scholarly journals On the Temperature Distribution of Glaciers in China

1990 ◽  
Vol 36 (123) ◽  
pp. 210-216 ◽  
Author(s):  
Huang Maohuan
Keyword(s):  
Surface Layer ◽  
Temperature Distribution ◽  
Air Temperature ◽  
Minimum Temperature ◽  
Low Temperatures ◽  
Characteristic Temperature ◽  
Near Surface ◽  
Ablation Area ◽  
Polar Type ◽  
Mean Annual Air Temperature

AbstractTo date, the temperatures of 22 glaciers in China have been measured. It is suggested that the minimum temperature at the base of the active layer in the upper part of the ablation area (Tmin) be used as a characteristic temperature and compared with mean annual air temperature (Ta). The temperature distribution is discussed for various glaciers. Polar-type glaciers are characterized by low temperatures with Tmin < −10°C, Tmin close to Tv and a cold base in general; sub-polar-type glaciers with −10°C < Tmin < −1.0°C, Tmin higher than Tv and a melting base are usually located beneath the middle of the ablation area; and temperate-type glaciers with Tmin < −1.0°C, certainly higher than Ta and a sub-freezing near-surface layer in the ablation area all the year round, because the snow cover is thinner in winter.

scholarly journals On the Temperature Distribution of Glaciers in China

1990 ◽  
Vol 36 (123) ◽  
pp. 210-216 ◽  
Author(s):  
Huang Maohuan
Keyword(s):  
Surface Layer ◽  
Temperature Distribution ◽  
Air Temperature ◽  
Minimum Temperature ◽  
Low Temperatures ◽  
Characteristic Temperature ◽  
Near Surface ◽  
Ablation Area ◽  
Polar Type ◽  
Mean Annual Air Temperature

AbstractTo date, the temperatures of 22 glaciers in China have been measured. It is suggested that the minimum temperature at the base of the active layer in the upper part of the ablation area (Tmin) be used as a characteristic temperature and compared with mean annual air temperature (Ta). The temperature distribution is discussed for various glaciers. Polar-type glaciers are characterized by low temperatures withTmin&lt; −10°C,Tminclose toTvand a cold base in general; sub-polar-type glaciers with −10°C &lt;Tmin&lt; −1.0°C,Tminhigher thanTvand a melting base are usually located beneath the middle of the ablation area; and temperate-type glaciers withTmin&lt; −1.0°C, certainly higher thanTaand a sub-freezing near-surface layer in the ablation area all the year round, because the snow cover is thinner in winter.

scholarly journals The Temperature of Halite Crystallization in the Badenian Saline Basins, in the Context of Paleoclimate Reconstruction of the Carpathian Area

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 831
Author(s):  
Anatoliy R. Galamay ◽  
Krzysztof Bukowski ◽  
Igor M. Zinczuk ◽  
Fanwei Meng
Keyword(s):  
Temperature Distribution ◽  
Air Temperature ◽  
Fluid Inclusions ◽  
Middle Miocene ◽  
Single Phase ◽  
Dead Sea ◽  
Paleoclimate Reconstruction ◽  
Near Surface ◽  
Carpathian Region ◽  
Primary Fluid

Currently, fluid inclusions in halite have been frequently studied for the purpose of paleoclimate reconstruction. For example, to determine the air temperature in the Middle Miocene (Badenian), we examine single-phase primary fluid inclusions of the bottom halites (chevron and full-faceted) and near-surface (cumulate) halites collected from the salt-bearing deposits of the Carpathian region. Our analyses showed that the temperatures of near-bottom brines varied in ranges from 19.5 to 22.0 °C and 24.0 to 26.0 °C, while the temperatures of the surface brines ranged from 34.0 to 36.0 °C. Based on these data, such as an earlier study of lithology and sedimentary structures of the Badenian rock salts, the crystallization of bottom halite developed in the basin from concentrated and cooled near-surface brines of about 30 m depth. Our results comply with the data on the temperature distribution in the modern Dead Sea.

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 The influence of superimposed-ice formation on the sensitivity of glacier mass balance to climate change

1997 ◽  
Vol 24 ◽  
pp. 186-190 ◽  
Author(s):  
John Woodward ◽  
Martin Sharp ◽  
Anthony Arendt
Keyword(s):  
Mass Balance ◽  
Air Temperature ◽  
High Arctic ◽  
Snow Accumulation ◽  
Ice Formation ◽  
Mean Annual Temperature ◽  
Glacier Mass Balance ◽  
Specific Mass ◽  
Near Surface ◽  
Mean Annual Air Temperature

The formation of superimposed ice at the surface of high-Arctic glaciers is an important control on glacier mass balance, but one which is usually modelled in only a schematic fashion. A method is developed to predict the relationship between the thickness of superimposed ice formed and the mean annual air temperature (which approximates the ice temperature at 14 m depth). This relationship is used to investigate the dependence of the proportion of snowpack water equivalent which forms superimposed ice on changes in mean annual temperature and patterns of snow accumulation. Increased temperatures are likely to reduce the extent of the zone of superimposed-ice accumulation and the thickness of superimposed ice formed. This will have a negative effect on glacier mass balance. This is true even if warming occurs only in the winter months, since near-surface ice temperatures will respond to such warming. For John Evans Glacier, Ellesmere Island, Nunavut, Canada (79°40’ N, 74°00’ W), a 1°C rise in mean annual air temperature due solely to winter warming is predicted to reduce the specific mass balance of the glacier by 0.008 m a–1 as a result of decreased superimposed-ice formation. Although such a response is small in comparison to the changes which might result from summer warming, it is nonetheless significant given the very low specific mass balance of many high-Arctic glaciers.

