ucar.unidata.geoloc.vertical.HybridSigmaPressure Maven / Gradle / Ivy
/*
* Copyright (c) 1998-2018 University Corporation for Atmospheric Research/Unidata
* See LICENSE for license information.
*/
package ucar.unidata.geoloc.vertical;
import ucar.ma2.*;
import ucar.ma2.ArrayDouble.D1;
import ucar.nc2.*;
import ucar.nc2.constants.CDM;
import ucar.nc2.units.SimpleUnit;
import ucar.unidata.util.Parameter;
import java.io.IOException;
import java.util.List;
/**
* Create a 3D height(z,y,x) array using the netCDF CF convention formula for
* "Hybrid Sigma Pressure".
*
* pressure(x,y,z) = a(z)*p0 + b(z)*surfacePressure(x,y)
* or
*
* pressure(x,y,z) = ap(z) + b(z)*surfacePressure(x,y)
*
* @author caron
* @see http://cf-pcmdi.llnl.gov/
*/
public class HybridSigmaPressure extends VerticalTransformImpl {
/** P-naught identifier */
public static final String P0 = "P0_variableName";
/** Surface pressure name identifier */
public static final String PS = "SurfacePressure_variableName";
/** The "a" variable name identifier */
public static final String A = "A_variableName";
/** The "a" variable name identifier */
public static final String AP = "AP_variableName";
/** The "b" variable name identifier */
public static final String B = "B_variableName";
/** value of p-naught */
private double p0;
/** ps, a, and b variables */
private Variable psVar, aVar, bVar, p0Var;
/** If has AP, this is a pressure value and has to be also in the same units as PS */
private String apUnits = "";
/** a and b Arrays */
private Array aArray, bArray;
/**
* Construct a coordinate transform for sigma pressure
*
* @param ds netCDF dataset
* @param timeDim time dimension
* @param params list of transformation Parameters
*/
public HybridSigmaPressure(NetcdfFile ds, Dimension timeDim, List params) {
super(timeDim);
String psName = getParameterStringValue(params, PS);
String aName = getParameterStringValue(params, A);
String bName = getParameterStringValue(params, B);
String p0Name = getParameterStringValue(params, P0);
String apName = getParameterStringValue(params, AP);
if (apName != null) {
aVar = ds.findVariable(apName);
} else {
aVar = ds.findVariable(aName);
}
if (aVar != null) {
String unitValue = aVar.attributes().findAttributeString(CDM.UNITS, null);
if (unitValue != null) {
apUnits = unitValue;
}
}
psVar = ds.findVariable(psName);
bVar = ds.findVariable(bName);
units = psVar.findAttributeString(CDM.UNITS, "none");
if (p0Name != null) {
p0Var = ds.findVariable(p0Name);
apUnits = units; // Won't need transformation for AP = A * P0 * 1 (in this case)
}
}
/**
* Get the 3D vertical coordinate array for this time step.
*
* @param timeIndex the time index. Ignored if !isTimeDependent().
* @return vertical coordinate array
* @throws IOException problem reading data
* @throws InvalidRangeException _more_
*/
public ArrayDouble.D3 getCoordinateArray(int timeIndex) throws IOException, InvalidRangeException {
Array psArray = readArray(psVar, timeIndex);
if (null == aArray) {
aArray = aVar.read();
bArray = bVar.read();
// p0 = (p0Var == null) ? 1.0 : p0Var.readScalarDouble();
p0 = computeP0();
}
int nz = (int) aArray.getSize();
Index aIndex = aArray.getIndex();
Index bIndex = bArray.getIndex();
// it's possible to have rank 3 because pressure can have a level, usually 1
// Check if rank 3 and try to reduce
if (psArray.getRank() == 3)
psArray = psArray.reduce(0);
int[] shape2D = psArray.getShape();
int ny = shape2D[0];
int nx = shape2D[1];
Index psIndex = psArray.getIndex();
ArrayDouble.D3 press = new ArrayDouble.D3(nz, ny, nx);
double ps;
for (int z = 0; z < nz; z++) {
double term1 = aArray.getDouble(aIndex.set(z)) * p0;
// AP might need unit conversion
if (!apUnits.equals(units)) {
term1 = convertPressureToPSUnits(apUnits, term1);
}
double bz = bArray.getDouble(bIndex.set(z));
for (int y = 0; y < ny; y++) {
for (int x = 0; x < nx; x++) {
ps = psArray.getDouble(psIndex.set(y, x));
press.set(z, y, x, term1 + bz * ps);
}
}
}
return press;
}
/**
* Get the 1D vertical coordinate array for this time step and point
*
* @param timeIndex the time index. Ignored if !isTimeDependent().
* @param xIndex the x index
* @param yIndex the y index
* @return vertical coordinate array
* @throws java.io.IOException problem reading data
* @throws ucar.ma2.InvalidRangeException _more_
*/
public D1 getCoordinateArray1D(int timeIndex, int xIndex, int yIndex) throws IOException, InvalidRangeException {
Array psArray = readArray(psVar, timeIndex);
if (null == aArray) {
aArray = aVar.read();
bArray = bVar.read();
// p0 = (p0Var == null) ? 1.0 : p0Var.readScalarDouble();
p0 = computeP0();
}
int nz = (int) aArray.getSize();
Index aIndex = aArray.getIndex();
Index bIndex = bArray.getIndex();
// it's possible to have rank 3 because pressure can have a level, usually 1
// Check if rank 3 and try to reduce
if (psArray.getRank() == 3)
psArray = psArray.reduce(0);
Index psIndex = psArray.getIndex();
ArrayDouble.D1 press = new ArrayDouble.D1(nz);
double ps;
for (int z = 0; z < nz; z++) {
double term1 = aArray.getDouble(aIndex.set(z)) * p0;
// AP might need unit conversion
if (!apUnits.equals(units)) {
term1 = convertPressureToPSUnits(apUnits, term1);
}
double bz = bArray.getDouble(bIndex.set(z));
ps = psArray.getDouble(psIndex.set(yIndex, xIndex));
press.set(z, term1 + bz * ps);
}
return press;
}
private double computeP0() throws IOException {
if (p0Var == null)
return 1.0; // Has AP variable
double p0 = p0Var.readScalarDouble();
// Units check: P0 must have same units as PS
String p0UnitStr = p0Var.attributes().findAttributeString(CDM.UNITS, null);
if (p0UnitStr == null)
throw new IllegalStateException();
if (!units.equalsIgnoreCase(p0UnitStr)) {
p0 = convertPressureToPSUnits(p0UnitStr, p0);
}
return p0;
}
private double convertPressureToPSUnits(String unit, double val) {
SimpleUnit psUnit = SimpleUnit.factory(units);
SimpleUnit ptopUnit = SimpleUnit.factory(unit);
double factor = ptopUnit.convertTo(1.0, psUnit);
return val * factor;
}
}