scholarly journals The mass and energy balance of ice within the Eisriesenwelt cave, Austria

2011 ◽  
Vol 5 (1) ◽  
pp. 245-257 ◽  
Author(s):  
F. Obleitner ◽  
C. Spötl
Keyword(s):  
Energy Balance ◽  
Balance Model ◽  
Wave Radiation ◽  
Rock Surface ◽  
Seepage Water ◽  
Cave System ◽  
Calculated Energy ◽  
Sensitivity Studies ◽  
Major Loss ◽  
Basic Features

Abstract. Meteorological measurements were performed in a prominent ice cave (Eisriesenwelt, Austria) during a full annual cycle. The data show the basic features of a dynamically ventilated cave system with a well distinguished winter and summer regime. The calculated energy balance of the cave ice is largely determined by the input of long-wave radiation originating at the host rock surface. On average the turbulent fluxes withdraw energy from the surface. This is more pronounced during winter due to enhanced circulation and lower humidity. During summer the driving gradients reverse sign and the associated fluxes provide energy for melt. About 4 cm of ice were lost at the measurement site during a reference year. This was due to some sublimation during winter, while the major loss resulted from melt during summer. Small amounts of accumulation occurred during spring due to refreezing of seepage water. These results are largely based on employing a numerical mass and energy balance model. Sensitivity studies prove reliability of the calculated energy balance regarding diverse measurement uncertainties and show that the annual mass balance of the ice strongly depends on cave air temperature during summer and the availability of seepage water in spring.

scholarly journals The mass and energy balance of ice within the Eisriesenwelt cave, Austria

2010 ◽  
Vol 4 (3) ◽  
pp. 1741-1779 ◽  
Author(s):  
F. Obleitner ◽  
Ch. Spötl
Keyword(s):  
Energy Balance ◽  
Balance Model ◽  
Wave Radiation ◽  
Rock Surface ◽  
Seepage Water ◽  
Cave System ◽  
Long Wave ◽  
Sensitivity Studies ◽  
Major Loss ◽  
Basic Characteristics

Abstract. Meteorological and glaciological measurements were performed in a prominent ice cave (Eisriesenwelt, Austria) during a full annual cycle. The observed meteorological conditions feature the basic characteristics of a dynamically ventilated cave system with a well distinguished winter and summer regime. The calculated energy balance of the ice is largely predetermined by the input of long-wave radiation originating at the host rock surface. On average the turbulent fluxes withdraw energy from the surface. This is more pronounced during winter due to enhanced circulation and lower humidity. During summer the driving gradients reverse sign and the associated fluxes provide some energy for melt. About 4 cm of ice were lost at the measurements site during a reference year. This was due to some sublimation during winter, while the major loss resulted from melt during summer. Small amounts of accumulation occurred during spring due to refreezing of seepage water. These results are largely based on employing a numerical mass and energy balance model. Sensitivity studies prove their reliability regarding diverse measurement uncertainties and indicate that the annual mass balance essentially depends on summer temperature and the availability of seepage water in spring. The latter induces a considerable interannual and spatial variability of the mass budget.

scholarly journals Evaluation of the Simple Urban Energy Balance Model Using Selected Data from 1-yr Flux Observations at Two Cities

2009 ◽  
Vol 48 (4) ◽  
pp. 693-715 ◽  
Author(s):  
Toru Kawai ◽  
Mohammad Kholid Ridwan ◽  
Manabu Kanda
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Sensible Heat Flux ◽  
Energy Balance Model ◽  
Balance Model ◽  
Wave Radiation ◽  
Urban Energy Balance ◽  
Two Cities ◽  
Urban Energy

