Simple indices of global climate variability and change: Part I - Variability and correlation structure

Abstract

Some simple indices are used to describe global climate variability in observational data and climate model simulations. The indices are surface temperature based and include the global-mean, the land-ocean contrast, the meridional gradient, the inter-hemispheric contrast, and the magnitude of the annual cycle. These indices contain information independent of the variations of the global-mean temperature for unforced climate variations. They also represent the main features of the modelled surface temperature response to increasing greenhouse gases in the atmosphere. Hence, they should have a coherent response for greenhouse climate change. On interannual and decadal time scales, the variabi..