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 Spatial and seasonal effects of temperature variability in a positive degree-day glacier surface mass-balance model

2013 ◽  
Vol 59 (218) ◽  
pp. 1202-1204 ◽  
Author(s):  
Julien Seguinot
Keyword(s):  
Mass Balance ◽  
Seasonal Effects ◽  
Balance Model ◽  
Surface Mass Balance ◽  
Mass Balance Model ◽  
Glacier Surface ◽  
Surface Mass ◽  
Degree Day ◽  
Positive Degree ◽  
Effects Of Temperature

The positive degree-day model is a parameterization of surface melt widely used for its simplicity (Hock, 2003).

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 High resolution (1 km) positive degree-day modelling of Greenland ice sheet surface mass balance, 1870–2012 using reanalysis data

2016 ◽  
Vol 63 (237) ◽  
pp. 176-193 ◽  
Author(s):  
DAVID J. WILTON ◽  
AMY JOWETT ◽  
EDWARD HANNA ◽  
GRANT R. BIGG ◽  
MICHIEL R. VAN DEN BROEKE ◽  
...  
Keyword(s):  
Mass Balance ◽  
Climate Models ◽  
Local Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Reanalysis Data ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Degree Day ◽  
Positive Degree

ABSTRACTWe show results from a positive degree-day (PDD) model of Greenland ice sheet (GrIS) surface mass balance (SMB), 1870–2012, forced with reanalysis data. The model includes an improved daily temperature parameterization as compared with a previous version and is run at 1 km rather than 5 km resolution. The improvements lead overall to higher SMB with the same forcing data. We also compare our model with results from two regional climate models (RCMs). While there is good qualitative agreement between our PDD model and the RCMs, it usually results in lower precipitation and lower runoff but approximately equivalent SMB: mean 1979–2012 SMB (± standard deviation), in Gt a−1, is 382 ± 78 in the PDD model, compared with 379 ± 101 and 425 ± 90 for the RCMs. Comparison with in situ SMB observations suggests that the RCMs may be more accurate than PDD at local level, in some areas, although the latter generally compares well. Dividing the GrIS into seven drainage basins we show that SMB has decreased sharply in all regions since 2000. Finally we show correlation between runoff close to two calving glaciers and either calving front retreat or calving flux, this being most noticeable from the mid-1990s.

scholarly journals On the interest of positive degree day models for mass balance modeling in the inner tropics

2014 ◽  
Vol 8 (3) ◽  
pp. 2637-2684 ◽  
Author(s):  
L. Maisincho ◽  
V. Favier ◽  
P. Wagnon ◽  
R. Basantes Serrano ◽  
B. Francou ◽  
...  
Keyword(s):  
Mass Balance ◽  
Time Scale ◽  
Regional Scale ◽  
Heat Fluxes ◽  
Shortwave Radiation ◽  
Glacier Mass Balance ◽  
Mass Balances ◽  
Glacier Surface ◽  
Degree Day ◽  
Positive Degree

Abstract. A positive degree-day (PDD) model was tested on Antizana Glacier 15α (0.28 km2; 0°28' S, 78°09' W) to assess to what extent this approach is suitable for studying glacier mass balance in the inner tropics. Cumulative positive temperatures were compared with field measurements of melting amount and with surface energy balance computations. A significant link was revealed when a distinction was made between the snow and ice comprising the glacier surface. Significant correlations allowed degree-day factors to be retrieved for snow, and clean and dirty ice. The relationship between melt amount and temperature was mainly explained by the role of net shortwave radiation in both melting and in the variations in the temperature of the surface layer. However, this relationship disappeared from June to October (Period 1), because high wind speeds and low humidity cause highly negative turbulent latent heat fluxes. However, this had little impact on the computed total amount of melting at the annual time scale because temperatures are low and melting is generally limited during Period 1. At the daily time scale, melting starts when daily temperature means are still negative, because around noon incoming shortwave radiation is very high, and compensates for energy losses when the air is cold. The PDD model was applied to the 2000–2008 period using meteorological inputs measured on the glacier foreland. Results were compared to the glacier-wide mass balances measured in the field and were good, even though the melting factor should be adapted to the glacier surface state and may vary with time. Finally, the model was forced with precipitation and temperature data from the remote Izobamba station and NCEP-NCAR reanalysis data, also giving good results and showing that temperature variations are homogenous at the regional scale, meaning glacier mass balances can be modelled over large areas.

