Multidecadal variability (MDV) in the climate system has been a difficult issue in regional decadal climate prediction. While MDV is not simulated well by current coupled climate models, a two-tiered approach became an alternative, i.e., predicting decadal climate by using atmospheric general circulation models (AGCMs) forced by predicted sea surface temperature (SST). However, even if SST is known, how much climate variability over the lands can be simulated by the SST-forced AGCMs remained an open question.

The North Atlantic Oscillation (NAO) and Euro-Atlantic blocking are important low-frequency modes in the Northern Hemisphere, which have a significant adjustment on the weather in surrounding areas especially over Europe, for example, extreme cold events and heat waves.

As one of the most significant and powerful mid-latitude circulation systems, the East Asian winter monsoon (EAWM) dominates the wintertime climate of East Asia, leading to cold surges, snowstorms and freezing weathers as what happened to Southern China in early 2008. Meanwhile, it interacts intensely with the tropics, especially with the El Nino-Southern Oscillation (ENSO).

Atmospheric greenhouse gases (GHGs) continue to rise during recent years, yet global-mean surface temperature has shown no clear warming since about year 2000. This slowdown in global warming, often referred to as the global warming "hiatus", is in sharp contrast to model simulations which on average show strong warming since 2000.

Short-term droughts during the crop growing seasons sometimes occur together with abnormally high temperature. Positive feedbacks between the land and atmosphere often intensify the drought conditions. These droughts are recently termed as “flash droughts” due to their rapid development, unusual intensity and devastating impacts. A flash drought during the summer of 2013 affected 13 provinces in southern China, and damaged over 2 million hectares of crops in Guizhou and Hunan provinces alone.

Human activities have significantly altered land use and land cover over past centuries. Many previous studies suggested that Land use and land cover change (LULCC) can lead to significant changes in land-atmosphere fluxes, which in turn affect regional climate mean state.