clm_lake Module Reference

This module contains the CLM Lake model. More...

Functions/Subroutines
logical function	limit_temperature_by_climatology (xlat_d, xlon_positive)
subroutine	is_salty (xlat_d, xlon_positive, cannot_freeze, salty)
subroutine	calculate_z_dz_lake (i, input_lakedepth, clm_lakedepth, z_lake, dz_lake)
subroutine, public	clm_lake_run (flag_restart, im, km, me, master, fhour, idate, kdt, iopt_lake, iopt_lake_clm, min_lakeice, lakedepth_default, use_lakedepth, dtp, use_lake_model, clm_lake_initialized, frac_grid, frac_ice, lkm, tg3, pgr, zlvl, gt0, prsi, phii, qvcurr, gu0, gv0, xlat_d, xlon_d, ch, cm, dlwsfci, dswsfci, oro_lakedepth, wind, tsfc, flag_iter, flag_lakefreeze, isltyp, rainncprv, raincprv, evap_wat, evap_ice, hflx_wat, hflx_ice, gflx_wat, gflx_ice, ep1d_water, ep1d_ice, tsurf_water, tsurf_ice, tsfc_wat, tisfc, weasdi, snodi, hice, qss_water, qss_ice, cmm_water, cmm_ice, chh_water, chh_ice, uustar_water, uustar_ice, lake_t_snow, albedo, zorlw, zorli, lake_t2m, lake_q2m, weasd, snowd, fice, icy, salty, savedtke12d, snowdp2d, h2osno2d, snl2d, t_grnd2d, t_lake3d, lake_icefrac3d, t_soisno3d, h2osoi_ice3d, h2osoi_liq3d, h2osoi_vol3d, z3d, dz3d, zi3d, t1, qv1, prsl1, input_lakedepth, clm_lakedepth, cannot_freeze, errflg, errmsg)
subroutine	lakemain (forc_t, forc_pbot, forc_psrf, forc_hgt, forc_hgt_q, forc_hgt_t, forc_hgt_u, forc_q, forc_u, forc_v, forc_lwrad, prec, sabg, lat, z_lake, dz_lake, lakedepth, do_capsnow, h2osno, snowdp, snl, z, dz, zi, h2osoi_vol, h2osoi_liq, h2osoi_ice, t_grnd, t_soisno, t_lake, savedtke1, lake_icefrac, eflx_lwrad_net, eflx_gnet, eflx_sh_tot, eflx_lh_tot, t_ref2m, q_ref2m, dtime, watsat, tksatu, tkmg, tkdry, csol, taux, tauy, ram1, z0mg, ustar_out, errmsg, errflg, xlat_d, xlon_d)
subroutine	shallakefluxes (forc_t, forc_pbot, forc_psrf, forc_hgt, forc_hgt_q, forc_hgt_t, forc_hgt_u, forc_q, forc_u, forc_v, forc_lwrad, forc_snow, forc_rain, t_grnd, h2osno, snowdp, sabg, lat, dz, dz_lake, t_soisno, t_lake, snl, h2osoi_liq, h2osoi_ice, savedtke1, qflx_prec_grnd, qflx_evap_soi, qflx_evap_tot, eflx_sh_grnd, eflx_lwrad_out, eflx_lwrad_net, eflx_soil_grnd, eflx_sh_tot, eflx_lh_tot, eflx_lh_grnd, t_veg, t_ref2m, q_ref2m, taux, tauy, ram1, ws, ks, eflx_gnet, z0mg, ustar_out, errmsg, errflg, xlat_d, xlon_d)
	Calculates lake temperatures and surface fluxes for shallow lakes.
subroutine	shallaketemperature (t_grnd, h2osno, sabg, dz, dz_lake, z, zi, z_lake, ws, ks, snl, eflx_gnet, lakedepth, lake_icefrac, snowdp, eflx_sh_grnd, eflx_sh_tot, eflx_soil_grnd, t_lake, t_soisno, h2osoi_liq, h2osoi_ice, savedtke1, watsat, tksatu, tkmg, tkdry, csol, dtime, frac_iceold, qflx_snomelt, imelt, errmsg, errflg, xlat_d, xlon_d)
subroutine	soilthermprop_lake (snl, dz, zi, z, t_soisno, h2osoi_liq, h2osoi_ice, watsat, tksatu, tkmg, tkdry, csol, tk, cv, tktopsoillay, errmsg, errflg)
	Calculation of thermal conductivities and heat capacities of snow/soil layers (1) The volumetric heat capacity is calculated as a linear combination in terms of the volumetric fraction of the constituent phases.
