High-resolution climate datasets in hydrological impact studies: Assessing their value in alpine and pre-alpine catchments in southeastern Austria

Abstract. In the framework of the international CORDEX program, new regional climate model (RCM) simulations at high spatial resolutions are becoming available for the Mediterranean region (Med-CORDEX initiative). This study provides the first evaluation for hydrological impact studies of these high-resolution simulations. Different approaches are compared to analyze the climate change impacts on the hydrology of a catchment located in North Morocco, using a high-resolution RCM (ALADIN-Climate) from the Med-CORDEX initiative at two different spatial resolutions (50 km and 12 km) and for two different Radiative Concentration Pathway scenarios (RCP4.5 and RCP8.5). The main issues addressed in the present study are: (i) what is the impact of increased RCM resolution on present-climate hydrological simulations and on future projections? (ii) Are the bias-correction of the RCM model and the parameters of the hydrological model stationary and transferable to different climatic conditions? (iii) What is the climate and hydrological change signal based on the new Radiative Concentration Pathways scenarios (RCP4.5 and RCP8.5)? Results indicate that high resolution simulations at 12 km better reproduce the seasonal patterns, the seasonal distributions and the extreme events of precipitation. The parameters of the hydrological model, calibrated to reproduce runoff at the monthly time step over the 1984–2010 period, do not show a strong variability between dry and wet calibration periods in a differential split-sample test. However the bias correction of precipitation by quantile-matching does not give satisfactory results in validation using the same differential split-sample testing method. Therefore a quantile-perturbation method that does not rely on any stationarity assumption and produces ensembles of perturbed series of precipitation was introduced. The climate change signal under scenarios 4.5 and 8.5 indicates a decrease of respectively −30% to −57% in surface runoff for the mid-term (2041–2062), when for the same period the projections for precipitation are ranging between −15% and −19% and for temperature between +1.28°C and +1.87°C.

Download Full-text

Effects of univariate and multivariate bias correction on hydrological impact projections in alpine catchments

10.5194/hess-2018-317 ◽

2018 ◽

Cited By ~ 1

Author(s):

Judith Meyer ◽

Irene Kohn ◽

Kerstin Stahl ◽

Kirsti Hakala ◽

Jan Seibert ◽

...

Keyword(s):

Air Temperature ◽

Bias Correction ◽

Climate Model ◽

Historical Period ◽

Climate Variables ◽

Quantile Mapping ◽

Impact Studies ◽

Hydrological Impact ◽

Individual Variables ◽

Alpine Catchments

Abstract. Alpine catchments show a high sensitivity to climate variation as they include the elevation range of the snow line. Therefore, the correct representation of climate variables and their interdependence is crucial when describing or predicting hydrological processes. When using climate model simulations in hydrological impact studies, forcing meteorological data are usually downscaled and bias corrected, most often by univariate approaches such as quantile mapping of individual variables. However, univariate correction neglects the relationships that exist between climate variables. In this study glacio-hydrological simulations were performed for two partly glacierized alpine catchments using a recently developed multivariate bias correction method to post-process EURO-CORDEX regional climate model outputs between 1976 and 2100. These simulations were compared to those obtained by using the common univariate quantile mapping for bias correction. As both methods correct each climate variable’s distribution in the same way, the marginal distributions of the individual variables show no differences. Yet, regarding the interdependence of precipitation and air temperature, clear differences are notable in the studied catchments. Simultaneous correction based on the multivariate approach lead to more precipitation below air temperatures of 0 °C and therefore more simulated snowfall than with the data of the univariate approach. This difference translated to considerable consequences for the hydrological responses of the catchments. The multivariate bias correction forced simulations showed distinctly different results for projected snow cover characteristics, snowmelt-driven streamflow components, and expected glacier disappearance dates in the future. For the historical period the fraction of precipitation above and below 0 °C, the simulated snow water equivalents, glacier volumes, and the streamflow regime resulting from the multivariate-corrected data corresponded better with reference data than the results of univariate bias correction. Differences in simulated total streamflow due to the different bias correction approaches may be considered negligible given the generally large spread of the projections, but systematic differences in the seasonally delayed streamflow components from snowmelt in particular will matter from a planning perspective. While this study does not allow concluding definitively that multivariate bias correction approaches are generally preferable, it clearly demonstrates that incorporating or ignoring inter-variable relationships between air temperature and precipitation data can impact the conclusions drawn in hydrological climate change impact studies.

