scholarly journals Stream temperature evolution in Switzerland over the last 50 years

2019 ◽  
Author(s):  
Adrien Michel ◽  
Tristan Brauchli ◽  
Michael Lehning ◽  
Bettina Schaefli ◽  
Hendrik Huwald
Keyword(s):  
Water Temperature ◽  
Air Temperature ◽  
Temporal Trends ◽  
Stream Temperature ◽  
Strengthening Effect ◽  
Temperature Trends ◽  
Glacier Melt ◽  
Hydrological Variable ◽  
Wide Range ◽  
Alpine Rivers

Abstract. Stream temperature is a key hydrological variable for ecosystem and water resources management and is particularly sensitive to climate warming. Despite the wealth of meteorological and hydrological data, few studies have quantified observed stream temperature trends in the Alps. This study presents a detailed analysis of stream temperatures in 52 catchments in Switzerland, a country covering a wide range of alpine and lowland hydrological regimes. The influence of discharge, precipitation, air temperature and upstream lakes on stream temperatures and their temporal trends is analysed from multi-decade to seasonal time scales. Stream temperature has significantly increased over the past 5 decades, with positive trends for all four seasons. The mean trends for the last 20 years are +0.37 °C per decade for water temperature, resulting from joint effects of trends in air temperature (+0.39 °C per decade) in discharge (−10.1 % per decade) and in precipitation (−9.3 % per decade). For a longer time period (1979–2018), the trends are +0.33 °C per decade for water temperature, +0.46 °C per decade for air temperature, −3.0 % per decade for discharge and −1.3 % per decade for precipitation. We furthermore show that in alpine streams, snow and glacier melt compensates air temperature warming trends in a transient way. Lakes, on the contrary have a strengthening effect on downstream water temperature trends at all elevations. The identified stream temperature trends are furthermore shown to have critical impacts on ecological temperature thresholds, especially in lowland rivers, suggesting that these are becoming more vulnerable to the increasing air temperature forcing. Resilient alpine rivers are expected to become more vulnerable to warming in the near future due to the expected reductions in snow- and glacier melt inputs.

scholarly journals Stream temperature and discharge evolution in Switzerland over the last 50 years: annual and seasonal behaviour

2020 ◽  
Vol 24 (1) ◽  
pp. 115-142 ◽  
Author(s):  
Adrien Michel ◽  
Tristan Brauchli ◽  
Michael Lehning ◽  
Bettina Schaefli ◽  
Hendrik Huwald
Keyword(s):  
Water Temperature ◽  
Air Temperature ◽  
Water Resource Management ◽  
Temporal Trends ◽  
Stream Temperature ◽  
Mathematical Framework ◽  
Strengthening Effect ◽  
Temperature Trends ◽  
Glacier Melt ◽  
Wide Range

Abstract. Stream temperature and discharge are key hydrological variables for ecosystem and water resource management and are particularly sensitive to climate warming. Despite the wealth of meteorological and hydrological data, few studies have quantified observed stream temperature trends in the Alps. This study presents a detailed analysis of stream temperature and discharge in 52 catchments in Switzerland, a country covering a wide range of alpine and lowland hydrological regimes. The influence of discharge, precipitation, air temperature, and upstream lakes on stream temperatures and their temporal trends is analysed from multi-decadal to seasonal timescales. Stream temperature has significantly increased over the past 5 decades, with positive trends for all four seasons. The mean trends for the last 20 years are +0.37±0.11 ∘C per decade for water temperature, resulting from the joint effects of trends in air temperature (+0.39±0.14 ∘C per decade), discharge (-10.1±4.6 % per decade), and precipitation (-9.3±3.4 % per decade). For a longer time period (1979–2018), the trends are +0.33±0.03 ∘C per decade for water temperature, +0.46±0.03°C per decade for air temperature, -3.0±0.5 % per decade for discharge, and -1.3±0.5 % per decade for precipitation. Furthermore, we show that snow and glacier melt compensates for air temperature warming trends in a transient way in alpine streams. Lakes, on the contrary, have a strengthening effect on downstream water temperature trends at all elevations. Moreover, the identified stream temperature trends are shown to have critical impacts on ecological and economical temperature thresholds (the spread of fish diseases and the usage of water for industrial cooling), especially in lowland rivers, suggesting that these waterways are becoming more vulnerable to the increasing air temperature forcing. Resilient alpine rivers are expected to become more vulnerable to warming in the near future due to the expected reductions in snow- and glacier-melt inputs. A detailed mathematical framework along with the necessary source code are provided with this paper.

