THE
COMMUNITY
Noah
LAND-SURFACE MODEL (LSM)
ftp://ftp.emc.ncep.noaa.gov/mmb/gcp/ldas/noahlsm/ver_2.7.1
Collaborators:
Mike Ek, Vince Wong, Dag Lohmann, Victor Koren, John Schaake, Qingyun Duan,
George Gayno, Brian Moore, Pablo Grunmann, Dan Tarpley, Bruce Ramsay, Fei Chen,
Jinwon Kim, Hua-Lu Pan, Ying Lin, Curtis Marshall, Larry Mahrt, Tilden Meyers,
Paul Ruscher
1.0
Introduction
2.0
Model Heritage
3.0
Directory Contents and Quick-Start Guide to
Execution
4.0
Subroutine Summary and Calling Tree
5.0
Control File Contents and Function
6.0
Input Atmospheric Forcing File
7.0
LSM Initial Conditions
8.0
Specifying Model Parameters
9.0
Execution Output Files
10.0
Technical
References
1.0 INTRODUCTION
This
User’s Guide provides execution guidance for and physical description of the
public version of the community Noah LSM. This version of the Noah LSM is a stand-alone, uncoupled, 1-D column version used to
execute single-site land-surface simulations.
In this traditional 1-D uncoupled mode, near-surface atmospheric forcing
data is required as input forcing (see Sec 6.0). This LSM simulates soil moisture (both liquid and frozen), soil
temperature, skin temperature, snowpack depth, snowpack water equivalent (and
hence snowpack density), canopy water content, and the energy flux and water
flux terms of the surface energy balance and surface water balance. See Sec 10 for the lineage of key technical
references.
The
public server directory in which this User’s Guide resides also contains the
complete, self-contained Noah LSM
source code file, input control file, input atmospheric forcing file, and
example execution-time LSM output files for a full one-year 1998
simulation. This simulation is valid at
the Champaign, Illinois surface-flux site (40.01 N, 88.37 W) of NOAA/ARL
investigator Tilden Meyers. See Sec 3
for a “Quick-Start” guide to executing the Noah
LSM code in this directory to duplicate the cited 1998 simulation at this
site. To execute Noah LSM simulations at other sites for other initial times, study
Secs 5 through 8.
(Reminder: See Sec 3 for a “Quick-Start”
guide to executing the Noah LSM.)
2.0 MODEL HERITAGE
Beginning
in 1990, and accelerating after 1993 under sponsorship from the GEWEX/GCIP/GAPP
then GEWEX/GAPP Program Office of NOAA/OGP via collaboration with numerous
GCIP/GAPP/GAPP Principal Investigators (PIs), the Environmental Modeling
Center (EMC) of the National Centers
for Environmental Prediction (NCEP) joined with the NWS Office of Hydrology
(OH) and the NESDIS Office of Research and Applications (ORA) to pursue and
refine a modern-era LSM suitable for use in NCEP operational weather and
climate prediction models. Early in
this effort, NCEP carried out an intercomparison of four LSMs, including 1) a
simple bucket model, 2) the OSU LSM
(known as the Coupled Atmospheric boundary layer - Plant – Soil, CAPS,
model land-surface scheme in some PILPS studies), 3) the SSiB model, and 4) the
Simple Water Balance model (SWB) of OH.
The results of this intercomparison were reported in Chen et al. (1996,
see references therein for the four cited LSMs). As a result of the good performance of the OSU LSM in this study
and pre-existing hands-on experience with this LSM by various EMC staff members,
including Hua-Lu Pan and Ken Mitchell, EMC chose the OSU LSM for further
refinement and implementation in NCEP regional and global coupled weather and
climate models (and their companion data assimilation systems). The results of
the cited LSM intercomparison and the initial EMC refinements to the OSU LSM
were reported in Chen et al. (1996).
At
the beginning of the EMC LSM effort in 1990, the OSU LSM already had a 10-year
history. Its initial development was
carried out by OSU in a series of three papers (Mahrt and Ek, 1984; Mahrt and
Pan, 1984; and Pan and Mahrt, 1987). As
the EMC LSM effort unfolded during the 1990's, a series of NCEP extensions to
the OSU LSM were a) added by EMC and its GCIP/GAPP and other collaborators and
b) tested and validated in both uncoupled and coupled studies (see review of
these in Mitchell et al, 1999, 2000, and Ek et al. 2003). At NCEP, the LSM was first coupled to the
operational NCEP mesoscale Eta model on 31 Jan 96, with significant Eta LSM
refinements subsequently implemented on 18 Feb 97, 09 Feb 98, 03 Jun 98, 24 Jul
01, 26 Feb 02 12 June 02. In 1999, with
a) the new addition and testing of frozen soil and patchy snow cover physics in
the uncoupled LSM used for the NCEP-OH submission to PILPS-2d (Valdai, Russia),
and b) the growing number of external user requests for access to and use of
the NCEP LSM (e.g. GCIP/GAPP PIs), we decided the NCEP LSM had advanced to a
stage appropriate for formal public release (first in March 99).
In
2000, given a) the advent of the "New Millenium", b) a strong desire
by EMC to better recognize its LSM collaborators, and c) a new NCEP goal to
more strongly pursue and offer "Community Models", EMC decided to
coin the new name "NOAH"
for the LSM that had emerged at NCEP during the 1990s:
N: National Centers for Environmental Prediction (NCEP)
O: Oregon State University (Dept of Atmospheric Sciences)
A: Air Force (both AFWA and AFRL - formerly AFGL, PL)
H: Hydrologic Research Lab - NWS (now Office of Hydrologic Dev -- OHD)
We in EMC strive to explicitly acknowledge both the multi-group heritage and informal "community" useage of this LSM, going back to the early 1980’s. Since its beginning then at Oregon State University, the evolution of the present Noah LSM herein has spanned significant ongoing development efforts by the following groups:
NCEP/EMC: NCEP Environmental Modeling Center
(EMC)
(Mitchell, Ek,
Lohmann, Grunmann, Lin, Marshall, Chen, Rogers, Manikin,
Pan)
OSU:
Oregon
State University
(Mahrt, Pan, Ek,
Kim, Ruscher)
HRL: NWS Hydrology Lab - formerly
Office of Hydrology
(Schaake, Koren,
Duan)
AFWA:
Air Force Weather Agency -
formerly AFGWC
(Gayno, Mitchell, Moore)
AFRL: Air Force Research Lab - formerly
AFGL and PL
(Mitchell, Chang,
Hahn, Yang)
In
addition to “in-house” Noah LSM
development and validation by the above organizations, the following external
PIs (primarily GCIP/GAPP), have also performed valuable validations of the Noah LSM and its immediate NCEP 1990's
predecessors:
E.H.
Berbery and Rasmusson U.
Maryland (ARM/CART)
C.
Marshall, Basara, and Crawford U. Oklahoma (OU Mesonet)
Bastidas,
Burke, Yucel, Shuttleworth,
Sooroshian U.
Arizona (ARM/CART, AZNET)
A.
Robock and L. Luo Rutgers
U. (OU
Mesonet, ARM/CART)
A.K.
Betts Atmospheric
Res Inc (ISLSCP/FIFE)
C.D.
Peters-Lidard, Wood Princeton
U. (TOPLATS
extensions)
L.
Hinkelman and Ackerman Penn
State U. (ARM/CART)
T.H.
Chen, W. Qu, Henderson-Sellers, et al. RMIT (PILPS-2a)
E.
Wood, Lettenmaier, Liang, Lohmann: Princeton
U. (PILPS-2c)
A.
Schlosser, A.G. Slater, Robock, et al.
U. Maryland (PILPS-2d)
R.
Angevine NOAA/AL (Flatland Exp)
L.
Bowling and D. Lettenmaier Univ. Washington (PILPS-2e)
A.
Boone and J. Noilhan Meteo-France (Rhone/GLASS)
K.
