albedo atmosphere_transmissivity CalovGreveIntegrand DEBMSimplePointwise distance_factor_paleo distance_factor_present_day eccentricity hour_angle insolation insolation_diagnostic m_albedo_max m_albedo_min m_albedo_ocean m_albedo_slope m_constant_eccentricity m_constant_obliquity m_constant_perihelion_longitude m_eccentricity m_ice_density m_L m_melt_c1 m_melt_c2 m_melt_threshold_temp m_obliquity m_paleo m_perihelion_longitude m_phi m_positive_threshold_temperature m_refreeze_fraction m_refreeze_ice_melt m_solar_constant m_time m_transmissivity_intercept m_transmissivity_slope m_water_density melt obliquity orbital_parameters perihelion_longitude solar_declination_paleo solar_declination_present_day solar_longitude step

distance_factor_present_day() double pism::surface::DEBMSimplePointwise::distance_factor_present_day ( double  year_fraction ) static The unit-less factor scaling top of atmosphere insolation according to the earth's distance from the sun. The returned value is (d_bar / d)^2, where d_bar is the average distance from the earth to the sun and d is the current distance at a given time. Implements equation 2.2.9 from Liou (2002). Liou states: "Note that the factor (a/r)^2 never departs from the unity by more than 3.5%." (a/r in Liou is equivalent to d_bar/d here.) This quantity is equal to 1 / R^2, where R is the sun-earth distance in units of the semi-major axis of the earth's orbit. Definition at line 142 of file DEBMSimplePointwise.cc. References b0. Referenced by orbital_parameters().