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  • 1. Archfield, Stacey A.
    et al.
    Clark, Martyn
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Hay, Lauren E.
    McMillan, Hilary
    Kiang, Julie E.
    Seibert, Jan
    Hakala, Kirsti
    Bock, Andrew
    Wagener, Thorsten
    Farmer, William H.
    Andreassian, Vazken
    Attinger, Sabine
    Viglione, Alberto
    Knight, Rodney
    Markstrom, Steven
    Over, Thomas
    Accelerating advances in continental domain hydrologic modeling2015Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 51, nr 12, s. 10078-10091Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the past, hydrologic modeling of surface water resources has mainly focused on simulating the hydrologic cycle at local to regional catchment modeling domains. There now exists a level of maturity among the catchment, global water security, and land surface modeling communities such that these communities are converging toward continental domain hydrologic models. This commentary, written from a catchment hydrology community perspective, provides a review of progress in each community toward this achievement, identifies common challenges the communities face, and details immediate and specific areas in which these communities can mutually benefit one another from the convergence of their research perspectives. Those include: (1) creating new incentives and infrastructure to report and share model inputs, outputs, and parameters in data services and open access, machine-independent formats for model replication or reanalysis; (2) ensuring that hydrologic models have: sufficient complexity to represent the dominant physical processes and adequate representation of anthropogenic impacts on the terrestrial water cycle, a process-based approach to model parameter estimation, and appropriate parameterizations to represent large-scale fluxes and scaling behavior; (3) maintaining a balance between model complexity and data availability as well as uncertainties; and (4) quantifying and communicating significant advancements toward these modeling goals.

  • 2.
    Arheimer, Berit
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Lindström, Göran
    SMHI, Forskningsavdelningen, Hydrologi.
    Detecting Changes in River Flow Caused by Wildfires, Storms, Urbanization, Regulation, and Climate Across Sweden2019Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973Artikel i tidskrift (Refereegranskat)
  • 3.
    Bosshard, Thomas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Carambia, M.
    Goergen, K.
    Kotlarski, S.
    Krahe, P.
    Zappa, M.
    Schaer, C.
    Quantifying uncertainty sources in an ensemble of hydrological climate-impact projections2013Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 49, nr 3, s. 1523-1536Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The quantification of uncertainties in projections of climate impacts on river streamflow is highly important for climate adaptation purposes. In this study, we present a methodology to separate uncertainties arising from the climate model (CM), the statistical postprocessing (PP) scheme, and the hydrological model (HM). We analyzed ensemble projections of hydrological changes in the Alpine Rhine (Eastern Switzerland) for the near-term and far-term scenario periods 2024-2050 and 2073-2099 with respect to 1964-1990. For the latter scenario period, the model ensemble projects a decrease of daily mean runoff in summer (-32.2%, range [-45.5% to -8.1%]) and an increase in winter (+41.8%, range [+4.8% to +81.7%]). We applied an analysis of variance model combined with a subsampling procedure to assess the importance of different uncertainty sources. The CMs generally are the dominant source in summer and autumn, whereas, in winter and spring, the uncertainties due to the HMs and the statistical PP gain importance and even partly dominate. In addition, results show that the individual uncertainties from the three components are not additive. Rather, the associated interactions among the CM, the statistical PP scheme, and the HM account for about 5%-40% of the total ensemble uncertainty. The results indicate, in distinction to some previous studies, that none of the investigated uncertainty sources are negligible, and some of the uncertainty is not attributable to individual modeling chain components but rather depends upon interactions. Citation: Bosshard, T., M. Carambia, K. Goergen, S. Kotlarski, P. Krahe, M. Zappa, and C. Schar (2013), Quantifying uncertainty sources in an ensemble of hydrological climate-impact projections, Water Resour. Res., 49, 1523-1536, doi: 10.1029/2011WR011533.

