

10.1371/journal.pone.0153254 ◽

2016 ◽

Vol 11 (4) ◽

pp. e0153254 ◽

Cited By ~ 15

Author(s):

Roksana Majewska ◽

Peter Convey ◽

Mario De Stefano

Keyword(s):

Ross Sea ◽

Epiphytic Diatoms ◽

Terra Nova Bay ◽

Terra Nova

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Significance of selected halocarbons monitoring in air samples collected in the Terra Nova Bay region (northern Victoria Land, Antarctica)

Antarctic Science ◽

10.1017/s0954102099000322 ◽

1999 ◽

Vol 11 (2) ◽

pp. 261-264 ◽

Cited By ~ 3

Author(s):

Filippo Mangani ◽

Michela Maione ◽

Luciano Lattanzi

Keyword(s):

Ross Sea ◽

Atmospheric Concentration ◽

Air Samples ◽

Terra Nova Bay ◽

Victoria Land ◽

Rate Of Increase ◽

Terra Nova ◽

Concentration Levels

CCl3F (or CFC-11) and CCl2F2 (or CFC-12) were determined in air samples collected, during subsequent summer Antarctic campaigns, in different sampling sites in the Ross Sea Region. The samples were analysed by GC-ECD after enrichment. Data obtained since 1988–89 were plotted to observe the trend of CFCs atmospheric concentration levels. A decrease in the rate of increase of CFC-12 concentration was observed, whilst the concentration of CFC-11 was actually seen to be decreasing.

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