Winds and tides in the mid-latitude Southern Hemisphere upper mesosphere recorded with the Falkland Islands SuperDARN radar

Abstract. Meteor wind data from the first year of operation of the Falkland Islands SuperDARN radar (52° S, 59° W) are used to characterize the atmospheric tides and background winds in the upper mesosphere above the South Atlantic. Strong (>40 m s−1) semidiurnal tides are observed in the winter time and large amplitude (>60 m s−1) bursts of quasi two-day wave activity are seen in January 2011. Data are in good agreement with those presented from the SAAMER meteor radar (54° S, 68° W). Comparison with SuperDARN meteor wind data from a geographically similar Northern Hemisphere site at Goose Bay (53° N 60° W) reveal clear interhemispheric differences especially in the semidiurnal and terdiurnal components of the tides. The winter time amplitudes of the tides are much stronger in the Southern Hemisphere than in the north. Background winds are observed to be significantly more polewards and westwards throughout the year than those predicted by the empirical horizontal wind model HWM07.

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Horizontal wind model (HWM) (1990)

Planetary and Space Science ◽

10.1016/0032-0633(92)90211-6 ◽

1992 ◽

Vol 40 (4) ◽

pp. 556-557 ◽

Cited By ~ 2

Author(s):

A.E. Hedin

Keyword(s):

Horizontal Wind ◽

Wind Model

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Geothermal modeling of soil or mine tailings with concurrent freezing and deposition

Canadian Geotechnical Journal ◽

10.1139/t97-081 ◽

1998 ◽

Vol 35 (2) ◽

pp. 234-250 ◽

Cited By ~ 3

Author(s):

JF (Derick) Nixon ◽

Nick Holl

Keyword(s):

Snow Cover ◽

Mine Tailings ◽

Frozen Soil ◽

Freezing And Thawing ◽

Frozen Ground ◽

Geothermal Model ◽

Winter Time ◽

Upper Boundary ◽

Good Agreement

A geothermal model is described that simulates simultaneous deposition, freezing, and thawing of mine tailings or sequentially placed layers of embankment soil. When layers of soil or mine tailings are placed during winter subfreezing conditions, frozen layers are formed in the soil profile that may persist with time. The following summer, warmer soil placement may not be sufficient to thaw out layers from the preceding winter. Remnant frozen soil layers may persist for many years or decades. The analysis is unique, as it involves a moving upper boundary and different surface snow cover functions applied in winter time. The model is calibrated based on two uranium mines in northern Saskatchewan. The Rabbit Lake scenario involves tailings growth to a height of 120 m over a period of 24 years. At Key Lake, tailings increase in height at a rate of 1.3 m/year. Good agreement between the observed position of frozen layers and those predicted by the model is obtained. Long-term predictions indicate that from 80 to 200 years would be required to thaw out the frozen layers formed during placement, assuming 1992 placement conditions continue. Deposition rates of 1.5-3 m/year give the largest amounts of frozen ground. The amount of frozen ground is sensitive to the assumed snow cover function during winter.Key words: geothermal, model, tailings, freezing, deposition.

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ECTOMYCORRHIZAL FUNGI AND NON-AGARICOID BASIDIOMYCETOUS MACROMYCETES OF THE FALKLANDS

Edinburgh Journal of Botany ◽

10.1017/s0960428612000042 ◽

2012 ◽

Vol 69 (2) ◽

pp. 219-238 ◽

Cited By ~ 1

Author(s):

R. Watling

Keyword(s):

Southern Hemisphere ◽

Ectomycorrhizal Fungi ◽

Falkland Islands ◽

The World ◽

First Time

Fifty-one species of basidiomycetes are recorded from the Southern Atlantic archipelago of the Falkland Islands. Several other fungi are discussed in the light of these findings. Some of these fungi are recorded for the first time from the Falklands and especially from some of the smaller islands of the group adjacent to West and East Falkland. The world distributions of the fungi dealt with in this compilation, particularly in the southern hemisphere, are given where they are known. Comments are made on the possible reasons for the occurrence of the species in the Falklands, especially the ectomycorrhizal taxa.

