The response of winter Pacific North American pattern to strong volcanic eruptions
- 535 Downloads
The impact of volcanic eruptions on large-scale atmospheric circulation patterns has been well studied, but very little effort has been made on relating the response of Pacific North American (PNA) pattern to strong volcanic eruptions. Here we investigate the response of winter PNA to the largest volcanic eruptions using three different reanalysis datasets. We demonstrate a significant positive PNA circulation response to strong volcanic forcing in the first winter following the eruptions. This circulation pattern is associated with enhanced southwesterly winds advecting warm air from the tropical/subtropical Pacific into northwestern North America and leads to a significant warming in the region. However, no significant PNA signal is found for the second post-eruption winter. The PNA responses to volcanic forcing depend partly upon the modulation of the El Niño Southern Oscillation (ENSO) events. When the ENSO influence is linearly removed, this positive PNA signal is still robust during the first post-eruption winter, albeit with slightly decreased magnitude and significance. Our findings provide new evidence for volcanic forcing of the Pacific and North American climates. The results presented here may contribute to deconvolving modern and past continental-scale climate changes over North America.
KeywordsPNA ENSO Volcanic eruptions Superposed epoch analysis
We are grateful to Dr. Olivier Blarquez for his help with the superposed epoch analysis, Dong Chen and Haimao Lan for assistance with data processing. We also thank the editor and anonymous reviewers for their insightful comments that have greatly improved the quality of the paper. This work was supported by the China Young 1000-Talent Program and the National Science Foundation of China Grants (41305131).
- Charlton-Perez AJ, Baldwin MP, Birner T, Black RX, Butler AH, Calvo N, Davis NA, Gerber EP, Gillett N, Hardiman S (2013) On the lack of stratospheric dynamical variability in low-top versions of the CMIP5 models. J Geophys Res 118:2494–2505Google Scholar
- CPC (2016) Teleconnections: Pacific/North American pattern: monthly mean PNA index. National Weather Service Climate Prediction Center. Accessed 1 Jan 2016. www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/month_pna_index2.shtml
- Crowley TJ, North GR (1991) Paleoclimatology. Oxford University Press, New York, p 349Google Scholar
- Iles CE, Hegerl GC (2014) The global precipitation response to volcanic eruptions in the CMIP5 models. Environ Sci Lett 9:104012Google Scholar
- Iles CE, Hegerl GC, Schurer AP, Zhang X (2013) The effect of volcanic eruptions on global precipitation. J Geophys Res 118:8770–8786Google Scholar
- L’Heureux ML, Lee S, Lyon B (2013) Recent multidecadal strengthening of the Walker circulation across the tropical Pacific. Nat Clim Change 3:571–576Google Scholar
- Poli P, Hersbach H, Tan D, Dee D, Thepaut J-N, Simmons A, Peubey C, Laloyaux P, Komori T, Berrisford P (2013) The data assimilation system and initial performance evaluation of the ECMWF pilot reanalysis of the 20th-century assimilating surface observations only (ERA-20C). Technical report, ERA report series 14Google Scholar
- Zanchettin D, Bothe O, Graf HF, Lorenz SJ, Luterbacher J, Timmreck C, Jungclaus JH (2013) Background conditions influence the decadal climate response to strong volcanic eruptions. J Geophys Res 118:4090–4106Google Scholar