1.
Oni, Stephen, et al.
(författare)
Using dry and wet year hydroclimatic extremes to guide future hydrologic projections
2016
Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 20, s. 2811-2825
Tidskriftsartikel (refereegranskat) abstract
There are growing numbers of studies on climate change impacts on forest hydrology, but limited attempts have been made to use current hydroclimatic variabilities to constrain projections of future climatic conditions. Here we used historical wet and dry years as a proxy for expected future extreme conditions in a boreal catchment. We showed that runoff could be underestimated by at least 35% when dry year parameterizations were used for wet year conditions. Uncertainty analysis showed that behavioural parameter sets from wet and dry years separated mainly on precipitation-related parameters and to a lesser extent on parameters related to landscape processes, while uncertainties inherent in climate models (as opposed to differences in calibration or performance metrics) appeared to drive the overall uncertainty in runoff projections under dry and wet hydroclimatic conditions. Hydrologic model calibration for climate impact studies could be based on years that closely approximate anticipated conditions to better constrain uncertainty in projecting extreme conditions in boreal and temperate regions.
2.
Teutschbein, Claudia, 1985-, et al.
(författare)
Future Riverine Inorganic Nitrogen Load to the Baltic Sea From Sweden : An Ensemble Approach to Assessing Climate Change Effects
2017
Ingår i: Global Biogeochemical Cycles. - : American Geophysical Union (AGU). - 0886-6236 .- 1944-9224. ; 31:11, s. 1674-1701
Tidskriftsartikel (refereegranskat) abstract
The dramatic increase of bioreactive nitrogen entering the Earth’s ecosystems continues toattract growing attention. Increasingly large quantities of inorganic nitrogen are flushed from land towater, accelerating freshwater, and marine eutrophication. Multiple, interacting, and potentiallycountervailing drivers control the future hydrologic export of inorganic nitrogen. In this paper, we attempt toresolve these land-water interactions across boreal/hemiboreal Sweden in the face of a changing climatewith help of a versatile modeling framework to maximize the information value of existing measurementtime series. We combined 6,962 spatially distributed water chemistry observations spread over 31 years withdaily streamflow and air temperature records. An ensemble of climate model projections, hydrologicalsimulations, and several parameter parsimonious regression models was employed to project future riverineinorganic nitrogen dynamics across Sweden. The median predicted increase in total inorganic nitrogenexport from Sweden (2061–2090) due to climate change was 14% (interquartile range 0–29%), based on theensemble of 7,500 different predictions for each study site. The overall export as well as the seasonal patternof inorganic nitrogen loads in a future climate are mostly influenced by longer growing seasons and morewinter flow, which offset the expected decline in spring flood. The predicted increase in inorganic nitrogenloading due to climate change means that the political efforts for reducing anthropogenic nitrogen inputsneed to be increased if ambitions for reducing the eutrophication of the Baltic Sea are to be achieved.
3.
Stenfors, Elin, et al.
(författare)
Droughts in forested ecoregions in cold and continental climates : A review of vulnerability concepts and factors in socio-hydrological systems
2023
Ingår i: WIREs Water. - : John Wiley & Sons. - 2049-1948.
Tidskriftsartikel (refereegranskat) abstract
In a changing climate, drought risk and vulnerability assessments are becoming increasingly important. Following the global call for proactive drought risk management, drought vulnerability assessments are progressively taking their stage in the drought research community. As the manifestation of drought vulnerability is dependent on the social, ecological, and hydroclimatic context in which it occurs, identifying vulnerability factors relevant for specific climatological and ecological regions may improve the quality of vulnerability assessments. Meanwhile, a holistic overview of factors affecting vulnerability in polar and cold climates is currently lacking. These regions are home to large socio-hydrological systems including urban areas, energy systems, agricultural practices, and the boreal forest. By conducting an interdisciplinary systematic literature review, the manifestation and conceptualization of drought vulnerability were identified for forested ecoregions in the Köppen–Geiger D and E climates. Vulnerability factors, as described by several scientific disciplines, were identified and combined into a conceptual framework for drought vulnerability in the study region. The results demonstrate the wide range of conceptualizations that exist for assessing drought vulnerability, and the thematic differences between sectors such as forestry, water supply, and agriculture. The conceptual framework presented herein adopts a novel approach, categorizing vulnerability factors by their location in a socio-hydrological system, and their relation to blue or green water sources. This allowed for identification of systemic vulnerability patterns, providing new insights into regional differences in drought vulnerability and a base for stakeholders performing proactive drought risk assessments in the study region.
4.
Lyon, Steve W., et al.
(författare)
Problem-based learning and assessment in hydrology courses: Can non-traditional assessment better reflect intended learning outcomes?