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A 250-year periodicity in Southern Hemisphere westerly winds over the last 2600 years

Climate of the Past ◽

10.5194/cp-12-189-2016 ◽

2016 ◽

Vol 12 (2) ◽

pp. 189-200 ◽

Cited By ~ 22

Author(s):

C. S. M. Turney ◽

R. T. Jones ◽

C. Fogwill ◽

J. Hatton ◽

A. N. Williams ◽

...

Keyword(s):

Southern Hemisphere ◽

Global Climate Change ◽

Late Holocene ◽

Global Climate ◽

Falkland Islands ◽

The Core ◽

Atmosphere System ◽

Westerly Winds ◽

Ocean Atmosphere ◽

Southern Hemisphere Westerly Winds

Abstract. Southern Hemisphere westerly airflow has a significant influence on the ocean–atmosphere system of the mid- to high latitudes with potentially global climate implications. Unfortunately, historic observations only extend back to the late 19th century, limiting our understanding of multi-decadal to centennial change. Here we present a highly resolved (30-year) record of past westerly wind strength from a Falkland Islands peat sequence spanning the last 2600 years. Situated within the core latitude of Southern Hemisphere westerly airflow (the so-called furious fifties), we identify highly variable changes in exotic pollen and charcoal derived from South America which can be used to inform on past westerly air strength. We find a period of high charcoal content between 2000 and 1000 cal. years BP, associated with increased burning in Patagonia, most probably as a result of higher temperatures and stronger westerly airflow. Spectral analysis of the charcoal record identifies a pervasive ca. 250-year periodicity that is coherent with radiocarbon production rates, suggesting that solar variability has a modulating influence on Southern Hemisphere westerly airflow. Our results have important implications for understanding global climate change through the late Holocene.

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Evidence for a Rapid Global Climate Shift across the Late 1960s

Journal of Climate ◽

10.1175/jcli4177.1 ◽

2007 ◽

Vol 20 (12) ◽

pp. 2721-2744 ◽

Cited By ~ 120

Author(s):

Peter G. Baines ◽

Chris K. Folland

Keyword(s):

Southern Hemisphere ◽

North Atlantic ◽

Amazon Basin ◽

Storm Track ◽

Central Pacific ◽

Atlantic Sector ◽

The North ◽

The North Atlantic ◽

The 1950S ◽

African Sahel

Abstract It is shown that a number of important characteristics of the global atmospheric circulation and climate changed in a near-monotonic fashion over the decade, or less, centered on the late 1960s. These changes were largest or commonest in tropical regions, the Southern Hemisphere, and the Atlantic sector of the Northern Hemisphere. Some, such as the decrease in rainfall in the African Sahel, are well known. Others appear to be new, but their combined extent is global and dynamical linkages between them are evident. The list of affected variables includes patterns of SST; tropical rainfall in the African Sahel and Sudan, the Amazon basin, and northeast Brazil; pressure and SST in the tropical North Atlantic and the west and central Pacific; various branches of the southern Hadley circulation and the southern subtropical jet stream; the summer North Atlantic Oscillation; south Greenland temperature; the Southern Hemisphere storm track; and, quite likely, the Antarctic sea ice boundary. These changes are often strongest in the June–August season; changes are also seen in December–February but are generally smaller. In Greenland, annual mean temperature seems to be affected strongly, reflecting similar changes in SST throughout the year in the higher latitudes of the North Atlantic. Possible causes for these coordinated changes are briefly evaluated. The most likely candidates appear to be a likely reduction in the northward oceanic heat flux associated with the North Atlantic thermohaline circulation in the 1950s to 1970s, which was nearly in phase with a rapid increase in anthropogenic aerosol emissions during the 1950s and 1960s, particularly over Europe and North America.

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Saharan dust infrared optical depth and altitude retrieved from AIRS: a focus over North Atlantic – comparison to MODIS and CALIPSO

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-1953-2010 ◽

2010 ◽

Vol 10 (4) ◽

pp. 1953-1967 ◽

Cited By ~ 61

Author(s):

S. Peyridieu ◽

A. Chédin ◽

D. Tanré ◽

V. Capelle ◽

C. Pierangelo ◽

...

