Declination equation in tracer.F90 uses wrong year

[MrAzana]

The expression for declination in tracer.F90, which forms the basis for phytoplankton production seasonality uses the RELYR variable. However, RELYR is the time in fractional years since initial conditions, which means that for any initial conditions that start on another date than Jan 1st, seasonality will be off.

For instance, if IC are for Okt. 10, then the model will assume that the date is Jan 1st, for the purpose of calculating declination, and subsequently primary production.