scholarly journals PERICLIMv1.0: a model deriving palaeo-air temperatures from thaw depth in past permafrost regions

2021 ◽  
Vol 14 (4) ◽  
pp. 1865-1884
Author(s):  
Tomáš Uxa ◽  
Marek Křížek ◽  
Filip Hrbáček
Keyword(s):  
Air Temperature ◽  
Cold Climate ◽  
Active Layer Thickness ◽  
Full Potential ◽  
Temperature Characteristics ◽  
Air Temperatures ◽  
Climate Controls ◽  
Thaw Depth ◽  
Temperature Records ◽  
Permafrost Regions

Abstract. Periglacial features, such as various kinds of patterned ground, cryoturbations, frost wedges, solifluction structures, and blockfields, are among the most common relics of cold climate periods, which repetitively occurred throughout the Quaternary. As such, they are widespread archives of past environmental conditions. Climate controls on the development of most periglacial features, however, remain poorly known, and thus empirical palaeo-climate reconstructions based on them have limited validity. This study presents and evaluates a simple new inverse modelling scheme called PERICLIMv1.0 (PERIglacial CLIMate) that derives palaeo-air temperature characteristics related to the palaeo-active-layer thickness, which can be recognized using many relict periglacial features found in past permafrost regions. The evaluation against modern temperature records showed that the model reproduces air temperature characteristics with average errors ≤1.3 ∘C. The past mean annual air temperature modelled experimentally for two sites in the Czech Republic hosting relict cryoturbation structures was between -7.0±1.9 and -3.2±1.5 ∘C, which is well in line with earlier reconstructions utilizing various palaeo-archives. These initial results are promising and suggest that the model could become a useful tool for reconstructing Quaternary palaeo-environments across vast areas of mid-latitudes and low latitudes where relict periglacial assemblages frequently occur, but their full potential remains to be exploited.

scholarly journals PERICLIMv1.0: A model deriving palaeo-air temperatures from thaw depth in past permafrost regions

2020 ◽  
Author(s):  
Tomáš Uxa ◽  
Marek Křížek ◽  
Filip Hrbáček
Keyword(s):  
Success Rate ◽  
Air Temperature ◽  
Full Potential ◽  
Temperature Characteristics ◽  
Air Temperatures ◽  
Thaw Depth ◽  
Temperature Records ◽  
Mean Annual Air Temperature ◽  
Past Conditions ◽  
Permafrost Regions

Abstract. Periglacial features are among the most common relics of colder climates, which repetitively occurred throughout the Quaternary, and, as such, they are widespread archives of past conditions. Climatic controls on most periglacial features, however, remain poorly established, and thus empirical palaeo-climatic reconstructions based on them are far from reliable. This study introduces and evaluates a new simple inverse modelling scheme PERICLIMv1.0 (PERIglacial CLIMate) that aims to overcome these flaws through deriving the palaeo-air temperature characteristics coupled with the thickness of the palaeo-active layer, which can be recognized in many relict permafrost-related features. The evaluation against modern temperature records showed that the model reproduces air temperature characteristics, such as mean annual air temperature, mean air temperature of the warmest and coldest month and of the thawing and freezing season, with a mean error of ≤ 0.5 °C. Besides, air thawing and freezing indices both depart on average by 6 %, whereas the length of the thawing and freezing season tends to be on average underestimated and overestimated by 10 % and 4 %, respectively. The high model success rate is promising and suggests that it could become a powerful tool for reconstructing Quaternary palaeo-environments across vast areas of mid-latitudes where relict periglacial assemblages frequently occur, but their full potential remains to be exploited.

scholarly journals Nonlinear thermal and moisture dynamics of high Arctic wetland polygons following permafrost disturbance

2015 ◽  
Vol 12 (14) ◽  
pp. 11797-11831 ◽  
Author(s):  
E. Godin ◽  
D. Fortier ◽  
E. Lévesque
Keyword(s):  
Active Layer ◽  
Arid Region ◽  
High Arctic ◽  
Permafrost Soil ◽  
Active Layer Thickness ◽  
Green House Gas ◽  
Heterogeneous Nature ◽  
Thaw Depth ◽  
Moisture Dynamics ◽  
Permafrost Regions

