scholarly journals Non-stationary Responses of Tree-Ring Chronologies and Glacier Mass Balance to Climate in the European Alps

2011 ◽  
Vol 43 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Giovanni Leonelli ◽  
Manuela Pelfini ◽  
Rosanne D'Arrigo ◽  
Wilfried Haeberli ◽  
Paolo Cherubini
2012 ◽  
Vol 6 (4) ◽  
pp. 713-727 ◽  
Author(s):  
M. Huss

Abstract. This study addresses the extrapolation of in-situ glacier mass balance measurements to the mountain-range scale and aims at deriving time series of area-averaged mass balance and ice volume change for all glaciers in the European Alps for the period 1900–2100. Long-term mass balance series for 50 Swiss glaciers based on a combination of field data and modelling, and WGMS data for glaciers in Austria, France and Italy are used. A complete glacier inventory is available for the year 2003. Mass balance extrapolation is performed based on (1) arithmetic averaging, (2) glacier hypsometry, and (3) multiple regression. Given a sufficient number of data series, multiple regression with variables describing glacier geometry performs best in reproducing observed spatial mass balance variability. Future mass changes are calculated by driving a combined model for mass balance and glacier geometry with GCM ensembles based on four emission scenarios. Mean glacier mass balance in the European Alps is −0.31 ± 0.04 m w.e. a−1 in 1900–2011, and −1 m w.e. a−1 over the last decade. Total ice volume change since 1900 is −96 ± 13 km3; annual values vary between −5.9 km3 (1947) and +3.9 km3 (1977). Mean mass balances are expected to be around −1.3 m w.e. a−1 by 2050. Model results indicate a glacier area reduction of 4–18% relative to 2003 for the end of the 21st century.


2013 ◽  
Vol 9 (6) ◽  
pp. 2451-2458 ◽  
Author(s):  
J. Duan ◽  
L. Wang ◽  
L. Li ◽  
Y. Sun

Abstract. A large number of glaciers in the Tibetan Plateau (TP) have experienced wastage in recent decades. And the wastage is different from region to region, even from glacier to glacier. A better understanding of long-term glacier variations and their linkage with climate variability requires extending the presently observed records. Here we present the first tree-ring-based glacier mass balance (MB) reconstruction in the TP, performed at the Hailuogou Glacier in southeastern TP during 1868–2007. The reconstructed MB is characterized mainly by ablation over the past 140 yr, and typical melting periods occurred in 1910s–1920s, 1930s–1960s, 1970s–1980s, and the last 20 yr. After the 1900s, only a few short periods (i.e., 1920s–1930s, the 1960s and the late 1980s) were characterized by accumulation. These variations can be validated by the terminus retreat velocity of Hailuogou Glacier and the ice-core accumulation rate in Guliya and respond well to regional and Northern Hemisphere temperature anomaly. In addition, the reconstructed MB is significantly and negatively correlated with August–September all-India monsoon rainfall (AIR) (r1871-2008 = −0.342, p < 0.0001). These results suggest that temperature variability is the dominant factor for the long-term MB variation at the Hailuogou Glacier. Indian summer monsoon precipitation does not affect the MB variation, yet the significant negative correlation between the MB and the AIR implies the positive effect of summer heating of the TP on Indian summer monsoon precipitation.


2012 ◽  
Vol 6 (1) ◽  
pp. 1-35 ◽  
Author(s):  
B. Marzeion ◽  
A. Nesje

Abstract. We present and validate a set of minimal models of glacier mass balance variability. The most skillful model is then applied to reconstruct 7735 individual time series of mass balance variability for all glaciers in the European Alps and Scandinavia. Subsequently, we investigate the influence of atmospheric variability associated with the North Atlantic Oscillation (NAO) on the glaciers' mass balances. We find a spatial coherence in the glaciers' sensitivity to NAO forcing which is caused by regionally similar mechanisms relating the NAO forcing to the mass balance: In Southwestern Scandinavia, winter precipitation causes a correlation of mass balances with the NAO. In Northern Scandinavia, temperature anomalies outside the core winter season cause an anti-correlation between NAO and mass balances. In the Western Alps, both temperature and winter precipitation anomalies lead to a weak anti-correlation of mass balances with the NAO, while in the Eastern Alps, the influences of winter precipitation and temperature anomalies tend to cancel each other, and only on the southern side a slight anti-correlation of mass balances with the NAO prevails.


