Modelling the temperature evolution of permafrost and seasonal frost in southern Norway during the 20th and 21st century

Abstract. A heat flow model was used to simulate both past and future ground temperatures of mountain permafrost in Southern Norway. A reconstructed air temperature series back to 1860 was used to evaluate the permafrost evolution since the end of the Little Ice Age in the region. The impact of a changing climate on discontinuous mountain permafrost until 2100 is predicted by using downscaled temperatures from an ensemble of downscaled climate models for the A1B scenario. From 13 borehole locations two consecutive years of ground temperature, air temperature and snow cover data are available for model calibration and validation. The boreholes are located at different elevations and in substrates having different thermal properties. With an increase of air temperature of ~+1.5 °C over 1860–2010 and an additional warming of +2.8 °C towards 2100 in air temperature, we simulate the evolution of ground temperatures for the borehole locations. According to model results, the active-layer thickness has increased since 1860 by about 0.5–5 m and >10 m for the sites Juvvass and Tron, respectively. The simulations also suggest that at an elevation of about 1900 m a.s.l. permafrost will degrade until the end of this century with a likelihood of 55–75% given the chosen A1B scenario.

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Modelling borehole temperatures in Southern Norway – insights into permafrost dynamics during the 20th and 21st century

The Cryosphere Discussions ◽

10.5194/tcd-6-341-2012 ◽

2012 ◽

Vol 6 (1) ◽

pp. 341-385 ◽

Cited By ~ 2

Author(s):

T. Hipp ◽

B. Etzelmüller ◽

H. Farbrot ◽

T. V. Schuler ◽

S. Westermann

Keyword(s):

Layer Thickness ◽

Active Layer ◽

Air Temperature ◽

Active Layer Thickness ◽

Ground Temperatures ◽

Air Temperatures ◽

Mountain Permafrost ◽

Southern Norway ◽

The Impact ◽

A1b Scenario

Abstract. A transient heat flow model was used to simulate both past and future ground temperatures of mountain permafrost and associated active layer thickness in Southern Norway. The model was forced by reconstructed air temperature starting from 1860, approximately coinciding with the Little Ice Age in the region. The impact of climate warming on mountain permafrost until 2100 is assessed by using downscaled air temperatures from a multi-model ensemble for the A1B scenario. For 13 borehole locations, records over three consecutive years of ground temperatures, air temperatures and snow cover data are available for model calibration and validation. The boreholes are located at different elevations and in substrates with different thermal properties. With an increase of air temperature of ~+1.5 °C over 1860–2010 and an additional warming of +2.8 °C until 2100, we simulate the evolution of ground temperatures for the borehole locations. According to model results, the active-layer thickness has increased since 1860 by 0.5–5 m and >10 m for the sites Juvvasshøe and Tron, respectively. The simulations also suggest that at an elevation of about 1900 m a.s.l. permafrost will degrade until the end of this century with a probability of 55–75% given the chosen A1B scenario.

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Modelling borehole temperatures in Southern Norway – insights into permafrost dynamics during the 20th and 21st century

The Cryosphere ◽

10.5194/tc-6-553-2012 ◽

2012 ◽

Vol 6 (3) ◽

pp. 553-571 ◽

Cited By ~ 32

Author(s):

T. Hipp ◽

B. Etzelmüller ◽

H. Farbrot ◽

T. V. Schuler ◽

S. Westermann

Keyword(s):

