scholarly journals First results and interpretation of energy-flux measurements over Alpine permafrost

2000 ◽  
Vol 31 ◽  
pp. 275-280 ◽  
Author(s):  
Catherine Mittaz ◽  
Martin Hoelzle ◽  
Wilfried Haeberli
Keyword(s):  
Energy Balance ◽  
Energy Exchange ◽  
Swiss Alps ◽  
High Mountain ◽  
Frozen Ground ◽  
Near Surface ◽  
Exchange Processes ◽  
Significant Difference ◽  
First Results ◽  
Coarse Surface

AbstractThe interaction of energy-exchange processes between the atmosphere and the Earth surface determines the surface temperature regime. It is of fundamental importance to the question whether frozen ground exists at a given site and how rapidly it may decay in response to a climatic perturbation. To further our understanding of these processes, measurements concerning near-surface energy-exchange processes were initiated in January 1997 on creeping permafrost at a high mountain site, Murtèl-Corvatsch, upper Engadin, Swiss Alps. Data on all important energy-balance fluxes were collected. In this paper, we present ground-temperature and energy-balance measurements from Murtèl-Corvatsch for a 2 year period, 1997–99. We will examine the relative importance of the energy-balance components and discuss special problems relating to the coarse surface layer. The results indicate a non-zero energy budget, with a positive deviation of up to 78 W m 4 in winter and a negative deviation of up to –130 W nT2 in summer. We propose that this overall imbalance of the energy-exchange fluxes, as well as the significant difference between mean annual surface and ground temperatures/can be explained by unmeasured advective energy fluxes that occur within the layer of large boulder blocks at the top of the permafrost.

scholarly journals Distributed snow and rock temperature modelling in steep rock walls using Alpine3D

2017 ◽  
Vol 11 (1) ◽  
pp. 585-607 ◽  
Author(s):  
Anna Haberkorn ◽  
Nander Wever ◽  
Martin Hoelzle ◽  
Marcia Phillips ◽  
Robert Kenner ◽  
...  
Keyword(s):  
Energy Balance ◽  
Snow Cover ◽  
Snow Depth ◽  
Spatial Scales ◽  
Swiss Alps ◽  
Balance Model ◽  
Near Surface ◽  
Surface Rock ◽  
Depth Data ◽  
Rock Temperature

Abstract. In this study we modelled the influence of the spatially and temporally heterogeneous snow cover on the surface energy balance and thus on rock temperatures in two rugged, steep rock walls on the Gemsstock ridge in the central Swiss Alps. The heterogeneous snow depth distribution in the rock walls was introduced to the distributed, process-based energy balance model Alpine3D with a precipitation scaling method based on snow depth data measured by terrestrial laser scanning. The influence of the snow cover on rock temperatures was investigated by comparing a snow-covered model scenario (precipitation input provided by precipitation scaling) with a snow-free (zero precipitation input) one. Model uncertainties are discussed and evaluated at both the point and spatial scales against 22 near-surface rock temperature measurements and high-resolution snow depth data from winter terrestrial laser scans.In the rough rock walls, the heterogeneously distributed snow cover was moderately well reproduced by Alpine3D with mean absolute errors ranging between 0.31 and 0.81 m. However, snow cover duration was reproduced well and, consequently, near-surface rock temperatures were modelled convincingly. Uncertainties in rock temperature modelling were found to be around 1.6 °C. Errors in snow cover modelling and hence in rock temperature simulations are explained by inadequate snow settlement due to linear precipitation scaling, missing lateral heat fluxes in the rock, and by errors caused by interpolation of shortwave radiation, wind and air temperature into the rock walls.Mean annual near-surface rock temperature increases were both measured and modelled in the steep rock walls as a consequence of a thick, long-lasting snow cover. Rock temperatures were 1.3–2.5 °C higher in the shaded and sunny rock walls, while comparing snow-covered to snow-free simulations. This helps to assess the potential error made in ground temperature modelling when neglecting snow in steep bedrock.

scholarly journals Quasi-3-D resistivity imaging – mapping of heterogeneous frozen ground conditions using electrical resistivity tomography

2009 ◽  
Vol 3 (3) ◽  
pp. 895-918 ◽  
Author(s):  
C. Kneisel ◽  
A. Bast ◽  
D. Schwindt
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Swiss Alps ◽  
Small Scale ◽  
Frozen Ground ◽  
Resistivity Tomography ◽  
Near Surface ◽  
Glacier Forefield ◽  
Mountain Permafrost ◽  
Ground Conditions

