Basic Description of Platform


The CoupModel has been developed to represent a platform with a number of models that could be linked together for the specific application of the user. A review of its model development, calibration procedures and previous applications are made here. For each application the user of the model can select different module and how they should be linked. In the next step appropriate input to run the model has to be specified based on the choice of modules. The modules include water, heat, tracers, chloride, nitrogen and carbon of any terrestrial ecosystem including soil, plant and atmosphere components. The spatial distribution is lumped or distributed to any used defined scale. Temporal resolution is from minutes to some 100-years. The platform allows the user to specify inputs as (1) forcing time series, (2) simple predefined patterns of variation by parameter functions or (3) dynamic parameters that could change value at specified dates during the simulation. Output variables from simulations can be compared with any independent measurement either as time series or as a single value. The performance is expressed as conventional statistical indicator or as log likelihood sums. Simulations are made as single runs to represent a unique input or as a multiple series of simulations based on random or systematic sampling of parameter values. Parameters can also represent an object that is a collection of different parameters to represent one certain system (for instance a soil profile). Two possible approaches: Bayesian or generalized likelihood uncertainty estimation (GLUE) may be used for calibration. The former is using a Markov chain Monte Carlo (MCMC) method to sample among parameter values based on predefined error parameters for estimation of log likelihoods.

Keywords: Richards Equation, Fourier equation, soil frost, snow, greenhouse gas emissions, soil carbon sequestration, climate change, water use efficiency, light use efficiency, nitrogen use efficiency, ecosystem


The CoupModel represents a platform of various modules (Jansson & Moon, 2001) that have been developed and modified since 1979 when the SOIL model was first published (Jansson & Halldin, 1979) with a basic description of how to simulate water and heat fluxes in a soil profile. The model has a strong focus on soil physics and presented a coupling between the Richards equation for the water flow with the corresponding Fourier equation for heat flows in a 1D domain. A major focus was to describe the hydrological processes during the course of a year with daily resolution within the boreal region. The model was later modified to include the turnover of nitrogen processes in soils and the SOILN was presented (Johnsson et al, 1987) with a direct coupling to the SOIL model. In its infanty the SOIL model was mainly used for forest ecosystem within the Boreal region (Jansson, 1987; Jansson et al, 1999 and Gustafsson et al, 2004) but was later applied to any type of terrestrial system including semi-arid regions (RockStröm et al, 1998) and regions with permafrost conditions (Hollesen et al, 2011). Various options for understanding and simulating macropore flows during unfrozen (Eckersten & Jansson, 1991) and frozen conditions (Stähli et al, 1996) have been implemented as options of the model. Most of the application was made by simulation of one single profile but various methods have been used to represent the connection of water flows from one position to another within the area as first presented by Espeby (1982) and later on was further developed to test the role of soil freezing on generation of runoff to a stream (Stähli et al, 2001).

The plant components were assumed to be governed by forcing inputs to the model but was further developed to include a dynamic plant representing both carbon and nitrogen processes (Eckersten & Jansson, 1991; Blombäck et al, 1995; Eckersten et al, 1995 and Eckersten et al, 1998). More recent developments have been made to includ various options of the plant growth with connection to a wide range of limiting factors for plant development (Karlberg et al, 2006, Zhang et al, 2007 and Wu et al, 2011a). Attention has been made on simulation of carbon sequestration in forest ecosystem (Svensson et al, 2008b) and in that case also simulation of climate impacts (Jansson et al, 1998). In addition more components have been added by including a detailed model for the denitrification as first presented by Norman et al (2008). Model improvement was carried out by adopting a detailed submodel of microbiological production of gaseous N from the PnET-N-DNDC model (Li et al., 2000). A submodel to follow trace elements within the soil-plant-atmosphere system (Gärdenäs et al, 2009) is also implemented as part of the platform. A submodel for how to simulate the spread of de-icing salt in the roadside environment has also been developed (Lundmark & Jansson, 2008). Other applications have been focusing on understanding detailed physical processes for common an artificial surface like asphalt (Jansson et al, 2006)

The CoupModel software (KTH, 2011) has been continuously improved and modified during the last 10 years but also prior that the previous SOIL and SOILN models have been distributed free of charge. A detailed technical description was first published by Jansson & Karlberg (2004) and later on it was also published as a translation to Chinese (Jansson & Karlberg, 2009). Today it is published online as a pdf document (Jansson & Karlberg, 2010) and as complete help library on the internet. The model has o a user-group that is administrated from KTH as an interactive forum for the users. Also informal courses and tutorials are available from KTH.