  • 4. De Lavenne, Alban
    et al.
    Andreassian, V.
    Thirel, G.
    Ramos, M. -H
    Perrin, C.
    A Regularization Approach to Improve the Sequential Calibration of a Semidistributed Hydrological Model2019Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973Artikel i tidskrift (Refereegranskat)
  • 5. Hutton, Christopher
    et al.
    Wagener, Thorsten
    Freer, Jim
    Han, Dawei
    Duffy, Chris
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Most computational hydrology is not reproducible, so is it really science?2016Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 52, nr 10, s. 7548-7555Artikel i tidskrift (Refereegranskat)
  • 6. Hutton, Christopher
    et al.
    Wagener, Thorsten
    Freer, Jim
    Han, Dawei
    Duffy, Chris
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Reply to comment by Anel on "Most computational hydrology is not reproducible, so is it really science?"2017Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 53, nr 3, s. 2575-2576Artikel i tidskrift (Refereegranskat)
  • 7. Hutton, Christopher
    et al.
    Wagener, Thorsten
    Freer, Jim
    Han, Dawei
    Duffy, Chris
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Reply to comment by Melsen et al. on "Most computational hydrology is not reproducible, so is it really science?"2017Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 53, nr 3, s. 2570-2571Artikel i tidskrift (Refereegranskat)
  • 8. Laiti, L.
    et al.
    Mallucci, S.
    Piccolroaz, S.
    Bellin, A.
    Zardi, D.
    Fiori, A.
    Nikulin, Grigory
    SMHI, Forskningsavdelningen, Klimatforskning - Rossby Centre.
    Majone, B.
    Testing the Hydrological Coherence of High-Resolution Gridded Precipitation and Temperature Data Sets2018Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 54, nr 3, s. 1999-2016Artikel i tidskrift (Refereegranskat)
  • 9. Lyon, Steve W.
    et al.
    Nathanson, Marcus
    Spans, Andre
    Grabs, Thomas
    Laudon, Hjalmar
    Temnerud, Johan
    SMHI, Forskningsavdelningen, Hydrologi.
    Bishop, Kevin H.
    Seibert, Jan
    Specific discharge variability in a boreal landscape2012Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 48, artikel-id W08506Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Specific discharge variations within a mesoscale catchment were studied on the basis of three synoptic sampling campaigns. These were conducted during stable flow conditions within the Krycklan catchment study area in northern Sweden. During each campaign, about 80 individual locations were measured for discharge draining from catchment areas ranging between 0.12 and 67 km(2). These discharge samplings allowed for the comparison between years within a given season (September 2005 versus September 2008) and between seasons within a given year (May 2008 versus September 2008) of specific discharge across this boreal landscape. There was considerable variability in specific discharge across this landscape. The ratio of the interquartile range (IQR) defined as the difference between the 75th and 25th percentiles of the specific discharges to the median of the specific discharges ranged from 37% to 43%. Factor analysis was used to explore potential relations between landscape characteristics and the specific discharge observed for 55 of the individual locations that were measured in all three synoptic sampling campaigns. Percentage wet area (i.e., wetlands, mires, and lakes) and elevation were found to be directly related to the specific discharge during the drier September 2008 sampling while potential annual evaporation was found to be inversely related. There was less of a relationship determined during the wetter post spring flood May 2008 sampling and the late summer rewetted September 2005 sampling. These results indicate the ability of forests to "dry out" parts of the catchment over the summer months while wetlands "keep wet" other parts. To demonstrate the biogeochemical implications of such spatiotemporal variations in specific discharge, we estimate dissolved organic carbon (DOC) exports with available data for the May 2008 and September 2008 samplings using both the spatially variable observed specific discharges and the spatially constant catchment average values. The average absolute difference in DOC export for the various subcatchments between using a variable and using a constant specific discharge was 28% for the May 2008 sampling and 20% for the September 2008 sampling.

  • 10. Magnusson, Jan
    et al.
    Gustafsson, David
    SMHI, Forskningsavdelningen, Hydrologi.
    Huesler, Fabia
    Jonas, Tobias
    Assimilation of point SWE data into a distributed snow cover model comparing two contrasting methods2014Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 50, nr 10, s. 7816-7835Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In alpine and high-latitude regions, water resource decision making often requires large-scale estimates of snow amounts and melt rates. Such estimates are available through distributed snow models which in some situations can be improved by assimilation of remote sensing observations. However, in regions with frequent cloud cover, complex topography, or large snow amounts satellite observations may feature information of limited quality. In this study, we examine whether assimilation of snow water equivalent (SWE) data from ground observations can improve model simulations in a region largely lacking reliable remote sensing observations. We combine the model output with the point data using three-dimensional sequential data assimilation methods, the ensemble Kalman filter, and statistical interpolation. The filter performance was assessed by comparing the simulation results against observed SWE and snow-covered fraction. We find that a method which assimilates fluxes (snowfall and melt rates computed from SWE) showed higher model performance than a control simulation not utilizing the filter algorithms. However, an alternative approach for updating the model results using the SWE data directly did not show a significantly higher performance than the control simulation. The results show that three-dimensional data assimilation methods can be useful for transferring information from point snow observations to the distributed snow model. Key Points <list id="wrcr21142-list-0001" list-type="bulleted"> <list-item id="wrcr21142-li-0001">Evaluating methods for assimilating snow observations into distributed models <list-item id="wrcr21142-li-0002">Assimilation can improve model skill also at locations without observations <list-item id="wrcr21142-li-0003">Assimilation of fluxes appears more successful than assimilation of states <doi origin="wiley" registered="yes">10.1002/(ISSN)1944-7973</doi

