scholarly journals Dynamics of the ice cap on King George Island, Antarctica: field measurements and numerical simulations

2010 ◽  
Vol 51 (55) ◽  
pp. 80-90 ◽  
Author(s):  
Martin Rückamp ◽  
Norbert Blindow ◽  
Sonja Suckro ◽  
Matthias Braun ◽  
Angelika Humbert
Keyword(s):  
Air Temperature ◽  
Water Layer ◽  
Climatic Conditions ◽  
King George Island ◽  
Differential Gps ◽  
Ice Flow ◽  
Climate Conditions ◽  
Ice Cap ◽  
Ice Surface ◽  
Mean Annual Air Temperature

AbstractKing George Island is located at the northern tip of the Antarctic Peninsula, which is influenced by maritime climate conditions. The observed mean annual air temperature at sea level is –2.4˚C. Thus, the ice cap is regarded as sensitive to changing climatic conditions. Ground-penetrating radar surveys indicate a partly temperate ice cap with an extended water layer at the firn/ice transition of the up to 700 m high ice cap. Measured firn temperatures are close to 0˚C at the higher elevations, and they differ considerably from the measured mean annual air temperature. The aim of this paper is to present ice-flow dynamics by means of observations and simulations of the flow velocities. During several field campaigns from 1997/98 to 2008/09, ice surface velocities were derived with repeated differential GPS measurements. Ice velocities vary from 0.7 m a−1 at the dome to 112.1 m a−1 along steep slopes. For the western part of the ice cap a three-dimensional diagnostic full-Stokes model was applied to calculate ice flow. Parameters of the numerical model were identified with respect to measured ice surface velocities. The simulations indicate cold ice at higher elevations, while temperate ice at lower elevations is consistent with the observations.

scholarly journals Surface velocity and ice discharge of the ice cap on King George Island, Antarctica

2013 ◽  
Vol 54 (63) ◽  
pp. 111-119 ◽  
Author(s):  
B. Osmanoğlu ◽  
M. Braun ◽  
R. Hock ◽  
F.J. Navarro
Keyword(s):  
Weighted Average ◽  
Large Mass ◽  
Surface Velocity ◽  
King George Island ◽  
Ice Flow ◽  
Radar Images ◽  
Ice Cap ◽  
Ice Surface ◽  
Air Temperatures

AbstractGlaciers on King George Island, Antarctica, have shown retreat and surface lowering in recent decades, concurrent with increasing air temperatures. A large portion of the glacier perimeter is ocean-terminating, suggesting possible large mass losses due to calving and submarine melting. Here we estimate the ice discharge into the ocean for the King George Island ice cap. L-band synthetic aperture radar images covering the time-span January 2008 to January 2011 over King George Island are processed using an intensity-tracking algorithm to obtain surface velocity measurements. Pixel offsets from 40 pairs of radar images are analysed and inverted to estimate a weighted average surface velocity field. Ice thicknesses are derived from simple principles of ice flow mechanics using the computed surface velocity fields and in situ thickness data. The maximum ice surface speeds reach >225 m a-1, and the total ice discharge for the analysed flux gates of King George Island is estimated to be 0.720 ± 0.428 Gt a−1, corresponding to a specific mass loss of 0.64 ± 0.38 m w.e. a-1 over the area of the entire ice cap (1127 km2).

scholarly journals King George Island ice cap geometry updated with airborne GPR measurements

2012 ◽  
Vol 4 (1) ◽  
pp. 23-30 ◽  
Author(s):  
M. Rückamp ◽  
N. Blindow
Keyword(s):  
Numerical Modelling ◽  
Ice Thickness ◽  
King George Island ◽  
Differential Gps ◽  
Comprehensive Overview ◽  
Data Set ◽  
Airborne Measurements ◽  
Bedrock Topography ◽  
Ice Cap ◽  
Mandatory Requirement