Abstract. Low-centre polygonal terrain developing within gentle sloping surfaces and lowlands in the high Arctic have a potential to retain snowmelt water in their bowl-shaped centre and as such are considered high latitude wetlands. Such wetlands in the continuous permafrost regions have an important ecological role in an otherwise generally arid region. In the valley of the glacier C-79 on Bylot Island (Nunavut, Canada), thermal erosion gullies are rapidly eroding the permafrost along ice wedges affecting the integrity of the polygons by breaching and collapsing the surrounding rims. While intact polygons were characterized by a relative homogeneity (topography, snow cover, maximum active layer thaw depth, ground moisture content, vegetation cover), eroded polygons had a non-linear response for the same elements following their perturbation. The heterogeneous nature of disturbed terrains impacts active layer thickness, ground ice aggradation in the upper portion of permafrost, soil moisture and vegetation dynamics, carbon storage and terrestrial green-house gas emissions.

scholarly journals New insights into the environmental drivers of the circumpolar ground thermal regime

2018 ◽  
Author(s):  
Olli Karjalainen ◽  
Miska Luoto ◽  
Juha Aalto ◽  
Jan Hjort
Keyword(s):  
Thermal Regime ◽  
Climatic Factors ◽  
Global Climate ◽  
Thermal Conditions ◽  
Cold Climate ◽  
The Arctic ◽  
Environmental Drivers ◽  
Active Layer Thickness ◽  
Thermal Dynamics ◽  
Air Temperatures

Abstract. The thermal dynamics of permafrost shape Earth surface systems and human activity in the Arctic and have implications to global climate. Improved understanding of the fine-scale variability in the circumpolar ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related circumpolar observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (~1 km2) geospatial data to identify their key environmental drivers. The multivariate models fitted well to MAGT and ALT observations with average R2 values being ~0.94 and 0.78, respectively. Corresponding predictive performances in terms of root mean square error were ~1.31 °C and 87 cm. Freezing air temperatures were the main driver of MAGT in permafrost conditions while thawing temperatures dominated when permafrost was not present. ALT was most strongly related to solar radiation and precipitation with an important influence from soil properties. Our findings suggest that in addition to climatic factors, initial ground thermal conditions and local-scale topography-soil-driven variability need to be considered in order to realistically assess the impacts of climate change on cold-climate geoecosystems.

scholarly journals Permafrost Thaw and Ground Settlement Considering Long-Term Climate Impact in Northern Alaska

2021 ◽  
Author(s):  
Joey Yang ◽  
Kannon C. Lee ◽  
Haibo Liu
Keyword(s):  
Active Layer ◽  
Air Temperature ◽  
Climate Model ◽  
Ground Surface ◽  
North Slope ◽  
Active Layer Thickness ◽  
Near Surface ◽  
Surface Conditions ◽  
Air Temperatures ◽  
Ice Content

Abstract Alaska’s North Slope is predicted to experience twice the warming expected globally. When summers are longer and winters are shortened, ground surface conditions in the Arctic are expected to change considerably. This is significant for Arctic Alaska, a region that supports surface infrastructure such as energy extraction and transport assets (pipelines), buildings, roadways, and bridges. Climatic change at the ground surface has been shown to infiltrate soil layers beneath through the harmonic fluctuation of the active layer. Past studies found that warmer air temperature resulted in increasingly deeper thaw, leading to a deeper active layer. This study attempts to assess climate change based on the climate model data from the fifth phase of the Coupled Model Intercomparison Project and its impact on a study site on the North Slope. The predicted air temperature data are analyzed to evaluate how the freezing and thawing indices will change due to climate warming. A thermal model was developed that incorporated a ground surface condition defined by either undisturbed intact tundra or a gravel fill surface and applied climate model predicted air temperatures. Results indicate similar fluctuation in active layer thickness and values that fall within the range of minimum and maximum readings. It is found that the active layer thickens when the ground surface is either gravel fill or undisturbed tundra, but its thickness varies based on climate model predictions. These variations in active layer thickness are then analyzed by considering the near-surface frozen soil ice content. Analysis of results indicates that strain is most significant in the near-surface layers during thaw, indicating that settlement would be concurrent with annual thaw penetration. From this study, the climate model predicted air temperatures for a warming Arctic suggest that the thaw of near-surface frozen ground is largely dependent on ground surface conditions and the thermal properties of soil. Moreover, ice content is a major factor in the settlement predictions on Alaska’s North Slope. This study's results can help enhance the resilience of the existing and future new infrastructure in a changing Arctic environment.

scholarly journals Nonlinear thermal and moisture response of ice-wedge polygons to permafrost disturbance increases heterogeneity of high Arctic wetland

2016 ◽  
Vol 13 (5) ◽  
pp. 1439-1452 ◽  
Author(s):  
Etienne Godin ◽  
Daniel Fortier ◽  
Esther Lévesque
Keyword(s):  
Active Layer ◽  
Vegetation Dynamics ◽  
Arid Region ◽  
High Arctic ◽  
Permafrost Soil ◽  
Active Layer Thickness ◽  
Heterogeneous Nature ◽  
Thaw Depth ◽  
Ice Wedge ◽  
Permafrost Regions

