1   /* Copyright 2022-2025 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.water;
18  
19  import org.hipparchus.CalculusFieldElement;
20  
21  /** Interface for converting between relative humidity and water vapor pressure.
22   * @author Luc Maisonobe
23   * @since 12.1
24   */
25  public interface WaterVaporPressureProvider {
26  
27      /** Compute water vapor pressure.
28       * @param p pressure (Pa)
29       * @param t temperature (Kelvin)
30       * @param rh relative humidity, as a ratio (50% → 0.5)
31       * @return water vapor pressure (Pa)
32       */
33      double waterVaporPressure(double p, double t, double rh);
34  
35      /** Compute relative humidity.
36       * @param p pressure (Pa)
37       * @param t temperature (Kelvin)
38       * @param e water vapor pressure (Pa)
39       * @return relative humidity, as a ratio (50% → 0.5)
40       */
41      default double relativeHumidity(final double p, final double t, final double e) {
42          final double saturationPressure = waterVaporPressure(p, t, 1.0);
43          return e / saturationPressure;
44      }
45  
46      /** Compute water vapor pressure.
47       * @param <T> type of the field elements
48       * @param p pressure (Pa)
49       * @param t temperature (Kelvin)
50       * @param rh relative humidity, as a ratio (50% → 0.5)
51       * @return water vapor pressure (Pa)
52       */
53      <T extends CalculusFieldElement<T>> T waterVaporPressure(T p, T t, T rh);
54  
55      /** Compute relative humidity.
56       * @param <T> type of the field elements
57       * @param p pressure (Pa)
58       * @param t temperature (Kelvin)
59       * @param e water vapor pressure (Pa)
60       * @return relative humidity, as a ratio (50% → 0.5)
61       */
62      default <T extends CalculusFieldElement<T>> T relativeHumidity(final T p, T t, T e) {
63          final T saturationPressure = waterVaporPressure(p, t, p.getField().getOne());
64          return e.divide(saturationPressure);
65      }
66  
67  }