Recent changes in climate and permafrost temperatures at forested and polar desert sites in northern Canada1This article is one of a series of papers published in this CJES Special Issue on the theme of Fundamental and applied research on permafrost in Canada.

Climate and ground temperature records up to 30 years in length from permafrost monitoring sites in a polar desert at Alert, Nunavut, and a boreal forest at Table Mountain, Northwest Territories, were analyzed by season and year to assess the ground thermal response to recent climate warming. Methods were developed to standardize incomplete ground temperature data sets and to hindcast air temperatures for comparative analysis. The timing and magnitude of climate warming varied, beginning in the 1960s in the Mackenzie Valley and the 1970s in the High Arctic. Ground temperature increases occurred in both regions but varied in magnitude and timing in relation to the external forcing and permafrost conditions. Significant increases in winter air temperatures in both regions appear to be largely responsible for recent increases in ground temperature, particularly at the polar desert sites where snow cover is minimal.

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Proxy-based 300-year High Arctic climate warming record from Svalbard

Polar Record ◽

10.1017/s0032247419000275 ◽

2019 ◽

Vol 55 (3) ◽

pp. 132-141 ◽

Cited By ~ 1

Author(s):

Tomi P. Luoto ◽

Antti E. K. Ojala ◽

Marek Zajaczkowski

Keyword(s):

Climate Warming ◽

Break Point ◽

Warming Trend ◽

High Arctic ◽

Ice Age ◽

Arctic Climate ◽

Air Temperatures ◽

Summer Temperatures ◽

Meteorological Observations ◽

Arctic Climate Change

AbstractWe used fossil Chironomidae assemblages and the transfer function approach to reconstruct summer air temperatures over the past 300 years from a High Arctic lake in Hornsund, Svalbard. Our aims were to compare reconstructed summer temperatures with observed (last 100 years) seasonal temperatures, to determine a potential climate warming break point in the temperature series and to assess the significance and rate of the climate warming trend at the study site. The reconstructed temperatures were consistent with a previous proxy record from Svalbard and showed good correlation with the meteorological observations from Bjørnøya and Longyearbyen. From the current palaeoclimate record, we found a significant climate warming threshold in the 1930s, after which the temperatures rapidly increased. We also found that the climate warming trend was strong and statistically significant. Compared with the reconstructed Little Ice Age temperatures in late eighteenth century cooling culmination, the present day summer temperatures are >4°C higher and the temperature increase since the 1930s has been 0.5°C per decade. These results highlight the exceptionally rapid recent warming of southern Svalbard and add invaluable information on the seasonality of High Arctic climate change and Arctic amplification.

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Climate and ground temperature relations at sites across the continuous and discontinuous permafrost zones, northern Canada1This article is one of a series of papers published in this CJES Special Issue on the theme of Fundamental and applied research on permafrost in Canada.2Earth Science Sector (ESS) Contribution 20110128.

Canadian Journal of Earth Sciences ◽

10.1139/e11-075 ◽

2012 ◽

Vol 49 (8) ◽

pp. 865-876 ◽

Cited By ~ 48

Author(s):

Jennifer Throop ◽

Antoni G. Lewkowicz ◽

Sharon L. Smith

Keyword(s):

Active Layer ◽

High Arctic ◽

High Elevation ◽

Climatic Conditions ◽

Yukon Territory ◽

Ground Temperature ◽

Air Temperatures ◽

Discontinuous Permafrost ◽

Heat Effects ◽

Ice Content

Climate – ground temperature relations are examined under a range of conditions for 10 sites across northern Canada. The sites are located between 60°N and 83°N and at elevations of 40 to 1840 m above sea level. They encompass various environmental and climatic conditions, with permafrost temperatures that range from just below 0 to –15 °C. The substrates range from bedrock to fine-grained sediment with high ice content, and vegetation types include coniferous forests in the Mackenzie Valley, shrub tundra at high elevation in the southern Yukon Territory, and polar desert in the High Arctic. Permafrost conditions at all of these sites are determined primarily by air temperature, followed by snow and substrate conditions. The apparent thermal diffusivity is relatively high at colder sites and in bedrock and is lower at sites in sediment with high ice content. Snow has a greater influence on air–ground temperature relations at sites where mean annual air temperatures and active-layer moisture contents are relatively high, leading to physically significant latent heat effects and a slower freeze-back of the active layer.