scholarly journals Climate and basin drivers of seasonal river water temperature dynamics

2017 ◽  
Vol 21 (6) ◽  
pp. 3231-3247 ◽  
Author(s):  
Cédric L. R. Laizé ◽  
Cristian Bruna Meredith ◽  
Michael J. Dunbar ◽  
David M. Hannah
Keyword(s):  
Water Temperature ◽  
Air Temperature ◽  
Temporal Variability ◽  
Stream Water ◽  
Stream Temperature ◽  
Short Wave ◽  
Specific Humidity ◽  
Wave Radiation ◽  
Spatial And Temporal Variability ◽  
Wide Range

Abstract. Stream water temperature is a key control of many river processes (e.g. ecology, biogeochemistry, hydraulics) and services (e.g. power plant cooling, recreational use). Consequently, the effect of climate change and variability on stream temperature is a major scientific and practical concern. This paper aims (1) to improve the understanding of large-scale spatial and temporal variability in climate–water temperature associations, and (2) to assess explicitly the influence of basin properties as modifiers of these relationships. A dataset was assembled including six distinct modelled climatic variables (air temperature, downward short-wave and long-wave radiation, wind speed, specific humidity, and precipitation) and observed stream temperatures for the period 1984–2007 at 35 sites located on 21 rivers within 16 basins (Great Britain geographical extent); the study focuses on broad spatio-temporal patterns, and hence was based on 3-month-averaged data (i.e. seasonal). A wide range of basin properties was derived. Five models were fitted (all seasons, winter, spring, summer, and autumn). Both site and national spatial scales were investigated at once by using multi-level modelling with linear multiple regressions. Model selection used multi-model inference, which provides more robust models, based on sets of good models, rather than a single best model. Broad climate–water temperature associations common to all sites were obtained from the analysis of the fixed coefficients, while site-specific responses, i.e. random coefficients, were assessed against basin properties with analysis of variance (ANOVA). All six climate predictors investigated play a role as a control of water temperature. Air temperature and short-wave radiation are important for all models/seasons, while the other predictors are important for some models/seasons only. The form and strength of the climate–stream temperature association vary depending on season and on water temperature. The dominating climate drivers and physical processes may change across seasons and across the stream temperature range. The role of basin permeability, size, and elevation as modifiers of the climate–water temperature associations was confirmed; permeability has the primary influence, followed by size and elevation. Smaller, upland, and/or impermeable basins are the most influenced by atmospheric heat exchanges, while larger, lowland and permeable basins are the least influenced. The study showed the importance of accounting properly for the spatial and temporal variability of climate–stream temperature associations and their modification by basin properties.

scholarly journals Climate and basin drivers of seasonal river water temperature dynamics

2016 ◽  
Author(s):  
C. L. R. Laizé ◽  
C. Bruna Meredith ◽  
M. Dunbar ◽  
D. M. Hannah
Keyword(s):  
Water Temperature ◽  
Air Temperature ◽  
Temporal Variability ◽  
Stream Water ◽  
Spatial Scales ◽  
Stream Temperature ◽  
Random Coefficients ◽  
Specific Humidity ◽  
Spatial And Temporal Variability ◽  
Wide Range

Abstract. Stream water temperature is a key control of many river processes (e.g. ecology, biogeochemistry, hydraulics) and services (e.g. power plant cooling, recreational use). Consequently, the effect of climate change and variability on stream temperature is a major scientific and practical concern. This paper aimed (1) to improve the understanding of large-scale spatial and temporal variability in climate–water temperature associations, and (2) to assess explicitly the influence of basin properties as modifiers of these relationships. A dataset was assembled including six distinct modelled climatic variables (air temperature, downward shortwave and longwave radiation, wind speed, specific humidity, and precipitation) and observed stream temperatures for the period 1984–2007 at 35 sites located on 21 rivers within 16 basins (Great Britain geographical extent); the study focused on broad spatio-temporal patterns hence was based on three-month averaged data (i.e. seasonal). A wide range of basin properties was derived. Five models were fitted (all seasons, winter, spring, summer, and autumn). Both site and national spatial scales were investigated at once by using multi-level modelling with linear multiple regressions. Model selection used Multi-Model Inference, which provides more robust models, based on sets of good models, rather than a single best model. Broad climate-water temperature associations common to all sites were obtained from the analysis of the fixed coefficients, while site-specific responses, i.e. random coefficients, were assessed against basin properties with ANOVA. All six climate predictors investigated play a role as a control of water temperature. Air temperature and shortwave radiation are important for all models/seasons, while the other predictors are important for some models/seasons only. The form and strength of the climate-stream temperature association vary depending on season and on water temperature. The dominating climate drivers and physical processes may change across seasons, and across the stream temperature range. The role of basin permeability, size, and elevation as modifiers of the climate-water temperature associations was confirmed; permeability has the primary influence, followed by size and elevation. Smaller, upland, and/or impermeable basins are the most influenced by atmospheric heat exchanges, while larger, lowland and permeable basins are least influenced. The study showed the importance of accounting properly for the spatial and temporal variability of climate-stream temperature associations and their modification by basin properties.

