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Abstract. Paleoclimate archives, such as high-resolution ice core records, provide ameans to investigate past climate variability. Until recently, the Law Dome(Dome Summit South site) ice core record remained one of fewmillennial-length high-resolution coastal records in East Antarctica. A newice core drilled in 2017/2018 at Mount Brown South, approximately 1000 kmwest of Law Dome, provides an additional high-resolution record that willlikely span the last millennium in the Indian Ocean sector of EastAntarctica. Here, we compare snow accumulation rates and sea saltconcentrations in the upper portion (∼ 20 m) of three MountBrown South ice cores and an updated Law Dome record over the period1975–2016. Annual sea salt concentrations from the Mount Brown South siterecord preserve a stronger signal for the El Niño–Southern Oscillation(ENSO; austral winter and spring, r = 0.533, p < 0.001, Multivariate El Niño Index) compared to a previously defined Law Dome record of summer sea salt concentrations (November–February, r = 0.398, p = 0.010, SouthernOscillation Index). The Mount Brown South site record and Law Dome recordpreserve inverse signals for the ENSO, possibly due to longitudinalvariability in meridional transport in the southern Indian Ocean, althoughfurther analysis is needed to confirm this. We suggest that ENSO-related seasurface temperature anomalies in the equatorial Pacific drive atmosphericteleconnections in the southern mid-latitudes. These anomalies areassociated with a weakening (strengthening) of regional westerly winds tothe north of Mount Brown South that correspond to years of low (high) seasalt deposition at Mount Brown South during La Niña (El Niño)events. The extended Mount Brown South annual sea salt record (whencomplete) may offer a new proxy record for reconstructions of the ENSO overthe recent millennium, along with improved understanding of regionalatmospheric variability in the southern Indian Ocean, in addition to thatderived from Law Dome.
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This content will become publicly available on December 1, 2026
Waterline responses to climate forcing along the North American West Coast
Understanding waterline variability at seasonal to interannual timescales is crucial for predicting coastal responses to climate forcing. However, relationships between large-scale climate variability and coastal morphodynamics remain underexplored beyond intensively monitored sites. This study leverages a newly developed 25-year (1997–2022) satellite-derived waterline dataset along the North American West Coast. Our results reveal distinct latitudinal patterns in seasonal waterline change, with excursions exceeding 25 m in the Pacific Northwest, decreasing to less than 10 m in Southern California and farther south. Waterline fluctuations strongly follow wave power in the Pacific Northwest (R = −0.78), northern California (R = −0.75), and Baja California (R = −0.62), while Baja California Sur aligns more with sea-level variations (R = −0.42). Interannually, waterline change exhibits latitudinal dependence: south of southern California, variability is low, with major erosion confined to strong El Niño-Southern Oscillation (ENSO) events, while northern regions show mixed responses. ENSO-driven storm track shifts modulate winter wave climate, resulting in enhanced (attenuated) erosion from southern California to Baja California Sur during El Niño (La Niña). However, further north, ENSO impacts are less consistent, reflecting a complex interplay of storm track displacement and intensification. These findings highlight the spatial complexity of ENSO-driven morphodynamics and provide a framework for assessing climate-induced coastal vulnerability.
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- Award ID(s):
- 2103713
- PAR ID:
- 10617264
- Publisher / Repository:
- Communications Earth & Environment
- Date Published:
- Journal Name:
- Communications Earth & Environment
- Volume:
- 6
- Issue:
- 1
- ISSN:
- 2662-4435
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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