Arsenault, B. Cosgrove, P. Houser NASA-HSB (LDAS)
See
Sec 10 for technical references on the above external validations.
Lastly,
one crucial collaborator deserves special
mention, namely the NESDIS Office of Research and Applications (Tarpley,
Ramsay, Gutman, Kogan, Bailey), which has been the source of critical
global surface fields of a) vegetation greenness and its seasonality and b)
realtime snow cover, plus important GOES, satellite-based, hourly surface
validation fields of c) land surface skin temperature and d) solar insolation, both on a 0.50-degree
lat/lon CONUS grid.
3.0
DIRECTORY CONTENTS AND QUICK-START GUIDE TO EXECUTION
3.1
Basic_with_validation
The directory /mmb/gcp/ldas/noahlsm/ver_2.7.1/basic_with_validation on anonymous server ftp.emc.ncep.noaa.gov contains sixteen files as
follows: 1) this User’s Guide (file NOAH_LSM_USERGUIDE_2.7.1.doc), 2-3) the source code file split for the
User's convenience into two mutually exclusive files representing a)
"driver" routines and b) "physics" routines, 4) an input
control file that defines model configuration and provides initial conditions,
5) an input atmospheric forcing file, 6) a doc file describing the source and
valid period/location of this forcing file, 7-9) an input "namelist"
file triad that allows input of non-default physical parameters, 10-14) five execution-time output files, resulting
from an entire one-year 1998 simulation valid near the Champaign, Illinois
surface-flux site of Tilden Meyers of NOAA/ARL. This site is located at the lat/lon coordinates of (40.01 N, 88.37 W), 15) this user’s guide in
text format, 16) a tar file that contains the aforementioned 15 files. The16 filenames are listed below:
Filename Contents
1
-- NOAH_LSM_USERGUIDE_2.7.1.doc This User's Guide
2
-- DRIVER_WITH_VALIDATION.f "DRIVER" family of
routines of Noah_LSM
3
-- NOAH_LSM_SRC_2.7.1.f "PHYSICS" family of routines of Noah_LSM
source code
4
-- controlfile_ver_2.7.1 Input control file
5
-- forcing98_with_validation.dat Input near-surface atmospheric
forcing file
6
-- CHAMP_IL.doc Observing site description
7
-- namelist_filename.txt 1-line 50-char name of namelist-read
input file
8
-- soil_veg_namelist_ver_2.7.1 namelist-read
input file
9- doitall_2.7.1.sh Execute
DRIVER and SRC
10- PRTSCREEN.TXT.Z Execution “print * “ screen output
11- DAILY.TXT.Z Execution
Output File 1
12- HYDRO.TXT.Z Execution
Output File 2
13- THERMO.TXT.Z Execution
Output File 3
14- OBS_DATA.TXT.Z Execution Output Data File
15- README This user’s guide in text format
16- NOAH_LSM_2.7.1.tar tar file that
contains the above 15 files
All
files are text files, except files NOAH_LSM_USERGUIDE_2.7.1.doc and
CHAMP_IL.doc, which are MS Word files.
Download the tar file basic_with_validation.tar that contains all 15
files to your workstation. Use Unix
command “tar –xvf basic_with_validation.tar”
to create a Proceed with a Noah
LSM execution test as described below.
First
uncompress the “*.Z” files with the Unix uncompress command.
The
uncompress yields five upper-case “*.TXT” files. These TXT files are
output files. Move these “TXT*
files to a separate sister directory
for later comparison to the equivalent output files from your own local execution.
The
four lower-case files given by filenames
controlfile_ver_2.7.1
forcing98_with_validation.dat
namelist_filename.txt
soil_veg_namelist_ver_2.7.1
are
the four input files required during the execution of lsm.x. The “controlfile” (see Sec 5) contains model
configuration variables such as number and thickness of soil layers, number and
length of time steps, initial date/time of the simulation, lat/lon location of
the simulation site, initial conditions for all state variables, and
site-specific land classifications (integer indexes for vegetation-type,
soil-type, and surface-slope category).
The
file obs98.dat (see Sec 6) contains one year’s worth (1998) of 30-min observed
atmospheric forcing data and independent observed verification data (e.g. surface
energy fluxes and soil temperature) valid at the Champaing, Illinois
surface-flux site operated and maintained by Tilden Meyers of NOAA/ARL. The site is located at the lat/lon
coordinates of (40.01 N, 88.37 W).
Now
invoking
“doitall_2.7.1.sh”
will
launch and complete the 1998 one-year LSM simulation for the aforementioned
Illinois site, producing the same 5 “*.TXT” output files that you obtained
originally from the NCEP server.
Normal termination of the execution is marked by the termination message
“STOP: 0”. Since all the “*.TXT” files
are ascii files, one can and should confirm that the 5 output files from the
local simulation agree very closely with the originally downloaded output files
from NCEP.
The
output file PRTSCREEN.TXT contains the output from “Print *” write statements
in the
MAIN
program. In this Version 2.7.1, these
are the block of three “Print *” statements located within the time-step loop in the
PROGRAM MAIN source shortly
after the return from CALL SFLX . These
three Print * statements output the time step counter and the small surface
energy balance residual during each of the first 50 time steps and then every
50 time steps thereafter.
The
other four output files are the execution output data files of greater interest
and their contents are described in Sec 9.
One
important degree of freedom regarding these remaining four output files must be
cited here. The unit numbers for these
output files are 43, 45, 47, and 49, which are explicitly assigned in PROGRAM
MAIN (via variable names NOUT1, NOUT3, NOUT5, and NDAILY). The sign of these assigned unit numbers
controls whether the output is ascii or binary. The sign of all four unit numbers is determined by a signed
parameter (IBINOUT) read-in from the control file (see Sec 5). When the sign of IBINOUT is positive
(negative), the format of these four output files is binary (ascii). When the output format is ascii (binary)
then the extension *.TXT (*.GRS, meaning GrADS-readable) appears on the
generated filename. The ascii choice
(negative unit number sign) was invoked in the default control run you obtain
from the server.
3.2
Basic
The
directory /mmb/gcp/ldas/noahlsm/ver_2.7.1/basic on anonymous server ftp.emc.ncep.noaa.gov contains the same files as
in the directory basic_with_validation except for 2 different files
DRIVER_BASIC.f and forcing_basic98.dat.
The file CHAMP_IL.doc is missing as it is irrelevant. The basic driver DRIVER_BASIC.f reads the
near-surface input file forcing_basic98.dat that contains only the 7 observed
variables required for constructing Noah LSM forcing (cf. Sec.
6.2). This
basic driver is designed for reading data from regular surface sites that do
not measure surface fluxes or subsoil properties.
4.0 SUBROUTINE SUMMARY AND CALLING TREE
Below,
we describe PROGRAM MAIN in the "Driver family" of subroutines (file
DRIVER_WITH_VALIDATION.f or DRIVER_BASIC.f
as described in Sec. 3.2) and the "Physics family" of
subroutines (file NOAH_LSM_2.7.1.f ), comprised of physics
"sub-driver" routine SFLX and all subordinate subroutines.
4.1 The Driver Routines
Briefly
the ten main steps of the MAIN program are:
1)
read
in control file ( model configuration, site characteristics, and initial conditions)
2)
open
output file unit numbers
3)
invoke
time-step loop (including optional spin-up loop if indicated by control file)
4)
read
atmospheric forcing data and change its sign and units as expected by SFLX
5)
interpolate
monthly-mean surface greenness and albedo to julian day of time step
6)
assign
downward solar and longwave radiation from input forcing
7)
calculate
actual and saturated specific humidity from input atmospheric forcing
8)
assign
wind speed from input forcing
9)
invoke
LSM physics (CALL SFLX) to update state variables / sfc fluxes over one time
step
10)
write simulation output data each time step to four output files
The
section in driver PROGRAM MAIN associated with each of the above ten steps is
clearly delineated with comment line "DRIVER STEP n".
