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Abstract The Asian summer monsoon (ASM) is teleconnected to the El Niño Southern Oscillation (ENSO), but this relationship is nonstationary and has shifted significantly in recent decades. Characterizing the drivers of such shifts is crucial for improving ASM prediction and extreme event preparedness. Paleoclimate records indicate a link between ASM strength and solar activity on multidecadal‐to‐centennial timescales, but 20th‐century data are too short to test mechanisms. Here we evaluate how solar irradiance influences the ASM‐ENSO relationship using last‐millennium paleoclimate data assimilation reconstructions and model simulations. We find that high solar irradiance weakens the ENSO‐East Asian summer monsoon (EASM) correlation, but strengthens the ENSO‐South Asian summer monsoon (SASM) correlation. Solar irradiance likely influences the strength of the ENSO‐EASM and ENSO‐SASM teleconnections via changes in the Western Pacific Subtropical High and the amplitude of ENSO events, respectively. We suggest a need for considering solar activity in decadal ASM rainfall predictions under global warming scenarios.
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Enhanced North American ENSO Teleconnections During the Little Ice Age Revealed by Paleoclimate Data Assimilation
Abstract Teleconnection rainfall over North America may be systematically altered by tropical Pacific mean state changes. Characterizing teleconnection changes to improve prediction requires many realizations of ENSO events, but twentieth century data are temporally limited. To extend twentieth century records, we evaluate ENSO events in a new last‐millennium paleoclimate data assimilation reconstruction to deduce how mean state changes affect the magnitude/extent of ENSO‐driven rainfall in the United States. Despite global cooling during the Little Ice Age, the central‐eastern tropical Pacific warms relative to the Medieval Climate Anomaly, shifting teleconnections eastward and increasing rainfall anomalies in the southwestern United States. Teleconnections strengthen independently of ENSO amplitude; we thus suggest caution in using paleoclimate reconstructions of teleconnection rainfall as a proxy for ENSO amplitude. We demonstrate teleconnection rainfall is sensitive to the pattern of tropical Pacific mean SST changes, underscoring the importance of reducing uncertainties in future warming patterns in the tropical Pacific.
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- Award ID(s):
- 1805143
- PAR ID:
- 10452379
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 47
- Issue:
- 15
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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