Reconstruction of the annual balance of Vadret da Morteratsch, Switzerland, since 1865

AbstractWe have reconstructed the annual balance of Vadret da Morteratsch, Engadine, Switzerland, with a two-dimensional energy-balance model for the period 1865–2005. The model takes into account a parameterization of the surface energy fluxes, an albedo that decreases exponentially with snow depth as well as the shading effect of the surrounding mountains. The model was first calibrated with a 5 year record of annual balance measurements made at 20 different sites on the glacier between 2001 and 2006 using meteorological data from surrounding weather stations as input. To force the model for the period starting in 1865, we employed monthly temperature and precipitation records from nearby valley stations. The model reproduces the observed annual balance reasonably well, except for the lower part during the warmest years. Most crucial to the results is the altitudinal precipitation gradient, but this factor is hard to quantify from the limited precipitation data at high elevations. The simulation shows an almost continuous mass loss since 1865, with short interruptions around 1920, 1935 and 1980. A trend towards a more negative annual balance can be observed since the beginning of the 1980s. The simulated cumulative mass balance for the entire period 1865–2005 was found to be –46mw.e.

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Quality Assurance of Surface Wind Observations from Automated Weather Stations

Journal of Atmospheric and Oceanic Technology ◽

10.1175/2010jtecha1404.1 ◽

2010 ◽

Vol 27 (7) ◽

pp. 1101-1122 ◽

Cited By ~ 40

Author(s):

Pedro A. Jiménez ◽

J. Fidel González-Rouco ◽

Jorge Navarro ◽

Juan P. Montávez ◽

Elena García-Bustamante

Keyword(s):

Quality Assurance ◽

Wind Speed ◽

Meteorological Data ◽

Surface Wind ◽

Temporal Consistency ◽

Temperature And Precipitation ◽

Individual Time Series ◽

Weather Stations ◽

The Individual ◽

Regional Climates

Abstract Meteorological data of good quality are important for understanding both global and regional climates. In this respect, great efforts have been made to evaluate temperature- and precipitation-related records. This study summarizes the evaluations made to date of the quality of wind speed and direction records acquired at 41 automated weather stations in the northeast of the Iberian Peninsula. Observations were acquired from 1992 to 2005 at a temporal resolution of 10 and 30 min. A quality assurance system was imposed to screen the records for 1) manipulation errors associated with storage and management of the data, 2) consistency limits to ensure that observations are within their natural limits of variation, and 3) temporal consistency to assess abnormally low/high variations in the individual time series. In addition, the most important biases of the dataset are analyzed and corrected wherever possible. A total of 1.8% wind speed and 3.7% wind direction records was assumed invalid, pointing to specific problems in wind measurement. The study not only tries to contribute to the science with the creation of a wind dataset of improved quality, but it also reports on potential errors that could be present in other wind datasets.

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Relating glacier mass balance to meteorological data by using a seasonal sensitivity characteristic

Journal of Glaciology ◽

10.3189/172756500781833269 ◽

2000 ◽

Vol 46 (152) ◽

pp. 1-6 ◽

Cited By ~ 117

Author(s):

J. Oerlemans ◽

B. K. Reichert

Keyword(s):

Mass Balance ◽

Climate Sensitivity ◽

Significant Contribution ◽

Meteorological Data ◽

Balance Model ◽

Glacier Mass Balance ◽

Atmospheric Models ◽

Temperature And Precipitation ◽

The Mean ◽

Sensitivity Characteristic

AbstractWe propose to quantify the climate sensitivity of the mean specific balance B of a glacier by a seasonal sensitivity characteristic (SSC). The SSC gives the dependence of B on monthly anomalies in temperature and precipitation. It is calculated from a mass-balance model. We show and discuss examples for Franz-Josef Glacier (New Zealand), Nigardsbreen (Norway), Hintereisferner (Austria), Peyto Glacier (Canadian Rockies), Abramov Glacier (Kirghizstan) and White Glacier (Canadian Arctic). With regard to the climate sensitivity of B, the SSCs clearly show that summer temperature is the most important factor for glaciers in a dry climate. For glaciers in a wetter climate, spring and fall temperatures also make a significant contribution to the overall sensitivity. The SSC is a 2 × 12 matrix. Multiplying it with monthly perturbations of temperature and precipitation for a particular year yields an estimate of the balance for that year. We show that, with this technique, mass-balance series can be (re)constructed from long meteorological records or from output of atmospheric models.