scholarly journals A hierarchical model of daily stream temperature for regional predictions

2018 ◽  
Author(s):  
Daniel J Hocking ◽  
Kyle O'Neil ◽  
Benjamin H Letcher
Keyword(s):  
Water Temperature ◽  
Air Temperature ◽  
Hierarchical Model ◽  
Mean Squared Error ◽  
Thermal Sensitivity ◽  
Stream Temperature ◽  
Eastern United States ◽  
Validation Data ◽  
Temperature Records ◽  
Use Factors

Stream temperature is an important exogenous factor influencing populations of stream organisms such as fish, amphibians, and invertebrates. Many states regulate stream protections based on temperature. Therefore, stream temperature models are important, particularly for estimating thermal regimes in unsampled space and time. To help meet this need, we developed a hierarchical model of daily stream temperature and applied it across the eastern United States. Our model accommodates many of the key challenges associated with daily stream temperature models including the lagged response of water temperature to changes in air temperature, incomplete and widely-varying observed time series, spatial and temporal autocorrelation, and the inclusion of predictors other than air temperature. We used 248,517 daily stream temperature records from 1,352 streams to fit our model and 100,909 records were withheld for model validation. Our model had a root mean squared error of 0.61 C for the fitted data and 2.03 C for the validation data, indicating excellent fit and good predictive power for understanding regional temperature patterns. We then used our model to predict daily stream temperatures from 1980 - 2015 for all streams <200 km2 from Maine to Virginia. From these, we calculated derived stream metrics including mean July temperature, mean summer temperature, and the thermal sensitivity of each stream reach to changes in air temperature. Although generally water temperature follows similar latitudinal and altitudinal patterns as air temperature, there are considerable differences at the reach scale based on landscape and land-use factors.

scholarly journals Urbanization effects on surface air temperature trends in Thailand during 1970-2019

2020 ◽  
Vol 26 (5) ◽  
pp. 200378-0
Author(s):  
Boonlue Kachenchart ◽  
Chaiyanan Kamlangkla ◽  
Nattapong Puttanapong ◽  
Atsamon Limsakul
Keyword(s):  
Air Temperature ◽  
Large Scale ◽  
Urban Expansion ◽  
Great Influence ◽  
Surface Air Temperature ◽  
Urban Setting ◽  
Temperature Trends ◽  
Urban Warming ◽  
Wide Range ◽  
Increasing Trend

Continued urban expansion undergone in the last decades has converted many weather stations in Thailand into suburban and urban setting. Based on homogenized data during 1970-2019, therefore, this study examines urbanization effects on mean surface air temperature (Tmean) trends in Thailand. Analysis shows that urban-type stations register the strongest warming trends while rural-type stations exhibit the smallest trends. Across Thailand, annual urban-warming contribution exhibits a wide range (< 5% to 77%), probably manifesting the Urban Heat Island (UHI) differences from city to city resulting from the varied urban characteristics and climatic background. Country-wide average urban warming contribution shows a significant increasing trend of 0.15 <sup>o</sup>C per decade, accounting for 40.5% of the overall warming. This evidence indicates that urban expansion has great influence on surface warming, and the urban-warming bias contributes large fraction of rising temperature trends in Thailand. The increasing trend of annual Tmean for Thailand as a whole after adjusting urban-warming bias is brought down to the same rate as the annual global mean temperature trend, reflecting a national baseline signal driven by large-scale anthropogenic-induced climate change. Our results provide a scientific reference for policy makers and urban planners to mitigate substantial fraction of the UHI warming.