Layer Thickness ◽

Active Layer ◽

21St Century ◽

Little Ice Age ◽

Ice Age ◽

Active Layer Thickness ◽

Ground Temperatures ◽

Air Temperatures ◽

Mountain Permafrost ◽

Southern Norway

Abstract. This study aims at quantifying the thermal response of mountain permafrost in southern Norway to changes in climate since 1860 and until 2100. A transient one-dimensional heat flow model was used to simulate ground temperatures and associated active layer thicknesses for nine borehole locations, which are located at different elevations and in substrates with different thermal properties. The model was forced by reconstructed air temperatures starting from 1860, which approximately coincides with the end of the Little Ice Age in the region. The impact of climate warming on mountain permafrost to 2100 is assessed by using downscaled air temperatures from a multi-model ensemble for the A1B scenario. Borehole records over three consecutive years of ground temperatures, air temperatures and snow cover data served for model calibration and validation. With an increase of air temperature of ~1.5 °C over 1860–2010 and an additional warming of ~2.8 °C until 2100, we simulate the evolution of ground temperatures for each borehole location. In 1860 the lower limit of permafrost was estimated to be ca. 200 m lower than observed today. According to the model, since the approximate end of the Little Ice Age, the active-layer thickness has increased by 0.5–5 m and >10 m for the sites Juvvasshøe and Tron, respectively. The most pronounced increases in active layer thickness were modelled for the last two decades since 1990 with increase rates of +2 cm yr−1 to +87 cm yr−1 (20–430%). According to the A1B climate scenario, degradation of mountain permafrost is suggested to occur throughout the 21st century at most of the sites below ca. 1800 m a.s.l. At the highest locations at 1900 m a.s.l., permafrost degradation is likely to occur with a probability of 55–75% by 2100. This implies that mountain permafrost in southern Norway is likely to be confined to the highest peaks in the western part of the country.

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Paleoclimatic reconstruction during the Little Ice Age in the Llanganuco basin, Cordillera Blanca (Peru)

10.5194/egusphere-egu2020-1726 ◽

2020 ◽

Author(s):

Joshua Er Addi Iparraguirre Ayala ◽

Jose Úbeda Palenque ◽

Ronald Fernando Concha Niño de Guzmán ◽

Ramón Pellitero Ondicol ◽

Francisco Javier De Marcos García-Blanco ◽

...

Keyword(s):

3D Reconstruction ◽

Air Temperature ◽

Little Ice Age ◽

Ice Age ◽

Lapse Rate ◽

Ratio Method ◽

Equilibrium Line Altitude ◽

Paleoclimatic Reconstruction ◽

High Resolution Satellite Images ◽

The Impact

The Equilibrium Line Altitude (ELA, m) is a good indicator for the impact of climate change on tropical glaciers , because it varies in time and space depending on changes in temperature and/or precipitation.The estimation of the ELA and paleoELA using the Area x Altitude Balance Ratio method (AABR; Osmaston, 2005) requires knowing the surface and hypsometry of glaciers or paleoglaciers (Benn et al. 2005) and the Balance Ratio (BR) correct (Rea, 2009).In the Llanganuco basin (~ 9&#176;3&#180;S; 77&#176;37&#180;W) there are very well preserved moraines near the current glaciers front. These deposits provide information to reconstruct the extent of paleoglaciers since the Little Ice Age (LIA) and deduce some paleo-climatic variables.The goal of this work has been to reconstruct the paleotemperature (&#176;C) during LIA, deduced from the difference between ELA AABR2016 and paleoELA AABRLIA.The paleoclimatic reconstruction was carried out in 6 phases: Phase 1) Development of a detailed geomorphological map (scale 1/10,000), in order to&#160; identify glacial landforms (advance moraines and polished rocks) which, due to their geomorphological context, can be considered of LIA, so palaeoglaciers can be delimited. Current glacial extension was done using dry season, high resolution satellite images. Phase 2) Glacial bedrock Reconstruction from glacier surface following the GLABTOP methodology (Linsbauer et al 2009). Phase 3) 3D reconstruction of paleoglacial surface using GLARE tool, based on bed topography and flow lines for each defined paleoglacial (Pellitero et al., 2016). As perfect plasticity model does not reflect the tension generated by the side walls of the valley, form factors were calculated based on the glacier thickness, lateral moraines and the geometry of the valley following the equation proposed by Nye (1952), adjusting the thicknesses generated in the paleoglacial front. Phase 4) Calculation of BR in a reference glacier (Artesonraju; 8&#176; 56&#8217;S; 77&#186;38&#8217;W), near to the study area, using the product BR = b &#8226; z &#8226; s, where BR= Balance Ratio; b= mass balance measured in fieldwork 2004-2014 (m); z= average altitude (meters) and s= surface (m2) of each altitude band of the glacier (with intervals of 100 m altitude). A value BR = 2.3 was estimated. Phase 5) Automatic reconstruction of the ELA &#160;AABR2016 and paleoELA AABRLIA using ELA Calculation tool (Pellitero et al. 2015) after 3D reconstruction of the glacial and paleoglacial surface in phases 2 and 3. Phase 6) Estimation of paleotemperature during LIA by solving the equation of Porter et al. (1995): &#8710;T (&#176;C)= &#8710;ELA &#8226; ATLR, where &#8710;T= air temperature depression (&#186;C); &#8710;ELA = variation of ELA AABR 2016-LIA and ATLR = Air Temperature Lapse Rate, using the average global value of the Earth (0.0065 &#176;C/m), considered valid for tropics.The results obtained were: ELA AABR2016= 5260m, paleoELA AABRLIA= 5084m, and &#8710;T = 1.1 &#176;C. The reconstruction of air paleotemperature is consistent with different studies that have estimated values between 1&#8211;2 &#176;C colder than the present, with intense rainfall (Matthews & Briffa, 2005; Malone et al., 2015).

