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 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.

The periglacial environment of Great Britain during the Devensian

1977 ◽  
Vol 280 (972) ◽  
pp. 183-198 ◽  
Keyword(s):  
Great Britain ◽  
Air Temperature ◽  
Main Question ◽  
East Anglia ◽  
Scottish Highlands ◽  
Air Temperatures ◽  
Discontinuous Permafrost ◽  
Continuous Permafrost ◽  
Ice Wedge ◽  
Mean Annual Air Temperature

The main question considered is the extent to which extra-glacial Britain had a permafrost environment in the Devensian, so the three features used in identifying contemporary permafrost are discussed. These are ice wedge polygons, pingos and thaw lakes. As their environments have been studied estimates of temperatures may be made when they are found in a Devensian context. A theoretical case can be made for regarding some involutions as representing the former active layer of permafrost but they have not been related to a contemporary environment. They cannot therefore give a measurement of Devensian conditions. Fossil ice wedges are very widespread in Great Britain, being found from the English Channel to the Scottish Highlands, and associated with late Early, Middle and Late Devensian deposits. Today ice wedges grow in continuous permafrost where the mean annual air temperature is — 6 to — 8 °C or lower. Remains of pingos of the open system type which today develop in discontinuous permafrost with a mean annual air temperature of — 3 to — 6 °C, are found in Wales and East Anglia. These continued to form until the end of the Younger Dryas, and indicate that discontinuous permafrost in England and Wales thawed completely only with the beginning of the Flandrian. The pingos must have begun to form after the transition from continuous to discontinuous permafrost, which probably took place with the rise in temperatures ahead of the Allerød. The area of continuous permafrost and ice wedge formation in Alaska is almost limited to the tundra. Apart from the coastal zone, discontinuous permafrost carries boreal forest with mean July air temperatures of around 15 °C, so that periods of tree growth in the Devensian do not necessarily imply the temporary disappearance of permafrost. Continuous permafrost in southern England implies a minimum fall in mean annual air temperatures of 16-17 °C, and a fall in the July mean of 4-5 °C. During the maximum ice advance the fall in mean annual air temperatures is estimated to be as much as 25 °C, with a fall in the July mean of 10 °C.

scholarly journals Frost-Heaved Bedrock Features: A Valuable Permafrost Indicator

2007 ◽  
Vol 37 (3) ◽  
pp. 241-251 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Northern Hemisphere ◽  
Air Temperature ◽  
Free Water ◽  
Vertical Displacement ◽  
Climatic Data ◽  
Late 19Th Century ◽  
Exposed Rock ◽  
The Mean ◽  
Mean Annual Air Temperature ◽  
Permafrost Regions

ABSTRACT Frost-heaved bedrock features are periglacial forms produced by the vertical displacement of bedrock fragments. Blocks, frost-wedged from bare bedrock along joints, are raised above the general surface by heave. Although mentioned in the literature of the late 19th century, they have been described and studied in detail only recently. They are widespread in the northern hemisphere, notably in Canada, Greenland and Spitsbergen, where they develop in lithologies with well-developed systems of joints. Commonly, heaved blocks exhibit weathered and lichen-covered surfaces except at their base where freshly exposed rock indicates recent heaving. They result from frost processes, particularly from wedging and heaving due to pressure of the freezing of free-water in joints. Active and most non-active features are located in permafrost regions. The southermost occurrence in the northern hemisphere is the Groulx Mountains, in Québec (51°45'N, alt. 1000 m). The mean annual air temperature for the area of best-developed features ranges from -4° to -100C, with the number of days of frost ranging from 178 to 300. A thin snow cover is common to most sites. Based on climatic data and on the geographical distribution of frost-heaved bedrock features, it is suggested that permafrost occurrence is obvious. Relict features found outside the present-day permafrost zones should indicate former permafrost conditions.

