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.

scholarly journals Soil temperature study in Puerto Rico

1969 ◽  
Vol 93 (3-4) ◽  
pp. 149-171
Author(s):  
Jorge L. Lugo-Camacho ◽  
Miguel A. Muñoz ◽  
Juan Pérez-Bolívar ◽  
Gregory R. Brannon
Keyword(s):  
Puerto Rico ◽  
Soil Moisture ◽  
Soil Temperature ◽  
Sea Level ◽  
Air Temperature ◽  
Temperature Regime ◽  
Soil Series ◽  
Soil Temperature Regime ◽  
The Mean ◽  
Mean Annual Air Temperature

Soil temperature measurements from a climate monitoring network in Puerto Rico were evaluated and the difference between mean summer and mean winter soil temperature, known as isotivity value, was calculated. Air and soil temperature was collected from five weather stations of the USDA-Natural Resources Conservation Service from sea level to 1,019 m above sea level and from different soil moisture regimes. Isotivity values ranged from 1.2 to 3.9° C with an average of 2.6° C. The 750-m elevation was identified as the limit between the isohyperthermic and isothermic soil temperature regimes in the perudic soil moisture regime in Puerto Rico. The greatest differences between mean annual soil temperature and mean annual air temperature were observed at Guánica, Combate and Guilarte (2.1 ° C) stations. The smallest differences were observed at Maricao (0.8° C) and Isabela (1.8° C) stations. The study also indicated that the mean annual soil temperature in Puerto Rico can be estimated by adding 1.8° C to the mean annual air temperature or by the equation y = -0.007x + 28.0° C. The equation indicates that 97 percent of the time the behavior of the mean annual soil temperature is a function of elevation. According to the updated soil temperature regime boundaries, eight soil series were established in the Soil Survey of San Germán Area. In an area under the isothermic soil temperature regime, four soil series were classified as Oxisols (Haploperox), two soil series as Inceptisols (Eutrudepts) and two soil series as Mollisols (Argiudolls). This is the first field recognition of the Haploperox soil great group in the United States and its territories.

Spatial Prediction of Soil Temperature in China

2014 ◽  
Vol 955-959 ◽  
pp. 3718-3723
Author(s):  
Hui Zhi Zhang ◽  
Xue Zheng Shi
Keyword(s):  
Soil Temperature ◽  
Spatial Patterns ◽  
Air Temperature ◽  
Ordinary Kriging ◽  
Spatial Prediction ◽  
Regression Kriging ◽  
Auxiliary Variables ◽  
Geostatistical Methods ◽  
The Mean ◽  
Mean Annual Air Temperature

Temperature affects many soil biochemical and geochemical processes. The growth of plants, seed germination, circulations of carbon and nitrogen are all significantly influenced by soil temperature, thus it is important to estimate the spatial pattern of soil temperature. This paper shows the results of spatial patterns of mean annual soil temperature interpolated from the measurements of 698 meteorological stations in China. Four geostatistical methods, ordinary kriging (OK), regression kriging with mean annual air temperature (RK-1), regression kriging with latitude, longitude and elevation (RK-2) and regression kriging with multi-auxiliary predictors (RK-3), were compared. Ordinary kriging (OK) directly interpolated the mean annual soil temperature data extracted from meteorological stations to obtain the spatial patterns of the mean annual soil temperature. For the three regression kriging methods, intensive auxiliary variables (mean annual air temperature, elevation, latitude and longitude), which were correlated with mean annual soil temperature, were used to increase the accuracy of estimation. The results suggested that RK-3 preformed best, followed by RK-1 and RK-2. The intensive data of auxiliary variables used in the regression kriging significantly improved the accuracy of interpolation results.

scholarly journals Spatial and Temporal Distribution of Air Temperature in the Northern Hemisphere

2013 ◽  
Vol 6 (3) ◽  
pp. 177-182
Keyword(s):  
Time Series ◽  
20Th Century ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Temporal Distribution ◽  
Surface Air Temperature ◽  
Temperature Time Series ◽  
Mean Values ◽  
The Mean ◽  
Temperature Time

In the present study, the spatial and temporal surface air temperature variability for the Northern Hemisphere has been examined, for the period 1900-1996. Factor Analysis has been applied to 5o Latitude x 10o Longitude grid box data covering the area from almost the equator to 70o N. These data are anomalies of the mean annual air temperature from the respective mean values of the period 1961- 1990. The analysis showed that, mainly 20 regions were determined in the Northern Hemisphere with significantly covariant air temperature time series. The comparison of the trends of the mean annual surface air temperature time series of these regions, revealed such common characteristics as the minimum of the first decade of the 20th century and the recent years warming. The results of this study are also compared to the respective results of a former study in which data for the last half of the century (1948-1996) have been analyzed. The findings extracted indicate the stability of climate distribution in Northern Hemisphere during the 20th century.

scholarly journals Processes influencing near-surface heat transfer in Greenland's ablation zone

2018 ◽  
Author(s):  
Benjamin H. Hills ◽  
Joel T. Harper ◽  
Toby W. Meierbachtol ◽  
Jesse V. Johnson ◽  
Neil F. Humphrey ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Air Temperature ◽  
Moving Boundary ◽  
Radiative Energy ◽  
Ablation Zone ◽  
Transient Heating ◽  
Near Surface ◽  
The Mean ◽  
Surface Ice ◽  
Mean Annual Air Temperature

