Butts, Michael Brian

Christensen, Jens Hesselbjerg

Christensen, Ole Bøssing

Drews, Martin

Høgh Jensen, Karsten

Larsen, Morten Andreas Dahl

Refsgaard, Jens Christian

Online Research Database In Technology

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Downloaded from orbit.dtu.dk on: Dec 20, 2017Coupled regional climate and hydrology modelling at the catchment scaleLarsen, Morten Andreas Dahl; Drews, Martin; Refsgaard, Jens Christian; Høgh Jensen, Karsten; Butts,Michael Brian ; Christensen, Jens Hesselbjerg; Christensen, Ole BøssingPublished in:Proceedings of the 3rd International Lund Regional-Scale Climate Modelling WorkshopPublication date:2014Document VersionEarly version, also known as pre-printLink back to DTU OrbitCitation (APA):Larsen, M. A. D., Drews, M., Refsgaard, J. C., Høgh Jensen, K., Butts, M. B., Christensen, J. H., & Christensen,O. B. (2014). Coupled regional climate and hydrology modelling at the catchment scale. In Proceedings of the3rd International Lund Regional-Scale Climate Modelling Workshop (pp. 34-35)  3rd International Lund Regional-Scale  Climate Modelling Workshop 21st Century Challenges in Regional Climate Modelling 16-19 June 2014, Lund, Sweden  Abstract template This first page is for our information purposes only. Do not delete it! Begin your abstract on the next page.  Maximum is 2 pages in the given layout including figures and tables.  Here, please indicate below: This abstract is intended for  • Oral presentation - X • Poster presentation  (type an x after your choice)  This abstract fits best into the topic (see the conference website for more information): 1. Regional Climate and Earth System Models - X 2. Very-high-resolution RCMs 3. Challenges for RCM Evaluation and Application 4. RCM Ensembles  (type an x after your choice)  Corresponding author (if not First Author): Name: Morten Andreas Dahl Larsen   e-mail: madla@dtu.dk   Coupled regional climate and hydrology modelling at the catchment scale Morten Andreas Dahl Larsen1, Martin Drews1, Jens Christian Refsgaard2, Karsten Høgh Jensen3, Michael Brian Butts4, Jens Hesselbjerg Christensen5 and Ole Bøssing Christensen5 1 Technical University of Denmark, Denmark (madla@dtu.dk) 2 Geological Survey of Denmark and Greenland, Denmark 3 University of Copenhagen, Denmark  4DHI, Denmark 5 Danish Meteorological Institute, Denmark  1.      Introduction More and more regional climate models are being applied at scales down to even a few kilometres. At these scales the complex interactions between the atmosphere, the land surface, and the subsurface hydrology are crucial for understanding climate feedbacks at the regional to local scales. Many of the current regional climate models, however, have only a limited capability to represent all the parts of the terrestrial water cycle. This is particular true for the interactions between surface water and groundwater dependent ecosystems and surface water and groundwater resources, which in many cases have been shown to play a critical role in the regional earth system. In the present study we investigate a dynamically coupled version of the DMI-HIRHAM (Christensen et al., 2006) regional climate model and a comprehensive distributed hydrological modelling system, MIKE SHE [Højbjerg et al., 2013], nested inside the regional climate model. A particular challenge in coupling a climate model to a hydrological model resides in in the vastly different philosophies expressed by such codes. While regional climate models generally implement primary physical equations, hydrological models typically are heavily calibrated codes. Likewise, temporal and spatial resolutions are often quite different. Lastly, present versions of MIKE SHE are native only to the Microsoft Windows operating system, necessitating the development of a novel cross-platform model interface based on open-source OpenMI technology (Gregersen et al., 2005 and Gregersen et al., 2007). The coupled model has been evaluated for a groundwater-dominated catchment in the western part of Denmark, Skjern River, covering approx. 2500 km2 with a grid spacing of 500 m, which is embedded within a 4000 x 2800 km regional climate modelling domain with a horizontal resolution of approx. 11 km (Figure 1). The setup has proven stable and has been used for simulations of several years. Inside the shared model domains the coupled model enables two-way interactions between the atmosphere and the groundwater via the river and land surface through an energy-based land surface model (SWET) (Overgaard, 2005). In this manner the simple land surface model embedded in DMI-HIRHAM is effectively replaced by the superior land surface component of the combined MIKE SHE/SWET model, which includes a wider range of processes at the land surface and distributed three-dimensional subsurface flows as well as higher temporal and spatial resolution. Outside the shared domain DMI-HIRHAM utilizes its own embedded land surface model; however, the model nesting makes it possible to detect substantial feedbacks from the improved surface/subsurface hydrology to the atmosphere even outside the shared domain.  