The thermal regime of a permafrost body at Mont du Lac des Cygnes, Quebec

1990 ◽  
Vol 27 (5) ◽  
pp. 694-697 ◽  
Author(s):  
Michel Allard ◽  
Richard Fortier
Keyword(s):  
Air Temperature ◽  
Freezing Point ◽  
Quebec City ◽  
Eastern Canada ◽  
Alpine Forest ◽  
The Mean ◽  
Temperature Records ◽  
One Year ◽  
Mean Annual Air Temperature ◽  
Continuous Temperature

A low peat plateau in the alpine forest–tundra at Mont du Lac des Cygnes, 100 km northeast of Québec City, contains a permafrost body 2 m thick. At an elevation of 960 m, this is the southernmost known occurrence of alpine permafrost in eastern Canada. The terrain over the permafrost is windblown and bears a very thin and discontinuous snow cover. One year of continuous temperature records indicates that the mean annual air temperature at this site is about −1.3 °C. The permafrost remains at temperatures very near the freezing point for most of the year.

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.

scholarly journals Temperature conditions at the mountain study site of Bílý Kříž (the Beskids Mts.) during the past 20 years

Beskydy ◽  
2017 ◽  
Vol 10 (1-2) ◽  
pp. 113-122
Author(s):  
Irena Marková ◽  
Dalibor Janouš ◽  
Ondřej Nezval
Keyword(s):  
Air Temperature ◽  
Global Climate Change ◽  
Global Climate ◽  
Growth Season ◽  
Temperature Changes ◽  
Temperature Characteristics ◽  
The Past ◽  
Temperature Conditions ◽  
Mean Annual Air Temperature

Global climate change (including temperature changes) had already observable effects on the environment and humanity. Air temperature characteristics have been observed at the mountain study site of Bílý Kříž (the Beskids Mts., Czech Republic) since 1989. This paper presents an analysis of long-term (1997–2016) air temperature conditions at this study. Comparison is made of selected long-term mean air temperature characteristics with mean air temperature characteristics for the period 1997–2016. The results show slightly increasing air temperature, as indicated not only by values for mean annual air temperature but also by changes in number of extreme days (summer, tropical, ice, etc.) and occurrence of hot period. Moreover, the length of the growth season has increase slightly.

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.

Permafrost

2021 ◽  
Keyword(s):  
Active Layer ◽  
Air Temperature ◽  
Ground Surface ◽  
Rooting Depth ◽  
Permafrost Degradation ◽  
Frozen Ground ◽  
Air Temperatures ◽  
Discontinuous Permafrost ◽  
Deep Infiltration ◽  
Mean Annual Air Temperature

Permafrost is permanently frozen ground that remains continuously below 0 °C for two or more years. The upper level of permafrost, the permafrost table, can occur within a centimeter of the ground surface or at a depth of several meters. The active layer, which thaws each summer, overlies permafrost. Permafrost underlies about a quarter of the northern hemisphere and can form in sediment or bedrock and on land or under the ocean. Permafrost forms incrementally and, in the regions where it is up to 1 km thick, permafrost can represent thousands of years of formation. Permafrost is present at high latitudes and high altitudes. In these regions, permafrost can be described as continuous, discontinuous, sporadic, or isolated. Continuous permafrost forms at mean annual air temperatures below -5 °C and is laterally continuous, regardless of surface aspect or material. Discontinuous permafrost forms where the mean annual air temperature is between -2 and -4 °C, allowing permafrost to persist in 50 to 90 percent of the landscape. Permafrost is sporadic where 10 to <50 percent of the landscape is underlain by permafrost and mean annual air temperature is between 0 and -2 °C. Permafrost is considered isolated where less than 10 percent of the landscape is underlain by permafrost. When it is present, permafrost creates unique conditions. Permafrost forms an impermeable layer beneath the active layer, for example, which limits the rooting depth of plants and prevents infiltration by water during the summer. The lack of deep infiltration can facilitate formation of extensive wetlands in high-latitude areas that receive relatively little precipitation. Permafrost degradation (thaw) creates diverse environmental hazards, including instability of the ground surface that affects infrastructure and fluxes of water, sediment, and organic matter entering rivers, lakes and oceans. Permafrost degradation releases frozen microbes, some of which are pathogens, and organic carbon. Permafrost degradation also influences the geographic range of plants and animals and thus ecosystem processes and biotic communities. The greatest concern with permafrost degradation at present, however, is the potential for releasing significant carbon into the atmosphere. Globally, soils are the largest terrestrial reservoir of carbon and permafrost soils are the single largest component of the carbon reservoir. Carbon released by degrading permafrost can enter the atmosphere as the greenhouse gases carbon dioxide and methane, or the carbon can be taken up by plants or transported by rivers to the ocean and buried in marine sediments. The balance among these different pathways is largely unknown, but carbon release to the atmosphere presents a serious threat as a mechanism to enhance global warming.