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Glaciers in the High Arctic and recent environmental change

Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences ◽

10.1098/rsta.1995.0073 ◽

1995 ◽

Vol 352 (1699) ◽

pp. 321-334 ◽

Cited By ~ 41

Keyword(s):

Mass Balance ◽

Climate Warming ◽

Meteorological Data ◽

Ice Cores ◽

High Arctic ◽

Ice Age ◽

Geological Evidence ◽

Recent Climate ◽

Severnaya Zemlya ◽

Energy Balance Approach

High Arctic climate change over the last few hundred years includes the relatively cool Little Ice Age (LIA), followed by warming over the last hundred years or so. Meteorological data from the Eurasian High Arctic (Svalbard, Franz Josef Land, Severnaya Zemlya) and Canadian High Arctic islands are scarce before the mid-20th century, but longer records from Svalbard and Greenland show warming from about 1910-1920. Logs of Royal Navy ships in the Canadian Northwest Passage in the 1850s indicate temperatures cooler by 1-2.5 °C during the LIA. Other evidence of recent trends in High Arctic temperatures and precipitation is derived from ice cores, which show cooler temperatures (by 2-3 °C) for several hundred years before 1900, with high interdecadal variability. The proportion of melt layers in ice cores has also risen over the last 70-130 years, indicating warming. There is widespread geological evidence of glacier retreat in the High Arctic since about the turn of the century linked to the end of the LIA. An exception is the rapid advance of some surge-type ice masses. Mass balance measurements on ice caps in Arctic Canada, Svalbard and Severnaya Zemlya since 1950 show either negative or near-zero net balances, suggesting glacier response to recent climate warming. Glacier-climate links are modelled using an energy balance approach to predict glacier response to possible future climate warming, and cooler LIA temperatures. For Spitsbergen glaciers, a negative shift in mass balance of about 0.5 m a -1 is predicted for a 1 °C warming. A cooling of about 0.6 °C, or a 23% precipitation increase, would produce an approximately zero net mass balance. A ‘greenhouse-induced’ warming of 1 °C in the High Arctic is predicted to produce a global sea-level rise of 0.063 mm a -1 from ice cap melting.

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Recent climate warming drives ecological change in a remote high-Arctic lake

Scientific Reports ◽

10.1038/s41598-018-25148-7 ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 5

Author(s):

Lineke Woelders ◽

Jan T. M. Lenaerts ◽

Kimberley Hagemans ◽

Keechy Akkerman ◽

Thomas B. van Hoof ◽

...

Keyword(s):

Climate Warming ◽

High Arctic ◽

Ecological Change ◽

Arctic Lake ◽

Recent Climate

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Holocene ice wedge formation in the Eureka Sound Lowlands, high Arctic Canada

Quaternary Research ◽

10.1017/qua.2020.126 ◽

2021 ◽

pp. 1-13

Author(s):

Kethra Campbell-Heaton ◽

Denis Lacelle ◽

David Fisher ◽

Wayne Pollard

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Numerical Simulations ◽

High Arctic ◽

Desert Environment ◽

Peat Accumulation ◽

Polar Desert ◽

Molar Ratios ◽

Air Temperatures ◽

Ice Wedge

Abstract Ice wedges are ubiquitous periglacial features in permafrost terrain. This study investigates the timing of ice wedge formation in the Fosheim Peninsula (Ellesmere and Axel Heiberg Islands). In this region, ice wedge polygons occupy ~50% of the landscape, the majority occurring below the marine limit in the Eureka Sound Lowlands. Numerical simulations suggest that ice wedges may crack to depths of 2.7–3.6 m following a rapid cooling of the ground over mean winter surface temperatures of −18°C to −38°C, corresponding to the depth of ice wedges in the region. The dissolved organic carbon (DOC)/Cl molar ratios suggest that the DOC in the ice wedges is sourced from snowmelt and not from leaching of the active layer. Based on 32 14CDOC measurements from 15 ice wedges, the wedges were likely developing between 9000–2500 cal yr BP. This interval also corresponds to the period of peat accumulation in the region, a proxy of increased moisture. Considering that winter air temperatures remained favorable for ice wedge growth throughout the Holocene, the timing of ice wedge formation reflects changes in snowfall. Overall, this study provides the first reconstruction of ice wedge formation from a high Arctic polar desert environment.

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Investigation of the maximum and minimum temperatures in the semi-arid region of northeastern Brazil

Revista Agro mbiente On-line ◽

10.18227/1982-8470ragro.v5i2.514 ◽

2011 ◽

Vol 5 (2) ◽

pp. 82

Author(s):

Eunice Maia Andrade ◽

Meilla Marielle Araújo Rodrigues ◽

Marcos Amauri Bezerra Mendonça ◽

Luiz Carlos Guerreiro Chaves ◽

Rebeca Mendes Feitoza

Keyword(s):

