6. Data Atmosphere (DATM)

DATM is normally used to provide observational forcing data (or forcing data produced by a previous run using active components) to drive prognostic components. In the case of CESM, these would be: CLM (I compset), POP2 (C compset), and POP2/CICE (G compset). As a result, DATM variable settings are specific to the compset that will be targeted. As examples, CORE2_NYF (CORE2 normal year forcing) is the DATM mode used in C and G compsets. CLM_QIAN, CLMCRUNCEP, CLMGSWP3 and CLM1PT are DATM modes using observational data for forcing CLM in I compsets.

6.1. xml variables

The following are $CASEROOT xml variables that CIME supports for DATM. These variables are defined in $CIMEROOT/src/components/data_comps/datm/cime_config/config_component.xml. These variables will appear in env_run.xml and the resulting values are compset dependent.

Note

These xml variables are used by the the datm’s cime_config/buildnml script in conjunction with datm’s cime_config/namelist_definition_datm.xml file to generate the namelist file datm_in.

“DATM xml variables”

xml variable

description

DATM_MODE

Mode for atmospheric component

Valid values are: CORE2_NYF,CORE2_IAF,CLM_QIAN,CLM_QIAN_WISO,CLM1PT,CLMCRUNCEP,

CLMCRUNCEP_V5,CLMGSWP3,WW3,CPLHIST,CORE_IAF_JRA

DATM_PRESAERO

Optional prescribed aerosol forcing

DATM_TOPO

Optional Surface topography

DATM_CO2_TSERIES

Optional CO2 time series type

DATM_CPLHIST_DOMAIN_FILE

Coupler history forcing data mode - full pathname of model domain file

DATM_CPLHIST_CASE

Coupler history forcing data mode - case name

DATM_CPLHIST_DIR

Coupler history forcing data mode - directory containing coupler history data

DATM_CPLHIST_YR_ALIGN

Coupler history forcing data mode - simulation year corresponding to DATM_CPLHIST_YR_START

DATM_CPLHIST_YR_START

Coupler history forcing data mode - starting year to loop data over

DATM_CPLHIST_YR_END

Coupler history forcing data mode - ending year to loop data over

DATM_CLMNCEP_YR_ALIGN

I compsets only - simulation year corresponding to data starting year

DATM_CLMNCEP_YR_START

I compsets only - data model starting year to loop data over

DATM_CLMNCEP_YR_END

I compsets only - data model ending year to loop data over

Note

If DATM_MODE is set to CPLHIST, it is normally assumed that the model domain will be identical to all of the stream domains. To ensure this, the xml variables ATM_DOMAIN_PATH and ATM_DOMAIN_FILE are ignored and a valid setting must be given for DATM_CPLHIST_DOMAIN_FILE. If DATM_CPLHIST_DOMAIN_FILE is set to null, then the datm component domain information is read in from the first coupler history file in the target stream and it is assumed that the first coupler stream file that is pointed to contains the domain information for that stream. This is the default that should be used for this mode. Alternatively, DATM_CPLHIST_DOMAIN_FILE can be set to $ATM_DOMAIN_PATH/$ATM_DOMAIN_FILE in a non-default configuration.

6.2. datamode values

The xml variable DATM_MODE (described in DATM_MODE, datamode and streams) sets the streams that are associated with DATM and also sets the namelist variable datamode. datamode (which appears in shr_strdata_nml) specifies what additional operations need to be done by DATM on the streams before returning to the driver.

Each data model has its own set of supported datamode values. The following are the supported DATM datamode values, as defined in the file namelist_definition_datm.xml.

“Valid values for datamode namelist variable”

datamode variable

description

NULL

This mode turns off the data model as a provider of data to the coupler. The atm_present flag will be set to false and the coupler assumes no exchange of data to or from the data model.

COPYALL

The default science mode of the data model is the COPYALL mode. This mode will examine the fields found in all input data streams; if any input field names match the field names used internally, they are copied into the export array and passed directly to the coupler without any special user code. Any required fields not found on an input stream will be set to zero except for aerosol deposition fields which will be set to a special value.

CLMNCEP

In conjunction with NCEP climatological atmosphere data, provides the atmosphere forcing favored by the Land Model Working Group when coupling an active land model with observed atmospheric forcing. This mode replicates code previously found in CLM (circa 2005), before the LMWG started using the CIME coupling infrastructure and data models to do active-land-only simulations.

CORE2_NYF

Coordinated Ocean-ice Reference Experiments (CORE) Version 2 Normal Year Forcing.

CORE2_IAF

In conjunction with CORE Version 2 atmospheric forcing data, provides the atmosphere forcing favored by the Ocean Model Working Group when coupling an active ocean model with observed atmospheric forcing. This mode and associated data sets implement the CORE-IAF Version 2 forcing data, as developed by Large and Yeager (2008) at NCAR. Note that CORE2_NYF and CORE2_IAF work exactly the same way.