2011
Ingår i: Journal of Natural Resources & Life Sciences Education. - : Wiley. - 1539-1582 .- 1059-9053. ; 40:1, s. 199-205
Tidskriftsartikel (refereegranskat) abstract
Hydrology has at its core a focus on real-world applications and problems stemming from the importance of water for society and natural systems. While hydrology is firmly founded in traditional “hard” sciences like physics and mathematics, much of the innovation and excitement in current and future research-oriented hydrology comes through intersection with other disciplines. This leads to combinations of intended learning outcomes (ILOs) in hydrology courses that may not be easily or completely achieved using traditional lecture-based learning environments or using basic problem-solving techniques. Problem based learning (PBL) may work well in hydrology courses due to the focus on real-world applications and cross-discipline natureof modern hydrology. Since PBL differs from traditional teacher-centered approaches, student learning must be supported and assessed differently. This article focuses on identifying several non-traditional assessment forms to help facilitate the use of PBL approaches in hydrology courses. We present an example hydrology modeling course employing one such non-traditional PBLspecific form of assessment. Further, we seek to test the hypothesis that non-traditional assessment associated with PBL better reflects the ability of the students to achieve the ILOs in such courses. Results from the example course considered indicate that students not only preferred but also performed better in a PBL environment with its non-traditional form of assessment. This makes a strong case for incorporating both PBL and associated non-traditional forms of assessment into our teaching in hydrology and other applied science courses.
5.
Jaramillo, Fernando, et al.
(författare)
Dominant effect of increasing forest biomass on evapotranspiration: Interpretations of movement in Budyko space
2018
Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 22, s. 567-580
Tidskriftsartikel (refereegranskat) abstract
During the last 6 decades, forest biomass has increased in Sweden mainly due to forest management, with a possible increasing effect on evapotranspiration. However, increasing global CO 2 concentrations may also trigger physiological water-saving responses in broadleaf tree species, and to a lesser degree in some needleleaf conifer species, inducing an opposite effect. Additionally, changes in other forest attributes may also affect evapotranspiration. In this study, we aimed to detect the dominating effect(s) of forest change on evapotranspiration by studying changes in the ratio of actual evapotranspiration to precipitation, known as the evaporative ratio, during the period 1961-2012. We first used the Budyko framework of water and energy availability at the basin scale to study the hydroclimatic movements in Budyko space of 65 temperate and boreal basins during this period. We found that movements in Budyko space could not be explained by climatic changes in precipitation and potential evapotranspiration in 60% of these basins, suggesting the existence of other dominant drivers of hydroclimatic change. In both the temperate and boreal basin groups studied, a negative climatic effect on the evaporative ratio was counteracted by a positive residual effect. The positive residual effect occurred along with increasing standing forest biomass in the temperate and boreal basin groups, increasing forest cover in the temperate basin group and no apparent changes in forest species composition in any group. From the three forest attributes, standing forest biomass was the one that could explain most of the variance of the residual effect in both basin groups. These results further suggest that the water-saving response to increasing CO 2 in these forests is either negligible or overridden by the opposite effect of the increasing forest biomass. Thus, we conclude that increasing standing forest biomass is the dominant driver of long-term and large-scale evapotranspiration changes in Swedish forests.
6.
Teutschbein, Claudia, 1985-, et al.
(författare)
Evaluation of different downscaling techniques for hydrological climate-change impact studies at the catchment scale
2011
Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 37:9-10, s. 2087-2105
Tidskriftsartikel (refereegranskat) abstract
Hydrological modeling for climate-change impact assessment implies using meteorological variables simulated by global climate models (GCMs). Due to mismatching scales, coarse-resolution GCM output cannot be used directly for hydrological impact studies but rather needs to be downscaled. In this study, we investigated the variability of seasonal streamflow and flood-peak projections caused by the use of three statistical approaches to downscale precipitation from two GCMs for a meso-scale catchment in southeastern Sweden: (1) an analog method (AM), (2) a multi-objective fuzzy-rule-based classification (MOFRBC) and (3) the Statistical DownScaling Model (SDSM). The obtained higher-resolution precipitation values were then used to simulate daily streamflow for a control period (1961-1990) and for two future emission scenarios (2071-2100) with the precipitation-streamflow model HBV. The choice of downscaled precipitation time series had a major impact on the streamflow simulations, which was directly related to the ability of the downscaling approaches to reproduce observed precipitation. Although SDSM was considered to be most suitable for downscaling precipitation in the studied river basin, we highlighted the importance of an ensemble approach. The climate and streamflow change signals indicated that the current flow regime with a snowmelt-driven spring flood in April will likely change to a flow regime that is rather dominated by large winter streamflows. Spring flood events are expected to decrease considerably and occur earlier, whereas autumn flood peaks are projected to increase slightly. The simulations demonstrated that projections of future streamflow regimes are highly variable and can even partly point towards different directions.
7.
Teutschbein, Claudia, 1985-, et al.