NOTE:
The section of PROGRAM MAIN for Step 6 includes optional code (presently
commented out) for calculating the downward radiation from the input air
temperature and humidity if the input forcing file does not provide it.
NOTE: The section of PROGRAM MAIN for Step 8
includes optional code (presently commented out) for invoking a User-provided
routine to calculate the surface exchange coefficient for heat (Ch) in place
of the default scheme.
-
READCNTL:
read control file (including LSM initial conditions and site characteristics)
-
-----------
Begin optional Multi-year Spin-Up Loop: if invoked by control file
-------------
-
---------------------------------------
Begin: Time Step Loop -------------------------------------
-
READBND
: read atmospheric forcing data
(and observed validation variables)
-
MONTH-D: interpolate monthly albedo and veg
greenness to current julian day
-- JULDATE:
determine julian day for current time
-
QDATAP: calculate actual and saturated
specific humidity
-- E (function) calculate vapor
pressure
-
DQSDT
(function): slope of sat specific humidity wrt air temp (needed in PENMAN)
-- DQS (function)
intermediate value for routine dqsdt
-
SFLX: call to family of physics routines (see Sec
4.2) **** key call ****
-
PRTDAILY: write daily total values to output file 1 (once a
day only)
-
PRTHYDF: write LSM water related
variables to output file 2 (every
time step)
-
PRTHMF: write LSM energy related
variables to output file 3 (every time
step)
-
PRTBND: write out input atmospheric
forcing to output file 4 (every time
step)
-
-------------------------------
End: Time Step Loop
----------------------------------------------
-
------------------------End:
Optional Multi-year Spin-Up Loop---------------------------------
-
STOP
0
4.2 The SFLX Family of Subroutines
The SFLX family of subroutines contain the physics of the LSM and is rather self-contained. Each user should become familiar with the argument list of SFLX. This argument list is thoroughly documented at the top of subroutine SFLX. Once becoming familiar with the argument list, users could if they so choose create their own MAIN driver program with reasonably little effort. Calling SFLX each time step updates and returns all the LSM state variables and all the surface energy balance and surface water balance terms. In using SFLX in a coupled atmospheric model, the output arguments needed from SFLX are:
ETA - latent heat flux
H - sensible heat flux
T1 - skin temperature (from which to
calculate upward longwave radiation)
ALBEDO - (including snowpack effects) for
calculating upward solar radiation
REDPRM
-- set land-surface parameters
-- set soil-type dependent parameters
-- set veg-type dependent parameters
-- set other land-surface parameters
SNO_NEW
– update snow depth and snow density to account for new snowfall
SNFRAC –
determine snow cover fraction
ALCALC –
determine surface albedo (including snow cover fraction)
TDFCND
– compute soil thermal diffusivity
SNOWZ0
– compute snow roughness length (currently a null/no effect process)
SFCDIF
-- calculate surface exchange
coefficient for heat/moisture
CANRES
– compute canopy resistance
NOPAC – this path invoked if ZERO
snowpack on ground and zero snowfall (frozen precip)
-- surface skin
temperature updated via surface energy balance
SMFLX – compute a) surface water
fluxes and b) layer soil moisture update
DEVAP-
compute direct evaporation from top soil layer
TRANSP
– compute transpiration from vegetation canopy
SRT
– compute time-rate-of-change of soil moisture
WDFCND – compute hydraulic conductivity and diffusivity
SSTEP
– forward time-step integration of soil moisture rate-of-change
ROSR12 – tri-diagonal matrix solver
SHFLX
– compute a) ground heat flux and b) layer soil temperature update
HRT
– compute time-rate-of-change of soil temperature
TDFCND – compute soil thermal diffusivity (dependent on
soil moist.)
TBND – determine
soil layer interface temperature
SNKSRC –(function) compute heat sink/source from soil ice
phase change
TDFCND –
compute soil thermal diffusivity
FRH2O –
(function) calculate subzero unfrozen soil water
(or
HRTICE – as in HRT, but for sea-ice pack)
HSTEP
– forward time step integration of soil temperature rate-of-change
ROSR12 – tri-diagonal matrix solver
-
surface
skin temperature updated via surface energy balance
-
new
patchy snow cover treatment in above
-
snowmelt
computed if thermal and available energy conditions warrant
TRANSP
– see above
SRT
– see above
WDFCND – see above
SSTEP
– see above
ROSR12 – see above
SHFLX
– see above
HRT
– see above
TDFCND – see above
TBND – see above
SNKSRC – see above
TDFCND –
see above
FRH2O –
see above
HSTEP
– see above
SNOWPACK – update snow depth and
snow density owing to snow compaction
NOTES on SFLX Calling Tree:
1 –
Both the NOPAC and SNOPAC branches treat freezing processes within soil
2 –
Calling sequences under NOPAC and
SNOPAC via SMFLX and SHFLX are very similar
3 –
Snowpack physics in SNOPAC are treated mainly “in-line”, before calls to
SMFLX/SHFLX
4 –
SHFLX and subordinates do heat fluxes and soil temperature update
5 –
SMFLX and subordinates do water fluxes and soil moisture update
-- SMFLX operates independently of the soil
thermodynamics (SHFLX) and can stand
alone,
requiring only inputs of precipitation and potential evaporation
-- SHFLX cannot operate independently of soil
hydraulics, unless thermal conductivity
dependence on soil moisture dependence is removed (in routine TDFCND)
5.0 CONTROL FILE CONTENTS AND FUNCTION
The
filename of the control file is “controlfile_ver_2.7.1”. The user may want to have a printout of the
control file handy (about one page) when reviewing the comments below.
The
control file is read-in early in the MAIN program and provides inputs of the
following types of information: a)
valid location and start date/time of simulation, b) model configuration,
c)
name of input forcing file, d) integer indexes for land-sfc classes for the
site, e ) initial values of all the model state variables.
NOTE: The control file does not provide model physical parameters,
except for the lower boundary condition on the soil temperature (which should
be assigned the value of the annual mean sfc air temperature for the simulation
location). Physical parameters are set
in subroutine REDPRM and many of these parameters are dependent in REDPRM on
the veg-type index and soil-type index read from the control file.
The control file consists of
30 data lines that contain the following:
Line
01: LAT - simulation site latitude (positive N from equator, hundredths
of a degree)
Line
02: LON - simulation site longitude (positive W from Greenwich,
hundredths of a degree)
Note: The above serve only to document the valid
site of the input forcing data.
The physics do not use the above,
since forcing data provides downward solar radiation.
Above would be needed by a MAIN
driver that had to calculate downward solar radiation
Line
03: IBINOUT - either positive interge "1", or negative integer
"-1".
Negative sign invokes ascii text
output files with extension *.TXT
Postive sign
invokes binary output files with extension *.GRS -denoting GrADS readable
Line
04: JDAY - Integer Julian Day (1-366) of start of forcing data (start of
simulation)
Line
05: TIME - 4-digit "hhmm" integer time of day (local) at start
of forcing data,
hh is 2-digit hour (0-23) and mm is 2-digit minute
(0-59).
Note: Except for use of JDAY to to temporal
interpolation of monthly greenness and albedo read-in later below, the above
JDAY and TIME serve only to document the valid start date/time of the input forcing data. The physics do not use the above, since
forcing data provides downward solar radiation. Above would be needed by a MAIN driver that had to calculate
downward solar radiation
Line
06: NCYCLES – number of times the integration will cycle through the
input forcing data
(useful for multi-year spin-up runs,
wherein input forcing file spans one complete year)
Line
07: SYDAYS - number of days in spin-up year (either 365 or 366)
(relevant only if NCYCLE is 2 or
greater)
Line
08: L2nd_data: logical variable: value of .true. or .false.
if TRUE: then NCYCLES must be
set to 2 or greater, and thus invokes spin-up runs of
NCYCLE-1 spin-up years with first
forcing file given below, followed by 1 final cycle
(not necessarily full year)executed
from second forcing file below and representing the
final
production run period. Will write
output only during final cycle, unless two forcing
files have
the same name, then will write output from each cycle
if FALSE: then only first
named forcing file is used, still for the number of cycles given
by NCYCLE, and will write output
from every cycle
Note:
The true option for L2nd_data is useful for multi-year "PILPS-type"
spin-up runs
For
forcing files spanning only a partial year, L2nd_data should be false and
NCYCLE=1
Line
09: NRUN is the total number of simulation time steps per cycle.