CORE_IAF_JRA

In conjunction with JRA-55 Project, provides the atmosphere forcing when coupling an active ocean model with observed atmospheric forcing. This mode and associated data sets implement the JRA-55 v1.3 forcing data.

6.3. DATM_MODE, datamode and streams

The following table describes the valid values of DATM_MODE (defined in the config_component.xml file for DATM), and how they relate to the associated input streams and the datamode namelist variable. CIME will generate a value of DATM_MODE based on the compset.

“Relationship between DATM_MODE, datamode and streams”

DATM_MODE

description-streams-datamode

NULL

null mode

streams: none

datamode: NULL

CORE2_NYF

CORE2 normal year forcing (C ang G compsets)

streams: CORE2_NYF.GISS,CORE2_NYF.GXGXS,CORE2_NYF.NCEP

datamode: CORE2_NYF

CORE2_IAF

CORE2 interannual year forcing (C ang G compsets)

streams: CORE2_IAF.GCGCS.PREC,CORE2_IAF.GISS.LWDN,CORE2_IAF.GISS.SWDN,CORE2_IAF.GISS.SWUP,

CORE2_IAF.NCEP.DN10,CORE2_IAF.NCEP.Q_10,CORE2_IAF.NCEP.SLP_,CORE2_IAF.NCEP.T_10,CORE2_IAF.NCEP.U_10,

CORE2_IAF.NCEP.V_10,CORE2_IAF.CORE2.ArcFactor

datamode: CORE2_IAF

CORE_IAF_JRA

JRA-55 intra-annual year forcing(C ang G compsets)”

streams: CORE_IAF_JRA.PREC,CORE_IAF_JRA.LWDN,CORE_IAF_JRA.SWDN,

CORE_IAF_JRA.Q_10,CORE_IAF_JRA.SLP_,CORE_IAF_JRA.T_10,CORE_IAF_JRA.U_10,

CORE_IAF_JRA.V_10,CORE_IAF_JRA.CORE2.ArcFactor

datamode: CORE_IAF_JRA

CLM_QIAN_WISO

QIAN atm input data with water isotopes (I compsets)

streams: CLM_QIAN_WISO.Solar,CLM_QIAN_WISO.Precip,CLM_QIAN_WISO.TPQW

datamode: CLMNCEP

CLM_QIAN

QIAN atm input data (I compsets)

streams: CLM_QIAN.Solar,CLM_QIAN.Precip,CLM_QIAN.TPQW

datamode: CLMNCEP

CLMCRUNCEP

CRUNCEP atm input data (I compsets)

streams: CLMCRUNCEP.Solar,CLMCRUNCEP.Precip,CLMCRUNCEP.TPQW

datamode: CLMNCEP

CLMCRUNCEP_V5

CRUNCEP atm input data (I compsets)

streams: CLMCRUNCEP_V5.Solar,CLMCRUNCEP_V5.Precip,CLMCRUNCEP_V5.TPQW

datamode: CLMNCEP

CLMGSWP3

GSWP3 atm input data (I compsets)

streams: CLMGSWP3.Solar,CLMGSWP3.Precip,CLMGSWP3.TPQW

datamode: CLMNCEP

CLM1PT

single point tower site atm input data

streams: CLM1PT.$ATM_GRID

datamode: CLMNCEP

CPLHIST

user generated forcing data from using coupler history files used to spinup relevant prognostic components (for CESM this is CLM, POP and CISM)

streams: CPLHISTForcing.Solar,CPLHISTForcing.nonSolarFlux,

CPLHISTForcing.State3hr,CPLHISTForcing.State1hr

datamode: CPLHIST

WW3

WW3 wave watch data from a short period of hi WW3 wave watch data from a short period of hi temporal frequency COREv2 data

streams: WW3

datamode: COPYALL

6.4. Namelists

The DATM namelist file is datm_in (or datm_in_NNN for multiple instances). DATM namelists can be separated into two groups: stream-independent namelist variables that are specific to the DATM model and stream-specific namelist variables whose names are common to all the data models.

Stream dependent input is in the namelist group "shr_strdata_nml which is discussed in input streams and is the same for all data models.

