El Nino-Southern Oscillation (ENSO) plays the most conspicuous role in shaping the interannual (0 ~10 years) climate variability of the globe,which is a key concern for studies on climate change for both of the modern and historical periods.Different indices have been developed to characterize its features and evolutions.The indices are defined for different oceanic regions or including different oceanic and atmospheric components.However,the instrumental data to infer changes of ENSO are limited to the industrial era.This limits our ability to fully comprehend the regimes of ENSO in the historical period,when both anthropogenic activities play a less important role on climate change.Tree rings are to our knowledge the most frequently used data to reconstruct the ENSO variability of the past millennia,because they are climate sensitive,accurately dated,highly resolved and have a large and dense spatial coverage.Although numerous studies have been conducted on the linkages between ENSO and climate changes in both the instrumental and historical periods,it is still unknown about the responses of instrumental and tree-ring data to different indices of ENSO.This study presents a systematic survey on the linkages between different ENSO indices and the instrumental temperature,precipitation and the tree-ring data for different timescales in eastern Asia and North America.This can improve our understandings on the linkages between regional climate and different ENSO indices and can also shed lights on whether there are systematic biases for treering based ENSO reconstructions.This study employed the instrumental temperature and precipitation data,as well as a tree-ring network of 335 tree-ring chronologies,including 196 chronologies for eastern Asia and 139 chronologies for North America.All these chronologies are over 400 years and have been widely used for climate reconstructions including ENSO.