Climate is the average long-term pattern of weather activity over a region.
A GCM is a global, three-dimensional computer model of the climate system, which can be used to simulate the earth's climate. GCMs are highly complex and represent the effects of such factors as reflective and absorptive properties of atmospheric water vapor, greenhouse gas concentrations, clouds, solar heating, sea temperatures and ice boundaries. The most advanced GCMs include global representations of the atmosphere, oceans, and land surface.
A RCM is a comprehensive physical high resolution (less than 50km) climate model that covers a limited area of the globe, usually including the atmosphere and land surface components of the climate system, and containing representations of the important processes within the climate system (e.g., cloud, radiation, rainfall, soil hydrology).
Climate model parameters are numbers that quantify certain factors in the rules of a climate model. Quantities related to land surface types such as vegetation, land, water, or amounts of atmospheric convection, etc. are examples of climate parameters. Climate model parameters also include the specification of factors that are not simulated but rather prescribed, such as the amount of rain from a given amount of humidity, wind and temperature.
Africa is already vulnerable to extremes in climate, and current climate change projections suggest that the region will be more vulnerable in the future. Thus a climate study for this region is important both for economic reasons and for understanding future vulnerability. The climate modeling techniques developed here may be applied to other regions of the world in the future.
Climate simulations require three-dimensional information about temperature, pressure, wind, humidity and surface properties for the entire region being studied at a detailed grid level. In addition, information arriving at the boundary of the region over the time span being studied is needed. This requires a considerable amount of input data, and as the simulation runs, a large quantity of output data is produced.
The project will lead to the identification of combinations of key parameterizations that best simulate the varying climates of Africa. More accurate models will give researchers a better understanding of the implications of various natural and man-made influences on the African climate. In turn, this will enable policy makers to make important adaptation and mitigation decisions based on the best available information.
AfricanClimate@Home can run on computers that use a high speed internet connection and that run the Windows and Linux operating systems. AfricanClimate@Home will be available using the BOINC agent. You can check to see if you are using the BOINC agent by following the information available here. For system requirements, click here.
World Community Grid will produce a significant amount of atmospheric and surface data that will be analyzed and interpreted by researchers to better understand the ability and constraints faced by models simulating African climate.
The generated data will eventually be released to the general scientific community, as well as others interested in doing non-commercial climate research over the African region.
Each computer that receives a work unit for AfricanClimate@Home will compute a two week period for the climate model based on the same starting conditions as other computers that receive a copy of the same work unit. The result data for AfricanClimate@Home is very large (greater then 100MB). Very few computers are able to return a result of this size. Therefore the result file is divided between each computer computing the work unit and each returns a unique section of the result file. Additional information is returned as well to ensure that the section of the result file returned is correct.
The AfricanClimate@Home downloaded work unit size is anticipated to be approximately 77MB, which means it is approximately 150 times larger than a typical FightAIDS@Home or HPF2 work unit. Thus, a 756kbps network connection will take approximately 12-15 minutes to download the work unit. We have estimated that only about 33 percent of registered computers have enough bandwidth to be eligible to participate in this project.
AfricanClimate@Home presently uses WRF Model Version 2.2 (December 2006). In addition, this project is not using the Chemistry model of WRF.
The first phase of the project ran through July, 2008.