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Static pressure loading effects, complement to otemw1

The purpose of this procedure is to compute static air pressure loading effects to compare to the results of dynamic, air pressure driven tidal loading as computed by otemt1 or  otemw1.

The loading effect computed by otemt1/otemw1 is only due to the oceanic mass. A pressure anomaly that excites these dynamic water masses also loads the crust, both on land and on the sea bed. If the pressure anomaly becomes stationary, the displaced water will counterbalance the surface pressure, yielding to zero bottom pressure gradients (uiniform, near-zero combined bottom pressure).
Thus, in order to compute the combined dynamic water load and the static atmospheric load, this routine is employed to provide the static contribution.

The global effect of pressure on land can be computed using the procedures in /home/hgs/Oload/smhi. The remaining loading effects are then only due to static pressure inside the regional model. Those outside are assumed zero, i.e. we assume the inverted barometer assumption holds for the world ocean outside our area.

apload works with a subset of namelist parameters introduced in otemt1 and otemw1. And a few new ones.

      namelist /param/ path,t0,dt,tshift,nsamples,qcmib,iucmib
     &,                IAPT,APC,APX,APY,APVX,APVY,APWX,APWY
     &,                APPATH
     &,                iuevl,iutgg,dismax,qmyprc
     &,                geograph,geocxyz,greensf,fmtls,gpath
     &,                qload_everywhere, load_at_flags
     &,                cmib_at_flags, gmtopt

Their meaning is given below.

Processing options:

Loading masses at targeted flags. For the static loading case these would be the nodes flagged "S" "O" "A" or "a"

Mass imbalance is computed (due to masses at targeted nodes) and the loading effect due to the redistributed mass deficit is evaluated.

Pressure models:
We can employ the three pressure models introduced in otemt1/otemw1, (0) Gaussian bell, (1) and (2) gradients, and (>10) from global meteorological files.

Namelist parameters:

parameter        type       meaning                                             [default]

path           - char*64  - Path to the ETD.DMP file produced by otem16.
                            String should be right-delimeted by ']'               ['./]']

t0, dt         - real*8   - Starting time with respect to ETD.DMP epoch,
                            and increment. The program does not
                            interpolate in time; interpolation should be
                            carried out on the resulting time-series.       [0.0, 3600.0]

tshift ?

nsamples       - integer  - Number of steps forward in time.

IAPT           - integer  - Model type:
                              0 - PM0 - Travelling Gaussian bell (APC,APV*,APW*)
                              1 - PM1 - Gradient East (APC)
                              2 - PM2 - Gradient North (APC)
                           > 10 = file unit number - PMF, global air
                                  pressure fields  (APC,APPATH).
APC            - real     - PM0: Centre pressure in terms of inverted barometer
                                 effect, given in units of meter water column.
                            PMF: Bias to be removed from file data. The effect
                                 of 1000 hPa is already removed when unpacking
                                 the files. The remaining bias concerns the
                                 ellipsoidal component of global pressure.
                                 Since it's the temporal variation of pressure
                                 that drives our model, the ellipsoidal part
                                 can be masked away efficiently with a constant.
                                 It's on the order of 0.1 m.
APX,APY        - real     - PM0: Starting position of pressure anomaly, in grid
                                 units. It's are favourably outside the area.
APVX,APVY      - real     - PMO: Velocity (km/h) east (x) and north (y).
APWX,APWY      - real     - PMO: Half-width (km).
APPATH         - char*64  - PMF: Symbolic path to the unpacked pressure files.
                                 Default is APPATH=' ', i.e. the built-in default
                                 '/scratch/hgs/gap%%%%/m_@@@/d##.## '
                                 Replacement: '%%%%' by year, '@@' by decimal month
                                 '@@@' by lower-case character month,
                                 '$$$' by upper-case character month, first
                                 occurrence of '##' by day and second '##' by hour.

iuevl          - integer  - File unit number for loading time series output.
                            Three files are required (vertical, east, north )
                            for opening on iuevl, iuevl+1 and iuevl+2                  [65]
iutgg          - integer  - File unit number for tide gauge output                     [75]

geograph       - logical  - Site record contains longitude and latitude           [.false.]
geocxyz        - logical  - Site record contains geocentric XYZ                   [.false.]
fmtls          - char*64  - Format for reading the site record          ['(a16,4x,3f15.0)']

qload_everywhere - logical- Disregard flags
load_at_flags  - char*8   - Target flags for loading (right delimited ']')           ['L]']

greensf        - char*32  - Greens function code + ']'                       ['mc00egbc] ']
gpath          - char*64  - Greens functions directory             [' ' = internal default]
dismax         - real     - Greens function expansion maximum
                            distance                               [-1. = internal default]

qcmib          - logical  - compute regional mass imbalance
iucmib         - integer  - output file unit number for loading effect
                            due to mass imbalance. Three files are
                            required (vertical, east, north ) for
                            opening on iucmib, iucmib+1 and iucmib+2                   [62]
cmib_at_flags  - char*8   - Target flags for CMIB (right delimited ']')           ['SAaO]']

Example instruction file

Example given is for Gulf of Maine and St. Lawrence and air pressure loading from global meteo files.
The time epoch of modelling is taken from the ETD.DMP file, i.e. it has been selected in the most recent
run of otem16

 appath='/scratch/hgs/gap%%%%/m_@@@/d##.## ', dt=21600.d0
 apc=0.25, apx=-20.0, apy=60., apvx=30., apvy=0., apwx=500., apwy=500.
 qload_everywhere=.false., load_at_flags='SAa]'
31 ^ &/FLZU.DAT
65 B &/evlap2.rad
66 B &/evlap2.eas
67 B &/evlap2.nor
75 * &/evlap2.prs
 1, 65, -1
WESTFORD    7205      1492404.7400  -4457266.5170   4296881.7740
10, 65, -1

Linear interpolation of time series from a 6-hour file to 1-hour.

/home/hgs/bin/tslist evl-file -g'(i4,5(1x,i2),t33,f10.0)' -k3 -C -FF10.2 -R1,0.,1.