InvertedBarometer
From MohidWiki
This application creates water level time series for tide gauge locations according with the inverted (inverse) barometer effect.
Running options for this application are specified in an input file whose path is indicated in a nomfich.dat file.
Contents
Introduction
The inverted (inverse) barometer effect specifies that a 1 mb decrease of atmospheric pressure below a reference pressure results in a 1.01 cm increase in water level (e.g. Kantha, L., K. Whitmer, G. Born, 1994, "The Inverted Barometer Effect in Altimetry: A Study in the North Pacific").
This rule is generally considered to provide a rough measure of the water level change due to large scale circulation induced by water surface atmospheric pressure gradients.
The InvertedBarometer application applies this rule to obtain mean water level time series at tide gauge locations based on time and space variable atmospheric pressure data supplied in HDF5 format.
The time discretization of the time series is determined by the time discretization of the HDF5 data.
The calculation of water level is performed considering:
- the atmospheric pressure data for each time gauge location is considered the one available for the HDF5 grid cell where that tide gauge is geographically located; for this, the coordinate system in gauge files is assumed equal to coordinate system of pressure data in HDF5 files;
- the reference tide gauge water level, provided in tide gauge files, is considered equivalent to the reference atmospheric pressure assumed 101330.0 Pa in the application (following Dorandeu, J., P. Le Traon, 1999, "Effects of Global Mean Atmospheric Pressure Variations on Mean Sea Level Changes from TOPEX/Poseidon", Journal of Atmospheric and Oceanic Technology, Vol. 16, No. 9, pp. 1279-1283);
- the absolute water level at the tide gauge location in every HDF5 time instant is determined as:
(absolute tide gauge water level) = (reference tide gauge water level) + (water level change correspondent to the difference between the reference and actual atmospheric pressures)
The name of each time series file is automatically generated as the following concatenation:
(name of water level time series) = (user defined root name specific for each gauge file) + (name of the gauge location in gauge file) + (number of order of appearance of the gauge location in the gauge file)
The application can also create new tide gauge files for the ready use of the water level time series as tide gauge mean level time series in tidal forcing of MOHID Water.
Typical use:
Allows the transformation of gauge files for use for tidal forcing in MOHID Water models, to take into account the time evolution of the reference level of each gauge according to large scale circulation induced by atmospheric pressure change.
Data input requirements:
One or more HDF5 files with surface atmospheric pressure data, with rank 2D and Pa units, for a spatial domain containing tide gauge locations. The data must be located in the HDF5 path "/Results/atmospheric pressure" (according with MOHID name convention). If several, the HDF5 files must have common grid and non-overlapping time periods.
Grid file, in MOHID format (grid or grid data), with the definition of HDF5 data grid.
One or more gauge files (tidal components files), in MOHID format, containing information of gauge locations where water level time series are to be produced.
Ouput:
Time series files of water level for each gauge location provided by the supplied gauge files. Besides water level values each time serie have a column for covered/uncovered information, as required by MOHID Water; every time data is assumed covered (valued 1.0).
In case there are gauge locations outside the provided HDF5 grid those locations' coordinates and gauge file are saved in a Noinformation.dat file in the directory provided in ROOT_SRT in nomfich.dat file.
Optionally can also be produced new tide gauge files: a copy of the input tide gauge files with extra keywords connecting to the water level time series. These files can be readily used in MOHID Water as tidal components files with time variable gauge mean water level. For the gauge locations outside the HDF5 grid area the original gauge block is maintained in the new tide gauge file with no additional keywords.
Input file
The name of the input file must be provided in the nomfich.dat file in use.
(block for each HDF5 containing surface atmospheric pressure data; may be several,
order irrelevant)
<BeginHDF5File>
NAME : ... (path/name of HDF5 file containing atmospheric pressure data)
<EndHDF5File>
START_TIME : ... (start time for water level time series: yyyy mm dd hh mm ss)
END_TIME : ... (end time for water level time series: yyyy mm dd hh mm ss)
GRID_FILENAME : ... (path/name of grid file with HDF5 files's grid)
MAX_BUFFER_SIZE : ... (maximum buffer size, an integer value, for temporary time series
storage for each gauge location; 100000 = default)
(block for each gauge file containing locations for water level time series; may be several)
<BeginGaugeFile>
NAME : ... (path/name of gauge file)
TIMESERIE_NAME : ... (intended root path/name of output time series without extension)
WRITE_MOHID_INPUT : 0/1 (1 = create a new gauge file ready for MOHID Water use, 0 = not
to create; 0 = default)
(if WRITE_MOHID_INPUT : 1)
OUTPUTNAME : ... (path/name with extension of gauge file to be created for MOHID
Water use)
<EndGaugeFile>
Remarks: - time interval between pressure data values in HDF5 files may be variable: times series are constructed maintaing these intervals within and between files; - since no fixed DT is assumed for pressure data, no alerts are issued at InvertedBarometer run time because of data lacking intervals between HDF5 data files; - the path/name of time serie provided in the block for each gauge file is used as basis for all time series paths/names originated from that gauge file; the name of each time serie is completed in InvertedBarometer with the reference «GaugeName#», where GaugeName is the one provided in the gauge block in gauge file and # is the order of the gauge block in gauge file.
