lukeecomod / flush-satta

Computing inputs to FLUSH 3D soil model to study hydrology of drained peatland forest (Stenberg et al. 2018)

flush-satta

Computing inputs to FLUSH 3D soil model to study hydrology of drained peatland forest. (Stenberg et al. 2018, Hydrology of Drained Peatland Forest: Numerical Experiment on the Role of Tree Stand Heterogeneity and Management, https://www.mdpi.com/1999-4907/9/10/645)

The repository contains Python-codes, ini-files and input/output datafiles used to produce input data to FLUSH 3D soil model at Sattasuo drained peatland forest.

Satta_main.py is the main code, calls run_model from canopymodel.py. run_model.py is driver for canopy interception and evapotranspiration model CanopyGrid. The class is modified version of SpatHy -code.

Inputs: daily weather data (Precip, Tair, Rglob, VPD) & parameters defined in sattasuo.ini

• doy
• Prec - mm d-1
• Rg - global radiation Wm-2
• T, Tmax, Tmin - degC mean, max and minimum daily temperature
• VPD - kPa vapor pressure deficit

Calculates:

• interception of rain & snow in overstory canopy
• throughfall rate to understory layer
• virtual snowpack (snow water equivalent SWE, mm) evolution at forest floor
• interception of rain or meltwater at field/bottomlayer
• potential infiltration to soil
• evaporation from free water storages (canopy & field/bottom layer) is basen on Priestley-Taylor equilibrium evaporation; attenuation of radiation in canopy is exponential
• Transpiration from over- and understory layers (Tr_o, Tr_u, mmd-1) is computed assuming well-coupled conditions:

Tr_i = C x Gi x VPD / P,

where Gi is layer's integrated conductance (ms-1), VPD vapor pressure deficit (kPa) and P (kPa) ambient pressure. C = Cair * Mwater is conversion factor from ms-1 to kgm-2s-1.

The Gi is slight simplification on Launiainen et al. (2018) GMDD, modified from Saugier & Katerji, 1991 and Kelliher et al. 1995.

Gi = gsref * fQ * fVPD * fPheno * fRew

gsref = leaf stomatal conductance at 1kPa and saturated light (ms-1) fQ = light modifier, fVPD = vpd modifier, fPheno = phenology modifier, fRew = soil water modifier (here fRew = 1 since FLUSH accounts for restriction)

Returns:

• PotInf - mm d-1 potential infiltration rate to soil (i.e. throughfall below living moss layer)
• Tr_o - mm d-1 overstory transpiration rate
• Tr_u - mm d-1 understory transpiration rate
• Trfall - mm d-1 throughfall rate below overstory (comparison for measurements)
• Interc_o - mm d-1 interception rate overstory
• Interc_u - mm d-1 interception rate understory
• Evap_o - mm d-1 evaporation rate from ovestory storage
• Evap_u - mm d-1 evaporation rate from understory storage
• ET - mm d-1 total ET
• SWE - mm snow water equivalent