Abstract. Up to now an efficient 3-D geophysical mapping of the subsurface in mountainous environments with rough terrain has not been possible. A merging approach of several closely spaced 2-D electrical resistivity tomography (ERT) surveys to build up a quasi-3-D model of the electrical resistivity is presented herein as a practical compromise for inferring subsurface characteristics and lithology. The ERT measurements were realised in a small glacier forefield in the Swiss Alps with complex terrain exhibiting a small scale spatial variability of surface substrate. To build up the grid for the quasi-3-D measurements the ERT surveys were arranged as parallel profiles and perpendicular tie lines. The measured 2-D datasets were collated into one quasi-3-D file. A forward modelling approach – based on studies at a permafrost site below timberline – was used to optimize the geophysical survey design for the mapping of the mountain permafrost distribution in the investigated glacier forefield. Quasi-3-D geoelectrical imaging is a useful method for mapping of heterogeneous frozen ground conditions and can be considered as a further milestone in the application of near surface geophysics in mountain permafrost environments.

Analyzing Near Surface Temperature Inversions Across the Greenland Ice Sheet Using In-situ, Remote Sensing, and Reanalysis Data

2020 ◽  
Author(s):  
Alden Adolph ◽  
Wesley Brown ◽  
Karina Zikan ◽  
Robert Fausto
Keyword(s):  
Surface Temperature ◽  
Energy Exchange ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Near Surface ◽  
Surface Temperatures ◽  
Air Temperatures ◽  
Exchange Processes ◽  
Temperature Inversions

<p>As Arctic temperatures have increased, the Greenland Ice Sheet has exhibited a negative mass balance, with a substantial and increasing fraction of mass loss due to surface melt. Understanding surface energy exchange processes in Greenland is critical for our ability to predict changes in mass balance. In-situ and remotely sensed surface temperatures are useful for monitoring trends, melt events, and surface energy balance processes, but these observations are complicated by the fact that surface temperatures and near surface air temperatures can significantly differ due to the presence of inversions that exist across the Arctic. Our previous work shows that even in the summer, very near surface inversions are present between the 2m air and surface temperatures a majority of the time at Summit, Greenland. In this study, we expand upon these results and combine a variety of data sources to quantify differences between surface snow/ice temperatures and 2m air temperatures across the Greenland Ice Sheet and investigate controls on the magnitude of these near surface temperature inversions. In-situ temperatures, wind speed, specific humidity, and albedo data are provided from automatic weather stations operated by the Programme for Monitoring of the Greenland Ice Sheet (PROMICE). We use the Clouds and the Earth's Radiant Energy System (CERES) cloud area fraction data to analyze effects of cloud presence on near surface temperature gradients. The in-situ temperatures are compared to Modern-Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) and Moderate Resolution Imaging Spectrometer (MODIS) ice surface temperature data to extend findings across the ice sheet. Using PROMICE in-situ data from 2015, we find that these 2m temperature inversions are present 77% of the time, with a median strength of 1.7°C. The data confirm that the presence of clouds weakens inversions. Initial results indicate a RMSE of 3.9°C between MERRA-2 and PROMICE 2m air temperature, and a RMSE of 5.6°C between the two datasets for surface temperature. Improved understanding of controls on near surface inversions is important for use of remotely sensed snow surface temperatures and for modeling of surface mass and energy exchange processes.</p>

scholarly journals Distributed glacier mass-balance modelling as an important component of modern multi-level glacier monitoring

2006 ◽  
Vol 43 ◽  
pp. 335-343 ◽  
Author(s):  
Horst Machguth ◽  
Frank Paul ◽  
Martin Hoelzle ◽  
Wilfried Haeberli
Keyword(s):  
Energy Balance ◽  
Mass Balance ◽  
Climate Models ◽  
Numerical Models ◽  
Field Measurements ◽  
Length Change ◽  
Swiss Alps ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Spatio Temporal