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Blombäck, K., Stähli, M. and Eckersten, H. 1995. Simulation of water and nitrogen flows and plant growth for a winter wheat stand in central Germany, Ecological Modelling, 81:157-167.

Eckersten, H., Gärdenäs, A. & Jansson, P-E. 1995. Modelling Seasonal Nitrogen, Carbon, Water and Heat Dynamics of the Solling Spruce Stand. Ecological Modelling, 83: 119-129

Eckersten, H. & Jansson, PE. 1991. Modelling water flow, nitrogen uptake and production for wheat. Fertilizer Research 27:313329

Eckersten, H., Jansson, P-E. & Johnsson, H., 1998: SOILN Model, Version 9.2, User’s Manual. Division of Hydrotechnics, Communication 98:6. Swedish Agricultural University, Uppsala.

Hollesen, J, Elberling, B & Jansson, P-E. 2011. Future active layer dynamics and carbon dioxide production from thawing permafrost layers in Northeast Greenland. Global Change Biology 17(2), 911–926

.Gustafsson, D., Lewan, E. & Jansson, P-E. (2004): Modeling water and heat balance of the Boreal landscape – comparison of forest and arable land in Scandinavia. Journal of Applied Meteorology 43: 1750-1767

.Gärdenäs, A, Eckersten, H., Reinlert, A., Gustafsson, D., Jansson, P-E, Ekström, P.-A., Avila, R., Greger, M. (2009): Tracey – a simulation model of trace element fluxes in soil-plant system for long-term assessment of a radioactive groundwater contamination. Svensk kärnbränslehantering AB, Teknisk Rapport, SKB TR-09-24, 86 pp.

Jansson, C., Almkvist, E. &Jansson, P.E. (2006): Heat balance of an asphalt surface: observations and physically-based simulations. Meteorol. Appl. 13, 203–212.

Jansson, P.-E., Halldin, S., 1979. Model for the annual water and energy flow in a layered soil. Comparison of Forest and Energy Exchange Models, S. Halldin, Ed., Society for Ecological Modelling, 145–163.

Jansson, P-E, Svensson, M, Berggren Kleja, D. & Gustafsson, D. 2008. Simulated climate change impacts on fluxes of carbon in Norway spruce ecosystems along a climatic transect in Sweden. Biogeochemistry 89 (1), 81-94.

Jansson P-E, Cienciala E., Grelle A., Kellner E., Lindahl A. & Lundblad M. 1999. Simulated evapotranspiration from the Norunda forest stand during the growing season of a dry year, Agricultural and Forest Meteorology (98-99)1-4: 621-628

Jansson, P-E. and Karlberg, L., 2004: CoupModel – Coupled heat and mass transfer model for soil-plant-atmosphere systems. Royal Institute of Technology, Dept. of Land and Water Resources Engineering, Stockholm, TRITA-LWR report. 3087: 427 p

Jansson P-E and Karlberg L. 2009. Theory and Practice of Coupled Heat and Mass Transfer Model for Soil-Plant-Atmosphere System (in Chinese). ISBN: 978-7-03-025728-4. Science Press, China, pp. 1–309.

Jansson P-E and Karlberg L. 2010. Coupled Heat and Mass Transfer Model for Soil-Plant-Atmosphere Systems. Royal Institute of Technology. Stockholm. 484 pp, accessed January 2011 from CoupModel/coupmanual.pdf.

Jansson, P-E. & Moon, D.S., 2001: A coupled model of water, heat and mass transfer using object orientation to improve flexibility and functionality. Environmental Modelling and Software, 16:37-46

Johnsson H., Bergström, L., Jansson, P-E. and Paustian, K., 1987: Simulated nitrogen dynamics and losses in a layered agricultural soil. Agriculture. Ecosystems and Environment, 18:333-356.

Karlberg, L., Ben-Gal, A., Jansson, P-E. & Shani, U., 2006: Modelling transpiration and growth in salinity-stressed tomato under different climatic conditions. Ecological Modelling 190 (1-2): 15-40.