  • 11. Musselman, Keith N.
    et al.
    Molotch, Noah P.
    Margulis, Steven A.
    Lehning, Michael
    Gustafsson, David
    SMHI, Forskningsavdelningen, Hydrologi.
    Improved snowmelt simulations with a canopy model forced with photo-derived direct beam canopy transmissivity2012Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 48, artikel-id W10509Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The predictive capacity of a physically based snow model to simulate point-scale, subcanopy snowmelt dynamics is evaluated in a mixed conifer forest, southern Sierra Nevada, California. Three model scenarios each providing varying levels of canopy structure detail were tested. Simulations of three water years initialized at locations of 24 ultrasonic snow depth sensors were evaluated against observations of snow water equivalent (SWE), snow disappearance date, and volumetric soil water content. When canopy model parameters canopy openness and effective leaf area index were obtained from satellite and literature-based sources, respectively, the model was unable to resolve the variable subcanopy snowmelt dynamics. When canopy parameters were obtained from hemispherical photos, the improvements were not statistically significant. However, when the model was modified to accept photo-derived time-varying direct beam canopy transmissivity, the error in the snow disappearance date was reduced by as much as one week and positive and negative biases in melt-season SWE and snow cover duration were significantly reduced. Errors in the timing of soil meltwater fluxes were reduced by 11 days on average. The optimum aggregated temporal model resolution of direct beam canopy transmissivity was determined to be 30 min; hourly averages performed no better than the bulk canopy scenarios and finer time steps did not increase overall model accuracy. The improvements illustrate the important contribution of direct shortwave radiation to subcanopy snowmelt and confirm the known nonlinear melt behavior of snow cover.

  • 12. Nijzink, R.C.
    et al.
    Almeida, S.
    Pechlivanidis, Ilias
    SMHI, Forskningsavdelningen, Hydrologi.
    Capell, Réne
    SMHI, Forskningsavdelningen, Hydrologi.
    Gustafsson, David
    SMHI, Forskningsavdelningen, Hydrologi.
    Arheimer, Berit
    SMHI, Forskningsavdelningen, Hydrologi.
    Parajka, J.
    Freer, J.
    Han, D.
    Wagener, T.
    van Nooijen, R.R.P.
    Savenije, H.H.G.
    Hrachowitz, M.
    Constraining Conceptual Hydrological ModelsWith Multiple Information Sources2018Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 54, nr 10, s. 8332-8362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The calibration of hydrological models without streamflow observations is problematic, and the simultaneous, combined use of remotely sensed products for this purpose has not been exhaustively tested thus far. Our hypothesis is that the combined use of products can (1) reduce the parameter search space and (2) improve the representation of internal model dynamics and hydrological signatures. Five different conceptual hydrological models were applied to 27 catchments across Europe. A parameter selection process, similar to a likelihood weighting procedure, was applied for 1,023 possible combinations of 10 different data sources, ranging from using 1 to all 10 of these products. Distances between the two empirical distributions of model performance metrics with and without using a specific product were determined to assess the added value of a specific product. In a similar way, the performance of the models to reproduce 27 hydrological signatures was evaluated relative to the unconstrained model. Significant reductions in the parameter space were obtained when combinations included Advanced Microwave Scanning Radiometer ‐ Earth Observing System and Advanced Scatterometer soil moisture, Gravity Recovery and Climate Experiment total water storage anomalies, and, in snow‐dominated catchments, the Moderate Resolution Imaging Spectroradiometer snow cover products. The evaporation products of Land Surface Analysis ‐ Satellite Application Facility and MOD16 were less effective for deriving meaningful, well‐constrained posterior parameter distributions. The hydrological signature analysis indicated that most models profited from constraining with an increasing number of data sources. Concluding, constraining models with multiple data sources simultaneously was shown to be valuable for at least four of the five hydrological models to determine model parameters in absence of streamflow.