2.       Studies The task of individually calibrating and preparing each of the two modelling systems was performed in two studies preceding the coupled simulations (Larsen et al., 2013a and Larsen et al., in preparation). The coupled simulations were assessed in two separate studies: Through 26 simulations (see example in Figure 2), the first study investigates the overall performance and feasibility of the coupled setup as compared to uncoupled simulations and further investigated the Figure 1. HIRHAM regional climate model domain and theSkjern River catchment location within Denmark also showingthe HIRHAM grid cells.   influence of the data transfer interval between the models and model variability (Larsen et al. 2013b). The results are tested against ten variables: Six atmospheric observation data variables (precipitation, wind speed, air temperature, surface pressure, global radiation and relative humidity) (Figure 3) as well as four ground/surface energy flux and water balance variables (latent-,sensible- and soil- heat fluxes as well as river discharge). Using varied data transfer rates between the models of 12-120 min the coupled results show improvements with an increase in data transfer frequency. In general however, the coupled performance is poorer compared to the uncoupled. This is explained by the calibration and parameterization of each model prior to the coupling. A perspective for future experiments therefore includes coupled model calibration and further experiments are suggested to investigate performance on larger scales and in other regions. The anticipated improvement in the reproduction of land-surface-atmosphere flux exchanges, temporally and geographically, from the MIKE SHE/SWET model as compared to HIRHAM is investigated in the other study focusing on periods of non-normal weather. Periods of more pronounced drought/rainfall and temperature minima and maxima were therefore investigated.  References  Christensen, O. B., M. Drews, J. H. Christensen, K. Dethloff, K. Ketelsen, I. Hebestadt and A. Rinke (2006) The HIRHAM regional climate model version 5 (β), Danish Meteorological Institute Technical Report 06-17, Denmark. Gregersen, J. B., P. J. A. Gijsbers, S. J. P. Westen, and M. Blind (2005) OpenMI: the essential concepts and their implications for legacy software, Adv. Geosci., 4, 37–44, doi:10.5194/adgeo-4-37-2005. Gregersen, J. B., P. J. A. Gijsbers, and S. J. P. Westen (2007) Open modelling interface, J. Hydroinform., 9, 175–191, doi:10.2166/hydro.2007.023. Højbjerg, A. L., L. Troldborg, S. Stisen, B. B. S. Christensen and H. J. Henriksen (2013) Stakeholder driven update and improvement of a national water resources model, Environ. Modell. Softw., 40, 202-213.   Larsen, M. A. D., P. Thejll, J. H. Christensen, J. C. Refsgaard, and K. H. Jensen (2013a) On the role of domain size and resolution in the simulations with the HIRHAM region climate model, Clim. Dynam., 40, 2903–2918, doi:10.1007/s00382-012-1513-y. Larsen, M. A. D., J. C. Refsgaard, M. Drews, M. B. Butts, K. H. Jensen, J. H. Christensen and O. B. Christensen (2013b) Results from a full coupling of the HIRHAM regional climate model and the MIKE SHE hydrological model for a Danish catchment. Submitted to Hydrol. Earth Syst. Sc. Larsen, M. A. D., J. C. Refsgaard, K. H. Jensen, M. B. Butts, S. Stisen, and M. Mollerup (in preparation) Calibration of a distributed hydrology and land surface model using uncertain energy flux measurements. Overgaard, J. (2005) Energy-based land-surface modelling: new opportunities in integrated hydrological modeling, Ph.D. thesis, Institute of Environment and Resources, DTU, Technical University of Denmark, Denmark. Figure 2. The simulated spatial distribution of mean dailyevapotranspiration for the period June 5-11, 2009, from MIKESHE alone (observed forcing data), HIRHAM alone, coupled one-way (MIKE SHE simulation with HIRHAM forcing data and nofeedback to HIRHAM) and fully two-way coupled with dynamicfeedback.  Figure 3. The six climatic variables used in the assessment of thecoupled setup for the 10-18 July period, 2009, (precipitation is 1-31 August). The TI, HUV and CV runs each represent groups ofeight simulations varying the data transfer interval of 12-120 minutes (TI), assessing HIRHAM uncoupled variability (HUV) aswell as fully coupled variability (CV).   

Coupled regional climate and hydrology modelling at the catchment scale

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Coupled regional climate and hydrology modelling at the catchment scale

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