subroutine	phasechange_lake (snl, h2osno, dz, dz_lake, t_soisno, h2osoi_liq, h2osoi_ice, lake_icefrac, t_lake, snowdp, qflx_snomelt, eflx_snomelt, imelt, cv, cv_lake, lhabs)
	Calculation of the phase change within snow, soil, & lake layers: (1) Check the conditions for which the phase change may take place, i.e., the layer temperature is greater than the freezing point and the ice mass is not equal to zero (i.e. melting), or the layer temperature is less than the freezing point and the liquid water mass is greater than the allowable supercooled (i.e. freezing). (2) Assess the amount of phase change from the energy excess (or deficit) after setting the layer temperature to freezing point, depending on how much water or ice is available. (3) Re-adjust the ice and liquid mass, and the layer temperature: either to the freezing point if enough water or ice is available to fully compensate, or to a remaining temperature.
subroutine	shallakehydrology (dz_lake, forc_rain, forc_snow, begwb, qflx_evap_tot, forc_t, do_capsnow, t_grnd, qflx_evap_soi, qflx_snomelt, imelt, frac_iceold, z, dz, zi, snl, h2osno, snowdp, lake_icefrac, t_lake, endwb, snowage, snowice, snowliq, t_snow, t_soisno, h2osoi_ice, h2osoi_liq, h2osoi_vol, qflx_drain, qflx_surf, qflx_infl, qflx_qrgwl, qcharge, qflx_prec_grnd, qflx_snowcap, qflx_snowcap_col, qflx_snow_grnd_pft, qflx_snow_grnd_col, qflx_rain_grnd, qflx_evap_tot_col, soilalpha, zwt, fcov, rootr_column, qflx_evap_grnd, qflx_sub_snow, qflx_dew_snow, qflx_dew_grnd, qflx_rain_grnd_col, watsat, tksatu, tkmg, tkdry, csol, dtime, errmsg, errflg)
	Calculation of Shallow Lake Hydrology. Full hydrology of snow layers is done. However, there is no infiltration, and the water budget is balanced with qflx_qrgwl. Lake water mass is kept constant. The soil is simply maintained at volumetric saturation if ice melting frees up pore space. Likewise, if the water portion alone at some point exceeds pore capacity, it is reduced. This is consistent with the possibility of initializing the soil layer with excess ice. The only real error with that is that the thermal conductivity will ignore the excess ice (and accompanying thickness change).
subroutine	qsat (t, p, es, esdt, qs, qsdt)
	Computes saturation mixing ratio and the change in saturation mixing ratio with respect to temperature.
subroutine	tridiagonal (lbc, ubc, lbj, ubj, jtop, numf, filter, a, b, c, r, u)
subroutine	snowwater (lbc, ubc, num_snowc, filter_snowc, num_nosnowc, filter_nosnowc, snl, do_capsnow, qflx_snomelt, qflx_rain_grnd, qflx_sub_snow, qflx_evap_grnd, qflx_dew_snow, qflx_dew_grnd, dz, dtime, h2osoi_ice, h2osoi_liq, qflx_top_soil)
	Evaluate the change of snow mass and the snow water onto soil. Water flow within snow is computed by an explicit and non-physical based scheme, which permits a part of liquid water over the holding capacity (a tentative value is used, i.e. equal to 0.033*porosity) to percolate into the underlying layer. Except for cases where the porosity of one of the two neighboring layers is less than 0.05, zero flow is assumed. The water flow out of the bottom of the snow pack will participate as the input of the soil water and runoff. This subroutine uses a filter for columns containing snow which must be constructed prior to being called.