AbstractModern concepts of worldwide glacier monitoring include numerical models for (1) interconnecting the different levels of observations (local mass balance, representative length change, glacier inventories for global coverage) and (2) extrapolations in space (coupling with climate models) and time (backward and forward). In this context, one important new tool is distributed mass-balance modelling in complex mountain topography. This approach builds on simplified energy-balance models and can be applied for investigating the spatio-temporal representativity of the few mass-balance measurements, for estimating balance values at the tongue of unmeasured glaciers in order to derive long-term average balance values from a great number of glaciers with known length change, and for assessing special effects such as the influence of Sahara dust falls on the albedo and mass balance or autocorrelation effects due to surface darkening of glaciers with strongly negative balances. Experience from first model runs in the Swiss Alps and from applications to the extreme conditions in summer 2003 provides evidence about the usefulness of this approach for glacier monitoring and analysis of glacier changes in high-mountain regions. The main difficulties concern the spatial variability of the input parameters (e.g. precipitation, snow cover and surface albedo) and the uncertainties in the parameterizations of the components of the energy balance. Field measurements remain essential to tie the models to real ground conditions.

scholarly journals Decadal O3 variability at the Mt. Cimone WMO/GAW global station (2,165 m a.s.l., Italy) and comparison with two high-mountain “reference” sites in Europe

Elem Sci Anth ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
P. Cristofanelli ◽  
F. Fierli ◽  
F. Graziosi ◽  
M. Steinbacher ◽  
C. Couret ◽  
...  
Keyword(s):  
Atmospheric Transport ◽  
Dispersion Model ◽  
Particle Dispersion ◽  
Air Pollutant ◽  
Swiss Alps ◽  
High Mountain ◽  
Near Surface ◽  
Specific Source ◽  
Surface O3

Tropospheric ozone (O3) is a greenhouse gas as well as a harmful air pollutant with adverse effects on human health and vegetation: The observation and attribution of its long-term variability are key activities to monitor the effectiveness of pollution reduction protocols. In this work, we present the analysis of multi-annual near-surface O3 (1996–2016) at the Mt. Cimone (CMN, Italian northern Apennines) WMO/GAW global station and the comparison with two “reference” high-mountain sites in Europe: Jungfraujoch (JFJ, Swiss Alps) and Mt. Zugspitze (ZUG/ZSF, German Alps). Negative O3 trends were observed at CMN over the period 1996–2016 (from –0.19 to –0.22 ppb yr–1), with the strongest tendencies as being observed for the warm months (May–September: –0.32 ppb yr–1 during daytime). The magnitude of the calculated O3 trends at CMN are 2 times higher than those calculated for ZUG/ZSF and 3–4 times higher than for JFJ. With respect to JFJ and ZUG/ZSF, higher O3 values were observed at CMN during 2004–2008, while good agreement is found for the remaining periods. We used Lagrangian simulations by the FLEXPART particle dispersion model and near-surface O3 data over different European regions, for investigating the possibility that the appearance of the O3 anomalies at CMN could be related to variability in the atmospheric transport or in near-surface O3 over specific source regions. Even if it was not possible to achieve a general robust explanation for the occurrence of the high O3 values at CMN during 2004–2008, the variability of (1) regional and long-range atmospheric transport at CMN and (2) European near-surface O3 could motivate the observed anomalies in specific seasons and years. Interestingly, we found a long-term variability in air mass transport at JFJ with enhanced (decreased) contributions from Western European (intercontinental regions).

scholarly journals Seasonal differences in surface energy exchange and accumulation at Summit, Greenland

2000 ◽  
Vol 31 ◽  
pp. 387-390 ◽  
Author(s):  
Mary R. Albert ◽  
Robert L. Hawley
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Seasonal Changes ◽  
Energy Exchange ◽  
Ice Core ◽  
Snow Accumulation ◽  
Seasonal Differences ◽  
Near Surface ◽  
Snow Chemistry ◽  
Transfer Processes

AbstractThe 1997–98 Summit (Greenland) winter-over experiment was conducted to investigate the seasonal changes that might affect snow-air transfer processes and snow chemistry for polar ice-core interpretation This paper discusses meteorological measurements that were obtained during the experiment We use the measurements in energy-balance modeling to investigate seasonal differences in the snow-air energy exchange, and to investigate the timing of snow accumulation. We found that the surface energy exchange has distinct seasonal differences. The winter (November-February) has both the coldest average temperatures of the year and the largest temperature variations. The winter also has both the largest peak wind speeds and the longest periods of sustained high winds. Most of the water-vapor transport across the snow-air interface occurs in the summer, indicating that summer may be the primary season for near-surface snow metamorphism. Snow-depth sounder results indicate that snowfall occurs throughout the year at Summit, and thus that the ice-core record may not be affected by large seasonal gaps in the precipitation if accumulation patterns have not changed. The changes in air temperature, wind speed and radiation cause clear seasonal differences in the surface energy balance and snow-surface characteristics that are likely to cause seasonal changes in air-snow transfer processes and snow chemistry as well.

