scholarly journals Degree-day melt models for paleoclimate reconstruction from tropical glaciers: calibration from mass balance and meteorological data of the Zongo glacier (Bolivia, 16<b>°</b> S)

2011 ◽  
Vol 7 (3) ◽  
pp. 2119-2158 ◽  
Author(s):  
P.-H. Blard ◽  
P. Wagnon ◽  
J. Lavé ◽  
A. Soruco ◽  
J.-E. Sicart ◽  
...  
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Short Wave ◽  
Substantial Improvement ◽  
Applied Model ◽  
Tropical Glaciers ◽  
Degree Day ◽  
Cordillera Real ◽  
Geological Timescale ◽  
Snow And Ice

Abstract. This paper describes several simple positive degree-day models (hereafter referred as "PDD models") designed to provide past climatic reconstruction from tropical glacier paleo-equilibrium altitude lines (paleo-ELA). Several ablation laws were tested and calibrated using the monthly ablation and meteorological data recorded from 1997 to 2006 on the Zongo glacier (Cordillera Real, Bolivia, 16° S). The performed inversion analyses indicate that the model provides a better reconstruction of the mass balance if the ablation is modeled with different melting factors for snow and ice. The inclusion of short-wave solar radiations does not induce a substantial improvement. However, this type of model may be very useful to quantify the effects of local topographic (orientation, shading) and to take into account incoming solar radiation changes at geological timescale. The performed sensitivity test indicates that, in spite of the uncertainty in the calibrated snow-ice ablation factors, all models are able to provide paleotemperatures with ~1 °C uncertainty for a given paleoprecipitation. This error includes a 50 m uncertainty in the estimate of the paleoELA. Finally, the models are characterized by different precipitation-temperature sensitivities: if a similar warming is applied, model including different ablation factors for snow and ice requires a lower precipitation increase (by ∼15 %) than others to maintain the ELA.

scholarly journals Micrometeorological conditions and surface mass and energy fluxes on Lewis Glacier, Mt Kenya, in relation to other tropical glaciers

2013 ◽  
Vol 7 (4) ◽  
pp. 1205-1225 ◽  
Author(s):  
L. I. Nicholson ◽  
R. Prinz ◽  
T. Mölg ◽  
G. Kaser
Keyword(s):  
Energy Balance ◽  
Mass Balance ◽  
Cloud Cover ◽  
Meteorological Data ◽  
Snow Accumulation ◽  
Energy Fluxes ◽  
Glacier Surface ◽  
Monte Carlo Optimization ◽  
Surface Mass ◽  
Tropical Glaciers

Abstract. The Lewis Glacier on Mt Kenya is one of the best-studied tropical glaciers, but full understanding of the interaction of the glacier mass balance and its climatic drivers has been hampered by a lack of long-term meteorological data. Here we present 2.5 yr of meteorological data collected from the glacier surface from October 2009 to February 2012. The location of measurements is in the upper portion of Lewis Glacier, but this location experiences negative annual mass balance, and the conditions are comparable to those experienced in the lower ablation zones of South American glaciers in the inner tropics. In the context of other glaciated mountains of equatorial East Africa, the summit zone of Mt Kenya shows strong diurnal cycles of convective cloud development as opposed to the Rwenzoris, where cloud cover persists throughout the diurnal cycle, and Kilimanjaro, where clear skies prevail. Surface energy fluxes were calculated for the meteorological station site using a physical mass- and energy-balance model driven by measured meteorological data and additional input parameters that were determined by Monte Carlo optimization. Sublimation rate was lower than those reported on other tropical glaciers, and melt rate was high throughout the year, with the glacier surface reaching the melting point on an almost daily basis. Surface mass balance is influenced by both solid precipitation and air temperature, with radiation providing the greatest net source of energy to the surface. Cloud cover typically reduces the net radiation balance compared to clear-sky conditions, and thus the frequent formation of convective clouds over the summit of Mt Kenya and the associated higher rate of snow accumulation are important in limiting the rate of mass loss from the glacier surface. The analyses shown here form the basis for future glacier-wide mass and energy balance modeling to determine the climate proxy offered by the glaciers of Mt Kenya.

scholarly journals Glacier surface mass balance modeling in the inner tropics using a positive degree-day approach