subroutine	snowcompaction (lbc, ubc, num_snowc, filter_snowc, snl, imelt, frac_iceold, t_soisno, h2osoi_ice, h2osoi_liq, dtime, dz)
	Determine the change in snow layer thickness due to compaction and settling. Three metamorphisms of changing snow characteristics are implemented, i.e., destructive, overburden, and melt. The treatments of the former two are from SNTHERM.89 and SNTHERM.99 (1991, 1999). The contribution due to melt metamorphism is simply taken as a ratio of snow ice fraction after the melting versus before the melting.
subroutine	combinesnowlayers (lbc, ubc, num_snowc, filter_snowc, snl, h2osno, snowdp, dz, zi, t_soisno, h2osoi_ice, h2osoi_liq, z)
	Combine snow layers that are less than a minimum thickness or mass If the snow element thickness or mass is less than a prescribed minimum, then it is combined with a neighboring element.
subroutine	dividesnowlayers (lbc, ubc, num_snowc, filter_snowc, snl, dz, zi, t_soisno, h2osoi_ice, h2osoi_liq, z)
	Subdivides snow layers if they exceed their prescribed maximum thickness.
subroutine	combo (dz, wliq, wice, t, dz2, wliq2, wice2, t2)
	Combines two elements and returns the following combined variables: dz, t, wliq, wice.
subroutine	buildsnowfilter (lbc, ubc, num_nolakec, filter_nolakec, snl, num_snowc, filter_snowc, num_nosnowc, filter_nosnowc)
	Constructs snow filter for use in vectorized loops for snow hydrology.
subroutine	frictionvelocity (pgridcell, forc_hgt, forc_hgt_u, forc_hgt_t, forc_hgt_q, lbp, ubp, fn, filterp, displa, z0m, z0h, z0q, obu, iter, ur, um, ustar, temp1, temp2, temp12m, temp22m, u10, fv, fm)
	Calculation of the friction velocity, relation for potential temperature and humidity profiles of surface boundary layer. The scheme is based on the work of Zeng et al. (1998): Intercomparison of bulk aerodynamic algorithms for the computation of sea surface fluxes using TOGA CORE and TAO data. J. Climate, Vol. 11, 2628-2644.
real(kind_lake) function	stabilityfunc1 (zeta)
real(kind_lake) function	stabilityfunc2 (zeta)
subroutine	moninobukini (ur, thv, dthv, zldis, z0m, um, obu)
subroutine, public	clm_lake_init (con_pi, karman, con_g, con_sbc, con_t0c, rhowater, con_csol, con_cliq, con_hfus, con_hvap, con_rd, con_cp, rholakeice, clm_lake_debug, clm_debug_print, con_eps_model, con_fvirt_model, errmsg, errflg)
subroutine	lakeini (kdt, isltyp, gt0, snowd, weasd, lakedepth_default, fhour, oro_lakedepth, savedtke12d, snowdp2d, h2osno2d, snl2d, t_grnd2d, t_lake3d, lake_icefrac3d, t_soisno3d, h2osoi_ice3d, h2osoi_liq3d, h2osoi_vol3d, z3d, dz3d, zi3d, fice, hice, min_lakeice, tsfc, use_lake_model, use_lakedepth, im, prsi, xlat_d, xlon_d, clm_lake_initialized, input_lakedepth, tg3, clm_lakedepth, km, me, master, errmsg, errflg)