Line
10: DT – floating point length of time step (secs) used in physical
integration
Note: DT should NOT be larger than one hour (3600
secs)
Note: There must be one forcing data record in
forcing file for each time step
Line
11: NSOIL - integer number of soil layers
Note:
NSOIL must be 2 or greater, NOT to exceed 20, strongly recommend at least 4
Line
12: Z – height in meters above ground of atmospheric forcing data
Note: In observed forcing data, the height of the
temperature/humidity observation (e.g. 2 m) is often different from the height
of the wind observation (e.g. 10 m ).
When that is the case, we recommend using the height of the wind
observation for Z.
Line
13: SLDPTH - thickness values for the NSOIL soil layers in meters (chosen by user), starting with the
uppermost layer and proceeding downward
Note: We recommend that each succeeding soil layer
downward not exceed 3 times the thickness of the soil layer above it. For the common 4-layer configuration, we
recommend
Layer 1: 10 cm (.10 m)
Layer 2: 30 cm (.30 m)
Layer 3: 60 cm (.60 m)
Layer 4:100 cm (1.0 m)
Note: The physical equations in the LSM predict
the soil moisture/temperature state variables at the midpoint of each model
soil layer.
NOTE:!! Sum total of all soil layer thicknesses
should not exceed about 2/3 of depth parameter ZBOT. The
lower boundary condition TBOT of soil temperature is applied at the depth
specified by parameter ZBOT, whose current default value of -8.0 meters is set
in routine REDPRM (ZBOT follows negative sign convention for soil depth), but
this default can be changed via the optional NAMELIST I/O in REDPRM.
Line
14: - filename of the first input
forcing file (up to 72 characters)
Line
15: - filename of the second input
forcing file (up to 72 characters)
Note:
see above discussion of logical variable "L2nd_data
Note:
the two forcing files may be the same name (used for both spin-up and
production years)
NOTE !! : User should contact NCEP Point of Contact given at top of Page 1 for recommended values for Lines 12-18
Line
16: SOILTP - soil type integer index (range 1-9), see definitions in
routine REDPRM
Line
17: VEGTYP veg type integer index (range 1-13), see definitions in
routine REDPRM
Line
18: SLOPTYP sfc slope integer index (range 1-9), see definitions in
routine REDPRM
Note:
SLOPTYP is a sfc slope category (flat, steep, mixed, etc) used in the bottom
drainage
Line
19: ALBEDO – 12 monthly values of surface albedo fraction (snow-free)
for simulation site
Note:
LSM physics will internally add snow cover effects to ALBEDO
Line
20: SHDFAC - 12 monthly values
of green vegetation fraction for simulation site
NOTE !! See contact point at top of this User's Guide to get monthly
vegetation greenness values for your simulation site of interest.
NCEP
now sets monthly SHDFAC using the global database and publication of
Gutman, G. and A. Ignatov, 1998: The
derivation of the green vegetation fraction from
NOAA/AVHRR for use in numerical weather prediction
models. International Journal
of Remote Sensing, 19,
1533-1543.
This
latter work provides a 5-year, monthly mean, global database of green
vegetation fraction at 0.144 degree resolution, obtained from NDVI. The authors forcefully argue that the two
AVHRR channels that are used to derive NDVI do NOT provide sufficient degrees
of freedom to derive BOTH vegetation greenness and LAI independently. They instead argue for embracing all the
seasonality of vegetation in the greenness fraction and holding the LAI at a
fixed constant annual value in the range of 1-5 (thus LAI becomes a tuning
parameter). NCEP has obtained
reasonable behavior with LAI=4.
Line
21: SNOALB – maximum albedo expected over deep snow
Robinson, D.A., and G. Kukla, 1985: Maximum surface
albedo of seasonally snow-
Covered Lands in the Northern Hemisphere. J. Climate
Appl. Meteor., 23, 1626-1634
(See Fig. 4 therein for depiction from digital
database).
Line
22: ICE – Flag to invoke sea-ice
physics (always set to 0 for land-mass simulations)
Note: The integer flag “ICE” forces branch to sea-ice physics in LSM.
Be aware that this ICE flag has no bearing on soil ice
physics in NCEP LSM.
Line 23: TBOT – set to the climo annual mean sfc air temperature (K) for the modeled site
.
Note: TBOT serves as the annually fixed, soil-temperature bottom-boundary condition at a soil depth of ZBOT. ZBOT is currently set at a default 8-meter depth (-8.0) in routine REDPRM. ZBOT is the assumed nominal soil depth where the amplitude of the soil-temperature annual cycle is near zero (e.g. about double the e-folding depth in the soil of the annual cycle of surface air temperature).
Initial conditions for all state variables follows:
Line 24: T1 – initial skin temperature (K). Can be set to initial air temperature. Model physics
rapidly spins this up in first few 2-3 time steps.
Line 25: STC (1-NSOIL): initial soil temperature (K), in each soil layer
Line 26: SMC (1-NSOIL): initial volumetric total soil moisture (liquid and frozen) in each layer
(usually in the range .1-.43)
Note: Initial SMC should not exceed soil saturation (porosity), as set in routine REDPRM for given soil class.
Line 27: SH2O (1-NSOIL): initial volumetric liquid soil moisture (unfrozen) in each layer
Note: initial SH2O must not exceed porosity, nor exceed initial SMC
NOTE: During conditions of no soil freezing, SH2O=SMC in each layer.
NOTE: Initializing soil ice (case of SH2O less than SMC) is very difficult. Recommend starting the model run in the warm season and letting the physics spin-up soil ice, or running multi-year spin-up cycles.
Line 28: CMC – initial canopy water content (m). Set to zero as physics rapidly spins this up.
Line 29: SNOWH – initial snow depth (m)
Line 30: SNEQV – initial water equivalent (m) of above snowdepth. If not observed, dividing
SNOWH by 5 gives a nominal initial value.
6.0
ATMOSPHERIC FORCING FILE
6.1 Forcing with Validation
As is typical with many off-line, uncoupled LSMs, the NCEP LSM requires the following near-surface atmospheric forcing data, preferably at 30-minute time intervals (or interpolated to
30-minute time intervals or smaller from say 1-6 hour interval observations -- Aside note: for observation intervals longer than 1-hour, the incoming surface solar insolation needs to be interpolated with a solar zenith angle weighting, in order to capture the full amplitude of the diurnal solar insolation).
Air temperature
at height Z above ground
Air humidity
at height Z above ground
Surface pressure
at height Z above ground
Wind speed
at height Z above ground
Surface downward longwave radiation
Surface downward solar radiation
Precipitation
For
the example one-year LSM simulation provided with this User’s Guide, we were
extremely fortunate to benefit from the collaboration of GCIP/GAPP-sponsored PI
Tilden Meyers of NOAA/ARL, who operates a flux site located just south of
Champaign, IL (40.01 N lat, 88.37 W lon).
The
site characteristics and observing instrumentation are described in the MS Word
document
CHAMP_IL,
provided by courtesy of Tilden Meyers, and available in same directory as this
User’s Guide.
The
1998 forcing file from the above flux site is available as filename
“forcing98_with_validation.dat” in the same directory as this User’s
Guide. This file contains one record
for each 30-minute observation time and the file spans the entire calendar year
of 1998 (hence 2 X 24 X 365 = 17520 records).