2016 ◽  
Author(s):  
L. Maisincho ◽  
V. Favier ◽  
P. Wagnon ◽  
V. Jomelli ◽  
R. Basantes Serrano ◽  
...  
Keyword(s):  
Wind Speed ◽  
Mass Balance ◽  
Shortwave Radiation ◽  
Surface Mass Balance ◽  
Glacier Surface ◽  
Surface Mass ◽  
Model Based ◽  
Degree Day ◽  
Positive Degree ◽  
Snow And Ice

Abstract. We present a basic ablation model combining a positive degree-day approach to calculate melting and a simple equation based on wind speed to compute sublimation. The model was calibrated at point scale (4900 m a.s.l.) on Antizana Glacier 15 (0.28 km2; 0°28' S, 78°09' W) with data from March 2002 to August 2003 and validated with data from January to November 2005. Cross validation was performed by interchanging the calibration and validation periods. Optimization of the model based on the calculated surface energy balance allowed degree-day factors to be retrieved for snow and ice, and suggests that melting started when daily air temperature was still below 0 °C, because incoming shortwave radiation was intense around noon and resulted in positive temperatures for a few hours a day. The model was then distributed over the glacier and applied to the 2000–2008 period using meteorological inputs measured on the glacier foreland to assess to what extent this approach is suitable for quantifying glacier surface mass balance in Ecuador. Results showed that a model based on temperature, wind speed, and precipitation is able to reproduce a large part of surface mass-balance variability of Antizana Glacier 15 even though the melting factors for snow and ice may vary with time. The model performed well because temperatures were significantly correlated with albedo and net shortwave radiation. Because this relationship disappeared when strong winds result in mixed air in the surface boundary layer, this model should not be extrapolated to other tropical regions where sublimation increases during a pronounced dry season or where glaciers are located above the mean freezing level.

scholarly journals Micrometeorological conditions and surface mass and energy fluxes on Lewis glacier, Mt Kenya, in relation to other tropical glaciers

2012 ◽  
Vol 6 (6) ◽  
pp. 5181-5224 ◽  
Author(s):  
L. Nicholson ◽  
R. Prinz ◽  
T. Mölg ◽  
G. Kaser
Keyword(s):  
Energy Balance ◽  
Mass Balance ◽  
Cloud Cover ◽  
Meteorological Data ◽  
Snow Accumulation ◽  
Energy Fluxes ◽  
Glacier Surface ◽  
Monte Carlo Optimization ◽  
Surface Mass ◽  
Tropical Glaciers

Abstract. The Lewis Glacier on Mt Kenya is one of the best-studied tropical glaciers, but full understanding of the interaction of the glacier mass balance and climate forcing has been hampered by a lack of long term meteorological data. Here we present 2.5 yr of meteorological data collected from the glacier surface from October 2009–February 2012, which indicate that mean meteorological conditions in the upper zone of Lewis Glacier are comparable to those experienced in the ablation zones of South American tropical glaciers. In the context of other glaciated mountains of equatorial east Africa, the summit zone of Mt Kenya shows strong diurnal cycles of convective cloud development as opposed to the Rwenzoris where cloud cover persists throughout the diurnal cycle and Kilimanjaro where clear skies prevail. Surface energy fluxes were calculated for the meteorological station site using a physical mass- and energy-balance model driven by hourly measured meteorological data and additional input parameters that were determined by Monte Carlo optimization. Sublimation rate was lower than those reported on other tropical glaciers and melt rate was high throughout the year, with the glacier surface reaching the melting point on an almost daily basis. Surface mass balance is influenced by both solid precipitation and air temperature, with radiation providing the greatest net source of energy to the surface. Cloud cover typically reduces the net radiation balance compared to clear sky conditions, and thus the more frequent formation of convective clouds over the summit of Mt Kenya, and the associated higher rate of snow accumulation are important in limiting the rate of mass loss from the glacier surface. The analyses shown here are the basis for glacier-wide mass and energy balance modeling to determine the climate proxy offered by the glaciers of Mt Kenya.

scholarly journals Climatic drivers of seasonal glacier mass balances: an analysis of 6 decades at Glacier de Sarennes (French Alps)

2012 ◽  
Vol 6 (3) ◽  
pp. 2115-2160
Author(s):  
E. Thibert ◽  
N. Eckert ◽  
C. Vincent
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Late Winter ◽  
Equilibrium Line Altitude ◽  
French Alps ◽  
Ice Melt ◽  
Air Temperatures ◽  
Climatic Drivers ◽  
Main Component ◽  
Snow And Ice

