A comparison of hydrological models with different level of complexity in Alpine regions in the context of climate change

Abstract. This study compares the ability of two degree-day models (Poli-Hydro and a degree-day implementation of Alpine3D) and one full energy-balance melt model (Alpine3D) to predict the discharge on two partly glacierized Alpine catchments of different size and intensity of exploitation, under present conditions and climate change as projected at the end of the century. For present climate, the magnitude of snow melt predicted by Poli-Hydro is sensibly lower than the one predicted by the other melt schemes, and the melting season is delayed by one month. This difference can be explained by the combined effect of the reduced complexity of the melting scheme and the reduced computational temporal resolution. The degree-day implementation of Alpine3D reproduces a melt season closer to the one obtained with its full solver; in fact, the onset of the degree-day mode still depends upon the full energy-balance solver, thus not bringing any particular benefit in terms of inputs and computational load, unlike with Poli-Hydro. Under climate change conditions, Alpine3D is more sensitive than Poli-Hydro, reproducing discharge curves and volumes shifted by one month earlier as a consequence of the earlier onset of snow melt. Despite their benefits, the coarser temporal computational resolution and the fixed monthly degree-days of simpler melt models like Poli-Hydro make them controversial to use for climate change applications with respect to energy-balance ones. Nevertheless, under strong river regulation, the influence of calibration might even overshadow the benefits of a full energy-balance scheme.

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Future water temperature of rivers in Switzerland under climate change investigated with physics-based models

10.5194/hess-2021-194 ◽

2021 ◽

Author(s):

Adrien Michel ◽

Bettina Schaefli ◽

Nander Wever ◽

Harry Zekollari ◽

Michael Lehning ◽

...

Keyword(s):

Climate Change ◽

21St Century ◽

Temperature Increase ◽

Emission Scenarios ◽

River Temperature ◽

Alpine Regions ◽

Low Emission ◽

High Emission ◽

Swiss Plateau ◽

Alpine Catchments

Abstract. Rivers are ecosystems highly sensitive to climate change and projected future increase in air temperature is expected to increase the stress for these ecosystems. Rivers are also an important socio-economical factor. In addition to changes in water availability, climate change will impact the temperature of rivers. This study presents a detailed analysis of river temperature and discharge evolution over the 21st century in Switzerland, a country covering a wide range of Alpine and lowland hydrological regimes. In total, 12 catchments are studied. They are situated both in the lowland Swiss Plateau and the Alpine regions and cover overall 10 % of the country’s area. This represents the so far largest study of climate change impacts on river temperature in Switzerland. The impact of climate change is assessed using a chain of physics-based models forced with the most recent climate change scenarios for Switzerland including low, mid, and high emissions pathways. A clear warming of river water is modelled during the 21st century, more pronounced for the high emission scenarios and toward the end of the century. For the period 2030–2040, median warming in river temperature of +1.1 °C for Swiss Plateau catchments and of +0.8 °C for Alpine catchments are expected compared to the reference period 1990–2000 (similar for all emission scenarios). At the end of the century (2080–2090), the median annual river temperature increase ranges between +0.9 °C for low emission and +3.5 °C for high emission scenarios for both Swiss Plateau and Alpine catchments. At the seasonal scale, the warming on the Swiss Plateau and in the Alpine regions exhibits different patterns. For the Swiss Plateau, the spring and fall warming is comparable to the warming in winter, while the summer warming is stronger but still moderate. In Alpine catchments, only a very limited warming is expected in winter. A marked discharge increase in winter and spring is expected in these catchments due to enhanced snowmelt and a larger fraction of liquid precipitation. Accordingly, the period of maximum discharge in Alpine catchments, currently occurring during mid-summer, will shift to earlier in the year by a few weeks (low emission) or almost two months (high emission) by the end of the century. In summer, the marked discharge reduction in Alpine catchments for high emission scenarios leads to an increase in sensitivity of water temperature to low discharge, which is not observed in the Swiss Plateau catchments. In addition, an important soil warming is expected due to glacier and snow cover decrease. These effects combined lead to a summertime river warming of +6.0 °C in Alpine catchments by the end of the century for high emission scenarios. Two metrics are used to show the adverse effects of river temperature increase both on natural and human systems. All results of this study along with the necessary source code are provided with this manuscript.

