Abstract
We assess the ability of the DePreSys3 prediction system to predict the summer (JJAS) surface-air temperature over North East Asia. DePreSys3 is based on a high resolution ocean–atmosphere coupled climate prediction system (~ 60 km in the atmosphere and ~ 25 km in the ocean), which is full-field initialized from 1960 to 2014 (26 start-dates). We find skill in predicting surface-air temperature, relative to a long-term trend, for 1 and 2–5 year lead-times over North East Asia, the North Atlantic Ocean and Eastern Europe. DePreSys3 also reproduces the interdecadal evolution of surface-air temperature over the North Atlantic subpolar gyre and North East Asia for both lead times, along with the strong warming that occurred in the mid-1990s over both areas. Composite analysis reveals that the skill at capturing interdecadal changes in North East Asia is associated with the propagation of an atmospheric Rossby wave, which follows the subtropical jet and modulates surface-air temperature from Europe to Eastern Asia. We hypothesise that this ‘circumglobal teleconnection’ pattern is excited over the Atlantic Ocean and is related to Atlantic multi-decadal variability and the associated changes in precipitation over the Sahel and the subtropical Atlantic Ocean. This mechanism is robust for the 2–5 year lead-time. For the 1 year lead-time the Pacific Ocean also plays an important role in leading to skill in predicting SAT over Northeast Asia. Increased temperatures and precipitation over the western Pacific Ocean was found to be associated with a Pacific-Japan like-pattern, which can affect East Asia’s climate.
Highlights
Simulations performed with Ocean–Atmosphere General Circulation Models (OAGCM) under the Climate Model Intercomparison Project, phase 5 (CMIP5) (Taylor et al 2012), provide climate predictions for the upcoming 100 years
We focus the analysis of skill for surface air temperature (SAT) averaged over four regions defined on the Fig. 1d: the subpolar gyre [SPG; 50°N–65°N; 60°W–10°W; as defined in Robson et al (2012)], the Atlantic Multidecadal Variability [AMV; 0°N–60°N; 80°E–0°W, as defined in Trenberth and Shea (2006)], North East Asia (NEA) [40°N–50°N; 90°E–130°E; as defined in Chen and Lu (2014)] and we add the global mean surface temperature (GMST; 90°S–90°N; 180°W–180°E)
In this study we examine skill at capturing surface air temperature (SAT) in the DePreSys3 decadal prediction system
Summary
Simulations performed with Ocean–Atmosphere General Circulation Models (OAGCM) under the Climate Model Intercomparison Project, phase 5 (CMIP5) (Taylor et al 2012), provide climate predictions for the upcoming 100 years (the so-called radiative concentration pathways emission scenarios). CMIP simulations suffer from severe limitations in predicting climate at a shorttime horizon (< 10 years), as highlighted by the “hiatus” in global-mean surface temperature rise (Watanabe et al 2013; Kosaka and Xie 2013; Meehl et al 2014). To fill this gap, initialized near-term (or decadal) prediction systems have been developed (Meehl et al 2009) to provide better predictions than uninitialized simulations (Bellucci et al 2013; Karspeck et al 2015) on seasonal-to-decadal timescales. Near-term climate prediction systems are useful tools to provide predictions at interannual-to-decadal timescales, which are helpful to calibrate plans and actions related to climatic events due to
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