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Abstract In the U.S. Great Plains (GP), diagnosing precipitation variability is key in developing an understanding of the present and future availability of water in the region. Building on previous work investigating U.S. GP pluvial years, this study uses ERA twentieth century (ERA-20C) reanalysis data to investigate key circulation anomalies driving GP precipitation anomalies during a subset of GP pluvial years (called in this paper Pattern pluvial years). With previous research showing links between tropical Pacific sea surface temperature (SST) anomalies and GP climate variability, this study diagnoses the key circulation anomalies through an analysis of SSTs and their influence on the atmosphere. Results show that during Pattern southern Great Plains (SGP) pluvial years, central tropical Pacific SST anomalies are coincident with key atmospheric anomalies across the Pacific basin and North America. During northern Great Plains (NGP) Pattern pluvial years, no specific pattern of oceanic anomalies emerges that forces the circulation anomaly feature inherent in specific NGP pluvial years. Utilizing the results for SGP pluvial years, a conceptual model is developed detailing the identified pathway for the occurrence of circulation patterns that are favorable for pluvial years over the SGP. Overall, results from this study show the importance of the identified SGP atmospheric anomaly signal and the potential for predictability of such events.
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Snow Accumulation Variability at the South Pole From 1983 to 2020, Associated With Central Tropical Pacific Forcing
Abstract Despite a variety of efforts made to measure snow accumulation at the South Pole (SP), snow accumulation changes and their mechanism have not yet been fully explained. Here, SP stake farm measurements, global sea surface temperature observations, and atmospheric circulation data from European Centre for Medium‐Range Weather Forecasts Reanalysis version 5 were used to investigate the annual and seasonal snow accumulation changes at the SP during 1983–2020, and their association with central tropical Pacific Sea surface temperature variations. SP annual snow accumulation decreased significantly for the 1983–2007 period at a rate of −39.7 ± 1.4 mm decade−1, but switched to a dramatically positive trend during 2008–2020 (108.7 ± 2.7 mm decade−1), with the strongest increase in the austral autumn. The switch to a dramatically upward trend can largely be attributed to a cyclonic anomaly over the South Atlantic and an anticyclonic anomaly over the Drake Passage, causing the enhanced advection of warm and wet air into the SP. These circulation patterns were generated by an atmospheric Rossby wave train forced by rapid warming in the central tropical Pacific during 2008–2020.
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- PAR ID:
- 10479738
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Atmospheres
- Volume:
- 128
- Issue:
- 24
- ISSN:
- 2169-897X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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