Abstract. Ice geometry is a mandatory requirement for numerical modelling purposes. In this paper we present a consistent data set for the ice thickness, the bedrock topography and the ice surface topography of the King George Island ice cap (Arctowski icefield and the adjacent central part). The new data set is composed of ground based and airborne ground penetrating radar (GPR) and differential GPS (DGPS) measurements, obtained during several field campaigns. Blindow et al. (2010) already provided a comprehensive overview of the ground based measurements carried out in the safely accessible area of the ice cap. The updated data set incorporates airborne measurements in the heavily crevassed coastal areas. Therefore, in this paper special attention is paid to the airborne measurements by addressing the instrument used, survey procedure, and data processing in more detail. In particular, the inclusion of airborne GPR measurements with the 30 MHz BGR-P30-System developed at the Institute of Geophysics (University of Münster) completes the picture of the ice geometry substantially. The compiled digital elevation model of the bedrock shows a rough, highly variable topography with pronounced valleys, ridges, and troughs. Mean ice thickness is 240 ± 6 m, with a maximum value of 422 ± 10 m in the surveyed area. Noticeable are bounded areas in the bedrock topography below sea level where marine based ice exists. The provided data set is required as a basis for future monitoring attempts or as input for numerical modelling experiments. The data set is available from the PANGAEA database at http://dx.doi.org/10.1594/PANGAEA.770567.

scholarly journals The Gregoriev Ice Cap length changes derived by 2-D ice flow line model for harmonic climate histories

2009 ◽  
Vol 1 (1) ◽  
pp. 55-91
Author(s):  
Y. V. Konovalov ◽  
O. V. Nagornov
Keyword(s):  
Numerical Solution ◽  
Air Temperature ◽  
Equilibrium Equation ◽  
Flow Line ◽  
Mechanical Equilibrium ◽  
Surface Mass ◽  
Ice Cap ◽  
Ice Surface ◽  
Glacier Length ◽  
Length Changes

Abstract. Different ice thickness distributions along the flow line and the flow line length changes of the Gregoriev Ice Cap, Terskey Ala-Tau, Central Asia, were obtained for some surface mass balance histories which can be considered as possible surface mass balances in the future. The ice cap modeling was performed by solving of steady state hydrodynamic equations in the case of low Reynolds number in the form of the mechanical equilibrium equation in terms of stress deviator components coupled with the continuity equation for incompressible fluid. The numerical solution was obtained by the finite difference method. A compound approximation of the ice surface boundary condition based on the extending of the mechanical equilibrium equation to ice surface points was applied. The approximation is considered as a way to overcome the problem of diagnostic equations numerical solution stability in the full model. The basal sliding can arise in the glacier tongue at certain climatic conditions and was introduced both through linear and through non-linear friction laws. A possible glacier length history, that corresponds to the regional climate changes derived from the tree-rings data, was obtained by the model. The correlations between the glacier length changes and annual air temperature histories were investigated within the simplified equation introduced by J. Oerlemans in the form of linear dependence of annual air temperature versus glacier length and time derivative of the length. The parameters of the dependence were derived from modeled glacier length histories that correspond to harmonic climate histories. The parameters variations were investigated for different periodicities of harmonic climate histories and appropriate dependences are presented in the paper. The results of the modeling are in a good agreement with the J. Oerlemans climatic model.

scholarly journals Recent Climatic Mass Balance of the Schiaparelli Glacier at the Monte Sarmiento Massif and Reconstruction of Little Ice Age Climate by Simulating Steady-State Glacier Conditions

Geosciences ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 272
Author(s):  
Stephanie Suzanne Weidemann ◽  
Jorge Arigony-Neto ◽  
Ricardo Jaña ◽  
Guilherme Netto ◽  
Inti Gonzalez ◽  
...  
Keyword(s):  
Steady State ◽  
Mass Balance ◽  
Air Temperature ◽  
Little Ice Age ◽  
Similar Rate ◽  
Climatic Conditions ◽  
Ice Age ◽  
Balance Model ◽  
Climate Conditions ◽  
Recent Climate