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Timing and magnitude of future annual runoff extremes in contrasting Alpine catchments in Austria

10.5194/hess-2021-92 ◽

2021 ◽

Author(s):

Sarah Hanus ◽

Markus Hrachowitz ◽

Harry Zekollari ◽

Gerrit Schoups ◽

Miren Vizcaino ◽

...

Keyword(s):

Climate Change ◽

High Elevation ◽

Annual Runoff ◽

Snow Melt ◽

Annual Maximum ◽

Ice Dynamics ◽

Rcp 8.5 ◽

Alpine Catchments ◽

Maximum Flows ◽

Hydrological Regimes

Abstract. Hydrological regimes of alpine catchments are expected to be strongly affected by climate change mostly due to their dependence on snow and ice dynamics. While seasonal changes have been studied extensively, studies on changes in the timing and magnitude of annual extremes remain rare. This study investigates the effects of climate change on runoff patterns in six contrasting alpine catchments in Austria using a process-based semi-distributed hydrological model and projections from 14 regional climate and global climate model combinations for RCP 4.5 and RCP 8.5. The study catchments represent a spectrum of different hydrological regimes, from pluvial-nival to nivo-glacial, as well as distinct topographies and land forms, characterizing different elevation zones across the Eastern Alps to provide a comprehensive picture of future runoff changes. The climate projections are used to model river runoff in 2071–2100, which are then compared to the 1981–2010 reference period for all study catchments. Changes in timing and magnitude of annual maximum and minimum flows as well as in monthly runoff and snow melt are quantified and analyzed. Our results indicate a substantial shift to earlier occurrences in annual maximum flows by 9 to 31 days and an extension of the potential flood season by one to three months for high-elevation catchments. For low-elevation catchments, changes in timing of annual maximum flows are less pronounced. Magnitudes of annual maximum flows are likely to increase by 2–18 % under RCP 4.5, while no clear changes are projected for four catchments under RCP 8.5. The latter is caused by a pronounced increase in evaporation and decrease in snow melt contributions which offset increases in precipitation. Minimum annual runoff occur 13–31 days earlier in the winter months for high-elevation catchments, whereas for low-elevation catchments a shift from winter to autumn by about 15–100 days is projected. While all catchments show an increase in mean magnitude of minimum flows by 7–30 % under RCP 4.5, this is only the case for four catchments under RCP 8.5. Our results suggest a relationship between the elevation of catchments and changes in timing of annual maximum and minimum flows. For the magnitude of the extreme flows, a relationship is found between catchment elevation and annual minimum flows, whereas this relationship is lacking between elevation and annual maximum flow.

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Water quality in urbanized alpine catchments of Central Asia - what happens after the ice?

10.5194/egusphere-egu2020-802 ◽

2020 ◽

Author(s):

Vadim Yapiyev ◽

Andrew Wade ◽

Zarina Saidaliyeva ◽

Maria Shahgedanova ◽

Vassiliy Kapitsa ◽

...

Keyword(s):