Abstract. Refined temporal signals are extracted from a glacier winter and summer mass balance series recorded at Glacier de Sarennes (French Alps) using variance decomposition. They are related to local and synoptic meteorological data in terms of interannual variability and structured trends. The winter balance has increased by +23% since 1976 due to more precipitation in early and late winter. The summer balance has decreased since 1982 due to a 43% increase in snow and ice melt. A 24-day lengthening of the ablation period – mainly due to longer ice ablation – is the main component in the overall increase in ablation. In addition, the last 25 yr have seen increases in ablation rates of 14 and 10% for snow and ice respectively. A simple degree-day analysis can account for both the snow/ice melt rate rise and the lengthening of the ablation period as a function of higher air temperatures. From the same analysis, the equilibrium line altitude of this 45° North latitude south-facing glacier has sensitivity to temperature of +93 m °C−1 around its mean elevation of 3100 m a.s.l. over 6 decades. The sensitivity of summer balance to temperature is −0.62 m w.e. yr−1 °C−1 for a typical 125-day long ablation season. Finally, the time structure of winter and summer mass balance terms are connected to NAO anomalies. Best correlations are obtained with winter NAO anomalies. However, they strongly depend on how the NAO signal is smoothed, so that the link between mass-balance seasonal terms and NAO signal remains tenuous and hard to interpret.

scholarly journals Climatic drivers of seasonal glacier mass balances: an analysis of 6 decades at Glacier de Sarennes (French Alps)

2013 ◽  
Vol 7 (1) ◽  
pp. 47-66 ◽  
Author(s):  
E. Thibert ◽  
N. Eckert ◽  
C. Vincent
Keyword(s):  
Mass Balance ◽  
Large Scale ◽  
Meteorological Data ◽  
Low Frequency ◽  
Late Winter ◽  
Equilibrium Line Altitude ◽  
French Alps ◽  
Ice Melt ◽  
Main Component ◽  
Snow And Ice

Abstract. Refined temporal signals extracted from a winter and summer mass balance series recorded at Glacier de Sarennes (French Alps) using variance decomposition are related to local meteorological data and large-scale North Atlantic Oscillation (NAO) anomalies in terms of interannual variability, trends of the low-frequency signals, and breaks in the time series. The winter balance has increased by &amp;plus;23% since 1976 due to more precipitation in early and late winter. The summer balance has decreased since 1982 due to a 43% increase in snow and ice melt. A 24-day lengthening of the ablation period – mainly due to longer ice ablation – is the main component in the overall increase in ablation. In addition, the last 25 yr have seen increases in ablation rates of 14 and 10% for snow and ice, respectively. A simple degree-day analysis can account for both the snow/ice melt rate rise and the lengthening of the ablation period as a function of higher air temperatures. From the same analysis, the equilibrium-line altitude of this 45° N latitude south-facing glacier has a sensitivity to temperature of &amp;plus;93 m °C−1 around its mean elevation of 3100 m a.s.l. over 6 decades. The sensitivity of summer balance to temperature is −0.62 m w.e. yr−1 °C−1 for a typical 125-day-long ablation season. Finally, the correlation of winter and summer mass balance terms with NAO anomalies is investigated. Singularly, highest values are obtained between winter NAO anomalies and summer balance. Winter NAO anomalies and winter balance and precipitation are almost disconnected. However, these results strongly depend on how the NAO signal is smoothed, so that the link between Sarennes mass balance seasonal terms and NAO signal remains tenuous and hard to interpret.

scholarly journals Degree-day modelling of the surface mass balance of Urumqi Glacier No. 1, Tian Shan, China

2010 ◽  
Vol 4 (1) ◽  
pp. 207-232 ◽  
Author(s):  
E. Huintjes ◽  
H. Li ◽  
T. Sauter ◽  
Z. Li ◽  
C. Schneider
Keyword(s):  
Spatial Distribution ◽  
Mass Balance ◽  
Meteorological Data ◽  
Model Performance ◽  
Western China ◽  
Shortwave Radiation ◽  
Small Scale ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Degree Day

