unifhycontrib.artemis

class unifhycontrib.artemis.SurfaceLayerComponent

Artemis provides a simple runoff production model designed to be comparable with the runoff-production models typically embedded within climate models.

It is driven with precipitation, radiation, temperature, humidity and wind speed on a daily time step and calculates canopy interception, evaporation, snowmelt, infiltration, and runoff. It uses a Rutter–Gash canopy formulation (Gash, 1979) to represent interception, together with Penman–Monteith evaporation calculated using available radiation data (Monteith, 1965). Soil moisture is accounted for using a two-layer model with saturation-excess runoff computed using a generalized TOPMODEL (Clark and Gedney, 2008). The snowpack is represented using a temperature-based model of accumulation and melt (Moore et al., 1999, Hock, 2003, Beven, 2011). Snow accumulates when precipitation falls while temperature is below a threshold temperature. When temperature is above a threshold for melt, melting occurs at a rate proportional to the difference between the current temperature and the melting temperature. This conceptual model is widely used (Hock, 2003, Zhang et al., 2006, Rango and Martinec, 1995, Beven, 2011) and gives performance comparable with that of more parameter rich energy balance models, despite their greater complexity (Parajka et al., 2010).

The surface layer component of Artemis comprises canopy interception, evaporation, and snowmelt.

Contributors

Simon Dadson [1,2]

Affiliations
  1. UK Centre for Ecology and Hydrology

  2. School of Geography and the Environment, University of Oxford

Licence

BSD-3

Copyright

2020, University of Oxford

Codebase

https://github.com/unifhy-org/unifhycontrib-artemis

Inputs

name

precipitation_flux

units

kg m-2 s-1

kind

dynamic

name

specific_humidity

units

1

kind

dynamic

name

surface_downwelling_shortwave_flux_in_air

units

W m-2

kind

dynamic

name

surface_downwelling_longwave_flux_in_air

units

W m-2

kind

dynamic

name

air_temperature

units

K

kind

dynamic

name

surface_albedo

units

1

kind

static

name

wind_speed

units

m s-1

kind

dynamic

name

vegetation_height

units

m

kind

static

name

leaf_area_index

units

1

kind

climatologic

frequency

monthly

Outputs

name

water_evaporation_flux_from_canopy

description

evaporation of the water on the leaf surface

units

kg m-2 s-1

Outwards

name

canopy_liquid_throughfall_and_snow_melt_flux

units

kg m-2 s-1

to

subsurface

method

mean

name

transpiration_flux_from_root_uptake

units

kg m-2 s-1

to

subsurface

method

mean

Constants

name

sigma_sb

description

Stefan-Boltzman constant

units

W m-2 K-4

default_value

5.67e-08

name

kappa

description

von Karman constant

units

1

default_value

4.1e-01

name

lambda_lh

description

latent heat of vaporisation (water vapour @ 288K) - M&U90 p.268

units

J kg-1

default_value

2.48e+06

name

rho_a

description

specific mass of (dry) air @ 288K - M&U90 p.268

units

kg m-3

default_value

1.22e+00

name

rho_lw

description

specific mass of liquid water

units

kg m-3

default_value

1.0e+03

name

c_p

description

specific heat of air - M&U90 p.267

units

J kg-1 K-1

default_value

1.01e+03

name

R_v

description

gas constant for water vapour - P&P77 p.23

units

J kg-1 K-1

default_value

4.615e+02

name

t_freeze

description

freezing point of water

units

K

default_value

2.73e+02

name

gamma

description

psychrometric constant [kPa/K] M&U90 p.181

units

kPa K-1

default_value

6.6e-02

name

D_s

description

drainage rate when canopy is full - Shuttleworth, 2007. p. 218; orig Rutter

units

m s-1

default_value

6.0e-09

name

b

description

canopy drainage decay term - Shuttleworth, 2007. p. 218

units

s-1

default_value

6.2e-02

name

F

description

degree-day melting factor - Beven 2000; 0.004 m/K/day

units

m K-1 s-1

default_value

4.6e-08

name

z

description

height measurement for wind speed

units

m

default_value

1.0e+01

States

name

canopy_store

units

m

name

snowpack_store

units

m

SpaceDomain Properties

name

land_sea_mask

required

False

name

flow_direction

required

False

name

cell_area

required

False