Climate Change ◽

Water Quality ◽

Drinking Water ◽

Central Asia ◽

Hot Spot ◽

Monitoring Program ◽

Tien Shan ◽

Low Flow ◽

Snow Melt ◽

Alpine Catchments

<p>Central Asia (CA) is considered a hot-spot for climate-change impact on the water-cycle because of a high density of glaciated, montane catchments. Of particular concern are catchments in the Tien Shan and the Pamir Mountains in the areas, where glacial-fed rivers flow past major urban centres, and in the west of Central Asia near the Caspian and Aral Seas. Climate-change studies, which focus on Central Asia, consider mainly long-term changes in air temperature and precipitation, shrinking glaciers and physical hydrology, complex transboundary water management and policy issues. While, water quality (WQ) has received much less attention yet is noted as a potential issue primarily due to exposure of heavy metals and trace elements due to glacial retreat, release of aerosols deposited in snow and ice, and the dilution of pollutants from urban and farmed areas further downstream. To fill this knowledge gap the current project &#8216;Solutions to secure clean water in the glacier-fed catchments of Central Asia &#8211; what happens after the ice?&#8217; established WQ monitoring program in four CA countries. The project aims to characterise and model, in a consistent and comparable way, the impacts of climate change and diminishing cryosphere on water availability and quality in the selected glacier-fed catchments informing environmental policies and adaptation strategies and building research capacity in the region. To this end WQ sampling and measurements were established in four glacier-fed alpine catchments on rivers passing major cities: Kishi and Ulken Almaty rivers (Kazakhstan, Almaty city), Ala-Archa River (Kyrgyzstan, Bishkek city), Chirchik River (Uzbekistan, Tashkent city), Varzob (Tajikistan, Dushanbe city). The WQ monitoring programme is based on bi-weekly sampling &#160;along river elevation profile from upstream (closer to glacierized &#160;area) to downstream (up to a reservoir or inflow to a major river). Groundwater (urban, artesian, springs), streamwater, reservoirs have been sampled and measured for temperature, electrical conductivity (EC), total dissolved solids (TDS), pH, nitrates, phosphates in situ and in the labs by local teams. These measurements are complemented by extended analysis for cations and anions during peak of steam flow (glacier and snow melt period) and low flow season in autumn (baseflow dominated). The preliminary results show that these catchments relatively clean with potentially toxic elements not exceeding WHO drinking water values in all monitored components. The dilution effect of glacier and snow melt on streamwater in summer is reflected in EC seasonal pattern. Primary concerns are elevated nitrate concentrations in urban groundwater in three studied catchments (Kyrgyzstan, Uzbekistan, and Tajikistan) with median values exceeding 10 mg/L of nitrate-N (a WHO&#8217;s drinking water guidelines threshold). The intermittent spikes of high phosphates in streamwater and groundwater in Uzbekistan in the autumn, in some cases reaching more than 4 mg/L (phosphate-P) are possibly linked to fertilizers wash-out by rainfall.</p>

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Selection of models to describe the temperature-dependent development of Neoleucinodes elegantalis (Lepidoptera: Crambidae) and its application to predict the species voltinism under future climate conditions

Bulletin of Entomological Research ◽

10.1017/s0007485321000195 ◽

2021 ◽

pp. 1-9

Author(s):

Hevellyn Talissa dos Santos ◽

Cesar Augusto Marchioro

Keyword(s):

Climate Change ◽

Linear Model ◽

Future Climate ◽

Future Climate Change ◽

Climate Change Scenarios ◽

Temperature Dependent ◽

Dependent Development ◽

Degree Day ◽

Non Linear ◽

The Impact

Abstract The small tomato borer, Neoleucinodes elegantalis (Guenée, 1854) is a multivoltine pest of tomato and other cultivated solanaceous plants. The knowledge on how N. elegantalis respond to temperature may help in the development of pest management strategies, and in the understanding of the effects of climate change on its voltinism. In this context, this study aimed to select models to describe the temperature-dependent development rate of N. elegantalis and apply the best models to evaluate the impacts of climate change on pest voltinism. Voltinism was estimated with the best fit non-linear model and the degree-day approach using future climate change scenarios representing intermediary and high greenhouse gas emission rates. Two out of the six models assessed showed a good fit to the observed data and accurately estimated the thermal thresholds of N. elegantalis. The degree-day and the non-linear model estimated more generations in the warmer regions and fewer generations in the colder areas, but differences of up to 41% between models were recorded mainly in the warmer regions. In general, both models predicted an increase in the voltinism of N. elegantalis in most of the study area, and this increase was more pronounced in the scenarios with high emission of greenhouse gases. The mathematical model (74.8%) and the location (9.8%) were the factors that mostly contributed to the observed variation in pest voltinism. Our findings highlight the impact of climate change on the voltinism of N. elegantalis and indicate that an increase in its population growth is expected in most regions of the study area.

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Linking climate, gross primary productivity, and site index across forests of the western United States

Canadian Journal of Forest Research ◽

10.1139/x11-086 ◽

2011 ◽

Vol 41 (8) ◽

pp. 1710-1721 ◽

Cited By ~ 53

Author(s):

Aaron R. Weiskittel ◽

Nicholas L. Crookston ◽

Philip J. Radtke

Keyword(s):

