tPrecipitationScaling.hh - pism - [fork] customized build of PISM, the parallel ice sheet model (tillflux branch)
HTML git clone git://src.adamsgaard.dk/pism
DIR Log
DIR Files
DIR Refs
DIR LICENSE
---
tPrecipitationScaling.hh (3039B)
---
1 // Copyright (C) 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2020 PISM Authors
2 //
3 // This file is part of PISM.
4 //
5 // PISM is free software; you can redistribute it and/or modify it under the
6 // terms of the GNU General Public License as published by the Free Software
7 // Foundation; either version 3 of the License, or (at your option) any later
8 // version.
9 //
10 // PISM is distributed in the hope that it will be useful, but WITHOUT ANY
11 // WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
12 // FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
13 // details.
14 //
15 // You should have received a copy of the GNU General Public License
16 // along with PISM; if not, write to the Free Software
17 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19 #ifndef PRECIPITATIONSCALING_H
20 #define PRECIPITATIONSCALING_H
21
22 #include "pism/coupler/AtmosphereModel.hh"
23 #include "pism/coupler/util/ScalarForcing.hh"
24
25 namespace pism {
26
27 class ScalarForcing;
28
29 namespace atmosphere {
30
31 /** Scaling precipitation using air temperature offsets
32 *
33 * This class implements the adjustment used to capture the influence of changing air
34 * temperature on precipitation. It uses scalar temperature offsets read from a file as an
35 * input.
36 *
37 * @f[
38 * P_{G}(x,y,t) = P_{G}(x,y,0)exp\left[\frac{0.169}{d}\left({\Delta}T(t)+ {\Delta}T_{SC}(t)\right)\right]
39 * @f]
40
41 * where @f$P_G(x,y,0)@f$ is the precipitation for the present
42 * Greenland ice sheet, obtained from the atmosphere model used as an
43 * input of this class. The time dependent precipitation is
44 * @f$P_G(x,y,t)@f$, @f$d@f$ is the @f${\delta}_{18}@f$ conversion factor
45 * of @f$2.4^{\circ}C/\frac{0}{00}@f$, and @f${\Delta}T_{SC}@f$ is a
46 * correction term for the change of altitude of the central dome
47 * during the Greenland ice sheet's evolution. The coefficient
48 * " @f$ 0.169/d @f$ " corresponds to a 7.3% change of precipitation rate
49 * for every @f$1^{\circ}C@f$ of temperature change (Huybrechts et al.
50 * 2002).
51 *
52 * One possible scheme for @f${\Delta}T_{SC}(t)@f$ (used in PISM) is
53 * to take it to be zero, which regards the height correction as
54 * belonging to the set of uncertainties related to the conversion
55 * between isotopic and temperature signals.
56 */
57 class PrecipitationScaling : public AtmosphereModel {
58 public:
59 PrecipitationScaling(IceGrid::ConstPtr g, std::shared_ptr<AtmosphereModel> in);
60 virtual ~PrecipitationScaling();
61
62 protected:
63 void init_impl(const Geometry &geometry);
64 void update_impl(const Geometry &geometry, double t, double dt);
65
66 void init_timeseries_impl(const std::vector<double> &ts) const;
67
68 const IceModelVec2S& mean_precipitation_impl() const;
69
70 void precip_time_series_impl(int i, int j, std::vector<double> &values) const;
71
72 protected:
73 double m_exp_factor;
74 std::unique_ptr<ScalarForcing> m_forcing;
75 mutable std::vector<double> m_scaling_values;
76
77 IceModelVec2S::Ptr m_precipitation;
78 };
79
80 } // end of namespace atmosphere
81 } // end of namespace pism
82
83 #endif /* PRECIPITATIONSCALING_H */