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.

scholarly journals The influence of superimposed-ice formation on the sensitivity of glacier mass balance to climate change

1997 ◽  
Vol 24 ◽  
pp. 186-190 ◽  
Author(s):  
John Woodward ◽  
Martin Sharp ◽  
Anthony Arendt
Keyword(s):  
Mass Balance ◽  
Air Temperature ◽  
High Arctic ◽  
Snow Accumulation ◽  
Ice Formation ◽  
Mean Annual Temperature ◽  
Glacier Mass Balance ◽  
Specific Mass ◽  
Near Surface ◽  
Mean Annual Air Temperature

The formation of superimposed ice at the surface of high-Arctic glaciers is an important control on glacier mass balance, but one which is usually modelled in only a schematic fashion. A method is developed to predict the relationship between the thickness of superimposed ice formed and the mean annual air temperature (which approximates the ice temperature at 14 m depth). This relationship is used to investigate the dependence of the proportion of snowpack water equivalent which forms superimposed ice on changes in mean annual temperature and patterns of snow accumulation.Increased temperatures are likely to reduce the extent of the zone of superimposed-ice accumulation and the thickness of superimposed ice formed. This will have a negative effect on glacier mass balance. This is true even if warming occurs only in the winter months, since near-surface ice temperatures will respond to such warming. For John Evans Glacier, Ellesmere Island, Nunavut, Canada (79°40’ N, 74°00’ W), a 1°C rise in mean annual air temperature due solely to winter warming is predicted to reduce the specific mass balance of the glacier by 0.008 m a–1 as a result of decreased superimposed-ice formation. Although such a response is small in comparison to the changes which might result from summer warming, it is nonetheless significant given the very low specific mass balance of many high-Arctic glaciers.

scholarly journals Improving the Stable Surface Layer in the NCEP Global Forecast System

2017 ◽  
Vol 145 (10) ◽  
pp. 3969-3987 ◽  
Author(s):  
Weizhong Zheng ◽  
Michael Ek ◽  
Kenneth Mitchell ◽  
Helin Wei ◽  
Jesse Meng
Keyword(s):  
Surface Layer ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Global Forecast System ◽  
Surface Cooling ◽  
Forecast System ◽  
Near Surface ◽  
Stable Surface ◽  
Stable Surface Layer ◽  
Ncep Global Forecast System

This study examines the performance of the NCEP Global Forecast System (GFS) surface layer parameterization scheme for strongly stable conditions over land in which turbulence is weak or even disappears because of high near-surface atmospheric stability. Cases of both deep snowpack and snow-free conditions are investigated. The results show that decoupling and excessive near-surface cooling may appear in the late afternoon and nighttime, manifesting as a severe cold bias of the 2-m surface air temperature that persists for several hours or more. Concurrently, because of negligible downward heat transport from the atmosphere to the land, a warm temperature bias develops at the first model level. The authors test changes to the stable surface layer scheme that include introduction of a stability parameter constraint that prevents the land–atmosphere system from fully decoupling and modification to the roughness-length formulation. GFS sensitivity runs with these two changes demonstrate the ability of the proposed surface layer changes to reduce the excessive near-surface cooling in forecasts of 2-m surface air temperature. The proposed changes prevent both the collapse of turbulence in the stable surface layer over land and the possibility of numerical instability resulting from thermal decoupling between the atmosphere and the surface. The authors also execute and evaluate daily GFS 7-day test forecasts with the proposed changes spanning a one-month period in winter. The assessment reveals that the systematic deficiencies and substantial errors in GFS near-surface 2-m air temperature forecasts are considerably reduced, along with a notable reduction of temperature errors throughout the lower atmosphere and improvement of forecast skill scores for light and medium precipitation amounts.

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

2018 ◽  
Vol 12 (10) ◽  
pp. 3215-3227 ◽  
Author(s):  
Benjamin H. Hills ◽  
Joel T. Harper ◽  
Toby W. Meierbachtol ◽  
Jesse V. Johnson ◽  
Neil F. Humphrey ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Air Temperature ◽  
Thermal Structure ◽  
Radiative Energy ◽  
Ablation Zone ◽  
Transient Heating ◽  
Near Surface ◽  
The Mean ◽  
Surface Ice ◽  
Mean Annual Air Temperature

Abstract. To assess the influence of various heat transfer processes on the thermal structure of near-surface ice in Greenland's ablation zone, we compare in situ measurements with thermal modeling experiments. A total of seven temperature strings were installed at three different field sites, each with between 17 and 32 sensors and extending up to 21 m below the ice surface. In one string, temperatures were measured every 30 min, and the record is continuous for more than 3 years. We use these measured ice temperatures to constrain our modeling experiments, focusing on four isolated processes and assessing the relative importance of each for the near-surface ice temperature: (1) the moving boundary of an ablating surface, (2) thermal insulation by snow, (3) radiative energy input, and (4) subsurface ice 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 mean annual air temperature and the ice temperature at the depth where annual temperature variability is dissipated. Thus, in Greenland's ablation zone, the mean annual air temperature is not a reliable predictor of the near-surface ice temperature, as is commonly assumed.

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 a dry snow zone. The cold infiltration zone extends 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.

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