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Distributed mass-balance and climate sensitivity modelling of Engabreen, Norway

Annals of Glaciology ◽

10.3189/172756405781812998 ◽

2005 ◽

Vol 42 ◽

pp. 395-401 ◽

Cited By ~ 33

Author(s):

Thomas V. Schuler ◽

Regine Hock ◽

Miriam Jackson ◽

Hallgeir Elvehøy ◽

Matthias Braun ◽

...

Keyword(s):

Mass Balance ◽

Meteorological Data ◽

High Sensitivity ◽

Balance Model ◽

Glacier Mass Balance ◽

Index Method ◽

Temperature And Precipitation ◽

Simple Mass ◽

Climate Station ◽

The Impact

AbstractAssessing the impact of possible climate change on the water resources of glacierized areas requires a reliable model of the climate–glacier-mass-balance relationship. In this study, we simulate the mass-balance evolution of Engabreen, Norway, using a simple mass-balance model based on daily temperature and precipitation data from a nearby climate station. Ablation is calculated using a distributed temperature-index method including potential direct solar radiation, while accumulation is distributed linearly with elevation. The model was run for the period 1974/75–2001/02, for which annual mass-balance measurements and meteorological data are available. Parameter values were determined by a multi-criteria validation including point measurements of mass balance, mass-balance gradients and specific mass balance. The modelled results fit the observed mass balance well. Simple sensitivity experiments indicate a high sensitivity of the mass balance to temperature changes, as expected for maritime glaciers. The results suggest, further, that the mass balance of Engabreen is more sensitive to warming during summer than during winter, while precipitation changes affect almost exclusively the winter balance.

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Modelling the contribution of ice cliff melt to glacier mass loss at the catchment scale

10.5194/egusphere-egu21-7026 ◽

2021 ◽

Author(s):

Pascal Buri ◽

Evan S Miles ◽

Jakob Steiner ◽

Silvan Ragettli ◽

Francesca Pellicciotti

Keyword(s):

Mass Loss ◽

Mass Balance ◽

Meteorological Data ◽

High Mountain ◽

Catchment Scale ◽

Glacier Surface ◽

Surface Mass ◽

Mass Losses ◽

Weather Stations ◽

High Elevations

The melt rates of debris-covered glaciers in High Mountain Asia are highly heterogeneous and poorly constrained. Supraglacial cliffs are typical surface features of debris-covered glaciers and act as windows of energy transfer from the atmosphere to the ice, locally enhancing melt and mass losses of otherwise insulated ice. Despite this, their contribution to the glacier mass budget has never been quantified at the glacier scale.Here we simulate the specific melt of all supraglacial ice cliffs individually in a Himalayan catchment (Langtang Valley, Nepalese Himalayas), using a process-based ice cliff melt model that has previously been validated in the catchment. Cliff outlines and initial topography are derived from high-resolution stereo SPOT6-imagery and the model is forced by meteorological data from on- and off-glacier automatic weather stations within the valley, both for the 2014 melt season. The model simulates ice cliff backwasting by considering the cliff-atmosphere energy-balance, reburial by debris and the effects of adjacent ponds. We estimate the contribution of ice cliffs to glacier surface mass balance derived from ensemble mean geodetic thinning observations and emergence flux calculations for the same glaciers 2006-2015.We show that ice cliffs, although covering only 2.1 &#177;0.6 % of the debris-covered tongues, are partially responsible for the high thinning rates of debris-covered glacier tongues, leading to a catchment mass loss underestimation of 17 &#177;4 % if not considered. We show that cliffs enhance melt where other processes would suppress it, i.e. at high elevations or where debris is thick, and confirm that they contribute relatively more to glacier mass loss if oriented north.Our approach bridges a scale gap in our understanding of the processes of debris-covered glacier mass losses, and a new quantification of their catchment wide melt and mass balance.