Each 30-min record provides the following 33 observed variables (including
the 7 required LSM forcing variables, marked by “**”), listed in the order they
appear in each record of the file:
jday Julian
Day
time LST,
half hour ending
w_speed propeller anemometer (10
meters, Bondville ISIS)
w_dir wind
direction (10 meters, Bondville ISIS)
** Ta air temperature (C), at 3 m
** RH relative humidity at 3 m (list continued)
** Pres surface pressure in mb
** Rg incoming solar radiation (W/m2)
Par_in incoming
visible radiation (0.4‑0.7 um) in uE/m2/s
Par_out outgoing
or reflected visible light
Rnet net
radiation (W/m2)
GHF soil
or ground heat flux (W/m2)
** rain total rain for half hour (inches)
wet wetness
sensor (in voltage with higher values indicating wetness)
IRT surface
or skin temp (C)
2_cm soil
temp at 2 cm (C)
4_cm soil
temp at 4 cm
8_cm soil
temp at 8 cm
16_cm soil
temp at 16 cm
32_cm soil
temp at 32 cm
64_cm soil
temp at 64 cm
** u_bar average wind vector speed at 6-meters (m/s)
u’w’ kinematic
shear stress (m2/s2)
u’2 streamwise
velocity variance (m2/s2)
v’2 crosswind
velocity variance (m2/s2)
w’2 vertical
velocity variance(m2/s2)
H sensible
heat flux (W/m2)
LE latent
energy flux (W/m2)
CO2 CO2
flux (mg CO2/m2/s)
** LW_in
downwelling longwave from sky (W/m2)
sm_5 soil
volumetric water content at 5 cm zone (after November 19 1997)
sm_20 soil
volumetric water content at 20 cm zone (after November 19 1997)
sm_60 soil
volumetric water content at 60 cm zone (after November 19 1997)
In the LSM, program MAIN
reads in all 33 of the above variables at each time step via the call to
subroutine READBND, which also fills in occasional missing observations. Missing obs are very sparse and virtually always
involve missing values of the wind speed (u_bar at 6 m), for which the READBND
software substitutes (w_speed at 10 m with a reduction factor). Finally, the last section of routine READBND
performs unit conversions on “rain”, “Ta”, and “Pres” to convert them to the
units expected in the call to SFLX .
In addition to the
LSM-required atmospheric forcing variables in the above list, the other
variables in the list represent either a) independent validation data or b)
useful initial conditions for the LSM state variables. LSM initial conditions are discussed in the
next section.
At each time step in the
MAIN program, after the return from the physics update in CALL SFLX, useful LSM
validation data from the above observation file is written out to validation
output file OBS_DATA.TXT via call to routine PRTBND (e.g. LE, H, GHF, RNET,
IRT, and the layer by layer soil moisture and temperature).
6.2
Basic Forcing
The basic input near-surface atmospheric forcing file forcing98_basic.dat is a subset of the input file forcing98_with_validation.dat described in Section 6.1. This basic input forcing file is located at: ftp://ftp.emc.ncep.noaa.gov/mmb/gcp/ldas/noahlsm/ver_2.7.1/basic
This
file contains one record for each 30-minute observation time and the file spans
the entire calendar year of 1998 (hence 2 X 24 X 365 = 17520 records). Each 30-min record provides the following 9
observed variables (including the 7 required LSM forcing variables, marked by
“**”), listed in the order they appear in each record of the file:
jday Julian
Day
time LST,
half hour ending
** Ta air temperature (C), at 3 m
** RH relative humidity at 3 m
** Pres surface pressure in mb
** Rg incoming solar radiation (W/m2)
** rain total rain for half hour (inches)
** u_bar average wind vector speed at 6-meters (m/s)
** LW_in
downwelling longwave from sky (W/m2)
7.0 LSM INITIAL CONDITIONS
2 –
SH2O: liquid volumetric soil
moisture in each soil layer
3 –
STC: temperature
in each soil layer
4 –
T1: skin temperature
5 –
CMC: canopy water content
6–
SNOWH: snow depth
7 -
SNEQV: water-equivalent snow
depth
Typically,
a number of these state variables are not observed at a given validating
observation site. The following initial
variables were not available in the site observation file (obs98.dat):
SNEQV,
SNOWH, CMC, nor SMC (and SH2O) below 60 cm
Since
January 1998 was mild (El’Nino) at the given site, we assumed a) zero snow
cover (SNOWH=0.0, SNEQV=0.0) and b) zero soil ice (SMC=SH2O), plus we set
CMC=0.
While
we in general found the physical behavior of the observed data in file
obs98.dat to be very good, inspection of the observed soil moisture at the 20 and 60 cm levels showed them to be
virtually time invariant over the entire year, despite substantial wetting and
drying periods. Hence their accuracy is
very suspect.
It is typical for LSM simulations at a particular observation site to be hampered by non-observed
(e.g.
snowdepth, frozen soil moisture, deep soil moisture ) or ill-observed initial state variables (.e.g. soil
moisture). Facing this dilemma, the
Project for Intercomparison of Land-Surface Process Schemes (PILPS) has come to
urge modelers to use a one-year spin-up protocol, whereby the simulation for a
desired period (1998 here) is preceded
by a spin-up year (say 1997 in this case) where the spin-up year forcing is
repeated several years to allow the LSM to essentially achieve
equilibrium.
Tilden
Meyers provided us with the 1997 forcing data for his site, and we proceeded to
execute the PILPS-recommended spin-up protocol to provide all initial soil
states for the one-year 1998 production run provided in this directory.
Specifically,
in a prior run using the same model configuration as in the control file given
here and using L2nd_data = .false., NCYCLES= 10, and the aforementioned 1997
forcing file we call "obs97.dat", we executed a 10-year spin-up run
over the 1997 annual cycle in order to derive initial conditions of soil state
and snow state (turned out zero snowpack, because of warm fall and early winter
in 1997) for the 1998 production run provided here in the directory with this
User's Guide. In practice, a full
10-years of spin-up is not needed. We
generally recommend 3-5 years of spin-up.
8.0 SPECIFYING MODEL PARAMETERS
The
vast majority of the Noah LSM
land-surface parameters are set in subroutine REDPRM. However, the assignment of some land-surface parameters have not
yet been “collected” into the REDPRM setting and remain buried deep in the LSM
code. We feel these exceptions are
primarily parameters of secondary or tertiary importance. A few exceptions may be some parameters
used in the snowpack physics, such as the parameter that controls the amount of
supercooled water allowed in the soil over a range of sub-freezing
temperatures. We are working to
identify such parameters and bring them into the REDPRM setting in a future
release.
In
a broader sense, one should also consider the number (NSOIL) and thickness
(SLDPTH) of the soil layers (especially thickness
of top soil layer) specified in the control file to be adjustable
parameters.
Before
proceeding further in this section, the reader should have on hand a copy of
the subroutine REDPRM.
In
REDPRM, we define the NAMELIST named "/SOIL_VEG/", which includes ALL
the parameters defined in REDPRM, including parameter arrays whose elements
depend on soil type, vegetation type, or slope type. Moreover, this namelist includes three variables that
respectively define the number of classes (up to a maximum of 30) that we carry
for soil type, vegetation type, and slope type. With the powerful and robust flexibility of the namelist
construct, we can even make wholesale changes to the soil and vegetation
classification scheme used and the soil and vegetation parameters associated
with the change in classification. Thus
via the namelist read, we can change as little as one single universal
parameter, or multiple- element parameter arrays associated with a
classification, or the number of classification categories themselves, or a
combination of these, all without any recompiling of source code.
One
exercises the above flexibility through the input filename called
"namelist_filename.txt", which is read-in by routine REDPRM. This 1-line 50-char text file provides the
name of the namelist file, which the routine REDPRM then reads in as well. By this mechanism, one can carry multiple
namelist files (providing different parameter sets) in the same execution
directory. The contents of the 1-line
file "namelist_filename.txt" thus acts as a pointer to the namelist
file you wish to read-in during a given execution.
Every
namelist file so pointed to must begin with the following syntax:
$SOIL_VEG
LPARAM = .FALSE.$
or
$SOIL_VEG
LPARAM = .TRUE.$
with
the latter followed by at least one or more defined parameter values.