  • 13.
    Olsson, Jonas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Persson, M
    Albergel, J
    Berndtsson, R
    Zante, P
    Ohrstrom, P
    Nasri, S
    Multiscaling analysis and random cascade modeling of dye infiltration2002Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 38, nr 11, artikel-id 1263Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    [1] We aimed at investigating whether the spatial variability of infiltration in field soils, as visualized through dye infiltration experiments, is characterized by a multiscaling behavior. Digitized high-resolution dye images from three sites in an experimental catchment in Tunisia were analyzed using three indicators of scaling: empirical probability distribution functions, power spectra, and raw statistical moments. The two former indicators suggested a general scaling behavior of the data, which through the moments' analysis was found to be of multiscaling type. Random cascade processes are frequently used to model multiscaling processes, and we fitted the "universal multifractal'' (UM) model of Schertzer and Lovejoy [1987] to our data. The UM model closely reproduced the empirical K(q) functions, and simulated fields reproduced key features in the observed ones. The results indicate that multiscaling random cascade modeling is useful for statistically describing flow processes and solute transport under field conditions.

  • 14.
    Olsson, Jonas
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Persson, Magnus
    Jinno, Kenji
    Analysis and modeling of solute transport dynamics by breakdown coefficients and random cascades2007Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 43, nr 3, artikel-id W03417Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The small-scale variability and scaling properties of solute transport dynamics were investigated by laboratory experiments. Dye-stained water was applied at a constant flux in a Plexiglas Hele-Shaw cell filled with soil material, and the transport process was registered by digital photographs of the cell front, producing a very high resolution in both time (minutes) and space (millimeters). The experiments comprised different cell materials (uniform and natural sand) and different water fluxes. Scaling properties of vertically integrated dye mass distributions were analyzed and modeled using so-called breakdown coefficients (BDCs), which represent the multiplicative weights in a microcanonical random cascade process. The pdfs of BDCs varied with scale, indicating self-affine scaling, and were accurately approximated by beta distributions with a scaling parameter. Two versions of BDC-based random cascade models were used to simulate mass distributions at different time steps. The results support the applicability of random cascade models to subsurface transport processes.

  • 15.
    Pechlivanidis, Ilias
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Gupta, H.
    Bosshard, Thomas
    SMHI, Forskningsavdelningen, Hydrologi.
    An Information Theory Approach to Identifying a Representative Subset of Hydro-Climatic Simulations for Impact Modeling Studies2018Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 54, nr 8, s. 5422-5435Artikel i tidskrift (Refereegranskat)
  • 16.
    Pechlivanidis, Ilias
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Jackson, B.
    McMillan, H.
    Gupta, H.
    Use of an entropy-based metric in multiobjective calibration to improve model performance2014Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 50, nr 10, s. 8066-8083Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Parameter estimation for hydrological models is complicated for many reasons, one of which is the arbitrary emphasis placed, by most traditional measures of fit, on various magnitudes of the model residuals. Recent research has called for the development of robust diagnostic measures that provide insights into which model structural components and/or data may be inadequate. In this regard, the flow duration curve (FDC) represents the historical variability of flow and is considered to be an informative signature of catchment behavior. Here we investigate the potential of using the recently developed conditioned entropy difference metric (CED) in combination with the Kling-Gupta efficiency (KGE). The CED respects the static information contained in the flow frequency distribution (and hence the FDC), but does not explicitly characterize temporal dynamics. The KGE reweights the importance of various hydrograph components (correlation, bias, variability) in a way that has been demonstrated to provide better model calibrations than the commonly used Nash-Sutcliffe efficiency, while being explicitly time sensitive. We employ both measures within a multiobjective calibration framework and achieve better performance over the full range of flows than obtained by single-criteria approaches, or by the common multiobjective approach that uses log-transformed and untransformed data to balance fitting of low and high flow periods. The investigation highlights the potential of CED to complement KGE (and vice versa) during model identification. It is possible that some of the complementarity is due to CED representing more information from moments >2 than KGE or other common metrics. We therefore suggest that an interesting way forward would be to extend KGE to include higher moments, i.e., use different moments as multiple criteria. Key Points <list id="wrcr21161-list-0001" list-type="bulleted"> <list-item id="wrcr21161-li-0001">CED provides an appropriate quantitative measure of fit to the FDC <list-item id="wrcr21161-li-0002">Complements between CED and KGE extracted flow information <list-item id="wrcr21161-li-0003">CED-KGE achieves better performance than single or common multiobjectives <doi origin="wiley" registered="yes">10.1002/(ISSN)1944-7973</doi

