6.6. jules_hydrology.nml

This file sets the hydrology options. It contains one namelist called JULES_HYDROLOGY.

6.6.1. JULES_HYDROLOGY namelist members

JULES_HYDROLOGY::l_top
Type:logical
Default:F

Switch for a TOPMODEL-type model of runoff production.

TRUE
Use a TOPMODEL-type scheme. This is based on Gedney and Cox (2003); see also Clark and Gedney (2008).
FALSE
No TOPMODEL scheme.

See also

References:

  • Gedney, N. and P.M.Cox, 2003 , The sensitivity of global climate model simulations to the representation of soil moisture heterogeneity, J. Hydrometeorology, 4, 1265-1275.
  • Clark and Gedney, 2008, Representing the effects of subgrid variability of soil moisture on runoff generation in a land surface model, Journal of Geophysical Research - Atmospheres, 113, D10111, doi:10.1029/2007JD008940.
JULES_HYDROLOGY::l_pdm
Type:logical
Default:F

Switch for a PDM-type model of runoff production.

PDM is the Probability Distributed Model (Moore, 1985), implemented in JULES following Clark and Gedney (2008).

TRUE
Use a PDM scheme.
FALSE
No PDM scheme.

See also

References:

  • Moore, R. J. (1985), The probability-distributed principle and runoff production at point and basin scales, Hydrol. Sci. J., 30, 273-297.
  • Clark and Gedney, 2008, Representing the effects of subgrid variability of soil moisture on runoff generation in a land surface model, Journal of Geophysical Research - Atmospheres, 113, D10111, doi:10.1029/2007JD008940.

Only used if l_pdm = TRUE

JULES_HYDROLOGY::dz_pdm
Type:real
Default:1.0

The depth of soil considered by PDM (m).

A value of ~1m can be used.

JULES_HYDROLOGY::b_pdm
Type:real
Default:1.0

Shape factor for the pdf.

Only used if l_top = TRUE

JULES_HYDROLOGY::zw_max
Type:real
Default:6.0

The maximum allowed depth to the water table (m).

This is the depth to the bottom of an additional layer below the sm_levels soil layers and hence should be set to a value greater than SUM(dzsoil).

JULES_HYDROLOGY::ti_max
Type:real
Default:10.0

The maximum possible value of the topographic index.

JULES_HYDROLOGY::ti_wetl
Type:real
Default:1.5

A calibration parameter used in the calculation of the wetland fraction.

It is used to increment the “critical” value of the topographic index that is used to calculate the saturated fraction of the gridbox. It excludes locations with large values of the topographic index from the wetland fraction.

See Gedney and Cox (2003).