New version of MarkSimGCM includes data from 17 climate models from the IPCC 5th Assessment Report.

The MarkSim GCM tool can be used to generate multiple years of daily data that are characteristic of climate anywhere on the planet.  For current conditions, it uses the WorldClim dataset, an interpolated surface of weather station data from around the world mostly covering the years 1960-1990. 

The first version of MarkSim GCM became available in June 2011. It has now been updated, and it has some new features.  The Google Earth interface, in which the tool is embedded, has been updated.  As before, the user can pick any point on the earth’s surface and generate daily weather data for that point.  Now, the user can also plot climate data, in terms of the monthly mean values of rainfall and daily maximum and minimum temperature.

In addition, MarkSim GCM can be used to generate daily data that are to some extent characteristic of future climates, as projected using climate models.  The new version of MarkSim GCM now includes data from a total of seventeen individual climate models that were part of the IPCC’s Fifth Assessment Report (CMIP5).  A new feature of the updated tool is that the user can select any combination of these 17 models (just one, all 17, or any combination in between).  

The user can also chose which greenhouse-gas emissions pathway to use; in CMIP5, these are called “Representative Concentration Pathways", and contain a range of low, moderate and high emissions pathways. The highest, RCP8.5, leads to global temperature increases of nearly 5 °C by the year 2100. 

As for current conditions, the user can plot climate data for the combination of emissions pathways, year (to 2099) and model(s).

Go to the MarkSim GCM tool now

As before, MarkSim GCM can generate multiple realisations of years of daily data: rainfall, maximum and minimum temperatures and solar radiation. The downloadeable data files that are generated are fully compatible with the DSSAT (Decision Support System for Agrotechnology Transfer) crop modelling system. 

Currently, MarkSim uses an internal structure called CLX to hold the derived parameters for a model run. This structure also keeps track of the base climate data and the rotation of the record.  A new feature is that MarkSim GCM can output the CLX file itself, if the user desires.  In the future, this will greatly facilitate the use of MarkSim directly in modelling systems such as DSSAT.

There continue to be two versions of the tool.  One can be accessed on the MarkSim GCM website, in a Google Earth user interface.  An alternative version of the tool, which can be run via user-written scripts or calling programmes, is available at the CCAFS-Climate online platform, along with detailed documentation.

Read more: CCAFS-Climate has also been recently updated with datasets from the IPCC 5th Assessment Report. 


MarkSim GCM has been developed by Waen Associates with CCAFS support, in cooperation with CIAT and ILRI.