LPJ Version 1 (Fortran): The Original
The LPJ model was originally developed by a consortium led by I. Colin Prentice (then Max-Planck-Institute for Biogeochemistry, Jena; now at Bristol University), Wolfgang Cramer (PIK), and Martin Sykes (Lund University). The name derives from the three locations Lund-Potsdam-Jena but is no longer to be interpreted that way. Managed by a small steering committee, the consortium conducted regular meetings and consultations with key users of LPJ.
The LPJ model has its historical routes in the BIOME family of biogeographical equilibrium models that have been developed by a related and partially overlapping consortium since the early 1990ies.
LPJ coding lead authors in the period from 1997-2003 were Stephen Sitch (then PIK, now UK Met Office) and Benjamin Smith (Lund University). The original LPJ code ("LPJ version 1"), published in 2003, was written in Fortran and was published in 2003 (Sitch et al., Global Change Biology, 2003). It was updated hydrologically in 2004 (Gerten et al., Journal of Hydrology, 2004).
GUESS: LPJ Version 2 (C++): Species-Based
Since 2000, a separate version of LPJ ("LPJ version 2") has emerged that mainly comprises a species and stand-based simulation tool that is more detailed (and much slower) than LPJ but shares many of its core routines. This model, called LPJ-GUESS, may be operated in a mode that delivers LPJ. It was written mainly by Benjamin Smith at Lund University in the language C++ (though not taking advantage of most of the advanced features of C++, for reasons of readability in transfer to other groups). It has been the testbed for several published LPJ developments, most notably that of agriculture by Alberte Bondeau (Bondeau et al., Global Change Biology, 2007).
LPJmL Version 3 (C): A Consolidated LPJ
As of 2005, a consolidated and completely re-written modular version of LPJ ("LPJ version 3") has been created at PIK in the programming language C. At PIK, maintenance and development of all other LPJ versions has ceased and only this version will be continued. The principal authors of this code are Werner von Bloh and Sibyll Schaphoff, under the guidance of Wolfgang Lucht and Wolfgang Cramer (all PIK).
Beginning in 2004, Alberte Bondeau (PIK) has led a team developing an agricultural model for LPJ. The combined code, an extension of LPJ version 3 (in the language C) is referred to as LPJmL.
The LPJmL team at PIK comprised Sibyll Schaphoff, Alberte Bondeau, Dieter Gerten, Tim Erbrecht, Stephanie Jachner, Christoph Müller, Wolfgang Cramer and Wolfgang Lucht (all PIK). Pascalle Smith also contributed (then PIK, now LSCE).
Recent advances in LPJmL include river routing and agricultural irrigation.
A forestry module for LPJ is currently under development.
LPJmL version 4.0
After a long process of bringing together multiple model extensions that were developed in parallel, LPJmL version 4.0 was published in a comprehensive full model description (Schaphoff et al. 2018a), accompanied by a thorough and multi-featured model evaluation (Schaphoff et al. 2018b). This version is also the basis of releasing the source code publicly under the AGPLv3 license at https://github.com/PIK-LPJmL/LPJmL.
LPJmL version 5.0 with nitrogen
Shortly after the release of LPJmL version 4.0, the implementation of the terrestrial nitrogen dynamics in LPJmL were completed. This code version does not yet include all features of LPJmL version 4.0, in particular not yet the updated phenology scheme. The nitrogen implementation has been described and tested by von Bloh et al. 2018. A merged version of 4.0 and 5.0 (intended to be 5.1) is in preparation.
LPJ Users and other versions of LPJ
The LPJ consortium has always had a policy of "open and unrestricted access" to the LPJ code. There is a large number of LPJ users around the globe, and as a consequence a number of local LPJ versions (this has at times caused some confusion). If you are planning an LPJ study, please download the most recent version of the code, not a version you got from "somewhere" (unless you know what you're doing). There are regular updates to the code. The consortium has also always greatly welcomed feedback from users.