Samples
Input gauge file
<begingauge> NAME : Gauge LONGITUDE : -6.0000 13.0000 50.3724 LATITUDE : 43.0000 42.0000 22.8268 METRIC_X : -6.2307 METRIC_Y : 43.7063 REF_LEVEL : 2.0800 TIME_REF : 0.0000 O1 : 0.068361 320.9841 K1 : 0.065776 74.1854 N2 : 0.265215 71.0081 M2 : 1.294223 91.5081 K2 : 0.122431 119.8621 S2 : 0.463176 124.2623 <endgauge> <begingauge> NAME : Gauge LONGITUDE : -6.0000 4.0000 44.9939 LATITUDE : 44.0000 8.0000 40.5185 METRIC_X : -6.0792 METRIC_Y : 44.1446 REF_LEVEL : 2.0800 TIME_REF : 0.0000 O1 : 0.068554 320.9165 K1 : 0.065686 74.1463 N2 : 0.265796 71.2711 M2 : 1.296347 91.7997 K2 : 0.122623 120.1885 S2 : 0.464600 124.6422 <endgauge> <begingauge> NAME : Gauge LONGITUDE : -6.0000 13.0000 50.3759 LATITUDE : 44.0000 37.0000 53.5107 METRIC_X : -6.2307 METRIC_Y : 44.6315 REF_LEVEL : 2.0800 TIME_REF : 0.0000 O1 : 0.068675 321.2289 K1 : 0.066201 74.5448 N2 : 0.265124 71.9428 M2 : 1.290508 92.5688 K2 : 0.122080 120.9709 S2 : 0.462477 125.5901 <endgauge>
Input file
<BeginHDF5File> NAME : 1971ERA1973msl.hdf5 <EndHDF5File> GRID_FILENAME : 1971ERA1973.grd <BeginGaugeFile> NAME : TidalComponents.dat TIMESERIE_NAME : K:\Simula\GeneralData\Tide\CP WRITE_MOHID_INPUT : 1 OUTPUTNAME : K:\Simula\GeneralData\Tide\TidalComponentsWithMeanLevel.dat <EndGaugeFile> START_TIME : 1972 10 1 0 0 0 END_TIME : 1972 10 5 0 0 0
Output water level time series
Time Serie created by InvertedBarometer.exe
Based on pressure HDF5 2D data on grid by 1971ERA1973.grd
GRID_LOCALIZATION_I : 13
GRID_LOCALIZATION_J : 36
SERIE_INITIAL_DATA : 1972. 10. 1. 0. 0. 0.
TIME_UNITS : SECONDS
LONGITUDE : -6.000000 13.00000 50.37240
LATITUDE : 43.00000 42.00000 22.82680
Seconds YY MM DD HH MM SS water_level open_point
<BeginTimeSerie>
0.00 1972 10 1 0 0 0.0000 0.205845308304E+001 1.0
21600.00 1972 10 1 6 0 0.0000 0.207204771042E+001 1.0
43200.00 1972 10 1 12 0 0.0000 0.207506346703E+001 1.0
64800.00 1972 10 1 18 0 0.0000 0.209167337418E+001 1.0
86400.00 1972 10 2 0 0 0.0000 0.208186054230E+001 1.0
108000.00 1972 10 2 6 0 0.0000 0.211031007767E+001 1.0
129600.00 1972 10 2 12 0 0.0000 0.210468816757E+001 1.0
151200.00 1972 10 2 18 0 0.0000 0.209870862961E+001 1.0
172800.00 1972 10 3 0 0 0.0000 0.207271218300E+001 1.0
194400.00 1972 10 3 6 0 0.0000 0.205773806572E+001 1.0
216000.00 1972 10 3 12 0 0.0000 0.206882834435E+001 1.0
237600.00 1972 10 3 18 0 0.0000 0.209010624886E+001 1.0
259200.00 1972 10 4 0 0 0.0000 0.207881069183E+001 1.0
280800.00 1972 10 4 6 0 0.0000 0.209054899216E+001 1.0
302400.00 1972 10 4 12 0 0.0000 0.209281420708E+001 1.0
324000.00 1972 10 4 18 0 0.0000 0.210097479820E+001 1.0
345600.00 1972 10 5 0 0 0.0000 0.210286545753E+001 1.0
<EndTimeSerie>
Output gauge file (for MOHID water use)