(författare)
Future drought propagation through the water-energy-food-ecosystem nexus : A Nordic perspective
2023
Ingår i: Journal of Hydrology. - : Elsevier. - 0022-1694 .- 1879-2707. ; 617
Tidskriftsartikel (refereegranskat) abstract
Droughts can affect a multitude of public and private sectors, with impacts developing slowly over time. While droughts are traditionally quantified in relation to the hydrological components of the water cycle that they affect, this manuscript demonstrates a novel approach to assess future drought conditions through the lens of the water-energy-food-ecosystem (WEFE) nexus concept. To this end, a set of standardized drought indices specifically designed to represent different nexus sectors across 50 catchments in Sweden was computed based on an ensemble of past and future climate model simulations. Different patterns in the response of the four nexus sectors water, energy, food and ecosystem services to future climate change emerged, with different response times and drought durations across the sectors. These results offer new insights into the propagation of drought through the WEFE nexus in cold climates. They further suggest that future drought projections can be better geared towards decision makers by basing them on standardized drought indices that were specifically tailored to represent particular nexus sectors.
8.
Teutschbein, Claudia, 1985-, et al.
(författare)
Is bias correction of regional climate model (RCM) simulations possible for non-stationary conditions?
2013
Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 17:12, s. 5061-5077
Tidskriftsartikel (refereegranskat) abstract
In hydrological climate-change impact studies, regional climate models (RCMs) are commonly used to transfer large-scale global climate model (GCM) data to smaller scales and to provide more detailed regional information. Due to systematic and random model errors, however, RCM simulations often show considerable deviations from observations. This has led to the development of a number of correction approaches that rely on the assumption that RCM errors do not change over time. It is in principle not possible to test whether this underlying assumption of error stationarity is actually fulfilled for future climate conditions. In this study, however, we demonstrate that it is possible to evaluate how well correction methods perform for conditions different from those used for calibration with the relatively simple differential split-sample test.
9.
Wallin, Marcus, 1979-, et al.
(författare)
Carbon dioxide and methane emissions of Swedish low-order streams : a national estimate and lessons learnt from more than a decade of observations
2018
Ingår i: Limnology and Oceanography Letters. - : John Wiley & Sons. - 2378-2242. ; 3:3, s. 156-167
Tidskriftsartikel (refereegranskat) abstract
Low-order streams are suggested to dominate the atmospheric CO2 source of all inland waters. Yet, many large-scale stream estimates suffer from methods not designed for gas emission determination and rarely include other greenhouse gases such as CH4. Here, we present a compilation of directly measured CO2 and CH4 concentration data from Swedish low-order streams (> 1600 observations across > 500 streams) covering large climatological and land-use gradients. These data were combined with an empirically derived gas transfer model and the characteristics of a ca. 400,000 km stream network covering the entire country. The total stream CO2 and CH4 emission corresponded to 2.7 Tg C yr(-1) (95% confidence interval: 2.0-3.7) of which the CH4 accounted for 0.7% (0.02 Tg C yr(-1)). The study highlights the importance of low-order streams, as well as the critical need to better represent variability in emissions and stream areal extent to constrain future stream C emission estimates.
10.
Teutschbein, Claudia, 1985-, et al.
(författare)
Regional Climate Models for Hydrological Impact Studies at the Catchment Scale : A Review of Recent Modeling Strategies
2010
Ingår i: Geography Compass. - : Wiley. - 1749-8198. ; 4:7, s. 834-860
Tidskriftsartikel (refereegranskat) abstract
This article reviews recent applications of regional climate model (RCM) output for hydrological impact studies. Traditionally, simulations of global climate models (GCMs) have been the basis of impact studies in hydrology. Progress in regional climate modeling has recently made the use of RCM data more attractive, although the application of RCM simulations is challenging due to often considerable biases. The main modeling strategies used in recent studies can be classified into (i) very simple constructed modeling chains with a single RCM (S-RCM approach) and (ii) highly complex and computing-power intensive model systems based on RCM ensembles (E-RCM approach). In the literature many examples for S-RCM can be found, while comprehensive E-RCM studies with consideration of several sources of uncertainties such as different greenhouse gas emission scenarios, GCMs, RCMs and hydrological models are less common. Based on a case study using control-run simulations of fourteen different RCMs for five Swedish catchments, the biases of and the variability between different RCMs are demonstrated. We provide a short overview of possible bias-correction methods and show that inter-RCM variability also has substantial consequences for hydrological impact studies in addition to other sources of uncertainties in the modeling chain. We propose that due to model bias and inter-model variability, the S-RCM approach is not advised and ensembles of RCM simulations (E-RCM) should be used. The application of bias-correction methods is recommended, although one should also be aware that the need for bias corrections adds significantly to uncertainties in modeling climate change impacts.