Climate Change ◽

Growth Models ◽

Gross Primary Production ◽

Site Index ◽

Nonparametric Model ◽

Climate Change Scenarios ◽

Geographic Scale ◽

Potential Productivity ◽

The One ◽

The Relationship

Assessing forest productivity is important for developing effective management regimes and predicting future growth. Despite some important limitations, the most common means for quantifying forest stand-level potential productivity is site index (SI). Another measure of productivity is gross primary production (GPP). In this paper, SI is compared with GPP estimates obtained from 3-PG and NASA’s MODIS satellite. Models were constructed that predict SI and both measures of GPP from climate variables. Results indicated that a nonparametric model with two climate-related predictor variables explained over 68% and 76% of the variation in SI and GPP, respectively. The relationship between GPP and SI was limited (R2 of 36%–56%), while the relationship between GPP and climate (R2 of 76%–91%) was stronger than the one between SI and climate (R2 of 68%–78%). The developed SI model was used to predict SI under varying expected climate change scenarios. The predominant trend was an increase of 0–5 m in SI, with some sites experiencing reductions of up to 10 m. The developed model can predict SI across a broad geographic scale and into the future, which statistical growth models can use to represent the expected effects of climate change more effectively.

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Glaciohydrology of the Himalaya-Karakoram

Science ◽

10.1126/science.abf3668 ◽

2021 ◽

pp. eabf3668

Author(s):

Mohd. Farooq Azam ◽

Jeffrey S. Kargel ◽

Joseph M. Shea ◽

Santosh Nepal ◽

Umesh K. Haritashya ◽

...

Keyword(s):

Climate Change ◽

Water Resources ◽

Current Status ◽

Snow Melt ◽

Resources Management ◽

Critical Knowledge ◽

Glacier Melt ◽

Sustainable Water Resources Management ◽

The Himalaya ◽

Sustainable Water Resources

Understanding the response of Himalayan-Karakoram (HK) rivers to climate change is crucial for ~1 billion people who partly depend on these water resources. Policymakers tasked with the sustainable water resources management for agriculture, hydropower, drinking, sanitation, and hazards require an assessment of rivers’ current status and potential future changes. This review demonstrates that glacier and snow melt are important components of HK rivers, with greater hydrological importance for the Indus than Ganges and Brahmaputra basins. Total river runoff, glacier melt, and seasonality of flow are projected to increase until the 2050s, with some exceptions and large uncertainties. Critical knowledge gaps severely affect modeled contributions of different runoff components, future runoff volumes and seasonality. Therefore, comprehensive field- and remote sensing-based methods and models are needed.

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Snow specific surface area simulation using the one-layer snow model in the Canadian LAnd Surface Scheme (CLASS)

The Cryosphere ◽

10.5194/tc-7-961-2013 ◽

2013 ◽

Vol 7 (3) ◽

pp. 961-975 ◽

Cited By ~ 15

Author(s):

A. Roy ◽

A. Royer ◽

B. Montpetit ◽

P. A. Bartlett ◽

A. Langlois

Keyword(s):

Energy Balance ◽

Surface Energy ◽

Liquid Water ◽

Land Surface ◽

Surface Energy Balance ◽

Liquid Water Content ◽

Canadian Land Surface Scheme ◽

Snow Model ◽

Surface Scheme ◽

The One

Abstract. Snow grain size is a key parameter for modeling microwave snow emission properties and the surface energy balance because of its influence on the snow albedo, thermal conductivity and diffusivity. A model of the specific surface area (SSA) of snow was implemented in the one-layer snow model in the Canadian LAnd Surface Scheme (CLASS) version 3.4. This offline multilayer model (CLASS-SSA) simulates the decrease of SSA based on snow age, snow temperature and the temperature gradient under dry snow conditions, while it considers the liquid water content of the snowpack for wet snow metamorphism. We compare the model with ground-based measurements from several sites (alpine, arctic and subarctic) with different types of snow. The model provides simulated SSA in good agreement with measurements with an overall point-to-point comparison RMSE of 8.0 m2 kg–1, and a root mean square error (RMSE) of 5.1 m2 kg–1 for the snowpack average SSA. The model, however, is limited under wet conditions due to the single-layer nature of the CLASS model, leading to a single liquid water content value for the whole snowpack. The SSA simulations are of great interest for satellite passive microwave brightness temperature assimilations, snow mass balance retrievals and surface energy balance calculations with associated climate feedbacks.

