scholarly journals Heat flow variations in the Antarctic Continent

Author(s):  
Suze Nei Pereira Guimarães ◽  
Fábio Pinto Vieira ◽  
Valiya Mannathal Hamza

The present work provides a reappraisal of terrestrial heat flow variations in the Antarctic continent, based on recent advances in data analysis and regional assessments. The data considered include those reported at the website of IHFC and 78 additional sites where measurements have been made using a variety of techniques. These include values based on the Method of Magmatic Heat Budget (MHB) for 41 localities in areas of recent volcanic activity and estimates that rely on basal temperatures of glaciers in 372 localities that are known to host subglacial lakes. The total number of data assembled is 491, which has been useful in deriving a 10°x10° grid system of homogenized heat flow values and in deriving a new heat flow map of the Antarctic continent. The results reveal that the Antarctic Peninsula and western segment of the Antarctic continent has distinctly high heat flow relative to the eastern regions. The general pattern of differences in heat flow between eastern and western of Antarctic continent is in striking agreement with results based on seismic velocities.

Author(s):  
Jorge Luiz dos Santos Gomes ◽  
Fábio Pinto Vieira ◽  
Valiya Mannathal Hamza

A reappraisal of geothermal data of the mainland of Africa has been carried out based on data sets available at the IHFC website, incremented with updated information on volcanic activities of post Holocene times. Our compilation makes use of 1480 heat flow values that include 1327 observational data supplemented with 36 estimates derived from heat flow-age relation. In addition, the method of magmatic heat budget (MHB) has been employed in deriving deep crustal heat flow values for 117 for sites of recent volcanic activity, most of it located in Ethiopia. These data sets were regrouped into regular equal-area cells with dimensions of 5 x 5 degrees and subsequently employed in deriving maps of the regional distributions of heat flow and geothermal resources and interpreted on the basis of available information on tectonic setting and geological characteristics. The most prominent features are the relatively high values in the region of rift valleys in the eastern sector of the continent. High heat flow values also occur along north-south trending belts of Atlas Mountains in the north and pockets associated with the Cameroon volcanic chain on the west-central parts of the continent. The vertical distributions of temperatures were calculated for depths reaching down to 6 km. The associated resource base calculations indicate availability of high temperature resources in vast regions of the African continent.


2020 ◽  
Author(s):  
Pavel Talalay ◽  
Yazhou Li ◽  
Laurent Augustin ◽  
Gary Clow ◽  
Jialin Hong ◽  
...  

Abstract. The temperature at the Antarctic ice sheet bed and the temperature gradient in subglacial rocks have been directly measured only a few times, although extensive thermodynamic modelling has been used to estimate geothermal heat flux under ice sheet. During the last five decades, deep ice-core drilling projects at six sites – Byrd, WAIS Divide, Dome C, Kohnen, Dome F, and Vostok – have succeeded in reaching to, or nearly to, the bed in inland locations in Antarctica. When temperature profiles in these boreholes and heat flow model are combined with estimations of vertical velocity, the heat flow at ice sheet base is translated to a geothermal heat flux of 117.8 ± 3.3 mW m−2 at Byrd, 67.3 ± 8.6 mW m−2 at Dome C, 79.0 ± 5.0 mW m−2 at Dome F, and −3.3 ± 5.6 mW m−2 at Vostok, close to predicted values. However, estimations at Kohnen and WAIS Divide gave flux of 161.5 ± 10.2 mW m−2 and 251.3 ± 24.1 mW m−2, respectively, far higher than that predicted by existing heat flow models. The question arises as to whether this high heat flow represents regional values, or if the Kohnen and WAIS Divide boreholes were drilled over local hot spots.


