Event Title

Coherence between the Great Salt Lake level and the Pacific quasi-decadal oscillation

Location

Eccles Conference Center

Event Website

http:://water.usu.edu/

Start Date

4-20-2010 10:40 AM

End Date

4-20-2010 11:00 AM

Description

The atmospheric circulation patterns associated with the Pacific quasi-decadal oscillation (ODO) were investigated. Previous studies have shown that the Pacific ODO is characterized by a distinct life cycle with different phases represented from patterns of the sea surface temperature (SST) anomalies. While the SST patterns developed in the warm/cool phases of the Pacific ODO resembles those associated with the El Nino-Southern Oscillation, recurrent SST patterns are observed during the warm-to-cool/cool-to-warm transition phases. We report an atmospheric short-wave train across the North Pacific formed in close association with the transition-phase SST patterns of the Pacific ODO. This short-wave train is dynamically maintained and is likely forced by diabatic heating sources in Southeast Asia and the western tropical Pacific, with additional modulations from forcing sources in the central-eastern tropical Pacific. Such a transition-phase teleconnection may be important to some regions where the precipitation variation reveals strong quasi-decadal signals but is not directly correlated with the Pacific ODO. One such example is the Great Salt Lake (GSL) in the western United States. The lake level variation of the GSL features a pronounced 12 year signal and is highly coherent with the NINO4 SST anomalies at this same frequency. Pronounced quasi-decadal signals in precipitation, streamflow, water vapor flux, and drought conditions were observed throughout the Great Basin. It was found that recurrent atmospheric circulation patterns, developed over the Gulf of Alaska during the warm-to-cool and cool-to-warm transition phases of the Pacific ODO, modulate the synoptic transient activities over the western United States and, in turn, lead to the ODO in the hydrological cycle of the Great Basin. As the GSL integrates the hydrological responses in the Great Basin, the hydrological ODO is then transferred to the GSL elevation. Because the GSL elevation consistently lags the precipitation by a quarter-phase, i.e. about 3 years in the quasi-decadal time scale, these processes take an average of 6 years for the GSL elevation to eventually respond to the Pacific ODO. This creates a half-phase delay of the GSL elevation from the Pacific ODO, thereby forming the inverse, yet coherent, relationship between them.

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Apr 20th, 10:40 AM Apr 20th, 11:00 AM

Coherence between the Great Salt Lake level and the Pacific quasi-decadal oscillation

Eccles Conference Center

The atmospheric circulation patterns associated with the Pacific quasi-decadal oscillation (ODO) were investigated. Previous studies have shown that the Pacific ODO is characterized by a distinct life cycle with different phases represented from patterns of the sea surface temperature (SST) anomalies. While the SST patterns developed in the warm/cool phases of the Pacific ODO resembles those associated with the El Nino-Southern Oscillation, recurrent SST patterns are observed during the warm-to-cool/cool-to-warm transition phases. We report an atmospheric short-wave train across the North Pacific formed in close association with the transition-phase SST patterns of the Pacific ODO. This short-wave train is dynamically maintained and is likely forced by diabatic heating sources in Southeast Asia and the western tropical Pacific, with additional modulations from forcing sources in the central-eastern tropical Pacific. Such a transition-phase teleconnection may be important to some regions where the precipitation variation reveals strong quasi-decadal signals but is not directly correlated with the Pacific ODO. One such example is the Great Salt Lake (GSL) in the western United States. The lake level variation of the GSL features a pronounced 12 year signal and is highly coherent with the NINO4 SST anomalies at this same frequency. Pronounced quasi-decadal signals in precipitation, streamflow, water vapor flux, and drought conditions were observed throughout the Great Basin. It was found that recurrent atmospheric circulation patterns, developed over the Gulf of Alaska during the warm-to-cool and cool-to-warm transition phases of the Pacific ODO, modulate the synoptic transient activities over the western United States and, in turn, lead to the ODO in the hydrological cycle of the Great Basin. As the GSL integrates the hydrological responses in the Great Basin, the hydrological ODO is then transferred to the GSL elevation. Because the GSL elevation consistently lags the precipitation by a quarter-phase, i.e. about 3 years in the quasi-decadal time scale, these processes take an average of 6 years for the GSL elevation to eventually respond to the Pacific ODO. This creates a half-phase delay of the GSL elevation from the Pacific ODO, thereby forming the inverse, yet coherent, relationship between them.

https://digitalcommons.usu.edu/runoff/2010/AllAbstracts/21