We
recall that the beginning of Sec 3 listed all the filenames in the directory
/ver_2.7.1 with this User's Guide (Noah_LSM_USERGUIDE_2.7.1.doc). Inspecting the contents of filename
"namelist_filename.txt" therein, we find that this file points to the
filename ""soil_veg_namelist_ver_2.7.1". On inspection we find the contents of this
file to be
$SOIL_VEG
LPARAM = .FALSE.$ ,
hence
ALL the default values of the parameters defined in REDPRM will be retained
unchanged.
If
the contents of "namelist_filename.txt" instead pointed to filename
"namelist_chg_example", then we find on inspection that the contents
of the latter file are
$SOIL_VEG
LPARAM = .TRUE.$
$SOIL_VEG
NROOT_DATA = 3,3,3,3,3,3,2,2,2,2,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 $
$SOIL_VEG
Z0_DATA(7) = 0.15 $
$SOIL_VEG REFKDT_DATA = 1.0 $
In the above example, our execution will
utilize 1) new values for all the elements of array NROOT, 2) a new value for
the 7-th element of the array of roughness lengths (this element corresponding
to veg class #7, or perennial grassland), and 3) a new value for the scalar
surface runoff parameter REFKDT.
Below, we will review ALL the parameters
defined in REDPRM. All these parameters
are included in the NAMELIST /SOIL_VEG/, which is specified in routine REDPRM
as
NAMELIST
/SOIL_VEG/ SLOPE_DATA, RSMTBL, RGLTBL, HSTBL, SNUPX,
&
BB, DRYSMC, F11, MAXSMC, REFSMC, SATPSI, SATDK, SATDW,
&
WLTSMC, QTZ, LPARAM, ZBOT_DATA, SALP_DATA, CFACTR_DATA,
&
CMCMAX_DATA, SBETA_DATA, RSMAX_DATA, TOPT_DATA,
&
REFDK_DATA, FRZK_DATA, BARE, DEFINED_VEG, DEFINED_SOIL,
&
DEFINED_SLOPE, FXEXP_DATA, NROOT_DATA, REFKDT_DATA, Z0_DATA,
&
CZIL_DATA, LAI_DATA, CSOIL_DATA, SMLOW_DATA, SMHIGH_DATA
In the above
list, there are five kinds of land-surface parameters,
reviewed in order below.
a)
single
universal values
b)
values
dependent on the soil class index (default categories are 1- 9)
c) values
dependent on the vegetation class index (default categories are 1-13)
d) values
dependent on the surface slope index (default categories are 1-7)
e)
parameters specifying the numbers of vegetation, soil, and slope classes
A)
Universal values (16) (current default value in
this release listed)
CZIL = 0.20: Zilintikevich parameter (range 0.0 - 1.0), recommended range 0.2 - 0.4
Note: CZIL is a tuneable parameter, which controls the ratio of the roughness length for heat to the roughness length for momentum, and is known as the Zilintikevich coefficient. This parameter effectively allows tuning of the aerodynamic resistance of the atmospheric surface layer. Increasing CZIL increases aerodynamic resistance. For a full description and example impacts of this primary parameter, see the article by
Chen, F, Z. Janjic, and K. Mitchell, 1997: Impact of the atmospheric surface-layer
parameterizations in the new land-surface scheme of the NCEP mesoscale Eta model.
Boundary-Layer Meteor., 85, 391-421
REFDK= 2.0E-6: a parameter used with REFKDT below to compute sfc runoff parameter KDT
REFKDT = 3.0: surface runoff parameter (nominal range of 0.5 – 5.0)
NOTE: REFKDT is a tuneable parameter that significantly impacts surface infiltration and hence the partitioning of total runoff into surface and subsurface runoff. Increasing REFKDT decreases surface runoff. See next publication:
Schaake, J., V. Koren, Q.-Y. Duan, K. Mitchell, and F. Chen, 1996: Simple water
balance model for estimating runoff at different spatial and temporal scales.
J. Geophysical Res., 101, No. D3.
NOTE: REFDK corresponds to the saturation hydraulic conductivity Ksat for silty clay loam. If the latter parameter value is changed, then REFDK must be equated to that new value.
ZBOT = -8.0 m: nominal depth of TBOT: lower boundary condition on soil temp (range 3-20m)
(see discussion of ZBOT in discussion of TBOT in notes below Lines 13 and 23 of Control File in Section 5.0)
SMLOW = 0.5: ‘spread’ factor for
SMCWLT
SMHIGH = 3.0: ‘spread’ factor for
SMCREF
FXEXP = 2.0: bare soil
evaporation exponent (=1 yields linear reduction of bare soil evaporation with decreased soil moisture between SMCMAX
and SMCDRY, >1 yields greater-than-linear reduction)
SBETA= -2.0:used to compute veg
canopy effect on ground heat flux as a function of greenness
CSOIL = 2.00E+6: soil heat
capacity (J/m**3/K)
SALP = 2.7.1:shape parameter used
in function to infer percent area snow cover from snow depth
CFACTOR = 0.5: exponent used in function for canopy water
evaporation
CMCMAX =0.0005 (m): maximum canopy water capacity used in canopy
water evaporation
FRZK=0.15 a base reference value
(for light clay soil type) of parameter for the frozen-soil freeze factor
representing the ice content threshold above which frozen soil is impermeable
RSMAX=5000 (s/m) maximum stomatal
resistance used in canopy resistance routine CANRES
TOPT= 298(K) optimum air
temperature for transpiration in canopy resistance routine CANRES
RTDIS: array specifying vertical
root distribution, i.e. the fraction of total root mass present
in each soil layer
Note: RSMAX and TOPT are not yet functions of
vegetation class.
Note: Presently, RTDIS is set universally (not
dependent on vegetation class) and assumes a
uniform root
distribution throughout the specified number of root layers for the given
vegetation class.
B) Soil-class
dependent parameter arrays (10)
Routine REDPRM applies 9
soil texture classes. These classes are
defined near the top of routine REDPRM.
The parameters dependent on soil class are:
SMCMAX: maximum volumetric soil moisture (porosity)
SMCREF: soil moisture threshold for onset of some
transpiration stress
SMCWLT: soil moisture wilting point at which
transpiration ceases
SMCDRY: top layer soil moisture threshold at which
direct evaporation from soil ceases
DKSAT: saturated soil hydraulic conductivity
PSISAT: saturated soil matric potential
B: the “b” parameter in
hydraulic functions
DWSAT: saturated soil water diffusivity
QUARTZ: quartz content, used to compute soil
thermal diffusivity
FRZFACT: a
parameter used with FRZK to compute the value of parameter FRZX
Note: if soil parameters
such as SMCMAX and SMCREF or soil classification scheme are
changed, then parameters FRZK and FRZFACT
must be changed
C) Vegetation-class dependent parameters arrays (7)
Routine
PRMVEG applies the 13 “SiB” vegetation classes. These classes are described in the comment block at the top of
routine PRMVEG. The seven veg-class
dependent parameters are:
Z0:
(m)
roughness length
RCMIN (s/m) : minimal stomatal resistance used in canopy
resistance of routine CANRES
RGL: radiation stress parameter used in F1 term in canopy resistance
of routine CANRES
HS: coefficient used in vapor pressure deficit term F2 in canopy
resistance of routine CANRES
LAI: presently set to universal
value of 4.0 across all vegetation classes
Note:
seasonality of vegetation greenness carried by fraction of green vegetation
(SHDFAC)
NROOT: number of soil layers from
top down reached by roots; note: NROOT £ NSOIL
SNUP: the water-equivalent
snowdepth upper threshold at which
1)
100
percent snow cover is achieved for given veg class
2) maximum snow albedo is achieved for given
veg class
D) Surface-slope dependent parameter arrays (1)
Routine
REDPRM embodies 7 categories of surface slope.