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Historical ablation rates and their drivers in Greenland – assessing the potential of the Wegener expedition for modern glaciological research

10.5194/egusphere-egu2020-10032 ◽

2020 ◽

Author(s):

Jakob Abermann ◽

Wolfgang Schöner ◽

Robert Schjøtt Fausto

Keyword(s):

Air Temperature ◽

Grid Point ◽

Short Wave ◽

Ice Age ◽

Wave Radiation ◽

Climate Change Signal ◽

Horizontal Distance ◽

West Greenland ◽

Geometrical Change ◽

The Impact

Alfred Wegener contributed extraordinarily to early days of scientific explorations in Greenland. Involved in three expeditions, we present unique historical data that is stored at Graz University, where Wegener filled his last academic position until his tragic death in Greenland in 1930. In this contribution we reevaluate data from his last expedition 1929-1931 acquired at the Qaamarujuup Glacier in West Greenland (71&#176;09'N; 51&#176;11'W). Sub-weekly ablation measurements along with air temperature, humidity, pressure, wind and short-wave radiation data exist for two full ablation seasons both near sea level and in 950 m a.s.l.. The 20th Century reanalysis product of the nearest grid-point performs well reproducing air temperature variability. Coincidentally, this expedition was carried out during a very warm period that was in fact comparable to recent years. We compare vertical ablation gradients from the years 1929/1930 obtained at Qaamarujuup in West Greenland with recent observations from the closest PROMICE automated weather station and discuss differences in a centennial perspective. Furthermore, we present a time-series of glacier stages from the little ice age (LIA) maximum up to present and quantify area and volume changes since. The glacier margin was in close proximity (<50 m distance) to the ocean during the LIA maximum, 660 m and almost 3 km horizontal distance from the ocean in 1930 and in 2019, respectively. Such a drastic geometrical change manifests in differing drivers of the glacier boundary layer with the impact of the cooling ocean during summer decreasing with time as the glacier margin&#8217;s distance to the ocean increases. We discuss the potential in using historical glacio-meteorological measurements along with a detailed glacier history in order to extract geometrical feedbacks from the climate change signal.

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Degrading Mountain Permafrost in Southern Norway: Spatial and Temporal Variability of Mean Ground Temperatures, 1999-2009

Permafrost and Periglacial Processes ◽

10.1002/ppp.728 ◽

2011 ◽

Vol 22 (4) ◽

pp. 361-377 ◽

Cited By ~ 62

Author(s):

Ketil Isaksen ◽

Rune Strand Ødegård ◽

Bernd Etzelmüller ◽

Christin Hilbich ◽

Christian Hauck ◽

...

Keyword(s):

Temporal Variability ◽

Spatial And Temporal Variability ◽

Ground Temperatures ◽

Mountain Permafrost ◽

Southern Norway

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Modeling the temperature evolution of Svalbard permafrost during the 20th and 21st century

The Cryosphere ◽

10.5194/tc-5-67-2011 ◽

2011 ◽

Vol 5 (1) ◽

pp. 67-79 ◽

Cited By ~ 54

Author(s):

B. Etzelmüller ◽

T. V. Schuler ◽

K. Isaksen ◽

H. H. Christiansen ◽

H. Farbrot ◽

...

