A High-Resolution Numerical Simulation of the Wind Flow in the Ross Island Region, Antarctica

Seefeldt, Mark W.; Tripoli, Gregory J.; Stearns, Charles R.

doi:10.1175/1520-0493(2003)131<0435:ahrnso>2.0.co;2

Cited by 38 publications

(46 citation statements)

References 15 publications

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“…When the southerly wind flow is unable to override the topographical barriers, cold air piled up at the base of the topography, creating comparatively high pressure areas. This has been discussed in the work of Seefeldt et al (2003), Monaghan et al (2005), and Chenoli et al (2012). The manual analysis has been carried out to confirm the existence and position of the mesoscale systems since the reanalysis field cannot resolve the mesoscale lows.…”

Section: Synoptic Overviewmentioning

confidence: 90%

“…Earlier studies by O'Connor and Bromwich (1988), O'Connor et al (1994), and Burk et al (1999) also used a simple version of the Froude number equation to study the wind flow around the Ross Island. To understand the dynamics of the wind flow around the Ross Island area during high and low wind cases, Seefeldt et al (2003) used the Froude number calculations with a study of the equations of motion.…”

Section: Methodsmentioning

confidence: 99%

“…A shift in the wind direction from north-northwest to north-northeast to southerly was observed around this time in the AWS data from WF-AWS1. The shift in the wind direction to southerly at WF-AWS1 is due to the changes in stability and wind speed (Seefeldt et al 2003) explained in detail in section 5. The first peak observed in the wind speed was 16 m s 21 at 1600 UTC 10 October, when the low L2 showed an organized cloud pattern.…”

Section: Synoptic Overviewmentioning

confidence: 97%

“…The value of the Fr number was calculated using data from the radiosonde ascent at 2200 UTC 9 October before the SWE and at 1120 UTC 10 October 2003 during the event. At 2200 UTC 9 October Fr was found to be 0.492; therefore, the recirculated maritime air coming from the south lacked the energy to flow over the topographical features and must instead flow around it (Seefeldt et al 2003;Chenoli et al 2012). In this scenario McMurdo Station will experience northwesterly wind as shown in Fig.…”

Section: Details Of the Wind Flow Over The Northwest Rossmentioning

confidence: 99%

“…Strong katabatic winds are a significant feature along the coast of East Antarctica but are rarely experienced in the McMurdo Station area (Turner et al 2009), although some continental air masses can affect the region. However, the barrier winds created by the flow along the Transantarctic Mountains are a major feature in McMurdo Station/Ross Island region (Seefeldt et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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A Strong Wind Event on the Ross Ice Shelf, Antarctica: A Case Study of Scale Interactions

Chenoli

Turner

Samah

2015

Monthly Weather Review

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In situ observations, satellite imagery, numerical weather prediction, and reanalysis fields are used to investigate the synoptic and mesoscale environment of a strong wind event (SWE) at McMurdo Station/Ross Island region on the Ross Ice Shelf, Antarctica, on 10 October 2003. The SWE occurred during the passage of a sequence of three mesoscale low pressure systems from the central Ross Ice Shelf to the southwest Ross Sea. A potential vorticity (PV) analysis showed that the lows drew air of continental origin down the glacial valleys of the Transantarctic Mountains and onto the ice shelf as a katabatic drainage flow. However, the analysis indicated that the air mass associated with the SWE was of recurved maritime origin drawn in by the second mesoscale low (L2). This air mass approached McMurdo Station from the south where interactions with the orography played a critical role. In the early stages of the event, when the wind speed was less than 10 m s 21 , the air was deflected around the topographical features, such as Minna Bluff and Black and White Islands. As the pressure gradient increased, winds of more than 10 m s 21 crossed the orography and developed mountain waves along the lee slopes. When the Froude number became larger than 1, large-amplitude vertically propagating mountain waves developed over the McMurdo Station/Ross Island area, increasing the wind to 16 m s 21 . The reanalysis fields did not resolve the mesoscale lows; however, the Antarctic Mesoscale Prediction System (AMPS) model was able to simulate important characteristics of the SWE such as the mesoscale low pressure system, flow around the topographical barrier, and the mountain wave.