Keyword(s):

Optical Depth ◽

North Atlantic ◽

Western Indian Ocean ◽

Saharan Dust ◽

Orthogonal Polarization ◽

Dust Layer ◽

The North ◽

Moderate Resolution Imaging Spectroradiometer ◽

Good Agreement

Abstract. Monthly mean infrared (10 μm) dust layer aerosol optical depth (AOD) and mean altitude are simultaneously retrieved over the tropics (30° S–30° N) from almost seven years of Atmospheric Infrared Sounder (AIRS) observations covering the period January 2003 to September 2009. The method developed relies on the construction of look-up-tables computed for a large selection of atmospheric situations and follows two main steps: first, determination of the observed atmospheric thermodynamic situation and, second, determination of the dust properties. A very good agreement is found between AIRS-retrieved AODs and visible optical depths from the Moderate resolution Imaging Spectroradiometer (MODIS/Aqua) during the main (summer) dust season, in particular for three regions of the tropical North Atlantic and one region of the north-western Indian Ocean. Outside this season, differences are mostly due to the sensitivity of MODIS to aerosol species other than dust and to the more specific sensitivity of AIRS to the dust coarse mode. AIRS-retrieved dust layer mean altitudes are compared to the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP/CALIPSO) aerosol mean layer altitude for the period June 2006 to June 2009. Results for a region of the north tropical Atlantic downwind of the Sahara show a good agreement between the two products (σ≈360 m). Differences observed in the peak-to-trough seasonal amplitude, smaller from AIRS, are principally attributed to the large difference in spatial sampling of the two instruments. They also come from the intrinsic limit in sensitivity of the passive infrared sounders for low altitudes. These results demonstrate the capability of high resolution infrared sounders to measure not only dust aerosol AOD but also the mean dust layer altitude.

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Occurrence of suicide and seasonal variation

Revista de Saúde Pública ◽

10.1590/s0034-89101998000500002 ◽

1998 ◽

Vol 32 (5) ◽

pp. 408-412 ◽

Cited By ~ 20

Author(s):

Pedro Retamal C. ◽

Derek Humphreys

Keyword(s):

Seasonal Variation ◽

Statistical Analysis ◽

Southern Hemisphere ◽

Suicide Rate ◽

Seasonal Pattern ◽

Suicide Rates ◽

The North ◽

Political Center

OBJECTIVE: To review the estimated suicide rates for the Region Metropolitan, the main socio-political center in Chile, for the period 1979-1994, and to determine whether they follow a seasonal pattern. METHOD: Data available for the period 1979-94 at the Forensic Services in Chile was analyzed using ANOVA. RESULTS: It was register 5.386 suicides. While the "warm" months (October, November, December & January) concentrated 39.0% of cases, the so called "cold" months reported 28,7%. This contrast is made even clearer by the month-to-month analysis, showing the highest suicide rate in December (10.9%) against the lowest rate in June (7.0%). Further statistical analysis revealed these differences to be significant. CONCLUSION: The study shows that in Chile, representing as it does the Southern Hemisphere, the suicide rates tend to present a seasonal variation as has elsewhere been determined for in the North Hemisphere.

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Contrasting Phylogeographic Patterns Among Northern and Southern Hemisphere Fin Whale Populations With New Data From the Southern Pacific

Frontiers in Marine Science ◽

10.3389/fmars.2021.630233 ◽

2021 ◽

Vol 8 ◽

Author(s):

MJosé Pérez-Alvarez ◽

Sebastián Kraft ◽

Nicolás I. Segovia ◽

Carlos Olavarría ◽

Sergio Nigenda-Morales ◽

...

Keyword(s):

