CMIP5에서 나타난 PDO 모의 성능 향상 및 그 원인

Abstract

Pacific decadal oscillation (PDO) that is defined as the first mode of empirical orthogonal function of North Pacific sea surface temperature (SST) could affect variability of marine ecosystem as well as climate system in the North Pacific. We evaluate PDO reproducibility simulated from coupled general circulation models (CGCMs) of phase 3 and 5 of Climate model Intercomparison Project (i.e. CMIP3 and CMIP5, respectively) by investigating an interaction between PDO and El Nino - Southern Oscillation (ENSO), and a teleconnections between extratropics and tropics. PDO comparison between the CGCM simulation and observation during the period 1900-1998 shows that the PDO reproducibility has improved in the CMIP5 than that in the CMIP3. To assess how the PDO reproducibility can be improved in the CMIP5, sensitivity of precipitation to tropical SST and representation of Pacific/North American pattern were analyzed. The CGCMs in the CMIP5 show enhanced simulations of ENSO and teleconnections agreeing more with observations than that in the CMIP3. Our finding suggests that enhancement of ENSO reproducibility and teleconnections from tropics to extratropics contributes to the improvement of PDO reproducibility in CGCM of the CMIP5. We evaluate PDO reproducibility simulated from coupled general circulation models (CGCMs) of phase 3 and 5 of Climate model Intercomparison Project (i.e. CMIP3 and CMIP5, respectively) by investigating an interaction between PDO and El Nino - Southern Oscillation (ENSO), and a teleconnections between extratropics and tropics. PDO comparison between the CGCM simulation and observation during the period 1900-1998 shows that the PDO reproducibility has improved in the CMIP5 than that in the CMIP3. To assess how the PDO reproducibility can be improved in the CMIP5, sensitivity of precipitation to tropical SST and representation of Pacific/North American pattern were analyzed. The CGCMs in the CMIP5 show enhanced simulations of ENSO and teleconnections agreeing more with observations than that in the CMIP3. Our finding suggests that enhancement of ENSO reproducibility and teleconnections from tropics to extratropics contributes to the improvement of PDO reproducibility in CGCM of the CMIP5.