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Section: Synoptic Overviewmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Synoptic Overviewmentioning

confidence: 97%

Section: Details Of the Wind Flow Over The Northwest Rossmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Strong Wind Event on the Ross Ice Shelf, Antarctica: A Case Study of Scale Interactions

Chenoli

Turner

Samah

2015

Monthly Weather Review

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A climatology of strong wind events at McMurdo station, Antarctica

Chenoli

Turner

Samah

2012

Intl Journal of Climatology

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ABSTRACT:The first climatology of strong wind events (SWEs) at McMurdo station, Antarctica based on the in situ observations and reanalysis fields is presented. SWEs occur throughout the year, but with a minimum during the summer. They are associated with negative mean sea level pressure (MSLP) and upper height anomalies across the Ross Sea/Ice Shelf, as well as positive temperature anomalies at the station. Wind directions during SWEs exhibit a bimodal distribution of 135-180• and 45-90• . This distribution occurs because of the interaction of the predominantly southerly flow with the orography of Black and White Island and Minna Bluff. The east-northeast flow is associated with winds that are deflected around the orography, while the more southerly events have sufficient energy to override the barriers. The bimodal wind distribution is most common during the winter season since the southerly flow is stronger as a result of deeper cyclonic systems. SWEs also occur when there are large, positive MSLP anomalies at McMurdo station as ridges of high pressure build from the interior and enhance the pressure gradient between the continental high and offshore lows. The interannual variability in the number of winter SWEs is large. Years with many SWEs are associated with a deep climatological low centred over the north eastern Ross Ice Shelf. Years with few winter SWEs have a weakened mid-tropospheric vortex over the Ross Ice Shelf. There are periods when the index of the El Niño-Southern Oscillation (ENSO) correlates with the number of SWEs. However, the links are not statistically significant in the longer term. A similar link was also observed between the Southern Annular Mode (SAM) and the interannual variability in the number of SWEs. The relationship was found to be stronger when the phase of ENSO and the SAM were the same.KEY WORDS strong wind events; Antarctica; bimodal wind direction; interannual variability; mean sea level pressure; southern annular mode; wind speed

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Synoptic climatology of the Ross Ice Shelf and Ross Sea region of Antarctica: k‐means clustering and validation

Coggins

McDonald

Jolly

2013

Intl Journal of Climatology

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The surface wind regime of the Ross Ice Shelf (RIS) is dominated by northward outflow influenced by drainage from both East and West Antarctica and synoptic disturbances over the Ross Sea. To quantify the effects of the wind regime on the climate of the region, we produce a synoptic climatology of the RIS and Ross Sea via a k -means clustering technique applied to surface (10 m) winds from the ERA Interim reanalysis . We describe the generation of the climatology and discuss composites of surface winds, mean sea-level pressure and temperature, which show a high degree of internally consistent structure and are similar to previous synoptic climatologies. While some smallscale features are not fully resolved by the reanalysis, such as the channelling of katabatic flows, we identify a high degree of coherence between clustering results and available in situ data sources, suggesting that the ERA Interim represents the region well. We find that the surface wind field of the ice shelf is highly sensitive to the strength and position of cyclonic disturbances in the Ross Sea, the presence of which can aid outflow from the continental interior. Temperature displays a high level of sensitivity to circulation conditions due to the effects of steep temperature gradients surrounding the shelf and advective heat transport. Cold temperatures on the ice shelf coincide with drainage from East Antarctica, while warmer periods coincide with West Antarctic drainage; this is particularly clear during RIS air stream (RAS) events. The warmest periods occur during southward transport from the Ross Sea. The sensitivity of temperature to the origin of flows suggests circulation changes in the region are likely to significantly impact surface climate. Analysis of the frequency of varying synoptic events and their persistence confirms RAS is a very common and persistent feature of the region.

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A High-Resolution Numerical Simulation of the Wind Flow in the Ross Island Region, Antarctica

Cited by 38 publications

References 15 publications

A Strong Wind Event on the Ross Ice Shelf, Antarctica: A Case Study of Scale Interactions

A Strong Wind Event on the Ross Ice Shelf, Antarctica: A Case Study of Scale Interactions

A climatology of strong wind events at McMurdo station, Antarctica

Synoptic climatology of the Ross Ice Shelf and Ross Sea region of Antarctica: k‐means clustering and validation

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