Karlberg L, Gustafsson D, Jansson P-E (2006) Modelling carbon turnover in five terrestrial ecosystems in the boreal zone using multiple criteria of acceptance. AMBIO 35:448–458

Klemedtsson, L, Jansson, P-E, Gustafsson, D., Karlberg, L.Weslien, P.,von Arnold, K., Ernfors, M. ,Langvall, O., & Lindroth, A. 2008. Bayesian calibration method used to elucidate carbon turnover in forest on drained organic soil. Biogeochemistry , 89(1): 61-76KTH, 2011. CoupModel homepage and software. , accessed September 2011 from CoupModel

Lewan, L. 1993 Evaporation and discharge from arable land with cropped or bare soils during winter. Measurements and simulations. Agric. For. Met, 64:131-159

Li, C., Aber, J.D., Stange, F., Butterbach-Bahl, K. Papen, H., 2000. A process-oriented model of N2O and NO emissions from forest soils: 1. Model development. J. Geophysical Res., 105, 4369-4384.

Lundmark, A & Jansson, P-E 2009 Generic soil descriptions for modelling water and chloride dynamics in the unsaturated zone based on Swedish Geoderma,  150,: 85-95

Lundmark, A. & Jansson, P.-E. 2008. Estimating the fate of de-icing salt in a road-side environment by combining modelling and field observations. Water, Air and Soil Pollution 195: 215-232

Norman, J., P.E. Jansson, N. Farahbakhshazad, K. Butterbach-Bahl, C. Li and L. Klemedtsson, 2008. Simulation of NO and N2O emissions from a spruce forest during a freeze/thaw event using an N-flux sub-model from the PnET-N-DNDC model integrated to CoupModel. Ecological Modelling. 216(2), 18-30

Nylinder, J, Stenberg, M, Jansson, P-E, Klemedtsson, A.K., Weslien, P &Klemedtsson, L 2011 Modelling uncertainty for nitrate leaching and nitrous oxide emissions based on a Swedish field experiment with organic crop rotation Agriculture, Ecosystems and Environment 141 167–183

Rockström J., Jansson P-E., Barron J. 1998. Seasonal rainfall partitioning under runon and runoff conditions on sandy soil in Niger. On-farm measurements and water balance modelling, Journal of Hydrology (210)1-4, pp. 68-92

Schelde, K., Thomsen, A., Heidmann, T, Schjønning, P & Jansson, P-E. 1998. Diurnal fluctuations of water and Heat flows in a bare soil. Water Resources Research 34: 2919-2929Stähli, M. and Jansson, P-E., 1998: Test of two SVAT snow submodels during different winter conditions. Agricultural and Forest Meteorology, 92: 29-41

Stähli, M., Jansson, P-E. and Lundin, L-C. 1996. ‘Preferential water flow in a frozen soil – a two-domain model approach’, Hydrological Processes, 10:1305-1316

Stähli, M., Jansson, P.-E. & Lundin, L.-C., 1999: Soil moisture redistribution and infiltration in frozen sandy soils. Water Resources Research, 35 (1): 95-103

Stähli, M., Nyberg, L., Mellander, P-E., Jansson, P-E & Bishop, K. 2001. Soil frost effects on soil and runoff dynamics along a boreal transect: 2. Simulations. Hydrological Processes, 15: 927-941

Svensson, M., Jansson, P-E., Gustafsson, D. Berggren Kleja, D., Langvall, O., and Lindroth, A. 2008a. Bayesian calibration of a model describing carbon, water and heat fluxes for a Swedish boreal forest stand. Ecological Modelling, 213:331-344.

Svensson, M., Jansson, P-E & Kleja Berggren, D. 2008b . Modelling soil C sequestration in spruce forest ecosystems along a Swedish transect based on current conditions. Biogeochemistry, 89 (1), 95-119

Van Oijen, M, Cameron, D., Butterbach-Bahl, K., Farahbakhshazad, N, Jansson, P-E, Kiese, R., Rahn, K-H; & Werner, C. 2011 Bayesian calibration, comparison and analysis of four models for the biogeochemistry of a Norway spruce forest Agricultural and Forest Meteorology (In press, published online)

Wu SH, Jansson P-E and Kolari P. 2011a. Modeling seasonal courses of carbon fluxes and evapotranspiration in response to low temperature and moisture in a boreal Scots Pine ecosystem. Ecological Modelling 17, 3103-3119.

Wu SH, Jansson P-E and Zhang XY. 2011b. Modelling temperature, moisture and surface heat balance in the bare soil under seasonal frost conditions in China. European Journal of Soil Science (In Press).

Zhang, S., Lövdahl, L., Grip, H., Jansson, P.E., Tong, Y. (2007): Modelling the effects of mulching and fallow cropping on water balance in the Chinese Loess Plateau. Soil and Tillage Research 93(2), 283-298

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