Abstract
Decadal-scale climate variations over the Pacific Ocean and its surroundings are strongly related to the so-called Pacific decadal oscillation (PDO) which is coherent with wintertime climate over North America and Asian monsoon, and have important impacts on marine ecosystems and fisheries. In a near-term climate prediction covering the period up to 2030, we require knowledge of the future state of internal variations in the climate system such as the PDO as well as the global warming signal. We perform sets of ensemble hindcast and forecast experiments using a coupled atmosphere-ocean climate model to examine the predictability of internal variations on decadal timescales, in addition to the response to external forcing due to changes in concentrations of greenhouse gases and aerosols, volcanic activity, and solar cycle variations. Our results highlight that an initialization of the upper-ocean state using historical observations is effective for successful hindcasts of the PDO and has a great impact on future predictions. Ensemble hindcasts for the 20th century demonstrate a predictive skill in the upper-ocean temperature over almost a decade, particularly around the Kuroshio-Oyashio extension (KOE) and subtropical oceanic frontal regions where the PDO signals are observed strongest. A negative tendency of the predicted PDO phase in the coming decade will enhance the rising trend in surface air-temperature (SAT) over east Asia and over the KOE region, and suppress it along the west coasts of North and South America and over the equatorial Pacific. This suppression will contribute to a slowing down of the global-mean SAT rise.
| Original language | English |
|---|---|
| Pages (from-to) | 1833-1837 |
| Number of pages | 5 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 107 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - Feb 2 2010 |
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Pacific decadal oscillation hindcasts relevant to near-term climate prediction. / Mochizuki, Takashi; Ishii, Masayoshi; Kimoto, Masahide; Chikamoto, Yoshimitsu; Watanabe, Masahiro; Nozawa, Toru; Sakamoto, Takashi T.; Shiogama, Hideo; Awaji, Toshiyuki; Sugiura, Nozomi; Toyoda, Takahiro; Yasunaka, Sayaka; Tatebe, Hiroaki; Mori, Masato.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 107, No. 5, 02.02.2010, p. 1833-1837.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pacific decadal oscillation hindcasts relevant to near-term climate prediction
AU - Mochizuki, Takashi
AU - Ishii, Masayoshi
AU - Kimoto, Masahide
AU - Chikamoto, Yoshimitsu
AU - Watanabe, Masahiro
AU - Nozawa, Toru
AU - Sakamoto, Takashi T.
AU - Shiogama, Hideo
AU - Awaji, Toshiyuki
AU - Sugiura, Nozomi
AU - Toyoda, Takahiro
AU - Yasunaka, Sayaka
AU - Tatebe, Hiroaki
AU - Mori, Masato
PY - 2010/2/2
Y1 - 2010/2/2
N2 - Decadal-scale climate variations over the Pacific Ocean and its surroundings are strongly related to the so-called Pacific decadal oscillation (PDO) which is coherent with wintertime climate over North America and Asian monsoon, and have important impacts on marine ecosystems and fisheries. In a near-term climate prediction covering the period up to 2030, we require knowledge of the future state of internal variations in the climate system such as the PDO as well as the global warming signal. We perform sets of ensemble hindcast and forecast experiments using a coupled atmosphere-ocean climate model to examine the predictability of internal variations on decadal timescales, in addition to the response to external forcing due to changes in concentrations of greenhouse gases and aerosols, volcanic activity, and solar cycle variations. Our results highlight that an initialization of the upper-ocean state using historical observations is effective for successful hindcasts of the PDO and has a great impact on future predictions. Ensemble hindcasts for the 20th century demonstrate a predictive skill in the upper-ocean temperature over almost a decade, particularly around the Kuroshio-Oyashio extension (KOE) and subtropical oceanic frontal regions where the PDO signals are observed strongest. A negative tendency of the predicted PDO phase in the coming decade will enhance the rising trend in surface air-temperature (SAT) over east Asia and over the KOE region, and suppress it along the west coasts of North and South America and over the equatorial Pacific. This suppression will contribute to a slowing down of the global-mean SAT rise.
AB - Decadal-scale climate variations over the Pacific Ocean and its surroundings are strongly related to the so-called Pacific decadal oscillation (PDO) which is coherent with wintertime climate over North America and Asian monsoon, and have important impacts on marine ecosystems and fisheries. In a near-term climate prediction covering the period up to 2030, we require knowledge of the future state of internal variations in the climate system such as the PDO as well as the global warming signal. We perform sets of ensemble hindcast and forecast experiments using a coupled atmosphere-ocean climate model to examine the predictability of internal variations on decadal timescales, in addition to the response to external forcing due to changes in concentrations of greenhouse gases and aerosols, volcanic activity, and solar cycle variations. Our results highlight that an initialization of the upper-ocean state using historical observations is effective for successful hindcasts of the PDO and has a great impact on future predictions. Ensemble hindcasts for the 20th century demonstrate a predictive skill in the upper-ocean temperature over almost a decade, particularly around the Kuroshio-Oyashio extension (KOE) and subtropical oceanic frontal regions where the PDO signals are observed strongest. A negative tendency of the predicted PDO phase in the coming decade will enhance the rising trend in surface air-temperature (SAT) over east Asia and over the KOE region, and suppress it along the west coasts of North and South America and over the equatorial Pacific. This suppression will contribute to a slowing down of the global-mean SAT rise.
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U2 - 10.1073/pnas.0906531107
DO - 10.1073/pnas.0906531107
M3 - Article
C2 - 20080684
AN - SCOPUS:76649101457
VL - 107
SP - 1833
EP - 1837
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 5
ER -