Abstract. A distributed temperature-index melt model including potential shortwave radiation is used to calculate annual mean surface mass balance and the spatial distribution of melt rates on the east branch of Urumqi Glacier No. 1, north-western China. The lack of continuous datasets at higher temporal resolution for various climate variables suggests the application of a degree-day model with only few required input variables. The model is calibrated for a six day period in July 2007, for which daily mass balance measurements and meteorological data are available. Based on point measurements of mass balance, parameter values are optimised running a constrained multivariable function using the simplex search method. To evaluate the model performance, annual mass balances for the period 1987/88–2004/05 are calculated using NCEP/NCAR-Reanalysis data. The modelled values fit the observed mass balance with a correlation of 0.98 and an RMSE of 332 mm w.e. Furthermore, the calculated spatial distribution of melt rates shows an improvement in small-scale variations compared to the simple degree-day approach.

scholarly journals Eemian Greenland Surface Mass Balance strongly sensitive to SMB model choice

2018 ◽  
Author(s):  
Andreas Plach ◽  
Kerim H. Nisancioglu ◽  
Sébastien Le clec’h ◽  
Andreas Born ◽  
Petra M. Langebroek ◽  
...  
Keyword(s):  
Mass Balance ◽  
Regional Climate ◽  
Greenland Ice Sheet ◽  
Model Complexity ◽  
Surface Mass Balance ◽  
Potential Contribution ◽  
Surface Mass ◽  
Degree Day ◽  
Positive Degree ◽  
Uncertainty Estimates

Abstract. Understanding the behavior of the Greenland ice sheet in a warmer climate, and particularly its surface mass balance (SMB), is important for assessing Greenland’s potential contribution to future sea level rise. The Eemian interglacial, the most recent warmer-than-present period in Earth’s history approximately 125 000 years ago, provides an analogue for a warm summer climate over Greenland. The Eemian is characterized by a positive Northern Hemisphere summer insolation anomaly, which introduces uncertainties in Eemian SMB when using positive degree day estimates. In this study, we use Eemian global and regional climate simulations in combination with three types of SMB models – a simple positive degree day, an intermediate complexity, and a full surface energy balance model – to evaluate the importance of regional climate and model complexity for estimates of Greenland SMB. We find that all SMB models perform well under the relatively cool pre-industrial and late Eemian. For the relatively warm early Eemian, the differences between SMB models are large which is associated with the representation of insolation in the respective models. For all simulated time slices there is a systematic difference between globally and regionally forced SMB models, due to the different representation of the regional climate over Greenland. We conclude that both the resolution of the simulated climate as well as the method used to estimate the SMB, are important for an accurate simulation of Greenland’s SMB. Whether model resolution or SMB method is most important depends on the climate state and in particular the prevailing insolation pattern. We suggest that future Eemian climate model inter-comparison studies are combined with different SMB models to quantify Eemian SMB uncertainty estimates.

scholarly journals An 18-yr long (1993–2011) snow and meteorological dataset from a mid-altitude mountain site (Col de Porte, France, 1325 m alt.) for driving and evaluating snowpack models

2012 ◽  
Vol 4 (1) ◽  
pp. 13-21 ◽  
Author(s):  
S. Morin ◽  
Y. Lejeune ◽  
B. Lesaffre ◽  
J.-M. Panel ◽  
D. Poncet ◽  
...  
Keyword(s):  
Snow Depth ◽  
Snow Water Equivalent ◽  
Meteorological Data ◽  
Model Performance ◽  
Short Wave ◽  
Wave Radiation ◽  
Density Profiles ◽  
The Public ◽  
Snow Water ◽  
Snowpack Properties

Abstract. A quality-controlled snow and meteorological dataset spanning the period 1 August 1993–31 July 2011 is presented, originating from the experimental station Col de Porte (1325 m altitude, Chartreuse range, France). Emphasis is placed on meteorological data relevant to the observation and modelling of the seasonal snowpack. In-situ driving data, at the hourly resolution, consist of measurements of air temperature, relative humidity, windspeed, incoming short-wave and long-wave radiation, precipitation rate partitioned between snow- and rainfall, with a focus on the snow-dominated season. Meteorological data for the three summer months (generally from 10 June to 20 September), when the continuity of the field record is not warranted, are taken from a local meteorological reanalysis (SAFRAN), in order to provide a continuous and consistent gap-free record. Data relevant to snowpack properties are provided at the daily (snow depth, snow water equivalent, runoff and albedo) and hourly (snow depth, albedo, runoff, surface temperature, soil temperature) time resolution. Internal snowpack information is provided from weekly manual snowpit observations (mostly consisting in penetration resistance, snow type, snow temperature and density profiles) and from a hourly record of temperature and height of vertically free ''settling'' disks. This dataset has been partially used in the past to assist in developing snowpack models and is presented here comprehensively for the purpose of multi-year model performance assessment. The data is placed on the PANGAEA repository (http://dx.doi.org/10.1594/PANGAEA.774249) as well as on the public ftp server ftp://ftp-cnrm.meteo.fr/pub-cencdp/.

