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
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
&, qload_everywhere, load_at_flags
&, cmib_at_flags, gmtopt
Their meaning is given below.
Mass imbalance is computed (due to masses at targeted nodes) and the loading effect due to the redistributed mass deficit is evaluated.
We can employ the three pressure models introduced in otemt1/otemw1, (0) Gaussian bell, (1) and (2) gradients, and (>10) from global meteorological files.
- 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]
nsamples - integer - Number
of steps forward in time.
- 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
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 
iutgg - integer - File unit number for tide gauge output 
geograph - logical - Site
record contains longitude and latitude
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 + ']'
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 
cmib_at_flags - char*8 - Target flags for CMIB (right delimited ']') ['SAaO]']
Linear interpolation of time series from a 6-hour file to 1-hour.
evl-file -g'(i4,5(1x,i2),t33,f10.0)' -k3 -C -FF10.2 -R1,0.,1.