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Klimaforandringer: Perspektiv og skala i studiet af det høje nord

Tidsskriftet Antropologi ◽

10.7146/ta.v0i64.27323 ◽

2011 ◽

Author(s):

Kirsten Hastrup

Keyword(s):

Climate Change ◽

Vulnerable Populations ◽

The Other ◽

Social Worlds ◽

The One ◽

Strategic Perspective

Klima og klimaforandringer er blevet nye store temaer i antropologien, og det er påtrængende at stille kritiske spørgsmål til brugen af disse begreber, der synes at indeholde både konkret (lokalt) vejr og abstrakt (globalt) klima. Spørgsmålet er, hvordan man kan bruge „klimaet“ strategisk og produktivt i antropologiske analyser uden at gøre det til endnu en udefrakommende ulykke, der rammer klodens svage befolkninger. I artiklen argumenteres der for en nytænkning af skalabegrebet, som kan rumme både det „lokale“ og det „globale“, i og med at der er tale om et analytisk perspektiv snarere end et empirisk forhold. Herigennem åbnes der for en komparativ analyse af „klimaets“ infiltrering i det sociale og dets varierende forklaringsværdi. Artiklen trækker på forfatterens arbejde i Island og Grønland. Søgeord: klimaforandringer, skala, worlding, Island, Grønland English: Climate Explanations: Perspective and Scale in the Study of the High North“Climate” has entered into everyday parlance across the globe. In anthropology, “climate change” has opened up a new field of concern for vulnerable populations on the one hand and for the distinctiveness of the discipline on the other. In this article it is argued that while climate as such is a meteorological abstraction, it may also function as a strategic perspective, which allows for a comparison between ascribed values and dynamisms in social worlds. It is further shown how the implications of worldwide climate change open up for a new understanding of scale as an analytical rather than an empirical category. The substance draws from the author’s work in Northwest Greenland and in Iceland. Keywords: Climate change, scale, worlding, Iceland, Greenland

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Analysing the sensitivity of Hungarian landscapes based on climate change induced shallow groundwater fluctuation

Hungarian Geographical Bulletin ◽

10.15201/hungeobull.68.4.3 ◽

2019 ◽

Vol 68 (4) ◽

pp. 355-372 ◽

Cited By ~ 3

Author(s):

Zoltán Zsolt Fehér ◽

János Rakonczai

Keyword(s):

Climate Change ◽

Water Resources ◽

Water Resource ◽

Climatic Factors ◽

Shallow Groundwater ◽

Subsurface Water ◽

Groundwater Fluctuation ◽

Current Parameter ◽

Local Water ◽

The One

One of the undoubtedly recognizable consequences of the ongoing climate change in Hungary is the permanent change of groundwater depth, and consequently the sustainably reachable local water resources. These processes trigger remarkable changes in soil and vegetation. Thus, in research of sensitivity of any specific landscape to the varying climatic factors, monitoring and continuous evaluation of the water resources is inevitable. The presented spatiotemporal geostatistical cosimulation framework is capable to identify rearrangements of the subsurface water resources through water resource observations. Application of the Markov 2-type coregionalization model is based on the assumption, that presumably only slight changes have to be handled between two consecutive time instants, hence current parameter set can be estimated based on the spatial structures of prior and current dataset and previously identified parameters. Moreover, the algorithm is capable to take into consideration the significance of the geomorphologic settings on the subsurface water flow. Trends in water resource changes are appropriate indicators of certain areas climate sensitivity. The method is also suitable in determination of the main cause of the extraordinary groundwater discharges, like the one, observed from the beginning of the 1980’s in the Danube–Tisza Interfluve in Hungary.

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International Law Obligations Arising in relation to Nationally Determined Contributions

Transnational Environmental Law ◽

10.1017/s2047102518000110 ◽

2018 ◽

Vol 7 (2) ◽

pp. 251-275 ◽

Cited By ~ 3

Author(s):

Benoit Mayer

Keyword(s):

Climate Change ◽

International Law ◽

Paris Agreement ◽

The Other ◽

Other Hand ◽

Legal Obligations ◽

Nationally Determined Contributions ◽

The One

AbstractThis article analyzes the international law obligations that arise in relation to nationally determined contributions (NDCs). It argues that distinct and concurrent obligations arise from two separate sources. On the one hand, treaty obligations arise under the Paris Agreement, which imposes an obligation of conduct on parties: they must take adequate measures towards the realization of the mitigation targets contained in their NDCs. On the other hand, communications such as NDCs may constitute unilateral declarations that also create legal obligations. These unilateral declarations impose obligations of various types, which may extend beyond mitigation. For example, they may specify measures of implementation or demand the achievement of a particular result. The potential ‘double-bindingness’ of NDCs should be a central consideration in the interpretation of international law obligations regarding climate change.

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