Abstract The authors’ objective was to apply the Simple Urban Energy Balance Model for Mesoscale Simulation (SUMM) to cities. Data were selected from 1-yr flux observations conducted at three sites in two cities: one site in Kugahara, Japan (Ku), and two sites in Basel, Switzerland (U1 and U2). A simple vegetation scheme was implemented in SUMM to apply the model to vegetated cities, and the surface energy balance and radiative temperature TR were evaluated. SUMM generally reproduced seasonal and diurnal trends of surface energy balance and TR at Ku and U2, whereas relatively large errors were obtained for the daytime results of sensible heat flux QH and heat storage ΔQS at U1. Overall, daytime underestimations of QH and overestimations of ΔQS and TR were common. These errors were partly induced by the poor parameterization of the natural logarithm of the ratio of roughness length for momentum to heat (κB−1); that is, the observed κB−1 values at vegetated cities were smaller than the simulated values. The authors proposed a new equation for predicting this coefficient. This equation accounts for the existence of vegetation and improves the common errors described above. With the modified formula for κB−1, simulated net all-wave radiation and TR agreed well with observed values, regardless of site and season. However, at U1, simulated QH and ΔQS were still overestimated and underestimated, respectively, relative to observed values.

scholarly journals Development of a 10 year (2001–2010) 0.1° dataset of land-surface energy balance for mainland China

2014 ◽  
Vol 14 (10) ◽  
pp. 14471-14518 ◽  
Author(s):  
X. Chen ◽  
Z. Su ◽  
Y. Ma ◽  
S. Liu ◽  
Q. Yu ◽  
...  
Keyword(s):  
Energy Balance ◽  
High Resolution ◽  
Surface Energy ◽  
Land Surface ◽  
Surface Energy Balance ◽  
Water Cycle ◽  
Surface Radiation ◽  
Balance Model ◽  
Wave Radiation ◽  
The Tibetan Plateau

Abstract. In the absence of high resolution estimates of the components of surface energy balance for China, we developed an algorithm based on the surface energy balance system (SEBS) to generate a dataset of land-surface energy and water fluxes on a monthly time scale from 2001 to 2010 at a 0.1° × 0.1° spatial resolution by using multi-satellite and meteorological forcing data. A remote-sensing-based method was developed to estimate canopy height, which was used to calculate roughness length and flux dynamics. The land-surface flux dataset was validated against "ground-truth" observations from 11 flux tower stations in China. The estimated fluxes correlate well with the stations' measurements for different vegetation types and climatic conditions (average bias = 15.3 W m−2, RMSE = 26.4 W m−2). The quality of the data product was also assessed against the GLDAS dataset. The results show that our method is efficient for producing a high-resolution dataset of surface energy flux for the Chinese landmass from satellite data. The validation results demonstrate that more accurate downward long-wave radiation datasets are needed to be able to accurately estimate turbulent fluxes and evapotranspiration when using the surface energy balance model. Trend analysis of land-surface radiation and energy exchange fluxes revealed that the Tibetan Plateau has undergone relatively stronger climatic change than other parts of China during the last 10 years. The capability of the dataset to provide spatial and temporal information on water-cycle and land–atmosphere interactions for the Chinese landmass is examined. The product is free to download for studies of the water cycle and environmental change in China.

scholarly journals A Simple Energy-Balance Model to Calculate Ice Ablation at the Margin of the Greenland Ice Sheet

1990 ◽  
Vol 36 (123) ◽  
pp. 222-228 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole Β. Olesen
Keyword(s):  
Energy Balance ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ablation Rate ◽  
Short Wave ◽  
Energy Balance Model ◽  
Balance Model ◽  
Wave Radiation ◽  
Climate Data

AbstractData for daily ice ablation on two outlets from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), are used to test a simple energy-balance model which calculates ablation from climate data. The mean errors of the model are only −1.1 and −1.3 mm water d−1 for Nordbogletscher (14 months) and Qamanârssûp sermia (21 months), respectively, with standard deviations of ±13.6 and ±18.9 mm water d−1 for calculating daily ablation. The larger error for Qamanârssûp sermia may be due to variations in ice albedo but the model also underestimates ablation during Föhn events.According to the model, radiation accounts for about two-thirds of mean ablation for June-August at the two sites, while turbulent fluxes account for about one-third. The average ablation rate is higher at Qamanârssûp sermia than at Nordbogletscher because both sensible-heat flux and short-wave radiation are higher.