Trend of stream temperature and its drivers over the past 55 years in a large European River basin

2021 ◽  
Author(s):  
Hanieh Seyedhashemi ◽  
Florentina Moatar ◽  
Jean-Philippe Vidal ◽  
Dominique Thiery ◽  
Céline Monteil ◽  
...  
Keyword(s):  
River Basin ◽  
Air Temperature ◽  
Cold Water ◽  
Stream Temperature ◽  
Small Rivers ◽  
The South ◽  
Massif Central ◽  
The Past ◽  
Temperature Trends

&lt;p&gt;Air temperature has been increasing all around the world over the past decades. Owing to its sensitivity to air temperature, it is consequently expected that stream temperature experiences an increase as well. However, due to paucity of long-term stream temperature data, assessments of the magnitude of such trends in relation with landscape and hydrological changes have remained scarce.&lt;/p&gt;&lt;p&gt;The present study used a physically-based thermal model (T-NET: Temperature-NETwork), coupled with a semi-distributed hydrological model (EROS) to reconstruct past daily stream temperatures and discharges at the scale of the Loire River basin in France (10&lt;sup&gt;5&lt;/sup&gt; km&lt;sup&gt;2&lt;/sup&gt; with 52278 reaches). The ability of both models to reconstruct long-term trends was assessed at 44 gauging stations and 11 stream temperature stations. &amp;#160;&lt;/p&gt;&lt;p&gt;T-NET simulations over the 1963-2017 period show that there has been a significant increasing trend in stream temperatures for at least 70% of reaches in all seasons (median=0.36 &amp;#176;C/decade). Significantly increasing trends are more prominent in spring (Mar-May) and summer (Jun-Aug) with a median increase of 0.37 &amp;#176;C (0.11 to 0.8&amp;#176;C) and 0.42&amp;#176;C (0.14 to 1 &amp;#176;C) per decade, respectively. For 81 % of reaches, annual stream temperature trends are greater than annual air temperature trends (median ratio=1.21; interquartile ranges: 1.06-1.44). Greater increases in stream temperature in spring and summer are found in the south of the basin, mostly in the Massif Central (up to 1&amp;#176;C/decade) where greater increase in air temperature (up to 0.67 &amp;#176;C/decade) and greater decrease in discharge (up to -16%/decade) occur jointly. The increase of stream temperature is also higher in large rivers compared to small rivers where riparian vegetation shading mitigate the increase in temperature. For the majority of reaches, changes in stream temperature, air temperature, and discharge significantly intensified in the late 1980s.&lt;/p&gt;&lt;p&gt;These climate-induced changes in the annual and seasonal stream temperature could help us to explain shifts in the phenology and geographical distribution of cold-water fish especially in the south of the basin where trends are more pronounced.&lt;/p&gt;

scholarly journals Interannual Variability of Thermal Conditions in the Extratropical Zone of the South Pacific at the Turn of the XX–XXI Centuries

2020 ◽  
Vol 37 (6) ◽  
Author(s):  
I. D. Rostov ◽  
E. V. Dmitrieva ◽  
N. I. Rudykh ◽  
◽  
◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Water Temperature ◽  
Air Temperature ◽  
South Pacific ◽  
Water Area ◽  
Global Changes ◽  
Northwestern Part ◽  
The South ◽  
The Past ◽  
Temperature Trends

Purpose. The aim of the study consists in identifying the spatial-temporal features of interannual changes in the surface air temperature Ta, the sea surface temperature (SST) and the upper 1000-meter water layer temperature Tw in the extratropical zone of the South Pacific Ocean over the past four decades, which are manifested as a result of the planetary changes and a shift in the climatic regime at the turn of the XX–XXI centuries. Besides, the revealed features’ trends and their possible cause-and-effect relationships with the processes in the atmosphere and on the ocean surface are planned to be assessed. Methods and Results. Based on the Global Meteorological Network and Reanalysis data (NOAA), regional features and trends of the water and air temperature interannual fluctuations, and their relation to variations in the pressure and wind fields, intensity of the atmosphere action centers (AAC) and climatic indices (CI) over the past 4 decades have been determined. Applied were the methods of the cluster, correlation and regression analysis, as well as the apparatus of empirical orthogonal functions (EOF). The positive trends in changes of the Ta and SST fields are manifested mainly in the northwestern part of the region, where they are statistically significant and reach their maximum 0.4–0.6°C over 10 years in the Tasman Sea region and to the northeast of New Zealand. The water areas with minimal, negative or insignificant values of the air and water temperature trends are located on the southern and eastern peripheries of the water area under study – in the areas of influence of cold currents. Over the entire investigated water area, the trends in the mean annual SST and Ta were ~ 0.04–0.06°C/10 years that are 2–3 times less than those in the subarctic region of the North Pacific Ocean. The features of spatial-temporal variability of the water temperature trends at different horizons differ significantly from the characteristics of the SST trends. The trends’ spatial distribution is already transformed within the upper 200-m layer; and deeper, maximums of this value are observed in the southeastern part of the water area. Conclusions. The results obtained made it possible to characterize the degree of heterogeneity of response of the atmosphere surface layer, SST and vertical distribution of Tw in the extratropical zone of the South Pacific to the ongoing global changes, to identify the isolated areas, to estimate quantitatively the warming rate in these water areas, and to compare these estimates with those of the other regions in the Pacific Ocean. It is shown that the individual phases of alternation of the warm and cold periods in the interannual temperature variation are consistent with the changes of the regional CI and the AAC state; this fact emphasizes the inhomogeneous nature of these processes in space and time.

