Contributions of Internal Variability and External Forcing to the Recent Pacific Decadal Variations
[1];
[2];
[1]
- Key Laboratory of Meteorological Disaster, Ministry of Education (KLME)/Joint International Research Laboratory of Climate and Environment Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC‐FEMD) Nanjing University of Information Science and Technology Nanjing China, Department of Atmospheric and Environmental Sciences University at Albany, State University of New York Albany NY USA
- Department of Atmospheric and Environmental Sciences University at Albany, State University of New York Albany NY USA
Abstract There is substantial uncertainty in the relative contributions of internal variability and external forcing to the recent Pacific decadal variability, especially regarding their linkage with the Interdecadal Pacific Oscillation. By analyzing observations and large ensembles of coupled climate model simulations, here we show that observed Pacific decadal variations since 1920 resulted primarily from internal variability, although greenhouse gas (GHG) and other external forcing did modulate decadal variations in Pacific sea surface temperatures (SSTs) significantly, especially for the period since the early 1990s. Specifically, the GHG‐induced warming and the recovery from the volcanic cooling caused by the 1991 Pinatubo eruption led to large warming in the tropical Pacific during 1993–2012, while recent anthropogenic aerosols contributed to Pacific regional SST variations on multiyear to decadal scales, causing a La Niña‐like cooling pattern in the Pacific since 1998 in some of the models. Our results provide new evidence that both internal variability and external forcing have contributed to the recent decadal variations in Pacific SSTs since the early 1990s, although large uncertainties exist among the model‐simulated effects of anthropogenic aerosols.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- NONE; SC0012602
- OSTI ID:
- 1561341
- Journal Information:
- Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 14 Vol. 45; ISSN 0094-8276
- Publisher:
- American Geophysical Union (AGU)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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