These categories are described in a comment block near the top of
routine REDPRM. The parameter dependent
on slope class is:
SLOPE – a coefficient between
0.1-1.0 that modifies the drainage out the bottom of the last
soil layer. A larger surface slope implies larger
drainage
E) Classification dimension parameters (3)
Vegetation Types ("SiB-1") after
Dorman and Sellers (1989; JAM)
DEFINED_VEG = 13: the number of
SiB-1vegetation class categories, assigned as follows:
1:
BROADLEAF-EVERGREEN TREES
(TROPICAL FOREST)
2: BROADLEAF-DECIDUOUS
TREES
3:
BROADLEAF AND NEEDLELEAF TREES (MIXED FOREST)
4:
NEEDLELEAF-EVERGREEN TREES
5:
NEEDLELEAF-DECIDUOUS TREES (LARCH)
6:
BROADLEAF TREES WITH GROUNDCOVER (SAVANNA)
7:
GROUNDCOVER ONLY (PERENNIAL)
8:
BROADLEAF SHRUBS WITH PERENNIAL GROUNDCOVER
9:
BROADLEAF SHRUBS WITH BARE SOIL
10:
DWARF TREES AND SHRUBS WITH GROUNDCOVER (TUNDRA)
11:
BARE SOIL
12:
CULTIVATIONS (THE SAME PARAMETERS AS FOR TYPE 7)
13:
GLACIAL (THE SAME PARAMETERS AS FOR TYPE 11)
Soil Types
after Zobler (1986), except for quartz after Cosby et al (1984)
DEFINED_SOIL = 9: the number of
Zobler soil class categories, assigned as follows:
TEXTURE DESCRIPTION QUARTZ
CONTENT
1 COARSE LOAMY SAND (0.82)
2 MEDIUM SILTY CLAY LOAM (0.10)
3 FINE LIGHT CLAY (0.25)
4 COARSE-MEDIUM SANDY
LOAM (0.60)
5 COARSE-FINE SANDY CLAY (0.52)
6 MEDIUM-FINE CLAY LOAM (0.35)
7 COARSE-MED-FINE SANDY
CLAY LOAM (0.60)
8 ORGANIC (0.40)
9 GLACIAL LAND ICE LOAMY
SAND (0.82)
Slope Types
after Zobler (1986)
DEFINED_SLOPE = 9: the number of Zobler defined slope
categories, assigned as follows:
SLOPE CLASS PERCENT
SLOPE
1 0-8
2 8-30
3 > 30
4 0-30
5 0-8 & > 30
6 8-30 & > 30
7 0-8, 8-30, > 30
8 GLACIAL ICE
9 OCEAN/SEA
9.0 EXECUTION OUTPUT FILES
There
are five execution-time output files:
PRTSCREEN.TXT: holds results from “Print * “ output via
execution command line syntax of “lsm.x
>PRTSCREEN.TXT” (i.e. capture
of “screen” print). Presently file
contains the surface energy balance residual and time-step value for first 50
time steps, then every 50 steps thereafter.
a)
DAILY.TXT: contains daily-defined output values
once-per-day, from routine PRTDAILY,
such as daily total
evaporation and precipitation.
b)
HYDRO.TXT:
contains water related outputs at every "time step", from
routine PRTHYDF,
such as actual and
potential evaporation, soil moisture, snowdepth, snowmelt, runoff.
c)
THERMO.TXT:
contains energy related outputs at every "time step",from routine
PRTHMF,
such as skin temperature,
soil temperature, and all surface energy fluxes
d) OBS_DATA.TXT: output of observed input
forcing/validation data, from routine PRTBND,
such as incoming radiation, skin
temperature, soil temperature, precip, net radiation, latent,
sensible, and ground heat fluxes (i.e. this file echoes the input observation
file “obs98.dat”,
but with some units conversion for
compatibility with other model outputs)
10.0 MODEL HISTORY
Directory
Contents/Notes
------------------------------------------------------------------------
AFWA/
nearly equivalent to ver 2.2
------------------------------------------------------------------------
Eta_2.3/
ops version of Noah LSM ver 2.3
------------------------------------------------------------------------
Eta_2.3.1/
ops version of Noah LSM ver 2.3.1
------------------------------------------------------------------------
ver_2.3/
Noah LSM in operational mesoscale Eta model, nearly
identical physics to version 2.2 (July 2001)
------------------------------------------------------------------------
ver_2.3.1/
ver 2.3 +
modifications to soil heat flux for patchy snow cover
------------------------------------------------------------------------
ver_2.3.2/
ver 2.3.1 +
modification to soil moisture availability function in bare
soil evaporation calculation
------------------------------------------------------------------------
ver_2.4/
identical physics to ver 2.3, but with code
re-organization, more efficient
code, comments, etc.
------------------------------------------------------------------------
ver_2.5/
bug fix to TDFCND
soil heat capacity = 2.0E+6 [J/m^3/K]
ZBOT = -8 (meters)
------------------------------------------------------------------------
ver_2.5.1/
ver 2.5 +
modifications to soil heat flux for patchy snow cover
------------------------------------------------------------------------
ver_2.5.2/
ver 2.5.1 +
modification to soil moisture availability function in bare
soil evaporation calculation
------------------------------------------------------------------------
ver_2.6/
ver 2.5.2 +
change parameter CZIL from 0.20 to 0.075
reduce the parameter SMCREF
reduce interval between SMCREF and Field Capacity by 1/2
remove vegetation greenness factor from snow-albedo functn
reduce value of parameter SNUP by 1/2
increase value of parameter SALP from
2.6 to 4.0
------------------------------------------------------------------------
ver_PILPS-2e/
nearly identical to ver 2.5 model physics, but with
driver program specific to PILPS-2e
------------------------------------------------------------------------
ver_2.7.1
FROZEN PRECIP TYPE - add
so-called 'Lackmann' change to the
determination of frozen
precip type in the Noah LSM, i.e. in the coupled
mode pass Eta-microphysics
determined precip type (i.e. frozen or not)
to the Noah LSM, vs
poor-man use of Tair (1st model level above the
surface), with snow for
T<0C, rain otherwise. In the offline mode this
change may be null since
the same precip-type determination procedure
may be (is?) employed, use
of the 'poor-man' lowest level atmospheric
temperature check for
precip type, though in the driver program rather
within the SFLX code.
DIURNAL ALBEDO - pass net
solar (SOLNET in the calling argument list) to
Noah LSM from the offline
driver, or in the case of the coupled (meso
Eta model) land-surface
driver the solar net value implicitly accounts
for the solar zenith angle
correction of the solar albedo.
PATCHY SNOW COVER MOISTURE
FLUX - include separate calculation of snow sublimation and evap from non-snow-covered
surface.
11.0 TECHNICAL REFERENCES
11.1 Model Physics
Lineage (OSU, AFGL/PL/AFRL, AFGWC/AFWA, NCEP, OH/OHD)
Original
soil hydrodynamic physics:
Marht
and Pan, 1984, Boundary Layer Meteorol, 29, 1-20.
Stability-dependent
Penman potential evaporation:
Mahrt
and Ek, 1984, J. Clim. Appl. Meteorol, 23, 222-234.
Original
soil thermodynamic physics:
Pan
and Mahrt, 1987, Boundary Layer Meteorol, 38, 185-202.
Time-integration
scheme advancements:
Kalnay
and Kanamitsu, 1988: Mon. Wea. Rev., 116, 1945-1958
Canopy
resistance advancements:
Chen,
F., K. Mitchell, et al, 1996: J.
Geophys. Res., 101, No. D3, 7251-7268 (Secs. 3.1.1-3.1.2)
Surface
infiltration advancements:
Schaake,
J., et al., 1996: J. Geophys. Res., 101, 7461-7475.
Surface-layer
turbulence advancements:
Chen,
F., Z. Janjic, and K. Mitchell, 1997, Boundary-Layer Meteorol, 85, 391-421.
Bare
soil evaporation and vegetation greenness advancements:
Betts,
A., F. Chen, K. Mitchell, and Z. Janjic, 1997: Mon. Wea. Rev., 125, 2896-2916.