Variables
integer, parameter, public	kind_lake = kind_dbl_prec
logical, public	lakedebug = .false.
logical	debug_print = .false.
logical, parameter	pergro = .false.
logical, parameter	use_etalake = .false.
real(kind_lake), parameter	etalake = 1.1925*50**(-0.424)
	Set this to your desired value if USE_ETALAKE=.true.
integer, parameter	nlevsoil = 10
	number of soil layers
integer, parameter	nlevlake = 10
	number of lake layers
integer, parameter	nlevsnow = 5
	maximum number of snow layers
real(kind_lake), parameter	scalez = 0.025_kind_lake
	Soil layer thickness discretization (m)
integer, parameter	lbp = 1
	pft-index bounds
integer, parameter	ubp = 1
integer, parameter	lbc = 1
	column-index bounds
integer, parameter	ubc = 1
integer, parameter	num_shlakec = 1
	number of columns in lake filter
integer, dimension(1), parameter	filter_shlakec = 1
	lake filter (columns)
integer, parameter	num_shlakep = 1
	number of pfts in lake filter
integer, dimension(1), parameter	filter_shlakep = 1
	lake filter (pfts)
integer, dimension(1), parameter	pcolumn = 1
integer, dimension(1), parameter	pgridcell = 1
integer, dimension(1), parameter	cgridcell = 1
	gridcell index of column
integer, dimension(1), parameter	clandunit = 1
	landunit index of column
integer, parameter	begg = 1
integer, parameter	endg = 1
integer, parameter	begl = 1
integer, parameter	endl = 1
integer, parameter	begc = 1
integer, parameter	endc = 1
integer, parameter	begp = 1
integer, parameter	endp = 1
integer, parameter	column =1
logical, dimension(1), parameter	lakpoi = .true.
real(kind_lake), parameter	tcrit = 2.5
	critical temperature to determine rain or snow
real(kind_lake), parameter	tkwat = 0.6
	thermal conductivity of water [W/m/k]
real(kind_lake), parameter	tkice = 2.290
	thermal conductivity of ice [W/m/k]
real(kind_lake), parameter	tkairc = 0.023
	thermal conductivity of air [W/m/k]
real(kind_lake), parameter	snow_bd = 250
	constant snow bulk density (only used in special case here) [kg/m^3]
real(kind_lake)	pi
	ratio of the circumference of a circle to its diameter
real(kind_lake)	vkc
	von Karman constant [-]
real(kind_lake)	grav
	gravity constant [m/s2]
real(kind_lake)	sb
	stefan-boltzmann constant [W/m2/K4]
real(kind_lake)	tfrz
	freezing temperature [K]
real(kind_lake)	denh2o
	density of liquid water [kg/m3]
real(kind_lake)	denice
	density of ice [kg/m3]
real(kind_lake)	cpice
	Specific heat of ice [J/kg-K].
real(kind_lake)	cpliq
	Specific heat of water [J/kg-K].
real(kind_lake)	hfus
	Latent heat of fusion for ice [J/kg].
real(kind_lake)	hvap
	Latent heat of evap for water [J/kg].
real(kind_lake)	hsub
	Latent heat of sublimation [J/kg].
real(kind_lake)	invhvap
	1/hvap [kg/J]
real(kind_lake)	invhsub
	1/hsub [kg/J]
real(kind_lake)	rair
	gas constant for dry air [J/kg/K]
real(kind_lake)	cpair
	specific heat of dry air [J/kg/K]
real(kind_lake)	con_eps
	ratio of gas constants of air and water vapor [unitless]
real(kind_lake)	one_minus_con_eps
	1 - con_eps [unitless]
real(kind_lake)	con_fvirt
	1/con_eps - 1 [unitless]
real(kind_lake), parameter, public	spval = 1.e36
	special value for missing data (ocean)
real(kind_lake), parameter	depth_c = 50.
	below the level t_lake3d will be 277.0 !mchen
real(kind_lake), parameter	zero_h2o = 1e-12
	lower mixing ratio is is treated as zero
real(kind_lake), parameter	wimp = 0.05
	Water impermeable if porosity less than wimp.
real(kind_lake), parameter	ssi = 0.033
	Irreducible water saturation of snow.
real(kind_lake), parameter	cnfac = 0.5
	Crank Nicholson factor between 0 and 1.
integer, parameter	istsoil = 1
	!soil "water" type
real(kind_lake), dimension(19), parameter	sand = (/92.,80.,66.,20.,5.,43.,60.,10.,32.,51., 6.,22.,39.7,0.,100.,54.,17.,100.,92./)
real(kind_lake), dimension(19), parameter	clay = (/ 3., 5.,10.,15.,5.,18.,27.,33.,33.,41.,47.,58.,14.7,0., 0., 8.5,54., 0., 3./)
real(kind_lake), dimension(1:nlevlake)	zlak
	lake z (layers)
real(kind_lake), dimension(1:nlevlake)	dzlak
	lake dz (thickness)
real(kind_lake), dimension(1:nlevsoil)	zsoi
	soil z (layers)
real(kind_lake), dimension(1:nlevsoil)	dzsoi
	soil dz (thickness)
real(kind_lake), dimension(0:nlevsoil)	zisoi
	soil zi (interfaces)
real, dimension(1:25), parameter	saltlk_t = (/ 0.5, 0.,-0.5, 3., 4., 7., 8., 12., 13., 16., 19., 21., 23.5, 25., 26.,24.,23.,20.5,18., 15., 11.5, 8., 4., 1., 0.5/)
real, dimension(12), parameter	month_length = (/ 31, 29, 31, 30, 31, 30, 31, 30, 30, 31, 30, 31 /)
logical, parameter	include_all_salty_locations = .false.

Detailed Description

This lake scheme was taken from module_sf_lake in WRF 4.3.1, and modified for CCPP by Sam Trahan in June 2022.

The original documentation said:

The lake scheme was retrieved from the Community Land Model version 4.5 (Oleson et al. (2013) [154]) with some modifications by Gu et al. (2015) [74]. It is a one-dimensional mass and energy balance scheme with 20-25 model layers, including up to 5 snow layers on the lake ice, 10 water layers, and 10 soil layers on the lake bottom. The lake scheme is used with actual lake points and lake depth derived from the WPS, and it also can be used with user defined lake points and lake depth in WRF (lake_min_elev and lakedepth_default). The lake scheme is independent of a land surface scheme and therefore can be used with any land surface scheme embedded in WRF. The lake scheme developments and evaluations were included in Subin et al. (2012) [189] and Gu et al. (2015) [74] .