<begingauge> NAME : Gauge LONGITUDE : -6.0000 13.0000 50.3724 LATITUDE : 43.0000 42.0000 22.8268 METRIC_X : -6.2307 METRIC_Y : 43.7063 REF_LEVEL : 2.0800 TIME_REF : 0.0000 O1 : 0.068361 320.9841 K1 : 0.065776 74.1854 N2 : 0.265215 71.0081 M2 : 1.294223 91.5081 K2 : 0.122431 119.8621 S2 : 0.463176 124.2623 REF_EVOLUTION : Time Serie TIME_SERIE_FILE : K:\Simula\GeneralData\Tide\CPGauge1.bts REFLEVEL_COLUMN : 8 COVERED_COLUMN : 9 <endgauge> <begingauge> NAME : Gauge LONGITUDE : -6.0000 4.0000 44.9939 LATITUDE : 44.0000 8.0000 40.5185 METRIC_X : -6.0792 METRIC_Y : 44.1446 REF_LEVEL : 2.0800 TIME_REF : 0.0000 O1 : 0.068554 320.9165 K1 : 0.065686 74.1463 N2 : 0.265796 71.2711 M2 : 1.296347 91.7997 K2 : 0.122623 120.1885 S2 : 0.464600 124.6422 REF_EVOLUTION : Time Serie TIME_SERIE_FILE : K:\Simula\GeneralData\Tide\CPGauge2.bts REFLEVEL_COLUMN : 8 COVERED_COLUMN : 9 <endgauge> <begingauge> NAME : Gauge LONGITUDE : -6.0000 13.0000 50.3759 LATITUDE : 44.0000 37.0000 53.5107 METRIC_X : -6.2307 METRIC_Y : 44.6315 REF_LEVEL : 2.0800 TIME_REF : 0.0000 O1 : 0.068675 321.2289 K1 : 0.066201 74.5448 N2 : 0.265124 71.9428 M2 : 1.290508 92.5688 K2 : 0.122080 120.9709 S2 : 0.462477 125.5901 REF_EVOLUTION : Time Serie TIME_SERIE_FILE : K:\Simula\GeneralData\Tide\CPGauge3.bts REFLEVEL_COLUMN : 8 COVERED_COLUMN : 9 <endgauge>
How to Include the Inverted Barometer Effect in MOHID Simulations
To impose the inverted barometer effect in MOHID model simulations you have regard to the Hydrodynamic and Atmosphere modules. To visualize the effect the spatial gradient of atmospheric pressure should be appreciable. It means that the effect is visible in large scale models
Samples
Hydrodynamic Module
LOCAL_SOLUTION : 6 or 7 !6-GaugePlusSubModel and 7-AssimilaGaugeSubModel ATM_PRESSURE : 1 !activate the use of the property pressure ATM_PRESSURE_TYPE : 1 or 2 !OPTION 1 input data must be atmospheric pressure and OPTION 2 Mean Sea Level Pressure (MSLP) ATM_RAMP : 1 !activate a smooth period ATM_PERIOD : 86400 !is the period by default in MOHID if the user not provide any one
IMPOSE_INVERTED_BAROMETER : 1 !activates the inverted barometer approximation in the open boundary
INVERTED_BAROMETER_CELLS : 1 !allows restrain to specific cells in the open boundary where you want to impose the inverted barometer approximation
<begin_InvertBarometerCells> NAME : generic property DEFAULTVALUE : 0 TYPE_ZUV : z FILE_IN_TIME : NONE REMAIN_CONSTANT : 1 INITIALIZATION_METHOD : ASCII_FILE FILENAME : !Path and name of the file. The file is similar that that a grid data file with the specific i j cells in your domain <end_InvertBarometerCells>
Atmosphere Module
<beginproperty> NAME : atmospheric pressure or UNITS : Pa DESCRIPTION : Meteo-IST MM5 atmospheric pressure DEFAULTVALUE : 100000 REMAIN_CONSTANT : 0 FILE_IN_TIME : HDF FILENAME : !path and name of the file OUTPUT_HDF : 1 <endproperty>
<beginproperty> NAME : mean sea level pressure UNITS : Pa DESCRIPTION : mean sea level pressure GFS DEFAULTVALUE : 0. FILE_IN_TIME : HDF FILENAME : !Path and name of the file OUTPUT_HDF : 1 TIME_SERIE : 1 <endproperty>