Southern Hemisphere ◽

Phylogenetic Analyses ◽

Morphological Data ◽

Phylogeographic Structure ◽

Fin Whale ◽

Middle Latitudes ◽

The North ◽

Southeastern Pacific ◽

Fin Whales ◽

Dispersal Events

Four fin whale sub-species are currently considered valid: Balaenoptera physalus physalus in the North Atlantic, B. p. velifera in the North Pacific, B. p. quoyi and B. p. patachonica in the Southern Hemisphere. The last, not genetically validated, was described as a pygmy-type sub-species, found in low to mid latitudes of the Southern Hemisphere. Genetic analyses across hemispheres show strong phylogeographic structure, yet low geographic coverage in middle latitudes of the Southern Hemisphere impeded an assessment within the area, as well as evaluating the validity of B. p. patachonica. New mtDNA sequences from the Southeastern Pacific allowed an improved coverage of the species’ distribution. Our phylogenetic analyses showed three main lineages and contrasting phylogeographic patterns between Northern and Southern Hemispheres. Absence of recurrent female mediated gene flow between hemispheres was found; however, rare dispersal events revealing old migrations were noted. The absence of genetic structure suggests the existence of one single taxa within the Southern Hemisphere. Thus, until further evidence supporting this subspecies can be produced, such as genetic, ecological, behavioral, or morphological data, we propose that all fin whales from the Southern Hemisphere, including those from middle latitudes of the Southeastern Pacific belong to B. p. quoyi subspecies. This information is important for the current assessment of fin whales, contributing to the evaluation of the taxonomic classification and the conservation of the species.

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Thinlip grey mullet Liza ramada (Mugilidae) caught in a

Fauna norvegica ◽

10.5324/fn.v26i0.571 ◽

2008 ◽

Vol 26 ◽

Author(s):

Bror Jonsson ◽

Nina Jonsson

Keyword(s):

North Sea ◽

Total Mass ◽

First Year ◽

English Channel ◽

Grey Mullet ◽

Font Size ◽

Growth Season ◽

The North ◽

The North Sea ◽

First Year Of Life

Two individuals of thinlip grey mullet Liza ramada were collected in a southern Norwegian brook (58° 22’ N, 8° 37’ E) on 12th September 2007. The fish were 8.7 and 9.0 cm in total length, 6 and 7 g in total mass, and most probably in their first year of life. The nearest known spawning area of the species is south of the English Channel, meaning that they had probably moved at least 900 km across the North Sea during their first growth season. To our knowledge, this is the first published observation of the catadromous thinlip grey mullet from a Scandinavian freshwater course.

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Winter positions of Arctic front during periods of cooling and warming

Journal Ice and Snow ◽

10.15356/2076-6734-2016-4-493-501 ◽

2016 ◽

Vol 56 (4) ◽

pp. 493-501

Author(s):

A. Yu. Mikhailov ◽

A. N. Zolotokrylin ◽

T. B. Titkova

Keyword(s):

Standard Deviation ◽

The Arctic ◽

Horizontal Wind ◽

The North ◽

Arctic Front ◽

The Absolute ◽

Geostrophic Vortex ◽

Climate Cooling ◽

Relative Differences ◽

Geostrophic Advection

Winter positions of the Arctic front (AF) during the known periods of the climate cooling (1949–1980) and warming (1981–2012) were analyzed within the sector 10° W – 60° E. The AF positios were determined by the following indicators: 1) a surface pressure; 2) horizontal wind divergence; 3) geostrophic vortex; 4) geostrophic heat advection. The main extrema of these four dynamic characteristics coincide and fall on the latitude 72.5° N. This corresponds to the average position of the AF for a given resolution and confirms correctness of our choice of these characteristics as the AF indicators. Relative differences between mean profiles of all values of the above warm and cold periods were calculated using method of normalization of each value for the corresponding latitude by the standard deviation for the entire period (1949–2012). To study variability of the AF position we used mean yearly winter profiles of the variables under investigation together with the statistical analysis of positions of the extrema within the latitude degrees. For pressure and geostrophic advection positions of the absolute minima were determined while for geostrophic vortex and divergence – positions of the absolute maxima. The data show that according to different criteria the AF average positions for the period 1949–2012 lie within the zone 72.4–73.4 N. The interannual variability of the AF positions lies within the 1–2 degrees of latitude and corresponds to the range of the air temperature variability above the zone of maximal changes in the sea ice area. According to the standard deviation values of the divergence and the geostrophic vortex are the most stable in region of the AF passage. Comparison of differences of the studied characteristics between the warm and cold periods shows that the changes in the AF positions are not statistically significant (P(t) < 91% t‑criterion) unlike the changes in positions of isolines which characterize the warming (P(t) = 100%). Thus, despite significant changes in properties of the surface and the temperature regime to the north of 72.5 N (the warming), according to all the criteria the AF climatic position remains quasi‑stationary for 32‑year periods of averaging.

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