Download Full-text

High-resolution Med-CORDEX regional climate model simulations for hydrological impact studies: a first evaluation of the ALADIN-Climate model in Morocco

Hydrology and Earth System Sciences ◽

10.5194/hess-17-3721-2013 ◽

2013 ◽

Vol 17 (10) ◽

pp. 3721-3739 ◽

Cited By ~ 81

Author(s):

Y. Tramblay ◽

D. Ruelland ◽

S. Somot ◽

R. Bouaicha ◽

E. Servat

Keyword(s):

Climate Change ◽

High Resolution ◽

Regional Climate Model ◽

Bias Correction ◽

Hydrological Model ◽

Climate Model ◽

Regional Climate ◽

Impact Studies ◽

Hydrological Impact ◽

Split Sample

Abstract. In the framework of the international CORDEX program, new regional climate model (RCM) simulations at high spatial resolutions are becoming available for the Mediterranean region (Med-CORDEX initiative). This study provides the first evaluation for hydrological impact studies of one of these high-resolution simulations in a 1800 km2 catchment located in North Morocco. Different approaches are compared to analyze the climate change impacts on the hydrology of this catchment using a high-resolution RCM (ALADIN-Climate) from the Med-CORDEX initiative at two different spatial resolutions (50 and 12 km) and for two different Radiative Concentration Pathway scenarios (RCP4.5 and RCP8.5). The main issues addressed in the present study are: (i) what is the impact of increased RCM resolution on present-climate hydrological simulations and on future projections? (ii) Are the bias-correction of the RCM model and the parameters of the hydrological model stationary and transferable to different climatic conditions? (iii) What is the climate and hydrological change signal based on the new Radiative Concentration Pathways scenarios (RCP4.5 and RCP8.5)? Results indicate that high resolution simulations at 12 km better reproduce the seasonal patterns, the seasonal distributions and the extreme events of precipitation. The parameters of the hydrological model, calibrated to reproduce runoff at the monthly time step over the 1984–2010 period, do not show a strong variability between dry and wet calibration periods in a differential split-sample test. However the bias correction of precipitation by quantile-matching does not give satisfactory results in validation using the same differential split-sample testing method. Therefore a quantile-perturbation method that does not rely on any stationarity assumption and produces ensembles of perturbed series of precipitation was introduced. The climate change signal under scenarios 4.5 and 8.5 indicates a decrease of respectively −30 to −57% in surface runoff for the mid-term (2041–2062), when for the same period the projections for precipitation are ranging between −15 and −19% and for temperature between +1.3 and +1.9 °C.

Download Full-text

Effects of univariate and multivariate bias correction on hydrological impact projections in alpine catchments

Hydrology and Earth System Sciences ◽

10.5194/hess-23-1339-2019 ◽

2019 ◽

Vol 23 (3) ◽

pp. 1339-1354 ◽

Cited By ~ 17

Author(s):

Judith Meyer ◽

Irene Kohn ◽

Kerstin Stahl ◽

Kirsti Hakala ◽

Jan Seibert ◽

...

Keyword(s):