Abstract. To assess the influence of various mechanisms of heat transfer on the near-surface ice of Greenland's ablation zone, we incorporate highly resolved measurements of ice temperature into thermal modeling experiments. Seven separate temperature strings were installed at three different field sites, each with between 17 and 32 sensors and extending up to 20 m below the surface. In one string, temperatures were measured every 30 minutes, and the record is continuous for more than three years. We use these measured ice temperatures to constrain modeling analyses focused on four isolated processes to assess the relative importance of each to the near-surface ice temperature: 1) the moving boundary of an ablating surface, 2) thermal insulation by snow, 3) radiative energy input, and 4) temperature gradients below the seasonally active near-surface layer. In addition to these four processes, transient heating events were observed in two of the temperature strings. Despite no observations of meltwater pathways to the subsurface, these heating events are likely the refreezing of liquid water below 5–10 m of cold ice. Together with subsurface refreezing, the five heat transfer mechanisms presented here account for measured differences of up to 3 °C between the ice temperature at the depth where annual temperature variability is dissipated and the mean annual air temperature. Thus, in Greenland's ablation zone, the mean annual air temperature cannot be used to predict the near-surface ice temperature, as is commonly assumed.

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 15m Deep Temperatures in the Glaciers of Mont Blanc (French Alps)

1976 ◽  
Vol 16 (74) ◽  
pp. 197-203 ◽  
Author(s):  
L. Lliboutry ◽  
M. Briat ◽  
M. Creseveur ◽  
M. Pourchet
Keyword(s):  
Lower Limit ◽  
Air Temperature ◽  
French Alps ◽  
Ablation Area ◽  
The Alps ◽  
The Mean ◽  
Deep Temperature ◽  
Mean Annual Air Temperature ◽  
Rock Faces ◽  
Dry Snow Zone

AbstractThe top of Mont Blanc is adry snow zone. Thecold infiltration zoneextends between about 4 300 and 3 800 m. Its lower limit is lined by large cracks and ice cliffs, similar to bergschrunds. Near rock faces this limit is the bergschrund, which can descend as far as the 0°C isotherm of the mean annual air temperature, 3 100-3 200 m- At Col du Dôme (c, 4 250 m), 15 m deep temperature has increased 1.8 deg between the years 1911 and 1973, probably due to infiltration which happened there in the last few years. The ice in the ablation area is entirely temperate, while in dryer areas of the Alps it may be at 1°C to — 3°C in the vicinity of the firn line.

Flight activity of alate Adelgids (Homoptera, Aphidoidea) in southern England

1973 ◽  
Vol 62 (3) ◽  
pp. 507-516 ◽  
Author(s):  
C. I. Carter ◽  
G. Barson
Keyword(s):  
Host Plant ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Early Summer ◽  
Threshold Temperature ◽  
Flight Period ◽  
Pest Species ◽  
Summer Period ◽  
The Mean ◽  
Trap Catches

The flight periods of eight species of Adelgids were deduced from suction trap catches in a mixed woodland site at Alice Holt, Hampshire from 1965 to 1970. Nine species from other natural forest areas in the northern hemisphere occurred on trees in the study area, but some immigration may have contributed to the numbers trapped. Large catches (often >200 individuals per day) of three pest species, Adelges laricis Vall., A. cooleyi (Gill.) and Pineus pini (L.), occurred during late May and June. Only small catches (<10 individuals per day) were obtained during July–September. The sexuparae from the non-Picea hosts occurred mainly in May and June whereas the gallicolae from Picea hosts flew during certain periods from June to September. Analysis showed that the threshold temperature for flight was 16°C and that 64% or more of the total monthly catch occurred in the afternoon (13·00–19·00 h). The variation in length of the early summer flight period by ± one week was related to air temperature maxima, but the fluctuation ( ± one week) in the mean date for flight of each species in the early summer period is probably connected with the phenological condition of the host-plant.

scholarly journals Air temperature variability and trends over Greece

2013 ◽  
Vol 10 (2) ◽  
pp. 273-285
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Northern Region ◽  
Climatic Data ◽  
The South ◽  
Annual Time Series ◽  
Cooling Trend ◽  
The Mean ◽  
Temperature Levels ◽  
Summer Time

In this study, the variability and trends of the mean annual and seasonal surface air temperature in Greek peninsula are examined. The climatic data used, concern mean monthly values of air temperature of 20 meteorological stations of the Hellenic Meteorological Service, for the period 1951-2000. The air temperature time series for each station are analyzed, so that the variability and trends be described. Regarding the annual time series, a cooling trend is observed since the early 1960’s till the middle of the decade of 1970, when the trend reverses to heating till nowadays. It is remarkable that the today air temperature levels do not exceed the levels of the middle of the century. During the winter, it is crystal clear that a cooling trend exists from the middle of the decade of 1950 to the end of the decade of 1980, especially in the south region of the country. Afterwards an increasing trend is obvious till nowadays. The pattern in spring appears a slight heating trend in the northern region of Greece and a cooling trend in the south. The summer time series are similar to the annual ones, so the contribution of summer to annual variability is unquestionable. Generally speaking, the air temperature in autumn follows the same distribution in time. In the process, the Factor Analysis is applied on the mean annual and seasonal air temperature and thereafter the regions, within the air temperature covariates, are defined. Finally, the application of spectral analysis to annual and seasonal air temperature is regarded necessary so that the periodicities are derived.

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