scholarly journals Distributed snow and rock temperature modelling in steep rock walls using Alpine3D

2016 ◽  
Author(s):  
Anna Haberkorn ◽  
Nander Wever ◽  
Martin Hoelzle ◽  
Marcia Phillips ◽  
Robert Kenner ◽  
...  
Keyword(s):  
Energy Balance ◽  
Snow Cover ◽  
Swiss Alps ◽  
Balance Model ◽  
Scaling Method ◽  
Validation Data ◽  
Near Surface ◽  
Surface Rock ◽  
Rock Temperature ◽  
Heterogeneous Rock

Abstract. In this study we modelled the influence of the spatially and temporally heterogeneous snow cover on the surface energy balance and its impact on rock temperatures in two rugged, steep rock walls on the Gemsstock ridge, central Swiss Alps. The model used is the distributed, process based energy balance model Alpine3D in combination with a precipitation scaling method to introduce varying snow distribution. Near-surface rock temperatures are modelled for snow-covered and snow-free scenarios. The performance of Alpine3D, its limitations and uncertainties are discussed and evaluated against a dense network of 30 near-surface rock temperature measurements (0.1 m depth) distributed over both rock walls and high resolution (0.2 m) snow depth data derived from four winter terrestrial laser scans. Snow cover distribution and near-surface rock temperatures are convincingly modelled in the heterogeneous rock walls. The correction of winter precipitation input using a precipitation scaling method based on terrestrial laser scans greatly improves the results. In addition, the fine-scale resolution of the model domain (0.2 m) and of the validation data allows to consider the thermal effects of the strongly varying micro-topography and micro-climate in the rock walls. Mean annual near-surface rock temperature increase by 2 °C in the shaded rock wall and of 1 °C in the sun-exposed one were measured and modelled due to the accumulation of snow. Errors in rock temperature simulations can be explained by a lack of modelled lateral heat fluxes, as well as by errors caused by interpolation of wind and shortwave radiation.

scholarly journals Glacier-permafrost relations in a high-mountain environment: 5 decades of kinematic monitoring at the Gruben site, Swiss Alps

2021 ◽  
Author(s):  
Isabelle Gärtner-Roer ◽  
Nina Brunner ◽  
Reynald Delaloye ◽  
Wilfried Haeberli ◽  
Andreas Kääb ◽  
...  
Keyword(s):  
Mass Loss ◽  
Time Scale ◽  
Ground Surface ◽  
Satellite System ◽  
Swiss Alps ◽  
Aerial Images ◽  
High Mountain ◽  
Frozen Ground ◽  
Glacier Tongue ◽  
Glacier Ice

Abstract. Digitized aerial images were used to monitor the evolution of perennially frozen debris and polythermal glacier ice at the intensely investigated Gruben site in the Swiss Alps over a period of about 50 years. The photogrammetric analysis allowed for a compilation of detailed spatio-temporal information on flow velocities and thickness changes. In addition, high-resolution GNSS (Global Navigation Satellite System) and ground-surface temperature measurements were included in the analysis to provide insight into short-term changes. Over time, extremely contrasting developments and landform responses are documented. Viscous flow within the warming and already near-temperate rockglacier permafrost continued at a constant average but seasonally variable speed of typically decimetres per year, with low average surface lowering of centimeters to decimetres per year. This quite constant flow causes the continued advance of the characteristic convex, lava stream-like rockglacier with its over-steepened fronts. Thawing rates of ice-rich perennially frozen ground to strong climate forcing are obviously very low (centimetres per year) and the dynamic response strongly delayed (time scale decades to centuries). The adjacent cold debris-covered glacier tongue remained an essentially concave landform with diffuse margins, predominantly chaotic surface structure, intermediate thickness losses (decimetre per year) and clear signs of down-wasting and decreasing flow velocity. The former contact zone between the cold glacier margin and the upper part of the rockglacier with remains of buried glacier ice embedded on top of frozen debris exhibits complex phenomena of thermokarst in massive ice and backflow towards the topographic depression produced by the retreating glacier tongue. As is typical for glaciers in the Alps, the clean glacier part shows a rapid response (time scale years) to strong climatic forcing with spectacular retreat (> 10 meters per year) and mass loss (up to > 1 meter water equivalent specific mass loss per year). The system of periglacial lakes shows a correspondingly dynamic evolution and had to be controlled by engineering work for hazard protection.