The Cordillera Darwin Icefield loses mass at a similar rate as the Northern and Southern Patagonian Icefields, showing contrasting individual glacier responses, particularly between the north-facing and south-facing glaciers, which are subject to changing climate conditions. Detailed investigations of climatic mass balance processes on recent glacier behavior are not available for glaciers of the Cordillera Darwin Icefield and surrounding icefields. We therefore applied the coupled snow and ice energy and mass balance model in Python (COSIPY) to assess recent surface energy and mass balance variability for the Schiaparelli Glacier at the Monte Sarmiento Massif. We further used COSIPY to simulate steady-state glacier conditions during the Little Ice Age using information of moraine systems and glacier areal extent. The model is driven by downscaled 6-hourly atmospheric data and high resolution precipitation fields, obtained by using an analytical orographic precipitation model. Precipitation and air temperature offsets to present-day climate were considered to reconstruct climatic conditions during the Little Ice Age. A glacier-wide mean annual climatic mass balance of −1.8 ± 0.36 m w.e. a − 1 was simulated between between April 2000 and March 2017. An air temperature decrease between −0.9 ° C and −1.7 ° C in combination with a precipitation offset of up to +60% to recent climate conditions is necessary to simulate steady-state conditions for Schiaparelli Glacier in 1870.

scholarly journals King George Island ice cap geometry updated with airborne GPR measurements

2011 ◽  
Vol 4 (1) ◽  
pp. 123-139 ◽  
Author(s):  
M. Rückamp ◽  
N. Blindow
Keyword(s):  
Numerical Modelling ◽  
Ice Thickness ◽  
King George Island ◽  
Differential Gps ◽  
Comprehensive Overview ◽  
Data Set ◽  
Airborne Measurements ◽  
Bedrock Topography ◽  
Ice Cap ◽  
Mandatory Requirement

Abstract. Ice geometry is a mandatory requirement for numerical modelling purposes. In this paper we present a consistent data set for the ice thickness, the bedrock topography and the ice surface topography of the King George Island ice cap (Arctowski Icefield and the adjacent central part). The newly data set is composed of groundbased and airborne Ground Penetrating Radar (GPR) and differential GPS (DGPS) measurements, obtained during several field campaigns. Blindow et al. (2010) already provided a comprehensive overview of the groundbased measurements carried out in the safely accessible area of the ice cap. The updated data set incorporates airborne measurements in the heavily crevassed coastal areas. Therefore, in this paper special attention is paid to the airborne measurements by addressing the used instrument, survey, and data processing in more detail. In particular, the inclusion of airborne GPR measurements with the 30 MHz BGR-P30-System developed at the Institute of Geophysics (University of Münster) completes the picture of the ice geometry substantially. The compiled digital elevation model of the bedrock shows a rough, highly variable topography with pronounced valleys, ridges, and troughs. Mean ice thickness is ~240 m, with a maximum value of ~400 m in the surveyed area. Noticeable are bounded areas in the bedrock topography below sea level where marine based ice exists. The provided data set is required as a basis for future monitoring attempts or as input for numerical modelling experiments. The data set is available from the PANGAEA database at doi:10.1594/PANGAEA.770567.

scholarly journals CLIMATIC CONDITIONS OF THE ULYANOVSK REGION AND THEIR CHANGES

2021 ◽  
Author(s):  
Rаside B. Sharipova ◽  
Keyword(s):  
Air Temperature ◽  
Climatic Conditions ◽  
Monthly Precipitation ◽  
Clear Trend ◽  
Climate Conditions ◽  
June July August ◽  
Ulyanovsk Region ◽  
Average Monthly Precipitation ◽  
June July

The article summarizes the results of changes in climate conditions: the average annual air temperature for 1961-2018 in the Ulyanovsk region increased by 1.8°C, the most significant increase in temperature was observed in the last twenty-five-year period of time, in the winter pe-riod. There is a tendency to increase both average and seasonal values. When analyzing the time values of the dynamics of the average monthly precipitation amounts, it was found that: the min-imum amount of precipitation falls in the winter months, in June – July they are maximum. There is a clear trend of their growth in September, in the winter months: December, January, February, March. A steady decline in precipitation is observed in June, July, August, and November.

scholarly journals Regional Climate Change (Karelia, Russia)