Air Temperature ◽

Bias Correction ◽

Climate Model ◽

Climate Variables ◽

Quantile Mapping ◽

Impact Studies ◽

Temperature And Precipitation ◽

Hydrological Impact ◽

Individual Variables ◽

Alpine Catchments

Abstract. Alpine catchments show a high sensitivity to climate variation as they include the elevation range of the snow line. Therefore, the correct representation of climate variables and their interdependence is crucial when describing or predicting hydrological processes. When using climate model simulations in hydrological impact studies, forcing meteorological data are usually downscaled and bias corrected, most often by univariate approaches such as quantile mapping of individual variables, neglecting the relationships that exist between climate variables. In this study we test the hypothesis that the explicit consideration of the relation between air temperature and precipitation will affect hydrological impact modelling in a snow-dominated mountain environment. Glacio-hydrological simulations were performed for two partly glacierized alpine catchments using a recently developed multivariate bias correction method to post-process EURO-CORDEX regional climate model outputs between 1976 and 2099. These simulations were compared to those obtained by using the common univariate quantile mapping for bias correction. As both methods correct each climate variable's distribution in the same way, the marginal distributions of the individual variables show no differences. Yet, regarding the interdependence of precipitation and air temperature, clear differences are notable in the studied catchments. Simultaneous correction based on the multivariate approach led to more precipitation below air temperatures of 0 ∘C and therefore more simulated snowfall than with the data of the univariate approach. This difference translated to considerable consequences for the hydrological responses of the catchments. The multivariate bias-correction-forced simulations showed distinctly different results for projected snow cover characteristics, snowmelt-driven streamflow components, and expected glacier disappearance dates. In all aspects – the fraction of precipitation above and below 0 ∘C, the simulated snow water equivalents, glacier volumes, and the streamflow regime – simulations resulting from the multivariate-corrected data corresponded better with reference data than the results of univariate bias correction. Differences in simulated total streamflow due to the different bias correction approaches may be considered negligible given the generally large spread of the projections, but systematic differences in the seasonally delayed streamflow components from snowmelt in particular will matter from a planning perspective. While this study does not allow conclusive evidence that multivariate bias correction approaches are generally preferable, it clearly demonstrates that incorporating or ignoring inter-variable relationships between air temperature and precipitation data can impact the conclusions drawn in hydrological climate change impact studies in snow-dominated environments.

Download Full-text

Electron impact studies. VI. Mass spectra of esters and thioesters. Skeletal rearrangement on electron impact

Australian Journal of Chemistry ◽

10.1071/ch9670689 ◽

1967 ◽

Vol 20 (4) ◽

pp. 689 ◽

Cited By ~ 4

Author(s):

JH Bowie ◽

RG Cooks ◽

P Jakobsen ◽

S Lawesson ◽

G Schroll

Keyword(s):

Carbon Dioxide ◽

Carbon Monoxide ◽

High Resolution ◽

Electron Impact ◽

Mass Spectra ◽

Skeletal Rearrangement ◽

Unsaturated Esters ◽

Impact Studies ◽

Unsaturated Alcohols ◽

Metastable Ions

The mass spectra of representative series of simple alkyl acetoacetates, alkyl acetothioacetates, and some unsaturated esters derived from unsaturated alcohols or phenols are reported and discussed. The fragmentation schemes have been established by high resolution measurements, appropriate metastable ions, and by deuterium and 18O labelling. Many of the spectra show significant skeletal rearrangement fragments arising from either loss of carbon monoxide or carbon dioxide.

Download Full-text

Impact and uncertainty of climate projections on Alpine catchments using high-resolution models

10.5194/egusphere-egu21-13443 ◽

2021 ◽

Author(s):

Jorge Sebastian Moraga ◽

Nadav Peleg ◽

Simone Fatichi ◽

Peter Molnar ◽

Paolo Burlando

Keyword(s):