scholarly journals Energy Balance Indicators during the Transition Period and Early Lactation of Purebred Holstein and Simmental Cows and Their Crosses

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 309
Author(s):  
Deise Aline Knob ◽  
André Thaler Neto ◽  
Helen Schweizer ◽  
Anna C. Weigand ◽  
Roberto Kappes ◽  
...  
Keyword(s):  
Energy Balance ◽  
Milk Yield ◽  
Milk Composition ◽  
Negative Energy ◽  
The Other ◽  
Negative Energy Balance ◽  
Metabolic Energy ◽  
Genetic Groups ◽  
Significant Difference ◽  
Fat Thickness

Crossbreeding in dairy cattle has been used to improve functional traits, milk composition, and efficiency of Holstein herds. The objective of the study was to compare indicators of the metabolic energy balance, nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), glucose, body condition score (BCS) back fat thickness (BFT), as well as milk yield and milk composition of Holstein and Simmental cows, and their crosses from the prepartum period until the 100th day of lactation at the Livestock Center of the Ludwig Maximilians University (Munich, Germany). In total, 164 cows formed five genetic groups according to their theoretic proportion of Holstein and Simmental genes as follows: Holstein (100% Holstein; n = 9), R1-Hol (51–99% Holstein; n = 30), first generation (F1) crossbreds (50% Holstein, 50% Simmental; n = 17), R1-Sim (1–49% Holstein; n = 81) and Simmental (100% Simmental; n = 27). The study took place between April 2018 and August 2019. BCS, BFT blood parameters, such as BHBA, glucose, and NEFA were recorded weekly. A mixed model analysis with fixed effects breed, week (relative to calving), the interaction of breed and week, parity, calving year, calving season, milking season, and the repeated measure effect of cow was used. BCS increased with the Simmental proportion. All genetic groups lost BCS and BFT after calving. Simmental cows showed lower NEFA values. BHBA and glucose did not differ among genetic groups, but they differed depending on the week relative to calving. Simmental and R1-Sim cows showed a smaller effect than the other genetic groups regarding changes in body weight, BCS, or back fat thickness after a period of a negative energy balance after calving. There was no significant difference for milk yield among genetic groups, although Simmental cows showed a lower milk yield after the third week after calving. Generally, Simmental and R1-Simmental cows seemed to deal better with a negative energy balance after calving than purebred Holstein and the other crossbred lines. Based on a positive heterosis effect of 10.06% for energy corrected milk (ECM), the F1, however, was the most efficient crossbred line.

Effective and Ecological Technologies of Application of Structured Materials for Roadbed in the Permafrost Regions

2018 ◽  
Vol 284 ◽  
pp. 950-955
Author(s):  
V.G. Merzlikin ◽  
G.I. Bolkina ◽  
L.N. Ignatova
Keyword(s):  
Thermal State ◽  
Toxic Waste ◽  
The Arctic ◽  
Radiative Heat Exchange ◽  
High Mountain ◽  
Frozen Ground ◽  
Structured Materials ◽  
Environmental Measures ◽  
Soil Foundation ◽  
Support Engineering

The work is devoted to effective and ecological technologies for the application of functional structured materials for roads, railways, airfields on permafrost with forced cooling of the sub-soil foundation. The physical and mathematical simulation of the thermal state of frozen ground with single and double-layer coatings was performed. The temperature profiles of a model combine roadbed on the longstanding permafrost have been calculated at winter conditions of the Northern Hemisphere. This roadbed include an upper surface coating with low thermal conductivity and high emissivity in the long-wavelength IR range at convective-radiative heat exchange. The second high-conductive subsurface coating is laid on the underlying sub-soil and ensures its cooling as the “heat pump”. The efficiency of the proposed technology of roadbed construction based on the use of non-toxic waste of numerous industrial productions. The carried out research will be in demand for the specialists of transport support, engineering glaciology, in the field of climatology, oceanology, construction, environmental measures, and also in the presentation of financial and economic forecasts of the prospects for the development of polar and subpolar regions, the Arctic and the Antarctic, and high-mountain.

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