Changes between Version 1 and Version 2 of Tags/196/Daily_Interpolation

Timestamp:

2012-05-11T11:35:07+02:00 (12 years ago)

Author:

nvuilsce

Comment:

--

Tags/196/Daily_Interpolation

@@ -4 +4 @@
 Since the version 196, you can now use daily meteorological forcing files. 
 The following new variables are now requested:
- - Tmin: minimal daily temperature (K)
- - Tmax: maximal daily temperature (K)
+ - Tmin: minimal daily near-surface temperature (K)
+ - Tmax: maximal daily near-surface temperature (K)
  - precip: daily mean precipitation (kg m-2 s-1)
 The other variables requested as previously are:
- - Psurf: daily mean atmospheric pressure (hPa)
- - Qair: daily mean specific humidity (
+ - Psurf: daily mean surface pressure (hPa)
+ - Qair: daily mean near-surface specific humidity (kg/kg)
  - LWdown: daily mean long-wave incomming radiation (W m-2)
  - SWdown: daily mean short-wave incomming radiation (W m-2)
- - Wind (or Wind_N and Wind_E): daily mean wind speed (m s-1)
+ - Wind (or Wind_N and Wind_E): daily mean near-surface wind speed (m s-1)
+
+
+== Interpolation principles ==
+ - The temperature is varying within the day using a sinusoïdal function, maximal (Tmax value) at 2pm (local time) and minimal (Tmin value) at 2pm - daylength/2. The daylength is calculated and based on the solar angle calculation.
+ - The specific humidity is also varying within the day using a sinusoïdal function with qair_max and qair_min values calculated from the weathgen_qsat_2d function.
+ - The precipitation variable (precip) is split into rain and snow based on 0°C threshold. This split is done at each model time step (30 min usually) using the Tair interpolated value.
+ - The daily short-wave incomming radiation is distributed over the day using a the solar angle value at each time step as weight.
+ - Surface pressure, Long-wave radiation and Wind variables are linearly interpolated from day to day.