HESS Opinions: From response units to functional units: a thermodynamic reinterpretation of the HRU concept to link spatial organization and functioning of intermediate scale catchments

Zehe, Erwin; Ehret, Uwe; Pfister, Laurent; Blume, Theresa; Schröder, Boris; Westhoff, Martijn; Jackisch, Conrad; Schymanski, Stanislaus J.; Weiler, Markus; Schulz, Karsten; Allroggen, Niklas; Tronicke, Jens; Schaik, Loes van; Dietrich, Peter; Scherer, Ulrike; Eccard, J.; Wulfmeyer, Volker; Kleidon, Axel

doi:10.5194/hess-18-4635-2014

Cited by 100 publications

(114 citation statements)

References 147 publications

Supporting

Mentioning

103

Contrasting

Order By: Relevance

“…There have been many attempts to improve the parameterization of lumped and semi-distributed models by further discretizing the sub-basins into a given number of regions that exhibit nearly similar hydrologic behavior, i.e., the so-called HRU concept initially proposed by Leavesley et al (1983) and further developed by others (e.g., Flügel, 1995;Beldring et al, 2003;Blöschl et al, 2008;Viviroli et al, 2009;Zehe et al, 2014). Unfortunately, results obtained in these parameterization attempts have not been very successful in realistically representing the spatial variability of model parameters, states, and fluxes because of the lack of regionalized parameters and the unabridged reliance on parameter calibration to improve model performance (Kumar et al, 2010).…”

Section: The State Of the Artmentioning

confidence: 99%

Toward seamless hydrologic predictions across spatial scales

Samaniego

Kumar

Thober

et al. 2017

Hydrol. Earth Syst. Sci.

111

134

View full text Add to dashboard Cite

Abstract. Land surface and hydrologic models (LSMs/HMs) are used at diverse spatial resolutions ranging from catchment-scale (1-10 km) to global-scale (over 50 km) applications. Applying the same model structure at different spatial scales requires that the model estimates similar fluxes independent of the chosen resolution, i.e., fulfills a fluxmatching condition across scales. An analysis of state-of-theart LSMs and HMs reveals that most do not have consistent hydrologic parameter fields. Multiple experiments with the mHM, Noah-MP, PCR-GLOBWB, and WaterGAP models demonstrate the pitfalls of deficient parameterization practices currently used in most operational models, which are insufficient to satisfy the flux-matching condition. These examples demonstrate that J. Dooge's 1982 statement on the unsolved problem of parameterization in these models remains true. Based on a review of existing parameter regionalization techniques, we postulate that the multiscale parameter regionalization (MPR) technique offers a practical and robust method that provides consistent (seamless) parameter and flux fields across scales. Herein, we develop a general model protocol to describe how MPR can be applied to a particular model and present an example application using the PCR-GLOBWB model. Finally, we discuss potential advantages and limitations of MPR in obtaining the seamless prediction of hydrological fluxes and states across spatial scales.

show abstract

Section: The State Of the Artmentioning

confidence: 99%

Toward seamless hydrologic predictions across spatial scales

Samaniego

Kumar

Thober

et al. 2017

Hydrol. Earth Syst. Sci.

111

134

View full text Add to dashboard Cite

show abstract

“…On balance, we believe that modelling of catchments will significantly benefit from and may even require a convergence of different modelling strategies, in particular with respect to exploiting the features of organization in these complex systems (Dooge, 1986) in a hierarchical way, as for example suggested by Zehe et al (2014). Combining this with large sample comparative studies and more efficiently exploiting the information content of available data over a range of scales may eventually pave the way towards the formulation of meaningful and general scaling relationships that will be key to understanding how large-scale patterns emerge from first principles.…”

Section: Discussionmentioning

confidence: 99%

“…As already emphasized previously by many authors (e.g. Beven, 1989Beven, , 2001Beven, , 2006aKirchner, 2006;Zehe et al, 2014), these efforts to approach the closure problem in hydrology need to involve both, ways to reliably determine effective model parameters, i.e. the system boundary conditions, that integrate and reflect the natural heterogeneity within the model domain, as well as the development of equations that are physically consistent at the scale of application.…”

Section: Organized Complexity and Catchment Similaritymentioning

confidence: 99%

“…Ehret et al, 2014) has the advantage of significantly reducing the number of required effective model parameters. Importantly, this lumping process does not, as long as it is well tested to encapsulate the relevant dynamics of the system, necessarily involve a loss of information.…”