scholarly journals Long-term air temperature changes in Ljubljana (Slovenia) in comparison to Trieste (Italy) and Zagreb (Croatia)

2015 ◽  
Vol 23 (3) ◽  
pp. 17-26 ◽  
Author(s):  
Darko Ogrin
Keyword(s):  
Air Temperature ◽  
Urban Climate ◽  
Warming Trend ◽  
Climatic Conditions ◽  
City Growth ◽  
Temperature Changes ◽  
Air Temperatures ◽  
Urban Heat ◽  
The Impact ◽  
Mean Annual Air Temperature

Abstract The cities of Ljubljana, Trieste and Zagreb are proximate in terms of distance but differ in terms of geographical and climatic conditions. Continuous meteorological measurements in these cities began in the mid-19th century. The 100-year trends of changes in mean annual and seasonal air temperatures for these cities are presented here, evaluating the differences between them which result from their different geographical and climatic positions. Differences in trends between Ljubljana and Zagreb that result from different measurement histories and the impact of urban climate are also presented: the impact of city growth on air temperatures in Ljubljana after 1950 was not completely eliminated in the process of data homogenization. The lowest air warming trends occur in the maritime climate of Trieste (mean annual air temperature: + 0.8 °C × 100 yr−1), where measurements were continuously performed in the densely built-up section of the city. The strongest trends occur in Ljubljana, mainly due to city growth (mean annual air temperature: + 1.1 °C × 100 yr−1). Comparing the linear trends in Zagreb-Grič and in Ljubljana, the impact of Ljubljana's urban heat island on the 100-year warming trend was assessed at about 0.2 °C, at 0.3–0.4 °C for the trend after 1950, and if non-homogenized data are used, at about 0.5 °C.

On the dynamics of distribution of the American White Butterfly, Hyphantria cunea Drury, 1973 (Lepidoptera, Arctiidae), in Ukraine regarding the annual minimal air temperatures

2018 ◽  
Vol 14 (1) ◽  
pp. 44-57
Author(s):  
S. N. Shumov
Keyword(s):  
Air Temperature ◽  
Annual Reports ◽  
Complete Elimination ◽  
Hyphantria Cunea ◽  
White American ◽  
Gis Technologies ◽  
Data Analyses ◽  
Air Temperatures ◽  
Negative Temperatures

The spatial analysis of distribution and quantity of Hyphantria cunea Drury, 1973 across Ukraine since 1952 till 2016 regarding the values of annual absolute temperatures of ground air is performed using the Gis-technologies. The long-term pest dissemination data (Annual reports…, 1951–1985; Surveys of the distribution of quarantine pests ..., 1986–2017) and meteorological information (Meteorological Yearbooks of air temperature the surface layer of the atmosphere in Ukraine for the period 1951-2016; Branch State of the Hydrometeorological Service at the Central Geophysical Observatory of the Ministry for Emergencies) were used in the present research. The values of boundary negative temperatures of winter diapause of Hyphantria cunea, that unable the development of species’ subsequent generation, are received. Data analyses suggests almost complete elimination of winter diapausing individuals of White American Butterfly (especially pupae) under the air temperature of −32°С. Because of arising questions on the time of action of absolute minimal air temperatures, it is necessary to ascertain the boundary negative temperatures of winter diapause for White American Butterfly. It is also necessary to perform the more detailed research of a corresponding biological material with application to the freezing technics, giving temperature up to −50°С, with the subsequent analysis of the received results by the punched-analysis.

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