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Langfjordjøkelen, a rapidly shrinking glacier in northern Norway

Journal of Glaciology ◽

10.3189/2012jog11j014 ◽

2012 ◽

Vol 58 (209) ◽

pp. 581-593 ◽

Cited By ~ 31

Author(s):

Liss M. Andreassen ◽

Øyvind Nordli ◽

Al Rasmussen ◽

Kjetil Melvold ◽

Øyvind Nordli

Keyword(s):

Mass Balance ◽

Meteorological Data ◽

Balance Model ◽

Surface Mass Balance ◽

Mass Balance Model ◽

Surface Mass ◽

Northern Norway ◽

Ice Cap ◽

Geodetic Mass Balance ◽

Annual Balance

AbstractIn this paper we document changes of Langfjordjøkelen, a small ice cap in northern Norway. Surface mass-balance measurements have been carried out on an east-facing part (3.2 km2) of the ice cap since 1989. Measurements reveal a strong thinning; the balance year 2008/09 was the 13th successive year with significant negative annual balance (≤-0.30 m w.e.). The average annual deficit was 0.9m w.e. over 1989-2009. The recent thinning of Langfjordjøkelen is stronger than observed for any other glacier in mainland Norway. Maps from 1966, 1994 and 2008 show that the whole ice cap is shrinking. The total volume loss over 1966-2008 was 0.264 km3. The east-facing part has been greatly reduced in volume (46%), area (38%) and length (20%). For this part over 1994-2008, the cumulative direct mass balance (-14.5 m w.e.) is less negative than the geodetic mass balance (-17.7 m w.e.). A surface mass-balance model using upper-air meteorological data was used to reconstruct annual balances back to 1948 and to reconstruct unmeasured years 1994 and 1995. Sensitivity of annual balance to 1°C warming is -0.76 m w.e. and to 10% increase in precipitation is +0.20 m w.e.

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Using climate reanalysis data in conjunction with multi-temporal satellite thermal imagery to derive supraglacial debris thickness changes from energy-balance modelling

Journal of Glaciology ◽

10.1017/jog.2020.111 ◽

2021 ◽

pp. 1-19

Author(s):

Rebecca L. Stewart ◽

Matthew Westoby ◽

Francesca Pellicciotti ◽

Ann Rowan ◽

Darrel Swift ◽

...

Keyword(s):

Energy Balance ◽

Surface Energy ◽

Surface Energy Balance ◽

Current Knowledge ◽

Meteorological Data ◽

Reanalysis Data ◽

Balance Model ◽

Thermal Imagery ◽

Thickness Estimation ◽

Miage Glacier

Abstract Surface energy-balance models are commonly used in conjunction with satellite thermal imagery to estimate supraglacial debris thickness. Removing the need for local meteorological data in the debris thickness estimation workflow could improve the versatility and spatiotemporal application of debris thickness estimation. We evaluate the use of regional reanalysis data to derive debris thickness for two mountain glaciers using a surface energy-balance model. Results forced using ERA-5 agree with AWS-derived estimates to within 0.01 ± 0.05 m for Miage Glacier, Italy, and 0.01 ± 0.02 m for Khumbu Glacier, Nepal. ERA-5 data were then used to estimate spatiotemporal changes in debris thickness over a ~20-year period for Miage Glacier, Khumbu Glacier and Haut Glacier d'Arolla, Switzerland. We observe significant increases in debris thickness at the terminus for Haut Glacier d'Arolla and at the margins of the expanding debris cover at all glaciers. While simulated debris thickness was underestimated compared to point measurements in areas of thick debris, our approach can reconstruct glacier-scale debris thickness distribution and its temporal evolution over multiple decades. We find significant changes in debris thickness over areas of thin debris, areas susceptible to high ablation rates, where current knowledge of debris evolution is limited.

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Spatial distribution and temporal variability of open fire in China

International Journal of Wildland Fire ◽

10.1071/wf15213 ◽

2017 ◽

Vol 26 (2) ◽

pp. 122 ◽

Cited By ~ 7

Author(s):

Kunpeng Yi ◽

Yulong Bao ◽

Jiquan Zhang

Keyword(s):

Meteorological Data ◽

Fire Season ◽

Spatial And Temporal Patterns ◽

Burnt Area ◽

The North ◽

Temperature And Precipitation ◽

North Eastern ◽

Vegetation Fires ◽

Precipitation Variation ◽

Two Peaks

This study presents the spatial and temporal patterns of vegetation fires in China based on a combination of national fire records (1950–2010) and satellite fire data (2001–12). This analysis presents the first attempt to understand existing patterns of open fires and their consequences for the whole of China. We analysed inter- and intra-annual fire trends and variations in nine subregions of China as well as associated monthly meteorological data from 130 stations within a 50-year period. During the period 2001–12, an average area of 3.2 × 106 ha was consumed by fire per year in China. The Chinese fire season has two peaks occurring in the spring and autumn. The profiles of the burnt area for each subregion exhibit distinct seasonality. The majority of the vegetation fires occurred in the north-eastern and south-western provinces. We analysed quantitative relationships between climate (temperature and precipitation) and burnt area. The results indicate a synchronous relationship between precipitation variation and burnt area. The data in this paper reveal how climate and human activities interact to create China’s distinctive pyrogeography.