scholarly journals A Simple Energy-Balance Model to Calculate Ice Ablation at the Margin of the Greenland Ice Sheet

1990 ◽  
Vol 36 (123) ◽  
pp. 222-228 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole Β. Olesen
Keyword(s):  
Energy Balance ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ablation Rate ◽  
Short Wave ◽  
Energy Balance Model ◽  
Balance Model ◽  
Wave Radiation ◽  
Climate Data

AbstractData for daily ice ablation on two outlets from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), are used to test a simple energy-balance model which calculates ablation from climate data. The mean errors of the model are only −1.1 and −1.3 mm water d−1for Nordbogletscher (14 months) and Qamanârssûp sermia (21 months), respectively, with standard deviations of ±13.6 and ±18.9 mm water d−1for calculating daily ablation. The larger error for Qamanârssûp sermia may be due to variations in ice albedo but the model also underestimates ablation during Föhn events.According to the model, radiation accounts for about two-thirds of mean ablation for June-August at the two sites, while turbulent fluxes account for about one-third. The average ablation rate is higher at Qamanârssûp sermia than at Nordbogletscher because both sensible-heat flux and short-wave radiation are higher.

Snowmelt modeling in a balsam fir forest: comparison between an energy balance model and other simplified models

1991 ◽  
Vol 21 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Marcel Prévost ◽  
Richard Barry ◽  
Jean Stein ◽  
André P. Plamondon
Keyword(s):  
Energy Balance ◽  
Snow Cover ◽  
Air Temperature ◽  
Meteorological Parameters ◽  
Daily Basis ◽  
Energy Balance Model ◽  
Balsam Fir ◽  
Radiation Absorption ◽  
Balance Model ◽  
Wave Radiation

This study compares snowmelt models and determines the relative importance of the meteorological parameters affecting snowmelt during the 1985, 1986, and 1987 melt seasons in a dense balsam fir stand in Laurentide forest, 80 km north of the city of Québec. Net all-wave radiation, air temperature, wind speed, relative humidity, and rainfall were correlated with meltwater that reached the base of the snow cover as measured with a 20-m2 snow lysimeter. The estimation of energy balance components of the snow cover during the snowmelt period showed that while solar radiation absorption dominated, turbulent transfers as well as heat exchanges with ground and rain were negligible. The temperature index model SNOW-17 yielded predictions of snow cover outflow as accurately as the energy balance model, both explaining 64% of hourly outflow variation and more than 85% of daily outflow variation. Single meteorological parameters usually explained less than 25% of the hourly melt because of the meltwater transmission lag through the snowpack. On a daily basis, the relationships using air temperature or net all-wave radiation as sole index both explained nearly 70% of snowmelt outflow for the same period. Combining these two parameters with rainfall in the same equation increased the explained variance to 85%.

Modelling the surface mass balance of the Greenland Ice Sheet from 6000 BP to the year 2200

2020 ◽  
Author(s):  
Uta Krebs-Kanzow ◽  
Shan Xu ◽  
Hu Yang ◽  
Paul Gierz ◽  
Gerrit Lohmann
Keyword(s):  
Energy Balance ◽  
Mass Balance ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Atmospheric Composition ◽  
Balance Model ◽  
Wave Radiation ◽  
System Modelling ◽  
Surface Mass Balance ◽  
Surface Mass

