Kppa Updated to Version

Kppa fixes bugs in the data shuffling routines and changes certain default values to match KPP’s default values.


Please visit the Kppa downloads page to download the latest version.  Installation instructions can be found in the Kppa installation guide.

Changes to Default Values

Kppa 0.2.3 and KPP are written from the same literature but share no code, so the defaults are different between the two.  By default, Kppa has a much shorter timespan than KPP and its temperature model is time and location dependent while KPP assumes a constant temperature over the whole grid at all times.  Kppa 0.2.3 also uses a smoother sunlight model, the default absolute and relative tolerances are different, and Kppa uses Ros4 by default while KPP defaults to Rodas3.  Kppa’s minimum time delta is precision dependent, but KPP uses a fixed minimum time delta of 1e-5 regardless of the precision of concentration data.

These differences mean that either the Kppa-generated code or the KPP-generated code should be modified when comparing results from the two tools.  The figures below show how the default values impact a SAPRC’99 simulation.  In particular, Kppa’s smoother sunlight model and time/location-dependent temperature model dampen photolytic oscillations in HNO3.

Click the images to zoom.

SAPRC’99 results from KPP
SAPRC’99 results from Kppa without changing defaults.
SAPRC’99 results from Kppa after updating timespan.
SAPRC’99 results from Kppa after matching KPP defaults.