1 /* Copyright 2002-2024 Thales Alenia Space
2 * Licensed to CS Communication & Systèmes (CS) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * CS licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.orekit.models.earth.weather;
18
19 import org.hipparchus.CalculusFieldElement;
20 import org.hipparchus.util.FastMath;
21 import org.orekit.models.earth.weather.water.WaterVaporPressureProvider;
22
23 /** Converter for weather parameters that change with height.
24 * <p>
25 * Height variations correspond to equations 5.98, 5.99 and 5.100 from
26 * Guochang Xu, GPS - Theory, Algorithms and Applications, Springer, 2007
27 * </p>
28 * @author Luc Maisonobe
29 * @since 12.1
30 */
31 public class HeightDependentPressureTemperatureHumidityConverter {
32
33 /** Water pressure provider for water vapor pressure. */
34 private final WaterVaporPressureProvider provider;
35
36 /** Simple constructor.
37 * <p>
38 * Points outside of altitude range will be silently clipped back to range.
39 * </p>
40 * @param provider provider for water vapor pressure
41 */
42 public HeightDependentPressureTemperatureHumidityConverter(final WaterVaporPressureProvider provider) {
43 this.provider = provider;
44 }
45
46 /** Convert weather parameters.
47 * @param pth0 weather at reference altitude
48 * @param h altitude at which weather is requested
49 * @return converted weather
50 */
51 public PressureTemperatureHumidity convert(final PressureTemperatureHumidity pth0,
52 final double h) {
53
54 // retrieve parameters at reference altitude
55 final double rh0 = provider.relativeHumidity(pth0.getPressure(), pth0.getTemperature(), pth0.getWaterVaporPressure());
56
57 // compute changes due to altitude change
58 final double dh = h - pth0.getAltitude();
59 final double p = pth0.getPressure() * FastMath.pow(1.0 - 2.26e-5 * dh, 5.225);
60 final double t = pth0.getTemperature() - 6.5e-3 * dh;
61 final double rh = rh0 * FastMath.exp(-6.396e-4 * dh);
62
63 return new PressureTemperatureHumidity(h, p, t, provider.waterVaporPressure(p, t, rh),
64 pth0.getTm(), pth0.getLambda());
65
66 }
67
68 /** Convert weather parameters.
69 * @param <T> type of the elements
70 * @param pth0 weather at reference altitude
71 * @param h altitude at which weather is requested
72 * @return converted weather
73 */
74 public <T extends CalculusFieldElement<T>> FieldPressureTemperatureHumidity<T> convert(final FieldPressureTemperatureHumidity<T> pth0,
75 final T h) {
76 // retrieve parameters at reference altitude
77 final T rh0 = provider.relativeHumidity(pth0.getPressure(), pth0.getTemperature(), pth0.getWaterVaporPressure());
78
79 // compute changes due to altitude change
80 final T dh = h.subtract(pth0.getAltitude());
81 final T t = pth0.getTemperature().subtract(dh.multiply(6.5e-3));
82 final T p = pth0.getPressure().multiply(dh.multiply(2.26e-5).negate().add(1.0).pow(5.225));
83 final T rh = rh0.multiply(FastMath.exp(dh.multiply(-6.396e-4)));
84 return new FieldPressureTemperatureHumidity<>(h, p, t, provider.waterVaporPressure(p, t, rh),
85 pth0.getTm(), pth0.getLambda());
86 }
87
88 }