2015 ◽  
Vol 2 ◽  
pp. 356
Author(s):  
Larisa Nazarova
Keyword(s):  
Air Temperature ◽  
Global Climate ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Climatic Conditions ◽  
Temperature And Precipitation ◽  
The Mean ◽  
Weather Stations ◽  
Meteorological Observations ◽  
Mean Annual Air Temperature

The overview of climatic conditions in Karelia is based on the data from meteorological observations carried out in 1951-2009 at Roskomgidromet weather stations situated in the study area. Taking the period in question into account, the mean annual air temperature norm has increased by 0.2-0.3°C. The greatest deviation from multiyear averages of mean monthly air temperature is observed in January and March. The investigation of the changes the basic regional climate characteristics is very important in present time because the global climate is changed. The analysis the data about air temperature and precipitation, that were obtained for the different meteorological stations in the investigated region, shows that the regional climate is changed and the main tendencies are directly proportional to the change of the global characteristics.

scholarly journals Association between Climatic Conditions, Population Density and COVID-19 in Indonesia

2021 ◽  
Vol 50 (3) ◽  
pp. 879-887
Author(s):  
AZIZAH R. ◽  
SANTI MARTINI SANTI MARTINI ◽  
LILIS SULISTYORINI LILIS SULISTYORINI ◽  
MAHMUDAH MAHMUDAH ◽  
ADITYA SUKMA PAWITRA ◽  
...  
Keyword(s):  
Population Density ◽  
Air Temperature ◽  
Virus Disease ◽  
Climatic Conditions ◽  
Cluster Method ◽  
Tropical Region ◽  
Climate Factors ◽  
Climate Conditions ◽  
Exact Test ◽  
Populated Region

The first emergence of Corona Virus Disease 2019 (COVID-19) confirmed cases found in Wuhan, China, has become a global crisis. At least 177 countries have been affected over 43,000,000 confirmed cases of corona positive and more than one million deaths until October 27th, 2020. Recent research has analyzed any possible factors causing the COVID-19 spreads were climate factors and population density. Indonesia was a tropical region known as the high-populated country in the World, with a 52.9% area with a high mean air temperature and over 267.7 million populations. Our study aims to analyze the correlation between climate, population density, and COVID-19 in Indonesia. We used the K-means cluster method and Fisher’s exact test to determine climatic conditions, population density, and COVID-19 clusters and study the correlation. Our research found that there is a correlation between climatic conditions and population density with COVID-19 (p: 0,034; p:0,004). Warmer climate conditions and densely populated regions contributed to the risen COVID-19 transmission in Indonesia. These are highlighted by the evidence of the top six provinces with highest COVID-19 cases are province classified in warmer climatic conditions (high air temperature, low rainfall, and humidity) and a fairly-dense to densely populated region.

Deciphering the fallout of tephra on glaciers in past eruptions, the case history of the Katla 1918 eruption

2021 ◽  
Author(s):  
Magnus Tumi Gudmundsson ◽  
Gudrun Larsen ◽  
Maria H. Janebo ◽  
Thordis Hognadottir ◽  
Tinna Jonsdottir
Keyword(s):  
Mass Balance ◽  
Central Volcano ◽  
Tephra Layer ◽  
Ice Flow ◽  
Ice Cap ◽  
Ice Surface ◽  
History Of ◽  
Tephra Layers ◽  
Glacier Flow ◽  
Isopach Map