The stream-independent group is datm_nml and the DATM stream-independent namelist variables are:

datm_nml vars

description

decomp

decomposition strategy (1d, root)

1d => vector decomposition, root => run on master task

restfilm

master restart filename

restfils

stream restart filename

force_prognostic_true

TRUE => force prognostic behavior

bias_correct

if set, include bias correction streams in namelist

anomaly_forcing

if set, includ anomaly forcing streams in namelist

factorfn

filename containing correction factors for use in CORE2 modes (CORE2_IAF and CORE2_NYF)

presaero

if true, prescribed aerosols are sent from datm

iradsw

frequency to update radiation in number of time steps (of hours if negative)

wiso_datm

if true, turn on water isotopes

6.5. Streams independent of DATM_MODE value

In general, each DATM_MODE xml variable is identified with a unique set of streams. However, there are several streams in DATM that can accompany any DATM_MODE setting. Currently, these are streams associated with prescribed aerosols, co2 time series, topography, anomoly forcing and bias correction. These mode-independent streams are activated different, depending on the stream.

  • prescribed aerosol stream: To add this stream, set $DATM_PRESAERO to a supported value other than none.

  • co2 time series stream: To add this stream, set $DATM_CO2_TSERIES to a supported value other than none.

  • topo stream: To add this stream, set $DATM_TOPO to a supported value other than none.

  • anomaly forcing stream: To add this stream, you need to add any of the following keywword/value pair to the end of user_nl_datm:

    Anomaly.Forcing.Precip = <filename>
Anomaly.Forcing.Temperature = <filename>
Anomaly.Forcing.Pressure = <filename>
Anomaly.Forcing.Humidity = <filename>
Anomaly.Forcing.Uwind = <filename>
Anomaly.Forcing.Vwind = <filename>
Anomaly.Forcing.Shortwave = <filename>
Anomaly.Forcing.Longwave = <filename>

  • bias_correct stream: To add this stream, you need to add any of the following keywword/value pair to the end of user_nl_datm:

    BC.QIAN.CMAP.Precip = <filename>
BC.QIAN.GPCP.Precip = <filename>
BC.CRUNCEP.CMAP.Precip = <filename>
BC.CRUNCEP.GPCP.Precip = <filename>

6.6. DATM Field names

DATM defines a set of pre-defined internal field names as well as mappings for how those field names map to the fields sent to the coupler. In general, the stream input file should translate the stream input variable names into the datm_fld names for use within the data atmosphere model.

“DATM internal field names”

datm_fld (avifld)

driver_fld (avofld)

z

Sa_z

topo

Sa_topo

u

Sa_u

v

Sa_v

tbot

Sa_tbot

ptem

Sa_ptem

shum

Sa_shum

dens

Sa_dens

pbot

Sa_pbot

pslv

Sa_pslv

lwdn

Faxa_lwdn

rainc

Faxa_rainc

rainl

Faxa_rainl

snowc

Faxa_snowc

snowl

Faxa_snowl

swndr

Faxa_swndr

swvdr

Faxa_swvdr

swndf

Faxa_swndf

swvdf

Faxa_swvdf

swnet

Faxa_swnet

co2prog

Sa_co2prog

co2diag

Sa_co2diag

bcphidry

Faxa_bcphidry

bcphodry

Faxa_bcphodry

bcphiwet

Faxa_bcphiwet

ocphidry

Faxa_ocphidry

ocphodry

Faxa_ocphodry

ocphiwet

Faxa_ocphiwet

dstwet1

Faxa_dstwet1

dstwet2

Faxa_dstwet2

dstwet3

Faxa_dstwet3

dstwet4

Faxa_dstwet4

dstdry1

Faxa_dstdry1

dstdry2

Faxa_dstdry2

dstdry3

Faxa_dstdry3

dstdry4

Faxa_dstdry4

tref

Sx_tref

qref

Sx_qref

avsdr

Sx_avsdr

anidr

Sx_anidr

avsdf

Sx_avsdf

anidf

Sx_anidf

ts

Sx_t

to

So_t

snowhl

Sl_snowh

lfrac

Sf_lfrac

ifrac

Sf_ifrac

ofrac

Sf_ofrac

taux

Faxx_taux

tauy

Faxx_tauy

lat

Faxx_lat

sen

Faxx_sen

lwup

Faxx_lwup

evap

Faxx_evap

co2lnd

Fall_fco2_lnd

co2ocn

Faoo_fco2_ocn

dms

Faoo_fdms_ocn

precsf

Sa_precsf

prec_af

Sa_prec_af

u_af

Sa_u_af

v_af

Sa_v_af

tbot_af

Sa_tbot_af

pbot_af

Sa_pbot_af

shum_af

Sa_shum_af

swdn_af

Sa_swdn_af

lwdn_af

Sa_lwdn_af

rainc_18O

Faxa_rainc_18O

rainc_HDO

Faxa_rainc_HDO

rainl_18O

Faxa_rainl_18O

rainl_HDO

Faxa_rainl_HDO

snowc_18O

Faxa_snowc_18O

snowc_HDO

Faxa_snowc_HDO

snowl_18O

Faxa_snowl_18O

snowl_HDO

Faxa_snowl_HDO

shum_16O

Sa_shum_16O

shum_18O

Sa_shum_18O