Keyword(s):

Climate Models ◽

Global Climate ◽

Surface Air Temperature ◽

Thermal Conditions ◽

Global Climate Models ◽

Ground Temperature ◽

Active Layer Thickness ◽

Near Surface ◽

Ground Temperatures ◽

Rate Of Increase

Abstract. Variations in ground thermal conditions in Svalbard were studied based on measurements and modelling. Ground temperature data from boreholes were used to calibrate a transient heat flow model describing depth and time variations in temperatures. The model was subsequently forced with historical surface air temperature records and possible future temperatures downscaled from multiple global climate models. We discuss ground temperature development since the early 20th century, and the thermal responses in relation to ground characteristics and snow cover. The modelled ground temperatures show a gradual increase between 1912 and 2010, by about 1.5 °C to 2 °C at 20 m depth. The active layer thickness (ALT) is modelled to have increased slightly, with the rate of increase depending on water content of the near-surface layers. The used scenario runs predict a significant increase in ground temperatures and an increase of ALT depending on soil characteristics.

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Analyses of Climate Variations at Four Meteorological Stations on Remote Islands in the Croatian Part of the Adriatic Sea

Atmosphere ◽

10.3390/atmos11101044 ◽

2020 ◽

Vol 11 (10) ◽

pp. 1044

Author(s):

Ognjen Bonacci ◽

Matko Patekar ◽

Marco Pola ◽

Tanja Roje-Bonacci

Keyword(s):

Climate Change ◽

Time Series ◽

Water Resources ◽

Air Temperature ◽

Climate Models ◽

Adriatic Sea ◽

Temperature And Precipitation ◽

Intensive Exploitation ◽

Increasing Trends ◽

The Impact

The Mediterranean region is one of the regions in the world that is most vulnerable to the impact of imminent climate change. In particular, climate change has an adverse effect on both the ecosystem and socioeconomic system, influencing water availability for both human and environmental purposes. The most endangered water resources are along the coasts and on islands since they have relatively small volumes and are intensively exploited. We analyzed the time series of air temperature and precipitation measured at four meteorological stations (Komiža, Palagruža, Lastovo, and Biševo) located on small islands in the Croatian part of the Adriatic Sea in this study. The investigated time series extend from the 1950s to the present, being contemporaneous for approximately 50 years. Despite possessing discontinuity, they can be considered as representative for assessing climate change and variability in the scattered environment of the Croatian islands. The results showed increasing trends in the annual air temperature, while the annual cumulative precipitation did not show significant variations. In addition, the analyses of the monthly air temperature showed that statistically significant increasing trends occurred from April to August, suggesting a more severe impact during these months. These results are in accordance with regional and local studies and climate models. Although the climate variability during the analyzed period can be considered as moderate, the impact on water resources could be severe due to the combined effect of the increase in air temperature during warm periods and the intensive exploitation for tourism purposes.

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Modelling past and future permafrost conditions in Svalbard

The Cryosphere Discussions ◽

10.5194/tcd-4-1877-2010 ◽

2010 ◽

Vol 4 (4) ◽

pp. 1877-1908 ◽

Cited By ~ 1

Author(s):

B. Etzelmüller ◽

T. V. Schuler ◽

K. Isaksen ◽

H. H. Christiansen ◽

H. Farbrot ◽

...

Keyword(s):

Climate Model ◽

Theoretical Calculations ◽

Global Climate Model ◽

Temperature Data ◽

Ground Temperature ◽

Ice Age ◽

Active Layer Thickness ◽

Near Surface ◽

Ground Temperatures ◽

Rate Of Increase

Abstract. Variations in ground thermal conditions in Svalbard were studied based on measurements and theoretical calculations. Ground temperature data was used to calibrate a transient heat flow model describing depth and time variations in temperatures. The model was subsequently forced with historical surface air temperature data records and downscaled global climate model runs to project ground temperatures. We discuss ground temperature development since the early 20th century, and the thermal responses in relation to ground characteristics and snow cover. The modelled ground temperatures show a gradually increase since the end of the Little Ice Age (mid 19th century on Svalbard), by about 1.5 °C to 2 °C at 20 m depth. The active layer thickness (ALT) is modelled to have increased slightly, with the rate of increase depending on water content of the near-surface layers. The used scenario runs predict a significant increase in ground temperatures and an increase of ALT depending on soil characteristics.

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A bias-corrected CMIP5 dataset for Africa using CDF-t method. A contribution to agricultural impact studies

10.5194/esd-2017-111 ◽

2017 ◽

Cited By ~ 1

Author(s):

Adjoua Moise Famien ◽

Serge Janicot ◽

Abe Delfin Ochou ◽

Mathieu Vrac ◽

Dimitri Defrance ◽

...