scholarly journals The Northeast Asia mountain glaciers in the near future by AOGCM scenarios

2010 ◽  
Vol 4 (4) ◽  
pp. 435-445 ◽  
Author(s):  
M. D. Ananicheva ◽  
A. N. Krenke ◽  
R. G. Barry
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Northeast Asia ◽  
Morphological Structure ◽  
Kamchatka Peninsula ◽  
Baseline Period ◽  
Equilibrium Line Altitude ◽  
Mountain Glaciers ◽  
Glacier System ◽  
Glacier Terminus

Abstract. We studied contrasting glacier systems in continental (Orulgan, Suntar-Khayata and Chersky) mountain ranges, located in the region of the lowest temperatures in the Northern Hemisphere at the boundary of Atlantic and Pacific influences – and maritime ones (Kamchatka Peninsula) – under Pacific influence. Our purpose is to present a simple projection method to assess the main parameters of these glacier regions under climate change. To achieve this, constructed vertical profiles of mass balance (accumulation and ablation) based both on meteorological data for the 1950–1990s (baseline period) and ECHAM4 for 2049–2060 (projected period) are used, the latter – as a climatic scenario. The observations and scenarios were used to define the recent and future equilibrium line altitude and glacier terminus altitude level for each glacier system as well as areas and balance components. The altitudinal distributions of ice areas were determined for present and future, and they were used for prediction of glacier extent versus altitude in the system taking into account the correlation between the ELA and glacier-terminus level change. We tested two hypotheses of ice distribution versus altitude in mountain (valley) glaciers – "linear" and "non-linear". The results are estimates of the possible changes of the areas and morphological structure of northeastern Asia glacier systems and their mass balance characteristics for 2049–2060. Glaciers in the southern parts of northeastern Siberia and those covering small ranges in Kamchatka will likely disappear under the ECHAM4 scenario; the best preservation of glaciers will be on the highest volcanic peaks of Kamchatka. Finally, we compare characteristics of the stability of continental and maritime glacier systems under global warming.

scholarly journals Modelling the mass balance of northwest Spitsbergen glaciers and responses to climate change

1997 ◽  
Vol 24 ◽  
pp. 203-210 ◽  
Author(s):  
Kevin M. Fleming ◽  
Julian A. Dowdeswell ◽  
Johannes Oerlemans
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Meteorological Data ◽  
Balance Model ◽  
Greenhouse Warming ◽  
Weather Station ◽  
Mass Balances ◽  
Area Distribution ◽  
Sensitivity Tests ◽  
Precipitation Increase

An energy-balance model is used to calculate mass balance and equilibrium-line altitudes (ELAs) on two northwest Spitsbergen glaciers, Austre Brøggerbreen and Midre Lovénbreen, whose mass balances are at present negative, and for which greater than 20 year records of mass-balance data are available. The model takes meteorological data, ice-mass area distribution with altitude, and solar radiation as inputs. Modelling uses mean daily meteorological data from a nearby weather station, adjusted for altitude. Average net balances modelled for 1980–89 using models tuned to the decade’s average were –0.44 and –0.47 m w.e. for Lovénbreen and Brøggerbreen, respectively, compared with the measured averages of –0.27 and –0.36 m. Sensitivity tests on glacier response to greenhouse warming predict a net balance change of –0.61 m year–1 per °C temperature rise relative to today, and a rise in ELA of 90 m °C–1. Modelling of Little lee Age conditions in Spitsbergen suggests that a 0.6°C cooling or a precipitation increase of 23% would yield zero net mass balance for Lovénbreen and that further cooling would increase net balance by 0.30 m year–1 °C–1. Set in the context of similar modelling of southern Norwegian, Alpine and Greenland ice masses, these results support the suggestion that glaciers with a maritime influence (i.e. higher accumulation) are most sensitive to climate change, implying a gradient towards decreasing sensitivity as accumulation decreases eastward and with altitude in Svalbard.

Sign in / Sign up

Export Citation Format

Share Document