Minimum Temperature ◽

Northeastern Brazil ◽

Maximum Temperature ◽

Data Sets ◽

Air Temperatures ◽

Irregular Pattern ◽

Temperature Records ◽

Earth’S Climate ◽

Semi Arid Region ◽

Semi Arid

Temperature records all over the world provide evidence that the earth’s climate is changing. To investigate changes in the extreme temperatures of semi-arid regions, we analyzed 33 years (1975-2008) of monthly maximum and minimum air temperatures for three weather stations located in Quixeramobim, Crateús and Barbalha Cities, Ceará, Brazil. The data sets were provided by INMET (Instituto Nacional de Meteorologia), Brazil. Dataset of each station was shared in decades to better understand the temperature tendency as well as to identify the warmest one. The two most recent decades were the warmest at all three stations investigated, and the highest temperature values were observed for Barbalha station. The highest increases of maximum temperature occurred during the dry season (May/Dec), and the warmest month was October, during which temperature increases of up to 1.63 °C were observed in the 1980s. The minimum temperature increased substantially during the rainy season (Jan/Apr) and during the coldest months (Jun/Jul). The highest increase of minimum temperature (3.08°C) was observed in July at the Barbalha station. The Quixeramobim station showed no significant increases in minimum temperature. The results indicate that temperature increases occur in an irregular pattern, suggesting that various regional agents affect changes in temperature.

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Modeling the Impact of Atmospheric Warming on Staple Crop Growth in China in the 1960s and 2000s

Atmosphere ◽

10.3390/atmos12010036 ◽

2020 ◽

Vol 12 (1) ◽

pp. 36

Author(s):

Qing Zhang ◽

Wen Zhang ◽

Yongqiang Yu ◽

Tingting Li ◽

Lijun Yu

Keyword(s):

Winter Wheat ◽

Climate Warming ◽

Northeast China ◽

Cropping Systems ◽

Crop Growth ◽

East China ◽

Frequency Distributions ◽

Before And After ◽

The 1960S ◽

The Impact

Responses of crop growth to climate warming are fundamental to future food security. The response of crops to climate change may be subtly different at their growing stages. Close insights into the differentiated stage-dependent responses of crops are significantly important in making adaptive adjustments of crops’ phenological optimization and cultivar improvement in diverse cropping systems. Using the Agro-C model, we studied the influence of past climate warming on crops in typical cropping systems in China. The results showed that while the temperature had increased distinctly from the 1960s to 2000s, the temperature frequency distributions in the growth season of crops moved to the high-temperature direction. The low temperature days during the crop growth periods that suppress crop growth decreased in the winter wheat area in North and East China, rice and maize areas in Northeast China, and the optimum temperature days increased significantly. As a result, the above ground biomass (AGB) of rice and maize in Northeast China and winter wheat in North and East China increased distinctly, while that of rice in South China had no significant change. A comparison of the key growth periods before and after heading (silking) showed that the warming before heading (silking) made a great contribution to the increase in the AGB, especially for winter wheat.

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Field Test and Numerical Simulation on the Long-Term Thermal Response of PHC Energy Pile in Layered Foundation

Sensors ◽

10.3390/s21113873 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3873

Author(s):

Guozhu Zhang ◽

Ziming Cao ◽

Yiping Liu ◽

Jiawei Chen

Keyword(s):

Thermal Conductivity ◽

Heat Exchange ◽

Temperature Variation ◽

Thermal Response ◽

Ground Temperature ◽

Short Term ◽

Energy Pile ◽

Backfill Soil ◽

Short And Long Term

Investigation on the long-term thermal response of precast high-strength concrete (PHC) energy pile is relatively rare. This paper combines field experiments and numerical simulations to investigate the long-term thermal properties of a PHC energy pile in a layered foundation. The major findings obtained from the experimental and numerical studies are as follows: First, the thermophysical ground properties gradually produce an influence on the long-term temperature variation. For the soil layers with relatively higher thermal conductivity, the ground temperature near to the energy pile presents a slowly increasing trend, and the ground temperature response at a longer distance from the center of the PHC pile appears to be delayed. Second, the short- and long-term thermal performance of the PHC energy pile can be enhanced by increasing the thermal conductivity of backfill soil. When the thermal conductivities of backfill soil in the PHC pile increase from 1 to 4 W/(m K), the heat exchange amounts of energy pile can be enhanced by approximately 30%, 79%, 105%, and 122% at 1 day and 20%, 47%, 59%, and 66% at 90 days compared with the backfill water used in the site. However, the influence of specific heat capacity of the backfill soil in the PHC pile on the short-term or long-term thermal response can be ignored. Furthermore, the variation of the initial ground temperature is also an important factor to affect the short-and-long-term heat transfer capacity and ground temperature variation. Finally, the thermal conductivity of the ground has a significant effect on the long-term thermal response compared with the short-term condition, and the heat exchange rates rise by about 5% and 9% at 1 day and 21% and 37% at 90 days as the thermal conductivities of the ground increase by 0.5 and 1 W/(m K), respectively.

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