Abstract. Low-center polygonal terrains with gentle sloping surfaces and lowlands in the high Arctic have a potential to retain water in the lower central portion of ice-wedge polygons and are considered high-latitude wetlands. Such wetlands in the continuous permafrost regions have an important ecological role in an otherwise generally arid region. In the valley of the glacier C-79 on Bylot Island (Nunavut, Canada), thermal erosion gullies were rapidly eroding the permafrost along ice wedges affecting the integrity of the polygons by breaching and collapsing the surrounding rims. Intact polygons were characterized by a relative homogeneity in terms of topography, snow cover, maximum active layer thaw depth, ground moisture content and vegetation cover (where eroded polygons responded nonlinearly to perturbations, which resulted in differing conditions in the latter elements). The heterogeneous nature of disturbed terrains impacted active layer thickness, ground ice aggradation in the upper portion of permafrost, soil moisture, vegetation dynamics and carbon storage.

Climate Variability and Ecological Response of the Marine Ecosystem in the Western Antarctic Peninsula (WAP) Region

2003 ◽  
Author(s):  
Raymond C. Smith ◽  
William R. Fraser
Keyword(s):  
Sea Ice ◽  
Air Temperature ◽  
Antarctic Peninsula ◽  
Marine Ecosystem ◽  
Western Antarctic Peninsula ◽  
Sea Ice Extent ◽  
Half Century ◽  
Air Temperatures ◽  
Temperature Records ◽  
The Antarctic

The Antarctic Peninsula, a relatively long, narrow extension of the Antarctic continent, defines a strong climatic gradient between the cold, dry continental regime to its south and the warm, moist maritime regime to its north. The potential for these contrasting climate regimes to shift in dominance from season to season and year to year creates a highly variable environment that is sensitive to climate perturbation. Consequently, long-term studies in the western Antarctic Peninsula (WAP) region, which is the location of the Palmer LTER (figure 9.1), provide the opportunity to observe how climate-driven variability in the physical environment is related to changes in the marine ecosystem (Ross et al. 1996; Smith et al. 1996; Smith et al. 1999). This is a sea ice–dominated ecosystem where the annual advance and retreat of the sea ice is a major physical determinant of spatial and temporal change in its structure and function, from total annual primary production to the breeding success and survival of seabirds. Mounting evidence suggests that the earth is experiencing a period of rapid climate change, and air temperature records from the last half century confirm a statistically significant warming trend within the WAP during the past half century (King 1994; King and Harangozo 1998; Marshall and King 1998; Ross et al. 1996; Sansom 1989; Smith et al. 1996; Stark 1994; van den Broeke 1998; Weatherly et al. 1991). Air temperature–sea ice linkages appear to be very strong in the WAP region (Jacka 1990; Jacka and Budd 1991; King 1994; Smith et al. 1996; Weatherly et al. 1991), and a statistically significant anticorrelation between air temperatures and sea ice extent has been observed for this region. Consistent with this strong coupling, sea ice extent in the WAP area has trended down during this period of satellite observations, and the sea ice season has shortened. In addition, both air temperature and sea ice have been shown to be significantly correlated with the Southern Oscillation Index (SOI), which suggests possible linkages among sea ice, cyclonic activity, and global teleconnections.

Interactions between climate, vegetation and the active layer in soils at two Maritime Antarctic sites

2006 ◽  
Vol 18 (3) ◽  
pp. 323-333 ◽  
Author(s):  
N. Cannone ◽  
J.C. Ellis Evans ◽  
R. Strachan ◽  
M. Guglielmin
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
Air Temperature ◽  
Vegetation Type ◽  
Ground Surface ◽  
Active Layer Thickness ◽  
Maritime Antarctic ◽  
Orkney Islands ◽  
Signy Island ◽  
Air Temperatures

In the summer 2000–01, thermal monitoring of the permafrost active layer within various terrestrial sites covered by lichen, moss or grasses was undertaken at Jubany (King George Island) and Signy Island in the Maritime Antarctic. The results demonstrated the buffering effect of vegetation on ground surface temperature (GST) and the relationship between vegetation and active layer thickness. Vegetation type and coverage influenced the GST in both locations with highest variations and values in the Deschampsia and Usnea sites and the lowest variations and values in the Jubany moss site. Active layer thickness ranged from 57 cm (Jubany moss site) to 227 cm (Signy Deschampsia site). Active layer thickness data from Signy were compared with data collected at the same location four decades earlier. Using a regression equation for air temperature versus ground surface temperatures the patterns of changing air temperature over time suggest that the active layer thickness increased c. 30 cm between 1963 and 1990 and then decreased 30 cm between 1990 and 2000. The documented increased rate of warming (2°C ± 1) since 1950 for air temperatures recorded in the South Orkney Islands suggests that the overall trend of active layer thickness increase will be around 1 cm year−1.