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Application of a mass-balance model to a Himalayan glacier

Journal of Glaciology ◽

10.1017/s002214300000143x ◽

1999 ◽

Vol 45 (151) ◽

pp. 559-567 ◽

Cited By ~ 33

Author(s):

Rijan Bhakta Kayastha ◽

Tetsuo Ohata ◽

Yutaka Ageta

Keyword(s):

Mass Balance ◽

Surface Albedo ◽

Balance Model ◽

Mass Balance Model ◽

Mass Balances ◽

Climatic Parameters ◽

Glacier Surface ◽

Temperature And Precipitation ◽

Ice Surface ◽

Good Agreement

AbstractA mass-balance model based on the energy balance at the snow or ice surface is formulated, with particular attention paid to processes affecting absorption of radiation. The model is applied to a small glacier, Glacier AX010 in the Nepalese Himalaya, and tests of its mass-balance sensitivity to input and climatic parameters are carried out. Calculated and observed area-averaged mass balances of the glacier during summer 1978 (June-September) show good agreement, namely -0.44 and -0.46 m w.e., respectively.Results show the mass balance is strongly sensitive to snow or ice albedo, to the effects of screening by surrounding mountain walls, to areal variations in multiple reflection between clouds and the glacier surface, and to thin snow covers which alter the surface albedo. In tests of the sensitivity of the mass balance to seasonal values of climatic parameters, the mass balance is found to be strongly sensitive to summer air temperature and precipitation but only weakly sensitive to relative humidity.

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Summer drought in Switzerland 1981‒2020: Events, trends and drivers

10.5194/ems2021-208 ◽

2021 ◽

Author(s):

Simon C. Scherrer ◽

Christoph Spirig ◽

Martin Hirschi ◽

Felix Maurer ◽

Sven Kotlarski

Keyword(s):

Regional Climate Model ◽

Soil Water ◽

Climate Model ◽

Potential Evapotranspiration ◽

Meteorological Data ◽

Regional Climate ◽

Reanalysis Data ◽

Summer Drought ◽

Temperature And Precipitation ◽

Temperature Scaling

The Alpine region has recently experienced several dry summers with negative impacts on the economy, society and ecology. Here, soil water, evapotranspiration and meteorological data from several observational and model-based data sources is used to assess events, trends and drivers of summer drought in Switzerland in the period 1981&#8210;2020. 2003 and 2018 are identified as the driest summers followed by somewhat weaker drought conditions in 2020, 2015 and 2011. We find clear evidence for an increasing summer drying in Switzerland. The observed climatic water balance (-39.2&#160;mm/decade) and 0-1 m soil water from reanalysis (ERA5-Land: -4.7&#160;mm/decade; ERA5: -7.2&#160;mm/decade) show a clear tendency towards summer drying with decreasing trends in most months. Increasing evapotranspiration (potential evapotranspiration: +21.0&#160;mm/decade; ERA5-Land actual evapotranspiration: +15.1&#160;mm/decade) is identified as important driver which scales excellently (+4 to +7%/K) with the observed strong warming of about 2&#176;C. An insignificant decrease in precipitation further enhanced the tendency towards drier conditions. Most simulations of the EURO-CORDEX regional climate model ensemble underestimate the changes in summer drying. They underestimate both, the observed recent summer warming and the small decrease in precipitation. The changes in temperature and precipitation are negatively correlated, i.e. simulations with stronger warming tend to show (weak) decreases in precipitation. However, most simulations and the reanalysis overestimate the correlation between temperature and precipitation and the precipitation-temperature scaling on the interannual time scale. Our results emphasize that the analysis of the regional summer drought evolution and its drivers remains challenging especially with regional climate model data but considerable uncertainties also exist in reanalysis data sets.

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