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 Glacier Surface Mass Balance in the Suntar-Khayata Mountains, Northeastern Siberia

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1949 ◽  
Author(s):  
Yong Zhang ◽  
Xin Wang ◽  
Zongli Jiang ◽  
Junfeng Wei ◽  
Hiroyuki Enomoto ◽  
...  
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Surface Mass Balance ◽  
Negative Mass ◽  
Glacier Surface ◽  
Surface Mass ◽  
Northeastern Siberia ◽  
Response To Temperature ◽  
Rapid Mass

Arctic glaciers comprise a small fraction of the world’s land ice area, but their ongoing mass loss currently represents a large cryospheric contribution to the sea level rise. In the Suntar-Khayata Mountains (SKMs) of northeastern Siberia, in situ measurements of glacier surface mass balance (SMB) are relatively sparse, limiting our understanding of the spatiotemporal patterns of regional mass loss. Here, we present SMB time series for all glaciers in the SKMs, estimated through a glacier SMB model. Our results yielded an average SMB of −0.22 m water equivalents (w.e.) year−1 for the whole region during 1951–2011. We found that 77.4% of these glaciers had a negative mass balance and detected slightly negative mass balance prior to 1991 and significantly rapid mass loss since 1991. The analysis suggests that the rapidly accelerating mass loss was dominated by increased surface melting, while the importance of refreezing in the SMB progressively decreased over time. Projections under two future climate scenarios confirmed the sustained rapid shrinkage of these glaciers. In response to temperature rise, the total present glacier area is likely to decrease by around 50% during the period 2071–2100 under representative concentration pathway 8.5 (RCP8.5).

The Andes Cordillera. Part III: glacier surface mass balance and contribution to sea level rise (1979-2014)

2016 ◽  
Vol 37 (7) ◽  
pp. 3154-3174 ◽  
Author(s):  
Sebastian H. Mernild ◽  
Glen E. Liston ◽  
Christopher Hiemstra ◽  
Ryan Wilson
Keyword(s):  
Mass Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Surface Mass Balance ◽  
Glacier Surface ◽  
Surface Mass ◽  
The Andes ◽  
Andes Cordillera

scholarly journals The contribution of snowdrift sublimation to the surface mass balance of Antarctica

1998 ◽  
Vol 27 ◽  
pp. 251-259 ◽  
Author(s):  
Richard Bintanja
Keyword(s):  
Wind Speed ◽  
Mass Balance ◽  
Surface Mass Balance ◽  
Vertical Profiles ◽  
Sublimation Rate ◽  
Model Calculations ◽  
Surface Mass ◽  
Wind Speeds ◽  
Hourly Data ◽  
Sublimation Rates

This paper presents model calculations of snowdrift sublimation rates for year-round automatic weather station (AWS) data in Terre Adélie, Antarctica. The model calculates vertical profiles of wind speed, temperature, humidity and suspended-snow particles in the atmospheric surface layer, and takes into account the buoyancy effects induced by the stably stratified suspended-snow profile by means of an appropriate Richardson number. The model is able to simulate accurately vertical profiles of sublimation rate derived from direct measurements. The model is used to parameterise snowdrift-sublimation rates in terms of wind speed and air temperature. This parameterisation is then used to calculate snowdrift-sublimation rates from 3 hourly data of six AWSs along a transect from Dumont d'Urville to South Pole during one year. Results show that sublimation of suspended snow is negligible in the interior of Antarctica where wind speeds and temperatures are low, whereas near the windy and relatively warm coast its contribution is significant (up to 17cmw.e. a−1). Snowdrift-sublimation rates are highest during summer, when temperatures are highest, in spite of the fact that wind speeds are not as high as in winter. It is concluded that snowdrift sublimation is one of the major terms in the surface mass balance of Antarctica, in particular in the coastal regions.

scholarly journals Structural Characteristics of Snow Drifts and Cornices

1985 ◽  
Vol 6 ◽  
pp. 287-288 ◽  
Author(s):  
Renji Naruse ◽  
Hiroshi Nishimura ◽  
Norikazu Maeno
Keyword(s):  
Grain Size ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Mass Balance ◽  
Structural Characteristics ◽  
Wind Tunnel Experiment ◽  
Surface Mass Balance ◽  
Field Observations ◽  
Surface Mass ◽  
Horizontal Step

Sorting effects of snow particles during deposition were studied in field observations of snow cornices and wind-tunnel experiment of snow drifts. Grain size, density and hardness were larger at the upper part (root) of a cornice than at the lower part (scarp). Experiments with the use of a horizontal step in a wind-tunnel revealed the importance of redistribution of snow particles on the formation of drifts: at wind speed of 5 m/s, about 40% of particles fallen onto the surface behind a 0.1-m high step were removed by erosion, rebound and creep. The surface mass balance controlling the growth and shape of a drift are briefly discussed.

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