  • 17.
    Riml, Joakim
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Worman, Anders
    Response functions for in-stream solute transport in river networks2011Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 47, artikel-id W06502Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper analyzes the effects of different hydrological mechanisms on the solute response in watershed stream networks. Important processes are due to the hydraulic and chemical retention of reactive solutes in transient storage zones and the cumulative consequences of these processes from a single transport pathway as well as from the network of transport pathways. Temporal moments are derived for a distributed stream network and for a compartment-in-series model. The temporal moments are evaluated and are utilized to derive formal expressions for translating the network parameters into compartmental model parameters. The analysis reveals that in addition to the hydraulic and chemical retention processes, the morphological and topological properties of a watershed have a distinct impact on the central temporal moments in terms of averaging of the solute load weighted distances as well as the transport parameters over the network. Kinetic (rate-limited) transient storage affects second-order and higher central temporal moments and thus has a secondary effect on the parameterization of compartmental models. Additional considerable contributions to all temporal moments are introduced when parameter variability along transport pathways is considered. The paper demonstrates an improved model outcome for phosphorus transport in a small Swedish watershed by accounting for the overall network effects when parameterizing a compartment-in-series model.

  • 18.
    Riml, Joakim
    et al.
    SMHI.
    Worman, Anders
    Spatiotemporal decomposition of solute dispersion in watersheds2015Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 51, nr 4, s. 2377-2392Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Information about the effect of different dispersion mechanisms on the solute response in watersheds is crucial for understanding the temporal dynamics of many water quality problems. However, to quantify these processes from stream water quality time series may be difficult because the governing mechanisms responsible for the concentration fluctuations span a wide range of temporal and spatial scales. In an attempt to address the quantification problem, we propose a novel methodology that includes a spectral decomposition of the watershed solute response using a distributed solute transport model for the network of transport pathways in surface and subsurface water. Closed form solutions of the transport problem in both the Laplace and Fourier domains are used to derive formal expressions of (i) the central temporal moments of a solute pulse response and (ii) the power spectral response of a solute concentration time series. By evaluating high-frequency hydrochemical data from the Upper Hafren Watershed, Wales, we linked the watershed dispersion mechanisms to the damping of the concentration fluctuations in different frequency intervals reflecting various environments responsible for the damping. The evaluation of the frequency-dependent model parameters indicate that the contribution of the different environments to the concentration fluctuations at the watershed effluent varies with period. For the longest periods (predominantly groundwater transport pathways) we found that the frequency typical transport time of chloride was 100 times longer and that sodium had a 2.5 times greater retardation factor compared with the shortest periods (predominantly shallow groundwater and surface water transport pathways).

  • 19.
    Wetterhall, Fredrik
    et al.
    SMHI, Forskningsavdelningen, Hydrologi.
    Bardossy, Andras
    Chen, Deliang
    Halldin, Sven
    Xu, Chong-Yu
    Daily precipitation-downscaling techniques in three Chinese regions2006Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 42, nr 11, artikel-id W11423Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    [ 1] Four methods of statistical downscaling of daily precipitation were evaluated on three catchments located in southern, eastern, and central China. The evaluation focused on seasonal variation of statistical properties of precipitation and indices describing the precipitation regime, e. g., maximum length of dry spell and maximum 5-day precipitation, as well as interannual and intra-annual variations of precipitation. The predictors used in this study were mean sea level pressure, geopotential heights at 1000, 850, 700, and 500 hPa, and specific humidity as well as horizontal winds at 850, 700, and 500 hPa levels from the NCEP/NCAR reanalysis with 2.5 degrees x 2.5 degrees resolution for 1961 - 2000. The predictand was daily precipitation from 13 stations. Two analogue methods, one using principal components analysis (PCA) and the other Teweles-Wobus scores (TWS), a multiregression technique with a weather generator producing precipitation (SDSM) and a fuzzy-rule-based weather-pattern-classification method (MOFRBC), were used. Temporal and spatial properties of the predictors were carefully evaluated to derive the optimum setting for each method, and MOFRBC and SDSM were implemented in two modes, with and without humidity as predictor. The results showed that ( 1) precipitation was most successfully downscaled in the southern and eastern catchments located close to the coast, ( 2) winter properties were generally better downscaled, ( 3) MOFRBC and SDSM performed overall better than the analogue methods, ( 4) the modeled interannual variation in precipitation was improved when humidity was added to the predictor set, and ( 5), the annual precipitation cycle was well captured with all methods.

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