The Working Group on Subseasonal to Interdecadal Prediction (WGSIP) develops a programme of numerical experimentation for seasonal-to-interannual variability and predictability, with an emphasis on assessing and improving predictions.
The WCRP Joint Scientific Committee
(JSC) established a limited term (2005-2007) Task Force on Seasonal Prediction (TFSP) that drew upon expertise
from all the WCRP core projects (CLIVAR,
the WCRP Working Group on Numerical Experimentation
(WGNE) and the WCRP/CLIVAR Working Group on Coupled Modelling.
Since June 2007, the mandate of the TFSP has now been assigned by the JSC to the CLIVAR
Working Group on Subseasonal to Interdecadal Prediction (WGSIP).
The TFSP proposed the CHFP as a multi-model and multi-institutional experimental framework for sub-seasonal to decadal complete physical climate system prediction. By the complete physical climate system, we mean contributions from the atmosphere, oceans, land surface cryosphere and atmospheric composition in producing regional and sub-seasonal to decadal climate anomalies. This experimental framework is based on advances in climate research during the past decade, which have lead to the understanding that modeling and predicting a given climate anomaly over any region is incomplete without a proper treatment of the effects of SST, sea ice, snow cover, soil wetness, vegetation, stratospheric processes, and atmospheric composition (carbon dioxide, ozone, etc.).
The observed current climate changes are a combination of anthropogenic influences and natural variability. In addition to possible anthropogenic influence on climate due to changing the atmospheric composition, it is quite likely that land use in the tropics will undergo extensive changes, which will lead to significant changes in the biophysical properties of the land surface, which in turn will impact atmospheric variability on sub-seasonal to decadal time scales. It is therefore essential that the past research by two somewhat non-interacting communities (i.e., climate change and seasonal prediction) be merged into a focused effort to understand the predictability of the complete climate system.
Certain elements of the proposed experiment are already part of various WCRP activities. The intent here is to leverage these ongoing activities and to coordinate and synthesize these activities into a focused seasonal prediction experiment that incorporates all elements of the climate system. These experiments are the first necessary steps in developing seamless weekly-to-decadal prediction of the complete climate system.