Abstract Decadal variations in the El Niño‐Southern Oscillation (ENSO)'s influence on Southeast Asian rainfall are modulated by variability in the mean state of atmospheric circulation and moisture anomalies in the Indo‐Pacific Warm Pool (IPWP). Variations in the mean state are characterized by a tripolar pattern in sea surface temperatures (SST) spanning the Indian Ocean, central IPWP, and western Pacific regions. Due to ENSO teleconnection asymmetry, Southeast Asian rainfall is more sensitive to La Niña than El Niño. During positive phases of the tripole pattern, the mean state is drier, with reduced vertical motion over mainland Southeast Asia suppressing La Niña anomalies. In negative phases, the mean state is wetter, with enhanced vertical motion amplifying La Niña anomalies. From 1980 to 2015, relative SST trends show a negative tripole pattern, strengthening the ENSO ‐ Southeast Asian rainfall relationship. However, future projections for 2050–2100 suggest a positive tripole pattern, predicting a weakening of this relationship by 2100.
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Southern California winter precipitation variability reflected in 100-year ocean salinity record
Abstract Rainfall in southern California is highly variable, with some fluctuations explainable by climate patterns. Resulting runoff and heightened streamflow from rain events introduces freshwater plumes into the coastal ocean. Here we use a 105-year daily sea surface salinity record collected at Scripps Pier in La Jolla, California to show that El Niño Southern Oscillation and Pacific Decadal Oscillation both have signatures in coastal sea surface salinity. Averaging the freshest quantile of sea surface salinity over each year’s winter season provides a useful metric for connecting the coastal ocean to interannual winter rainfall variability, through the influence of freshwater plumes originating, at closest, 7.5 km north of Scripps Pier. This salinity metric has a clear relationship with dominant climate phases: negative Pacific Decadal Oscillation and La Niña conditions correspond consistently with lack of salinity anomaly/ dry winters. Fresh salinity anomalies (i.e., wet winters) occur during positive phase Pacific Decadal Oscillation and El Niño winters, although not consistently. This analysis emphasizes the strong influence that precipitation and consequent streamflow has on the coastal ocean, even in a region of overall low freshwater input, and provides an ocean-based metric for assessing decadal rainfall variability.
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- PAR ID:
- 10541659
- Publisher / Repository:
- Nature communications earth & environment
- Date Published:
- Journal Name:
- Communications Earth & Environment
- Volume:
- 4
- Issue:
- 1
- ISSN:
- 2662-4435
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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