modules_long (03/06/08)

CRHM Borland

long

This module defined in Classlong calculates long-wave radiation. Incoming Longwave radiation to Melting Snow: Observations, Sensitivity and Estimation in Northern Environments (Sicart et al., 2005?).

Observations

  • Qsi (W/m^2) - incident short-wave.

Observation Functions

  • QsiDtot(W/m^2*d) - daily total (cumulative) of average interval incident short-wave fluxes, Qsi.

observationVariables

  • Qli# (W/m^2) - calculated incoming long-wave.

Variables

  • tau () - atmospheric transmissivity.
  • Long  (W/m^2) - calculated incoming long-wave. Same as generated observation.

Parameters

  • none.

Variable Inputs

  • hru_t (°C) - air temperature.
  • hru_ea (kPa) - vapour pressure.
  • hru_rh (%) - relative humidity.
  • QdroDext (global)(MJ/m^2*d) - daily extraTerrestial direct.
  • QdroD (global) (MJ/m^2*d) - daily clear-sky direct.

Notes

tau = QsiDtot*(864000/10E6)/QdroDext.

Qli = 1.24*(e/T)^(1/7) (1 + 0.44*RH - 0.18*tau)sbcT^4 where RH lie in the range of 0 and 1 and T is °K.

The declared observation, Qsi# cannot be used as input as the daily total cannot be calculated.  If an attempt is made by the module to use a declared observation it will be automatically converted to the simple observation, i.e. Qsi# converted to Qsi.

 

History.

March 2008 - temperature, vapour pressure and relative humidity changed from using observations to the HRU variables.