Southern Hemisphere strong polar mesoscale cyclones in high-resolution datasets

Pezza, Alexandre Bernardes; Sadler, Katherine; Uotila, Petteri; Vihma, Timo; Mesquita, Michel D. S.; Reid, P

doi:10.1007/s00382-015-2925-2

Cited by 23 publications

(33 citation statements)

References 49 publications

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“…[] and Pezza et al . [] did not account for systems smaller than 400 km, which constitute more than half of our MC sample (Figure ). Figure shows that the mean MC lifetime is about 12 h (with a maximum of 60 h), the mean migration distance is about 750 km (maximum is 1800 km) and the mean propagation velocity is about 15 m/s (with a maximum of almost 40 m/s).…”

Section: Resultsmentioning

confidence: 99%

“…Pezza et al . [] and Uotila et al . [] alternatively reported high track densities along coastal East Antarctica; however, they disagreed with each other on the location of the second maximum which was in the Bellingshausen Sea by Pezza et al .…”

Section: Resultsmentioning

confidence: 99%

“…[] and Pezza et al . [] reported mean diameters of 700 km. The larger sizes of MCs revealed in reanalyses using tracking algorithms are due to an underestimation of the number of relatively small MCs that are not resolved by the coarse spatial resolution products.…”

Section: Resultsmentioning

confidence: 99%

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Southern Ocean mesocyclones and polar lows from manually tracked satellite mosaics

Verezemskaya

Tilinina

Gulev

et al. 2017

Geophysical Research Letters

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A new reference data set of mesocyclone activity over the Southern Ocean has been developed from the manual analysis of high‐resolution infrared satellite mosaics for winter 2004. Of the total 1735 mesocyclones which were identified and analyzed, about three quarters were classified as being “polar lows” (i.e., intense systems; see Rasmussen and Turner, 2003). The data set includes mesocyclone track, size, associated cloud vortex type, and background synoptic conditions. Maxima in track density were observed over the Bellingshausen Sea and around East Antarctica and are highly correlated with cyclogenesis regions. A comparison against QuikSCAT and reanalyses wind characteristics shows that the reanalyses, while capturing mesocyclone events, tend to considerably underestimate their wind speed (by up to 10 m s−1). This mesocyclone data set is available as a reference for further analysis of mesocyclones and for the evaluation and development of cyclone‐tracking algorithms.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Southern Ocean mesocyclones and polar lows from manually tracked satellite mosaics

Verezemskaya

Tilinina

Gulev

et al. 2017

Geophysical Research Letters

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“…For instance, it has been demonstrated that ERA-Interim does not fully reproduce polar lows (Zappa et al, 2014;Pezza et al, 2016). The reason is that the spatial scales of several phenomena are too small for reanalyses to be even theoretically able to reproduce them.…”

Section: Introductionmentioning

confidence: 99%

Higher Ocean Wind Speeds During Marine Cold Air Outbreaks

Kolstad¹

2017

Preprint

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Marine cold air outbreaks (MCAOs) are large-scale events in which cold air masses are advected over open ocean. It is well-known that these events are linked to the formation of polar lows and other mesoscale phenomena associated with high wind speeds, and that they therefore in some cases represent a hazard to maritime activities. However, it is still unknown whether MCAOs are generally conducive to higher wind speeds than normal. Here this is investigated by comparing ocean near-surface wind speeds during MCAOs in atmospheric reanalysis products with different horizontal grid spacings, along with two case studies using a convection-permitting numerical weather prediction model. The study regions are the Labrador Sea and the Greenland-Iceland-Norwegian (GIN) Seas, where MCAOs have been shown to be important for air-sea interaction and deep water formation. One of the main findings is that wind speeds during the strongest MCAO events are higher than normal and higher than wind speeds during less severe events. Limited evidence from the case studies suggests that reanalyses with grid spacings of more than 50 km underestimate winds driven by the large ocean-atmosphere energy fluxes during MCAOs. The peak times of MCAO usually occur when baroclinic waves pass over the regions. Therefore, the strong wind episodes during MCAOs generally last for just a few days. However, MCAOs can persist for 50 days or more.

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“…Articles about observational studies of subsynoptic-scale cyclones (those with a diameter less than 1000 km) in high southern latitudes indicate that these cyclonic perturbations can be observed at any longitude or latitude near the edge or over the sea ice zone, near the coastal margin of the Antarctic continent, and over the continental interior (Carrasco et al 2003;Uotila et al 2011;Pezza et al 2015). Moreover, the spatial seasonal and annual distribution of subsynotic cyclones revealed larger activity near the katabatic confluence zones (Carrasco and Bromwich, 1996;Carrasco et al 1997a, b;Turner et al 1996;Carrasco et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of subsynoptic-scale cyclogenesis around an idealized Antarctic continent

Carrasco

2017

Anales Instituto Patagonia (Chile)

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Southern Hemisphere strong polar mesoscale cyclones in high-resolution datasets

Cited by 23 publications

References 49 publications

Southern Ocean mesocyclones and polar lows from manually tracked satellite mosaics

Southern Ocean mesocyclones and polar lows from manually tracked satellite mosaics

Higher Ocean Wind Speeds During Marine Cold Air Outbreaks

Numerical simulation of subsynoptic-scale cyclogenesis around an idealized Antarctic continent

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