Climate Change ◽

High Resolution ◽

Climate Variability ◽

Soil Conditions ◽

Internal Climate Variability ◽

Mountainous Catchments ◽

Precipitation Decrease ◽

Alpine Catchments ◽

Impacts Of Climate Change

<p>Hydrological processes in mountainous catchments will be subject to climate change on all scales, and their response is expected to vary considerably in space. Typical hydrological studies, which use coarse climate data inputs obtained from General Circulation Models (GCM) and Regional Climate Models (RCM), focus mostly on statistics at the outlet of the catchments, overlooking the effects within the catchments. Furthermore, the role of uncertainty, especially originated from natural climate variability, is rarely analyzed. In this work, we quantified the impacts of climate change on hydrological components and determined the sources of uncertainties in the projections for two mostly natural Swiss alpine catchments: Kleine Emme and Thur. Using a two-dimensional weather generator, AWE-GEN-2d, and based on nine different GCM-RCM model chains, we generated high-resolution (2 km, 1 hour) ensembles of gridded climate inputs until the end of the 21<sup>st</sup> century. The simulated variables were subsequently used as inputs into the fully distributed hydrological model Topkapi-ETH to estimate the changes in hydrological statistics at 100-m and hourly resolutions. Increased temperatures (by 4&#176;C, on average) and changes in precipitation (decrease over high elevations by up to 10%, and increase at the lower elevation by up to 15%) results in increased evapotranspiration rates in the order of 10%, up to a 50% snowmelt, and drier soil conditions. These changes translate into important shifts in streamflow seasonality at the outlet of the catchments, with a significant increase during the winter months (up to 40%) and a reduction during the summer (up to 30%). Analysis at the sub-catchment scale reveals elevation-dependent hydrological responses: mean annual streamflow, as well as high and low flow extremes, are projected to decrease in the uppermost sub-catchments and increase in the lower ones. Furthermore, we computed the uncertainty of the estimations and compared them to the magnitude of the change signal. Although the signal-to-noise-ratio of extreme streamflow for most sub-catchments is low (below 0.5) there is a clear elevation dependency. In every case, internal climate variability (as opposed to climate model uncertainty) explains most of the uncertainty, averaging 85% for maximum and minimum flows, and 60% for mean flows. The results highlight the importance of modelling the distributed impacts of climate change on mountainous catchments, and of taking into account the role of internal climate variability in hydrological projections.</p>

Download Full-text

Added value of high-resolution regional climate simulations for regional impact studies

Meteorologische Zeitschrift ◽

10.1127/metz/2016/0701 ◽

2016 ◽

Vol 25 (3) ◽

pp. 291-304 ◽

Cited By ~ 10

Author(s):

Julia Hackenbruch ◽

Gerd Schädler ◽

Janus Willem Schipper

Keyword(s):

High Resolution ◽

Regional Climate ◽

Added Value ◽

Regional Impact ◽

Impact Studies ◽

Climate Simulations

Download Full-text

High resolution electron impact studies of electric dipole-forbidden states of benzene

Journal of Physics B Atomic and Molecular Physics ◽

10.1088/0022-3700/13/3/023 ◽

1980 ◽

Vol 13 (3) ◽

pp. 627-640 ◽

Cited By ~ 27

Author(s):

D G Wilden ◽

J Comer

Keyword(s):

High Resolution ◽

Electron Impact ◽

Electric Dipole ◽

Forbidden States ◽

Impact Studies ◽

Resolution Electron

Download Full-text

Timing of human-induced climate change emergence from internal climate variability for hydrological impact studies

Hydrology Research ◽

10.2166/nh.2018.059 ◽

2018 ◽

Vol 49 (2) ◽

pp. 421-437 ◽

Cited By ~ 21

Author(s):

Mei-Jia Zhuan ◽

Jie Chen ◽

Ming-Xi Shen ◽

Chong-Yu Xu ◽

Hua Chen ◽

...

Keyword(s):

Climate Change ◽

Climate Variability ◽

Climate Models ◽

Climate Model ◽

Climate Trends ◽

Impact Studies ◽

Internal Climate Variability ◽

Temperature And Precipitation ◽

Hydrological Impact ◽

Near Term

Abstract This study proposes a method to estimate the timing of human-induced climate change (HICC) emergence from internal climate variability (ICV) for hydrological impact studies based on climate model ensembles. Specifically, ICV is defined as the inter-member difference in a multi-member ensemble of a climate model in which human-induced climate trends have been removed through a detrending method. HICC is defined as the mean of multiple climate models. The intersection between HICC and ICV curves is defined as the time of emergence (ToE) of HICC from ICV. A case study of the Hanjiang River watershed in China shows that the temperature change has already emerged from ICV during the last century. However, the precipitation change will be masked by ICV up to the middle of this century. With the joint contributions of temperature and precipitation, the ToE of streamflow occurs about one decade later than that of precipitation. This implies that consideration for water resource vulnerability to climate should be more concerned with adaptation to ICV in the near-term climate (present through mid-century), and with HICC in the long-term future, thus allowing for more robust adaptation strategies to water transfer projects in China.

Download Full-text