PrecipitationScaling.cc

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// Copyright (C) 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2020, 2021, 2022, 2023, 2024, 2025 PISM Authors
//
// This file is part of PISM.
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// PISM is free software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the Free Software
// Foundation; either version 3 of the License, or (at your option) any later
// version.
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#include <cmath>                // exp()
 
#include "pism/coupler/atmosphere/PrecipitationScaling.hh"
 
#include "pism/util/ScalarForcing.hh"
#include "pism/util/Config.hh"
#include "pism/util/Logger.hh"
 
namespace pism {
namespace atmosphere {
 
PrecipitationScaling::PrecipitationScaling(std::shared_ptr<const Grid> grid,
                                           std::shared_ptr<AtmosphereModel> in)
  : AtmosphereModel(grid, in) {
 
  m_forcing.reset(new ScalarForcing(*grid->ctx(),
                                    "atmosphere.precip_scaling",
                                    "delta_T",
                                    "kelvin",
                                    "kelvin",
                                    "air temperature offsets"));
 
  m_exp_factor = m_config->get_number("atmosphere.precip_exponential_factor_for_temperature");
 
  m_precipitation = allocate_precipitation(grid);
}
 
void PrecipitationScaling::init_impl(const Geometry &geometry) {
  m_input_model->init(geometry);
 
  m_log->message(2,
                 "* Initializing precipitation scaling"
                 " using temperature offsets...\n");
}
 
void PrecipitationScaling::init_timeseries_impl(const std::vector<double> &ts) const {
  AtmosphereModel::init_timeseries_impl(ts);
 
  m_scaling_values.resize(ts.size());
  for (unsigned int k = 0; k < ts.size(); ++k) {
    m_scaling_values[k] = exp(m_exp_factor * m_forcing->value(ts[k]));
  }
}
 
void PrecipitationScaling::update_impl(const Geometry &geometry, double t, double dt) {
  m_input_model->update(geometry, t, dt);
 
  m_precipitation->copy_from(m_input_model->precipitation());
  m_precipitation->scale(exp(m_exp_factor * m_forcing->value(t + 0.5 * dt)));
}
 
const array::Scalar& PrecipitationScaling::precipitation_impl() const {
  return *m_precipitation;
}
 
void PrecipitationScaling::precip_time_series_impl(int i, int j, std::vector<double> &result) const {
  m_input_model->precip_time_series(i, j, result);
 
  for (unsigned int k = 0; k < m_scaling_values.size(); ++k) {
    result[k] *= m_scaling_values[k];
  }
}
 
} // end of namespace atmosphere
} // end of namespace pism