<p>Explosive eruptions in ice-covered volcanoes may deposit large volumes of tephra on the glaciated slopes.  The tephra can influence surface ablation and alter mass balance.  Ice melting by an eruption can change glacier geometry and temporarily alter the flow of outlet glaciers.  Conversely, when assessing the size of past tephra-producing eruptions in an ice-covered volcano the glacier complicates such estimates.  The effects of ice flow, dilation and shear need to be considered.  A tephra layer may get buried in the accumulation area, be transported by glacier flow and progressively removed over years-to-centuries by ice flow, eolian transport of exposed tephras and sediment transport in glacial rivers.  Here we report on a case study from the Mýrdalsjökull ice cap that covers the upper parts of the large Katla central volcano in south Iceland.  Most eruptions start beneath the 300-700 m thick ice cover within the Katla caldera, melt large volumes of ice and cause major jökulhlaups.  They also produce tephra layers that are preserved in soils around the volcano.  The most recent eruption in Katla occurred in October-November 1918, when a large tephra layer was deposited in a 3-weeks long eruption. By using a combination of (1) data obtained at or near the vent area within the SE-part of the Katla caldera in the year following the eruption, (2) mapping of the tephra as exposed at the present time in the ablation areas in the lower parts of the outlet glaciers, and (3) simple models of ice flow based on balance velocities and knowledge of mass balance, we estimate the location of fallout and the original thickness of the presently exposed tephra.  Photos taken in the vent area in 1919 indicate a tephra thickness of 20-30 m on the ice surface proximal to the vents.  The greatest thicknesses presently observed, 30-35 cm, occur where the layer outcrops in the lowermost parts of the ablation areas of the Kötlujökull and Sólheimajökull outlet glaciers.  A fallout location within the Katla caldera is inferred for the presently exposed tephra, as estimates of balance velocities imply lateral transport since 1918 of ~15 km for Kötlujökull, ~11 km for Sólheimajökull and about 2 km for the broad northern lobe of Sléttjökull.  The calculations indicate that ice transport with associated dilation of the glacier through the accumulation areas has resulted in significant thinning.   Thus, the layer that is now 0.3-0.35 m thick in the fastest flowing outlets is estimated to have been four to seven times thicker when it fell on the accumulation area within the ice-filled caldera.  In contrast, changes have been minor in the slowly moving Sléttjökull.  These findings allow for the construction of an isopach map for the glacier.  The results indicate that just under half of the total airborne tephra produced in the eruption fell within the Mýrdalsjökull glacier, with the remaining half spread out over a large part of Iceland.  These methods potentially allow for reconstruction of several tephra layers from ice-covered volcanoes in Iceland and elsewhere. </p>

Trends in the Phenology of Climber Roses under Changing Climate Conditions in Mazovia Lowland in Central Europe

2021 ◽  
Author(s):  
Marta Monder
Keyword(s):  
Central Europe ◽  
Air Temperature ◽  
Ornamental Plants ◽  
Ground Level ◽  
Weather Conditions ◽  
Frost Damage ◽  
Growth Conditions ◽  
Climatic Conditions ◽  
Climate Conditions ◽  
Urban Green Spaces

The genetic pool of valuable old ornamental cultivars and their in situ maintenance may be threated by climate change. Meanwhile, the ornamental plants like roses make up an important share of both gardens and urban green spaces, where they are particularly vulnerable to multistress growth conditions. The aim of this research was to evaluate the effect of changing climatic conditions on growth and flowering of 11 historic climber roses through long-term studies (2000-2017) conducted in Central Europe. The evaluation of plants consisted of assessment of frost damage and the timing of early phenological stages (starting of bud break, leaf unfolding) as well as gathering data on beginning, fullness and end of flowering and its abundance. Frost damage was not recorded in any year only in ‘Mme Plantier’, and did not occur for any cultivar after the winter in the years 2007, 2008, and 2014. Only a little damage to one-year shoots was recorded after the winter in the years 2015-2017. Frost damage to ‘Alberic Barbier’, ‘Albertine’, ‘Chaplin's Pink Climber’, ‘Orange Triumph clg’ and ‘Venusta Pendula’ led to pruning to ground level in every year excluding those listed above. Frost damage of once blooming roses limited their flowering; however, the many-year data-sets showed a trend for decreased frost damage and improved abundance of flowering, and these results can be interpreted as a response to the increase of average air temperature. The timing of bud breaking and leaf development in all climber roses was strictly correlated with average air temperature in the dormancy period. The reactions of climber roses to weather conditions confirmed the influence of climatic changes on ornamental crop plants in Central Europe, introducing the potential possibility for the wider application of climber roses, but without certainty of flowering every year.

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