<p>The surface mass balance scheme dEBM (diurnal Energy Balance Model) provides a novel interface between atmosphere and land ice for Earth System modelling, which is based on the energy balance of glaciated surfaces. In contrast to empirical schemes, dEBM accounts for changes in the Earth’s orbit and atmospheric composition. The scheme only requires monthly atmospheric forcing (precipitation, temperature, shortwave and longwave radiation and cloud cover) and is computationally inexpensive, which makes it particularly suitable to investigate the response of ice sheets to long term climate change.<br>Here, we analyze the surface mass balance of the Greenland Ice Sheet (GrIS)  based on a climate simulation which covers the last 6000 years and a climate projection which extends to the year 2200. We validate our results with recent surface mass balance estimates from observations and regional modelling. Our model results allow to compare two distinctly different warm periods: the Mid Holocene (approx. 6000 years before present), which is characterized by intensified summer insolation, and the next centuries,  which will be characterized by reduced outgoing long wave radiation. We also investigate whether the temperature - melt relationship, as used in empirical  schemes, remains stable under changing insolation and atmospheric composition.</p><p><em>Krebs-Kanzow, U., Gierz, P., & Lohmann, G. (2018). Brief communication: An ice surface melt scheme including the diurnal cycle of solar radiation. The Cryosphere, 12(12), 3923-3930.</em></p>

scholarly journals Surface temperatures and their influence on the permafrost thermal regime in high Arctic rock walls on Svalbard

2020 ◽  
Author(s):  
Juditha Undine Schmidt ◽  
Bernd Etzelmüller ◽  
Thomas Vikhamar Schuler ◽  
Florence Magnin ◽  
Julia Boike ◽  
...  
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
High Arctic ◽  
Heat Fluxes ◽  
Wave Radiation ◽  
Rock Surface ◽  
Permafrost Degradation ◽  
Data Set ◽  
Surface Temperatures

Abstract. Permafrost degradation in steep rock walls and associated slope destabilization have been studied increasingly in recent years. While most studies focus on mountainous and sub-Arctic regions, the occurring thermo-mechanical processes play an important role also in the high Arctic. A more precise understanding is required to assess the risk of natural hazards enhanced by permafrost warming in high Arctic rock walls. This study presents rock surface temperature measurements of coastal and non-coastal rock walls in a high Arctic setting on Svalbard. We applied the surface energy balance model CryoGrid 3 for evaluation, including adjusted radiative forcing to account for vertical rock walls. Our measurements and model results show that rock surface temperatures at coastal cliffs are up to 1.5 °C higher than non-coastal rock walls when the fjord is ice-free in the winter season, resulting from additional energy input due to higher air temperatures at the coast and radiative warming by relatively warm seawater. An ice layer on the fjord counteracts this effect, leading to similar rock surface temperatures as in non-coastal settings. Our results include a simulated surface energy balance with short-wave radiation as the dominant energy source during spring and summer, and long-wave radiation being the main energy loss. While sensible heat fluxes can both warm and cool the surface, latent heat fluxes are mostly insignificant. Simulations for future climate conditions result in a warming of rock surface temperatures and a deepening of active layer thickness for both coastal and non-coastal rock walls. Our field data present a unique data set of rock surface temperatures in steep high Arctic rock walls, while our model can contribute towards the understanding of factors influencing coastal and non-coastal settings and the associated surface energy balance.

scholarly journals Response of the Energy Balance on the Margin of the Greenland Ice Sheet to Temperature Changes

1990 ◽  
Vol 36 (123) ◽  
pp. 217-221 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Air Temperature ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Temperature Response ◽  
Greenland Ice Sheet ◽  
Energy Balance Model ◽  
Balance Model ◽  
Sensible Heat

AbstractDaily ice ablation on two outlet glaciers from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), is related to air temperature by a linear regression equation. Analysis of this ablation-temperature equation with the help of a simple energy-balance model shows that sensible-heat flux has the greatest temperature response and accounts for about one-half of the temperature response of ablation. Net radiation accounts for about one-quarter of the temperature response of ablation, and latent-heat flux and errors account for the remainder. The temperature response of sensible-heat flux at QQamanârssûp sermia is greater than at Nordbogletscher mainly due to higher average wind speeds. The association of high winds with high temperatures during Föhn events further increases sensible-heat flux. The energy-balance model shows that ablation from a snow surface is only about half that from an ice surface at the same air temperature.

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