Gutman,
G., and A. Ignatov, 1998: Int. J. Remote Sensing, 19, 1533-1543.
Ek, M., K. Mitchell, E. Rogers, et al, 2001: AMS 9th Mesoscale conference.
Mitchell,
K., M. Ek, D. Lohmann, et al, 2002: AMS
16th Hydrology conference.
Snowpack
and frozen ground physics advancements:
Koren,
V., et al., 1999: J. Geophys. Res.,
101, No. D3, 7251-7268.
Ek, M., K. Mitchell, E. Rogers, et al, 2001: AMS 9th Mesoscale conference.
Mitchell,
K., M. Ek, D. Lohmann, et al, 2002: AMS
16th Hydrology conference.
For
subsurface heat flux advancements:
Peters-Lidard,
C., M. Zion, and E. Wood, 1997: JGR, 102, No. D4, 4303-4324 (Sec. 2.1.2)
Peters-Lidard,
C., 1998: J. Atmos. Sci., 55, 1209-1224. (Sec. 2.b)
Lunardini,V.,1981:Heat
Transfer in Cold Climates. Van Nostrand Reinhold,1-731 (Sec. 4.12.1.1)
Chang,
S.,D.Hahn, C.-H.Yang, D.Norquist, and M.Ek, 1999: J. Appl. Meteorology, 38,
405-422.
Ek, M., K. Mitchell, E. Rogers, et al, 2001: AMS 9th Mesoscale conference.
Mitchell,
K., M. Ek, D. Lohmann, et al, 2002: AMS
16th Hydrology conference.
11.2 OSU Heritage: 1981-1998
(OSU)
Uncoupled
Mahrt
and Pan, 1984, Boundary Layer Meteorol, 29, 1-20.
Mahrt
and Ek, 1984, J. Clim. Appl. Meteorol,
23, 222-234.
Pan
and Mahrt, 1987, Boundary Layer Meteorol, 38,
185-202.
OSU
1-D PBL Model User’s Guide, Version 1.0.0, 1988.
OSU
1-D PBL Model User’s Guide, Version 1.0.4, 1991.
Ek,
M., and R. Cuenca, 1994, Boundary-Layer Meteorology, 70, 369-383.
11.3
Air Force Lineage: 1985-present (AFGWC,
AFGL/PL/AFRL)
Uncoupled
Mitchell,
1985 (AFGWC Tech Report)
Moore,
B., K. Mitchell, et al., 1990: 20th AMS Conf. Ag and Forest Meteorology, 7-11.
Chang,
S.,D.Hahn, C.-H.Yang, D.Norquist, and M.Ek, 1999: J. Appl. Meteorology, 38,
405-422.
Coupled
Yang,
C.-H., et al., 1989, AFGL Tech Report, GL-TR-89-0158, 262 pp.
11.4
NCEP Lineage: 1990-present (NMC,
NCEP)
Uncoupled
Chen,
F., K. Mitchell, et al., 1996: J. Geophys. Res., 101, No. D3, 7251-7268 (Secs.
3.1.1, 3.1.2)
Chen,
F., and K. Mitchell, 1999: J. Meteorol. Soc. of Japan, 77, 167-182. (GSWP
Special Issue)
Mitchell,
K., et al., 2000: 15th AMS Conf. on Hydrology, 1-4.
Chen,
T. H., Henderson-Sellers, et al, 1997:
J. Climate, 10, 1194-1215. (PILPS-2a)
Qu,
W., Henderson-Sellers, et al, 1998: J.
Atmos. Sci., 55, 1909-1927. (PILPS-2a)
Liang, X., E. Wood, D. Lettenmaier, et al., 1998: Global and Planetary Change, 19(1-4), 137-159. (PILPS-2c).
Lohmann, D., D. Lettenmaier, Liang, X., E. Wood, et al., 1998: Global Planet. Change, 19(1-4), 161-179. (PILPS-2c).
Wood, E., D. Lettenmaier, X. Liang, D. Lohmann, et al., 1998: Global Planet. Change, 19(1-4), 115-135. (PILPS-2c)
Slater, A.
G., C. A. Schlosser, et al., 2001: J.
Hydrometeorology, 2, 7-25. (PILPS-2d)
Schlosser,
C. A., A. G. Slater, et al., 2000: Mon.
Wea. Rev., 128, 301-321. (PILPS-2d)
Bowling, L., D. Lettenmaier, B. Nijssen,
J. Polcher, R. Koster and D. Lohmann, 2002, Global Planet. Change (PILPS 2e).
Boone, A., F. Habets, J. Noilhan, D.
Lohmann, et al., 2002: to be submitted
to BAMS, JGR, or J. Hydrometeorol. (Rhone/GLASS).
Coupled
Mitchell, K., 1994: 5th AMS Symposium on Global
Change Studies, 192-198.
Chen,
F., Z. Janjic, and K. Mitchell, 1997, Boundary-Layer Meteorol, 85, 391-421.
Betts,
A., F. Chen, K. Mitchell, and Z. Janjic, 1997: Mon. Wea. Rev., 125, 2896-2916.
Mitchell,
K., et al., 1999: 14th AMS Conf. on Hydrology, 261-264.
Marshall,
C., et al., 1999: 14th AMS Conf. on Hydrology, 265-268.
Mitchell,
K., et al., 2000: 15th AMS Conf. on Hydrology, 180-183.
Ek, M., K. Mitchell, E. Rogers, et al, 2001: AMS 9th Mesoscale conference.
Mitchell,
K., M. Ek, D. Lohmann, et al, 2002: AMS
16th Hydrology conference.
11.5
OHD Heritage: 1995-present (OH,
HRL, OHD)
Schaake
et al., 1996: J. Geophys. Res., 101, 7461-7475.
Koren,
V., et al.,1999: J.Geophys.Res.,101,7251-7268
11.6
External Validators of NCEP Noah
Model
Uncoupled
PILPS-2a
(two papers)
PILPS-2c
(three papers)
PILPS-2d
(three papers)
PILPS-2e
(three papers)
GSWP
(several papers)
Rhone/GLASS
(one paper)
Coupled
Berbery,
Rasmusson, Mitchell, 1996, JGR, 101,
7305-7319.
Yarosh,
Ropelewski, Mitchell, 1996, JGR, 101, 23289-23298.
Betts,
Chen, Mitchell, Janjic, 1997, Mon. Wea. Rev., 125, 2896-2916.
Yucel,
Shuttleworth, Washburne, Chen, 1998, Mon. Wea. Rev., 126, 1977-1991.
Berbery,
Mitchell, Benjamin, Smirnova, Ritchie, et al., 1999, JGR, 104, 19329-19348.
Berbery
and Rasmusson, 1999, Mon. Wea. Rev., 127, 2654-2673.
Yarosh,
Ropelewski, Berbery, 1999, JGR, 104, 19349-19360.
Hinkelman,
Ackerman, Marchand, 1999, JGR, 104, 19535-19549.
Berbery
and Collini, 2000, Mon. Wea. Rev., 128, 1328-1346.
Fennessy
and Shukla, 2000, J. Climate, 13, 2605-2627.
Angevine
and Mitchell, 2001, Mon. Wea. Rev., 129, 2761-2775.
Marshall,
Crawford, Mitchell, Stensrud, 2001, J. Hydrometeor., submitted.
Berbery,
2001, J. Climate, 14, 121-137.
11.7 NESDIS/ORA Land Surface Fields for NCEP
Operational Use
Daily N.H. 23-km snow cover:
Ramsay, B., 1998, Hydrological Processes, 12, 1537-1546.
Annual
cycle of monthly global vegetation greenness:
Gutman, G., and A. Ignatov, 1998, Int. J. Remote Sensing, 19, 1533-1543.
Annual
cycle of monthly snow-free surface albedo:
Csiszar, I., and G. Gutman, 1999, J. Geophys. Res., 104, 6215-6228.