2013 ◽  
Vol 47 ◽  
pp. 167-178 ◽  
Author(s):  
M. P. Andreev

Lichen flora and vegetation in the vicinity of the Russian base «Molodyozhnaya» (Enderby Land, Antarctica) were investigated in 2010–2011 in details for the first time. About 500 specimens were collected in 100 localities in all available ecotopes. The lichen flora is the richest in the region and numbers 39 species (21 genera, 11 families). The studied vegetation is very poor and sparse, but typical for coastal oases of the Antarctic continent. The poorness is caused by the extremely harsh climate conditions, insufficient availability of liquid water, ice-free land, and high insolation levels. The dominant and most common lichens are Rinodina olivaceobrunnea, Amandinea punctata, Candelariella flava, Physcia caesia, Caloplaca tominii, Lecanora expectans, Caloplaca ammiospila, Lecidea cancriformis, Pseudephebe minuscula, Lecidella siplei, Umbilicaria decussata, Buellia frigida, Lecanora fuscobrunnea, Usnea sphacelata, Lepraria and Buellia spp.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1551
Author(s):  
Zihuai Guo ◽  
Yibin Yao ◽  
Jian Kong ◽  
Gang Chen ◽  
Chen Zhou ◽  
...  

Global navigation satellite system (GNSS) can provide dual-frequency observation data, which can be used to effectively calculate total electron content (TEC). Numerical studies have utilized GNSS-derived TEC to evaluate the accuracy of ionospheric empirical models, such as the International Reference Ionosphere model (IRI) and the NeQuick model. However, most studies have evaluated vertical TEC rather than slant TEC (STEC), which resulted in the introduction of projection error. Furthermore, since there are few GNSS observation stations available in the Antarctic region and most are concentrated in the Antarctic continent edge, it is difficult to evaluate modeling accuracy within the entire Antarctic range. Considering these problems, in this study, GNSS STEC was calculated using dual-frequency observation data from stations that almost covered the Antarctic continent. By comparison with GNSS STEC, the accuracy of IRI-2016 and NeQuick2 at different latitudes and different solar radiation was evaluated during 2016–2017. The numerical results showed the following. (1) Both IRI-2016 and NeQuick2 underestimated the STEC. Since IRI-2016 utilizes new models to represent the F2-peak height (hmF2) directly, the IRI-2016 STEC is closer to GNSS STEC than NeQuick2. This conclusion was also confirmed by the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) occultation data. (2) The differences in STEC of the two models are both normally distributed, and the NeQuick2 STEC is systematically biased as solar radiation increases. (3) The root mean square error (RMSE) of the IRI-2016 STEC is smaller than that of the NeQuick2 model, and the RMSE of the two modeling STEC increases with solar radiation intensity. Since IRI-2016 relies on new hmF2 models, it is more stable than NeQuick2.


1988 ◽  
Vol 6 (3-4) ◽  
pp. 179-184 ◽  
Author(s):  
John A.E. Gibson ◽  
Russell C. Garrick ◽  
Harry R. Burton ◽  
Andrew R. McTaggart

2013 ◽  
Author(s):  
Aimen Amer ◽  
Rolando di Primio ◽  
Robert Ondrak ◽  
Vikram Unnithan

Polar Record ◽  
2013 ◽  
Vol 50 (2) ◽  
pp. 176-182 ◽  
Author(s):  
Łukasz Kaczmarek ◽  
Karel Janko ◽  
Jerzy Smykla ◽  
Łukasz Michalczyk

ABSTRACTIn thirteen (mostly soil) mixed samples, collected from nine localities on the Antarctic continent and some of the neighbouring islands, 788 specimens and 32 eggs of tardigrades were found. In total, five species were identified:Acutuncus antarcticus, Echiniscus jenningsi,Diphascon(D.)victoriae,Hypsibius dujardiniandRamajendas dastychisp. nov.A. antarcticuswas the most abundant (nearly 90% of all specimens) and was the prevailing taxon found in the majority of locations.R. dastychisp. nov. is the fourth species described in the exclusively Antarctic/sub-Antarctic genus. The new species differs from all other congeners by the presence of four gibbosities on the caudo-dorsal cuticle (configuration II:2–2) and also by some morphometric characters. In this paper we also briefly discuss the taxonomy and zoogeography of the genusRamajendas.


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