Improvements of the Driver of ORCHIDEE

These improvements will concern first the specifities of the driver (its capacity to read forcing files), not its performances that will be improved hopefully by the use of the IOServer. The focus is mainly on the use of forcing files at a 6 or 3-hourly time resolution (such as re-analysis), for which the driver interpolates the meteorological fields to calculate half-hourly fields.

Reminder

The driver of ORCHIDEE is expected to read forcing files with a very specific temporal structure. The fields read at a certain time step t in the NetCdf? file correspond to: the instantaneous value at t+1 for Temperature, Wind Speed, Air Pressure and Specific Humidity. the mean value between t and t+1 for Long and Short Wave Incomming Radiation and the Precipitation.

Instantaneous fields and the LongWave? Radiation are then linearly interpolated for each t:t+1 time period in order to calculate half-hourly value. The Precipitation field is downscaled to half-hourly resolution using a step distribution function with one parameter (spread_prec).