2021 ◽  
Author(s):  
Francesco Avanzi ◽  
Simone Gabellani ◽  
Edoardo Cremonese ◽  
Umberto Morra di Cella ◽  
Matthias Huss

&lt;p&gt;Glacier mass balance is an essential component of the water budget of high-elevation and high-latitude regions, and yet this process is rather oversimplified in most hydrological models. This oversimplification is particularly relevant when it comes to representing two mechanisms: ice flow dynamics and melt beneath a supraglacial debris cover. In 2010, Huss et al. proposed a parsimonious approach to account for&amp;#160; glacier dynamics in hydrological models without solving complex equations of three-dimensional ice flow, the so-called delta-h parametrization. On the other hand, accounting for melt of debris-covered ice is still challenging as&amp;#160; estimates of debris thickness are rare.&amp;#160;&lt;/p&gt;&lt;p&gt;Here, we leveraged a distributed dataset of glacier-thickness change to derive a glacier-specific delta-h parametrization for 54 glaciers across the Aosta Valley (Italy), as well as&amp;#160; develop a novel approach for modeling melt beneath supraglacial debris based on residuals between locally observed change in thickness and that expected by regional elevation gradients. This approach does not require any on-the-ground data on debris cover, and as such it is particularly suited for ungauged regions where remote sensing is the only, feasible source of information for modeling.&amp;#160;&lt;/p&gt;&lt;p&gt;We found an expected, significant variability in both the delta-h parametrization and residuals over debris-covered ice across glaciers, with somewhat steeper orographic gradients in the former compared to the curves originally proposed by Huss et al. for Swiss glaciers. At a regional scale, the glacier mass balance showed a clear transition between a regime dominated by active glacier flow above 2,300 m ASL and a debris-dominated regime below this elevation threshold, which makes accounting for melt in the debris-covered area essential to correctly capture the future fate of low-elevation glaciers. Implementing the delta-h parametrization and our proposed approach to melt beneath supraglacial debris into S3M, a distributed cryospheric model, yielded an improved realism in estimates of future changes in glacier geometry&amp;#160; compared to assuming non-dynamic downwasting.&lt;/p&gt;


2012 ◽  
Vol 6 (3) ◽  
pp. 661-673 ◽  
Author(s):  
B. Marzeion ◽  
A. Nesje

Abstract. We present and validate a set of minimal models of glacier mass balance variability. The most skillful model is then applied to reconstruct 7735 individual time series of mass balance variability for all glaciers in the European Alps and Scandinavia. Subsequently, we investigate the influence of atmospheric variability associated with the North Atlantic Oscillation (NAO) on the glaciers' mass balances. We find a spatial coherence in the glaciers' sensitivity to NAO forcing which is caused by regionally similar mechanisms relating the NAO forcing to the mass balance: in southwestern Scandinavia, winter precipitation causes a correlation of mass balances with the NAO. In northern Scandinavia, temperature anomalies outside the core winter season cause an anti-correlation between NAO and mass balances. In the western Alps, both temperature and winter precipitation anomalies lead to a weak anti-correlation of mass balances with the NAO, while in the eastern Alps, the influences of winter precipitation and temperature anomalies tend to cancel each other, and only on the southern side a slight anti-correlation of mass balances with the NAO prevails.


2005 ◽  
Vol 42 ◽  
pp. 303-310 ◽  
Author(s):  
Peter Jansson ◽  
Hans W. Linderholm

AbstractAssessing climate change and its effects on the cryosphere is important, and individual proxies are commonly used for such assessments. We have investigated the possibility of combining glacier mass balance and tree-ring data to better understand regional climate variability in Scandinavia. There are substantial differences between climate information in mass-balance and tree-ring data. Summer balance (bS) is strongly related to summer temperature, while winter balance (bW) is less readily interpreted in terms of a climate signal. Tree rings are good summer temperature proxies, but due to the complexity of tree growth factors (e.g. the effect of the previous winter’s climate) tree-ring records do not exclusively represent summer temperatures. Combining bS and tree-ring records will not likely yield additional summer climate information. The relationship of mass balance with the Arctic Oscillation is stronger than with the North Atlantic Oscillation, especially for northernmost Sweden, whereas no such correlations were found for tree-ring data. The agreement between bN records from both maritime south-central Norway and continental northernmost Sweden and tree-ring data from Jämtland, in a maritime/continental climate transition zone, suggests possibilities to combine mass-balance and tree-ring data to provide information about climate over the entire year on interannual timescales.