High-Northern-latitudes permafrost extend in MPI-ESM simulations of SSP126 and SSP585 

2021 ◽  
Author(s):  
Goran Georgievski ◽  
Philipp De Vrese ◽  
Stefan Hagemann ◽  
Victor Brovkin
Keyword(s):  
Active Layer ◽  
Extreme Events ◽  
Soil Freezing ◽  
Active Layer Thickness ◽  
Surface Boundary ◽  
Permafrost Degradation ◽  
Near Surface ◽  
Air Temperatures ◽  
Northern Latitudes ◽  
Thaw Depth

<p>The representation of permafrost related processes in Earth System Models (ESM) remains a challenge. A recent collaboration between two related projects (Kohlenstoff im Permafrost (Carbon in Permafrost) – KoPf, and Study Of the Development of Extreme Events over Permafrost areas – SODEEP) yielded a new vertical structure of the soil column in JSBACH, the land component of the Max Planck Institute (MPI) for Meteorology ESM (MPI-ESM). This feature resulted in a better representation of the vertical soil moisture dynamics and the energy transfer due to soil freezing and thawing, which is particularly relevant for the high northern latitudes.</p><p>Although, air temperatures are simulated reasonably well with the MPI-ESM, care must be taken not to introduce a bias when implementing new processes in the model or changing existing parametrizations. Here we investigate the permafrost extent in two Shared Socioeconomic Pathways (SSP) simulations (SSP126 and SSP585) with the MPI-ESM using prescribed ocean surface boundary conditions. Our results show a consistency between terrestrial and atmospheric dynamics, when comparing the permafrost extent determined on basis of simulated active layer thickness (soil variable) and Day Degree Thaw Index (DDTI; atmospheric variable). The latter is calculated as the annual sum of positive average daily 2m air temperatures and its square root can be used as an indicator of annual maximum thaw depth.</p><p>The SSP126 simulation shows that both DDTI and thaw depth stabilize within the range of the present-day interannual variability, while SSP585 indicates a substantial deepening of the active layer – resulting in a complete disappearance of near-surface permafrost in large parts of the high northern latitudes - and DDTI in SSP585 simulation increases in excess of 2000°C. These values at present characterize northern mid-latitudes i.e. landscapes not underlined by permafrost. A preliminary analysis indicates that the decline of the permafrost extent in SSP585 occurs mostly during the second half of 21st century. Furthermore, the SSP585 simulation also shows an increase in the number of extreme events relevant for permafrost degradation. The investigated extreme climate patterns (as defined in the frame of the SODEEP project) include abrupt warming (defined as occurrence of annual mean temperature above 5-year running mean) and increase in seasonal precipitation anomalies, as well as changes in specific snow characteristics.</p>

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

2012 ◽  
Vol 6 (1) ◽  
pp. 341-385 ◽  
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.

scholarly journals Air temperatures in Central Amazonia. III. - Vertical Temperature Distribution on a Clearcut Area and in a Secondary Forest near Manaus (Cold Front Conditions July 10 th. 1969)()

1972 ◽  
Vol 2 (3) ◽  
pp. 25-29 ◽  
Author(s):  
W. L. F. Brinkmann ◽  
M. N. Góes Ribeiro
Keyword(s):  
Air Temperature ◽  
Cold Front ◽  
Secondary Forest ◽  
Cold Air ◽  
Air Temperatures ◽  
Canopy Area ◽  
Yearly Average ◽  
Central Amazonia ◽  
Temperature Records ◽  
Vertical Temperature Distribution

Abstract Air temperatures under cold front conditions were recorded on July 10th 1969 inside and outside a secondary forest at Ducke Forest Reserve Air temperatures were measured at 2 towers and 8 corresponding levels ranging from 10 cm to 900 cm height. The absolute daily minimum air temperature recorded was 11.0°C, which is exceptionally low for Central Amazonia and 16.0°C below the yearly average air temperature at Manaus measured over a 45-year period of temperature records. The maximum 30-min range of air temperature was observed in the clearing (8.1°C), 7 meters above the ground. The strongest impact of air temperatures in the forest stand was recorded in the canopy area and in the ground stratum due to the formation of cold air cells and cold air sinks. The temperature profiles inside and outside the secondary forest at Ducke Forest Preserve during cold front conditions did not conform with the established temperature patterns in a tropical environment.

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