Experiment 5632
Last updated: September 2006
Parallel experiment 5632,inclduing the entire LM data assimilation cycle, is aimed
at testing FLake in LM.
- The LM1 domain is used to save computational resources.
- Lake grid boxes are identified with the external-parameter fields of lake
depth, DEPTH_LK, and of lake fraction, FR_LAKE, where FR_LAKE is consistent
with the LM land-sea mask FR_LAND.
- The LM binarieststlm_f90_LMFKcold (cold start) andtstlm_f90_LMFKwarm
(warm start) are developed with the lm_f90 library version 3.20. As
compared to the standard LM without a lake model, LM-FLake contains
numerous changes in the LM routines.
- The LM-FLake set-up is the same as in the LM(E) routine, except for changes
in the namelists
namelst_phyctl, namelst_gribout_forecast,
namelst_gribout_nudgecast, and namelst_gribout_nudge. Fluxes of
momentum and of sensible and latent heat are computed with the operational LM
surface-layer scheme. New flux calculation routines (MODULE src_flake_sfcflx)
are not used.
- In order to develop initial fields of LM-FLake prognostic variables, a "cold start" is
performed(on 1 January 2006 at 00 UTC in exp_5632).The lake surface temperature is initialized
with the SST provided by the LM analysis. The mixed-layer thickness is set to 10 m or
to the lake depth, whichever is smaller. The bottom temperature is set to the temperature
of maximum density of fresh water, the shape factor with respect to the temperature
profile in the thermocline is set to its minimum value of 0.5, and the mean
temperature of the water column is computed accordingly [see Eq.(23) in Mironov 2005].
For lake grid boxes with the lake depth smaller than 10 m, mixing down to the lake
bottom is assumed, i.e. the bottom temperature and the mean temperature of the water
columnare set equal to the surface temperature. No ice is assumed at the cold start
so that the ice thickness is zero, the ice surface temperature is equal
to the fresh-water freezing point, and the mixed-layer temperature is
equal to the lake surface temperature.
- After the LM-FLake cold start has once been performed, all consecutive runs
are the "warm start" runs that are initialised with the values of the
LM-FLake prognostic variables at the end of the preceding nudging run
(nudgecast) of the LM data assimilation cycle. That is,LM-FLakeis
run freely without any correction of FLake prognostic variables through
nudging or the like. The SST from the LM analysis (performed
once a day at 00 UTC) is not used by LM over lake grid boxes, although
this SST is saved in the exp_5632 data bank (T_SO, lv=0, ty=lm1an,tf=0).
- The experiment 5632 is performed over the period from 1 January 2006 to 28
June 2006; 48h forecasts initialised at 00UTC are made once a day.
NB! Although FLake has become a part of the official LM code, some changes are still
requiredat the testing phase, namely, in organize_data.f90, src_flake.f90,
src_input.f90, src_setup_vartab.f90, src_turbdiff.f90, src_turbulence.f90,
turbdiff.incf, and turbtran.incf
External-parameter fields
- Land-sea mask FR_LAND for LM1 domain.
- Lake-fraction field FR_LAKE for LM1
domain. Since no tile approach is used in LM (i.e. each LM grid-box is
characterised by a single land-cover type), only the grid-boxes with
the lake fraction greater than 0.5 are treated as lakes (deep blue
areas on the 0-0.5-1
lake-fraction plot).
- Lake-depth field DEPTH_LK for LM1
domain. Notice that for deep lakes (whose mean depth exceeds 50 m), a
"false bottom" is set at a depth of 50 m.
LM-FLake prognostic variables, time series
Time series of several LM-FLake variables, taken once a day at 00UTC, for a
number of lakes. Curves are computed by means of averaging over the LM grib-boxes that
constitute a lake in question as specified by the LM1 lake-depth external-parameter field
DEPTH_LK. The initial values of the LM-FLake variables from the 00UTC main
(nudgecast) run (ty=lm1mo,tf=0, vv=00) are plotted. Over lake points, these are equal to
the values of respective variables from the LM assimilation-cycle nudging runs (ty=lm1mo,
tf=13).The only exception is the surface temperature T_SO(0) from
the LM nudging that is compared with the T_SO(0) from the 00UTC LM SST
analysis. The following variables are shown:
- Lake surface temperatureT_SO (lv=0)
from the LM-FLake nudging (actually, the initial temperature from the main run is taken,
i.e. ty=lm1mo, tf=0, vv=00) versuslake surface temperature T_SO (lv=0) from the 00UTC
LM SST analysis (ty=lm1an, tf=0);
- mixed-layer temperatureT_WML_LK, mean temperature
of the water columnT_MNW_LK, temperature at
the water-bottom sediment interface T_BOT_LK, mixed-layer depth H_ML_LK, shape
factor with respect to the temperature profile in lake thermocline C_T_LK, ice surface
temperature T_ICE, and ice thickness H_ICE.
View plots
LM-FLake prognostic variables, x-y two-dimensional plots
Surface temperature (for lake grid boxes, DEPTH_LK>0):
- Lake surface temperature from the LM assimilation (nudging) cycle (T_SO, lv=0,
ty=lm1an, tf=13):
2006010100,
2006011500,
2006020100,
2006021500,
2006030100,
2006031500,
2006040100,
2006041500,
2006050100,
2006051500,
2006060100.
- Surface temperature difference (T_SO, lv=0, ty=lm1an) between the LM SST analysis (tf=0)
and the LM nudging (tf=13):
2006010100,
2006011500,
2006020100,
2006021500,
2006030100,
2006031500,
2006040100,
2006041500,
2006050100,
2006051500,
2006060100.
Ice thickness and ice surface temperature (for lake grid boxes, DEPTH_LK>0, over
part of the LM1 domain):
- Ice thickness H_ICE from the LM assimilation(nudging)cycle (ty=lm1an, tf=13):
2006010100,
2006011500,
2006020100,
2006021500,
2006030100,
2006031500,
2006040100,
2006041500,
2006050100,
2006051500,
2006060100.
- Ice surface temperature T_ICE from the LM assimilation(nudging)cycle (ty=lm1an, tf=13):
2006010100,
2006011500,
2006020100,
2006021500,
2006030100,
2006031500,
2006040100,
2006041500,
2006050100,
2006051500,
2006060100.
- Difference in the surface temperature (T_SO, lv=0, ty=lm1an) between the LM SST
analysis (tf=0) and the LM nudging (tf=13)over ice-covered lake grid boxes (H_ICE>0):
2006011500,
2006020100,
2006021500,
2006030100,
2006031500,
2006040100,
2006041500,
2006050100,
2006051500.
FLake prognostic variables (for lake grid boxes, DEPTH_LK>0):
- Mixed-layer thickness H_ML_LK from the LM assimilation(nudging)cycle (ty=lm1an, tf=13):
2006010100,
2006011500,
2006020100,
2006021500,
2006030100,
2006031500,
2006040100,
2006041500,
2006050100,
2006051500,
2006060100.
- ...