2019 ◽  
Vol 13 (2) ◽  
pp. 469-489
Author(s):  
Tobias Zolles ◽  
Fabien Maussion ◽  
Stephan Peter Galos ◽  
Wolfgang Gurgiser ◽  
Lindsey Nicholson

Abstract. Energy and mass-balance modelling of glaciers is a key tool for climate impact studies of future glacier behaviour. By incorporating many of the physical processes responsible for surface accumulation and ablation, they offer more insight than simpler statistical models and are believed to suffer less from problems of stationarity when applied under changing climate conditions. However, this view is challenged by the widespread use of parameterizations for some physical processes which introduces a statistical calibration step. We argue that the reported uncertainty in modelled mass balance (and associated energy flux components) are likely to be understated in modelling studies that do not use spatio-temporal cross-validation and use a single performance measure for model optimization. To demonstrate the importance of these principles, we present a rigorous sensitivity and uncertainty assessment workflow applied to a modelling study of two glaciers in the European Alps, extending classical best guess approaches. The procedure begins with a reduction of the model parameter space using a global sensitivity assessment that identifies the parameters to which the model responds most sensitively. We find that the model sensitivity to individual parameters varies considerably in space and time, indicating that a single stated model sensitivity value is unlikely to be realistic. The model is most sensitive to parameters related to snow albedo and vertical gradients of the meteorological forcing data. We then apply a Monte Carlo multi-objective optimization based on three performance measures: model bias and mean absolute deviation in the upper and lower glacier parts, with glaciological mass balance data measured at individual stake locations used as reference. This procedure generates an ensemble of optimal parameter solutions which are equally valid. The range of parameters associated with these ensemble members are used to estimate the cross-validated uncertainty of the model output and computed energy components. The parameter values for the optimal solutions vary widely, and considering longer calibration periods does not systematically result in better constrained parameter choices. The resulting mass balance uncertainties reach up to 1300 kg m−2, with the spatial and temporal transfer errors having the same order of magnitude. The uncertainty of surface energy flux components over the ensemble at the point scale reached up to 50 % of the computed flux. The largest absolute uncertainties originate from the short-wave radiation and the albedo parameterizations, followed by the turbulent fluxes. Our study highlights the need for due caution and realistic error quantification when applying such models to regional glacier modelling efforts, or for projections of glacier mass balance in climate settings that are substantially different from the conditions in which the model was optimized.


2013 ◽  
Vol 79 (2) ◽  
pp. 123-137 ◽  
Author(s):  
Nathan L. Malcomb ◽  
Gregory C. Wiles

AbstractGlacier mass-balance reconstructions provide a means of placing relatively short observational records into a longer-term context. In western North America, mass-balance records span four to five decades and capture a relatively narrow window of glacial behavior over an interval that was dominated by warming and ablation. We use temperature- and moisture-sensitive tree-ring series to reconstruct annual mass balance for six glaciers in the Pacific Northwest and Alaska. Mass-balance models rely on the climatic sensitivity of tree-ring chronologies and teleconnection patterns in the North Pacific. The reconstructions extend through the mid to latter portions of the Little Ice Age (LIA) and explore the role of climate variability in forcing mass balance across multiple environmental gradients. Synchronous positive mass-balance intervals coincide with regional moraine building and solar minima, whereas differences in LIA glacier behavior are related to synoptic climate forcing. Secular warming in the late 19th century to present corresponds with the only multi-decadal intervals of negative mass balance in all glacier reconstructions. This suggests that contemporary retreat in western North America is unique with respect to the last several centuries and that regional patterns of glacier variability are now dominated by global climate forcing.


Sign in / Sign up

Export Citation Format

Share Document