Keyword(s):

West Africa ◽

Air Temperature ◽

Climate Models ◽

Global Climate Models ◽

Cumulative Distribution ◽

Shortwave Radiation ◽

Climate Change Scenarios ◽

Data Set ◽

Near Surface ◽

The Impact

Abstract. The objective of this paper is to present a new data set of bias-corrected CMIP5 global climate models (GCMs) daily data over Africa. This dataset was obtained in using the Cumulative Distribution Function Transform (CDF-t) method, a method that has been applied on several regions and contexts but never on Africa. Here CDF-t is used over the period 1950–2099 combining historical runs and climate change scenarios on 6 variables, precipitation, mean near-surface air temperature, near-surface maximum air temperature, near-surface minimum air temperature, surface down-welling shortwave radiation, and wind speed, which are critical variables for agricultural purposes. Evaluation of the results is carried out over West Africa on a list of priority users-based metrics that was discussed and selected with stakeholders and on simulated yield using a crop model simulating maize growth. Bias-corrected GCMs data are compared with another available dataset of bias-corrected GCMs, and the impact of three different reference datasets on bias-corrections is also examined in details. CDF-t is very effective in removing the biases and in reducing the high inter-GCMs scattering. Differences with other bias-corrected GCMs data are mainly due to the differences between the reference datasets. This is particular true for surface down-welling shortwave radiation, which has impacts in terms of simulated maize yields. Projections of future yields over West Africa have quite different levels, depending on bias-correction method used, but they all show a similar relative decreasing trend over the 21st century.

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Investigating the Relation of Arctic Tropospheric Bro Derived by Satellite Remote Sensing to Sea Ice Age and Meteorological Driving Mechanisms Under the Impact of Arctic Amplification

10.5194/egusphere-egu2020-16914 ◽

2020 ◽

Author(s):

Ilias Bougoudis ◽

Anne-Marlene Blechschmidt ◽

Andreas Richter ◽

Sora Seo ◽

John Burrows

Keyword(s):

Wind Speed ◽

Sea Ice ◽

Air Temperature ◽

Ice Age ◽

Atmospheric Composition ◽

The Arctic ◽

Arctic Amplification ◽

German Research Foundation ◽

The Impact

Arctic Amplification, the rapid increase of air temperature in higher latitudes over the last decades, is expected to have drastic impacts on all the sub-systems of the Arctic ecosystem. Bromine Oxides play a key role in the atmospheric composition of the Arctic. During polar spring, bromine molecules are released from young sea ice covered regions.&#160; A rapid chemical chain reaction starts, the -so called 'bromine explosion', which depletes ozone, alters the production of OH, and thereby eventually changes the oxidizing capacity of the troposphere. Halogens oxidize elemental to gaseous mercury, which may then be deposited and harm the ecosystem. Based on current literature, there is considerable uncertainty on the impact of Arctic Amplification on halogen evolution. On one hand, the melting of multi-year sea ice should result in formation of more young sea ice, which favors bromine release. On the other hand, BrO explosion events are triggered by low temperatures, an effect expected to be reduced due to Arctic Amplification. Moreover, changes of other meteorological drivers, such as cyclone frequency and wind speed may impact on BrO amounts in the Arctic troposphere.In this study, a long-term time-series of tropospheric BrO derived from 4 UV-VIS instruments (GOME, SCIAMACHY, GOME-2A, GOME-2B) is used as a basis, in order to investigate the impact of Arctic Amplification on BrO amounts in the Arctic. The long-term BrO data is being compared to sea ice age (NSIDC) and meteorological (air temperature, mean sea level pressure, wind speed and boundary layer height from ERA-5 & ASR-2) data. Our results focus on determining the relation between tropospheric BrO and its drivers, and especially on how the drivers impact on the formation of BrO plumes. Different cases studies throughout the 22 years of the BrO dataset were performed and evaluated. The changes in the tropospheric BrO abundances come in general agreement with changes in the drivers of BrO explosion events.&#160;We gratefully acknowledge the funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) &#8211; Projektnummer 268020496 &#8211; TRR 172, within the Transregional Collaborative Research Center &#8220;ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)&#179;&#8221;.

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