Section: Modelling Myths -Or Not?mentioning

confidence: 99%

“…When carefully implemented, spatially distributed formulations, e.g. based on hydrological response units or related concepts (Beven and Kirkby, 1979;Knudsen et al, 1986;Flügel, 1995;Winter, 2001;Seibert et al, 2003;Uhlenbrook et al, 2004, 2010Schmocker-Fackel et al, 2007Gharari et al, 2011;Zehe et al, 2014;Haghnegahdar et al, 2015), with an equilibrated balance between process heterogeneity and information/data availability and tested and evaluated against multivariate observed response dynamics, and conceptual models have been shown to be versatile enough to identify and represent the dominant hydrological processes and their heterogeneity in a catchment (e.g. Boyle et al, 2001;Fenicia et al, 2008a, b;Winsemius et al, 2008;Kumar et al, 2013;Hrachowitz et al, 2014;Nijzink et al, 2016a) within limited uncertainty.…”

Section: Modelling Myths -Or Not?mentioning

confidence: 99%

See 2 more Smart Citations

HESS Opinions: The complementary merits of competing modelling philosophies in hydrology

Hrachowitz

Clark

2017

Hydrol. Earth Syst. Sci.

181

130

View full text Add to dashboard Cite

Abstract. In hydrology, two somewhat competing philosophies form the basis of most process-based models. At one endpoint of this continuum are detailed, high-resolution descriptions of small-scale processes that are numerically integrated to larger scales (e.g. catchments). At the other endpoint of the continuum are spatially lumped representations of the system that express the hydrological response via, in the extreme case, a single linear transfer function. Many other models, developed starting from these two contrasting endpoints, plot along this continuum with different degrees of spatial resolutions and process complexities. A better understanding of the respective basis as well as the respective shortcomings of different modelling philosophies has the potential to improve our models. In this paper we analyse several frequently communicated beliefs and assumptions to identify, discuss and emphasize the functional similarity of the seemingly competing modelling philosophies. We argue that deficiencies in model applications largely do not depend on the modelling philosophy, although some models may be more suitable for specific applications than others and vice versa, but rather on the way a model is implemented. Based on the premises that any model can be implemented at any desired degree of detail and that any type of model remains to some degree conceptual, we argue that a convergence of modelling strategies may hold some value for advancing the development of hydrological models.

show abstract

Do we need a Community Hydrological Model?

Weiler

Beven

2015

Water Resour. Res.

View full text Add to dashboard Cite

We believe that there are too many models in hydrology and we should ask ourselves the question, if we are currently wasting time and effort in developing another model again instead of focusing on the development of a Community Hydrological Model. In other fields, this kind of models has been quite successful, but due to several reasons, no single community model has been developed in the field of hydrology yet. The concept, strength, and weakness of a community model were discussed at the Chapman Conference on Catchment Spatial Behaviour and Complex Organisation held in Luxembourg in September 2014. This discussion as well as our own opinions about the potential of a community models or at least the necessary discussion to establish one are debated in this commentary. There are Too Many Models in HydrologyThis is partly because every generation of PhD students thinks they could do better, partly because there is a wide range of different types of applications with different needs in hydrology, and partly because there is no agreement on a common set of concepts for the process representations. However, many of those models are similar in structure (for both the ''bucket'' model and the ''physically based'' model cases) so that the same, or very similar, concepts have been programmed and tested over and over again. There are advantages to this when models are simple, of course, but as model and data implementations get more and more complex this could be considered a waste of community effort and resources.In the atmospheric modeling domain, there have been initiatives to have community models, both for the atmosphere itself (e.g., CESM [Hurrell et al., 2013] and WRF [Skamarock and Klemp, 2008]) and for the land surface boundary condition, including a representation of the hydrology (e.g., NOAH-MP within WRF [Niu et al., 2011] and CLM [Lawrence et al., 2011]). These models have structured version release and development test bed programs. The Community Land Model (CLM) is widely used as a land surface parameterization in the hydrometeorological community but has not made much impact on the hydrological modeling community. It is not even mentioned in Beven [2012], because it is aimed at partitioning the surface energy balance for different surfaces within a grid, rather than getting better predictions of river discharges. Indeed, it would not pass scrutiny as a satisfactory hydrological model for many hydrologists. Some models developed within the hydrological modeling community have also been released in open source form with a view to building up a large user community (e.g., SWAT, HYPE, or different model codes in R and MATLAB for HBV, TOPMODEL, or Dynamic TOPMODEL (see R codes for both models at http://cran. r-project.org) [e.g., Str€ omqvist et al., 2012;Buytaert, 2013;Fuka et al., 2014;Metcalfe et al., 2015]), and a number of model repositories also exist (e.g., at CSDMS, http://csdms.colorado.edu).The trend in hydrology has rather been to create even more new models, or to provide metamodeling fr...

show abstract

HESS Opinions: From response units to functional units: a thermodynamic reinterpretation of the HRU concept to link spatial organization and functioning of intermediate scale catchments

Cited by 100 publications

References 147 publications

Toward seamless hydrologic predictions across spatial scales

Toward seamless hydrologic predictions across spatial scales

HESS Opinions: The complementary merits of competing modelling philosophies in hydrology

Do we need a Community Hydrological Model?

Contact Info

Product

Resources

About