scholarly journals Evaluating the Effects of Urbanization Evolution on Air Temperature Trends Using Nightlight Satellite Data

Atmosphere ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 117 ◽  
Author(s):  
Roberta Paranunzio ◽  
Serena Ceola ◽  
Francesco Laio ◽  
Alberto Montanari
Keyword(s):  
Air Temperature ◽  
Temporal Evolution ◽  
Spatial Scales ◽  
Temporal Trends ◽  
Global Scale ◽  
Satellite Measurements ◽  
Middle Income ◽  
Multiple Spatial Scales ◽  
Temperature Trends ◽  
Weather Stations

Confounding factors like urbanization and land-use change could introduce uncertainty to the estimation of global temperature trends related to climate change. In this work, we introduce a new way to investigate the nexus between temporal trends of temperature and urbanization data at the global scale in the period from 1992 to 2013. We analyze air temperature data recorded from more than 5000 weather stations worldwide and nightlight satellite measurements as a proxy for urbanization. By means of a range of statistical methods, our results quantify and outline that the temporal evolution of urbanization affects temperature trends at multiple spatial scales with significant differences at regional and continental scales. A statistically significant agreement in temperature and nightlight trends is detected, especially in low and middle-income regions, where urbanization is rapidly growing. Conversely, in continents such as Europe and North America, increases in temperature trends are typically detected along with non-significant nightlight trends.

Anthropo-generated Climate Change in Europe

1992 ◽  
Vol 19 (4) ◽  
pp. 349-353 ◽  
Author(s):  
Robert C. Balling ◽  
Sherwood B. Idso
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Strong Support ◽  
Surface Air Temperature ◽  
The United States ◽  
The Past ◽  
Temperature And Precipitation ◽  
Temperature Trends ◽  
Wide Range ◽  
Northern Hemispheric

In reviewing the results of our analyses of European temperature and precipitation data, we see patterns that are similar to those discovered in our prior studies of the United States and the British Isles: precipitation begins to increase at about the time that Northern Hemispheric SO2 emissions began their rapid ascension, while prior upward trends of surface-air temperature are dramatically truncated.We also find that surface-air temperature trends of different localities over the past three-and-a-half decades are closely tied to the amount of aerosol sulphates in the atmosphere above them. The wide range and thrust of these several observations, along with their theoretical expectation, provides strong support for the premise that anthropo-generated climate change is indeed occurring in Europe, but that it may well be SO2-induced rather than CO2-induced.

Landscape Influences on Stream Habitats and Biological Assemblages

2006 ◽  
Keyword(s):  
Spatial Variation ◽  
Water Temperature ◽  
Air Temperature ◽  
Forest Cover ◽  
Global Climate ◽  
Spatial Scales ◽  
Land Use Changes ◽  
Covariance Structure ◽  
Stream Temperature ◽  
Landscape Features

<em>Abstract.</em>—Relatively little information is available regarding the environmental factors influencing water temperature in streams draining low-elevation, glaciated landscapes in the upper Midwest. We used multiple regression analysis and covariance structure analysis (CSA) to identify the landscape features that influence spatial variation in mean July water temperature in 282 lower Michigan stream sites and to determine the spatial scales over which these features operate. Both modeling approaches explained from 63% to 65% of the spatial variation in stream temperatures and suggested that thermal regimes in lower Michigan are influenced by a suite of landscape factors operating at catchment and local scales. However, CSA, because it incorporated both direct and indirect effects, provided a more robust approach for identifying the relative influence of landscape features on stream temperature. Our CSA model suggested that catchment area, latitude, local groundwater inputs, local forest cover, air temperature, percent catchment agriculture, percent catchment lakes and wetlands, and percent catchment coarse-textured geology were important factors structuring spatial variation in stream temperatures. Our analysis also suggested that impacts on stream temperature from land cover/ land use changes are of similar or greater magnitude as those resulting from increases in air temperature associated with global climate warming.

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