CalovGreveIntegrand

CalovGreveIntegrand() static double pism::surface::CalovGreveIntegrand ( double  sigma, double  TacC  ) static Compute the integrand in integral (6) in [CalovGreve05]. The integral is $$\mathrm{PDD} = \int_{t_0}^{t_0+\mathtt{dt}} dt\, \bigg[\frac{\sigma}{\sqrt{2\pi}}\,\exp\left(-\frac{T_{ac}(t)^2}{2\sigma^2}\right) + \frac{T_{ac}(t)}{2}\,\mathrm{erfc} \left(-\frac{T_{ac}(t)}{\sqrt{2}\,\sigma}\right)\bigg]$$ This procedure computes the quantity in square brackets. The value $T_{ac}(t)$ in the above integral is in degrees C. Here we think of the argument TacC as temperature in Celsius, but really it is the temperature above a threshold at which it is "positive". This integral is used for the expected number of positive degree days. The user can choose $\sigma$ by option -pdd_std_dev. Note that the integral is over a time interval of length dt instead of a whole year as stated in CalovGreve05 . If sigma is zero, return the positive part of TacC. Definition at line 94 of file localMassBalance.cc. Referenced by pism::surface::PDDMassBalance::get_PDDs().