Teleconnective Response of the Pacific–North American Region Atmosphere to Large Central Equatorial Pacific SST Anomalies

Livezey, Robert E.; Masutani, Michiko; Leetmaa, Ants; Rui, Hualan; Ji, Ming; Kumar, Arun

doi:10.1175/1520-0442(1997)010<1787:trotpn>2.0.co;2

Cited by 148 publications

(119 citation statements)

References 22 publications

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“…These factors are 1) cold-episode conditions in the tropical Pacific and 2) an extremely persistent negative phase of the North Atlantic oscillation. Mature-phase cold-episode conditions favor an enhanced upperlevel ridge over the high latitudes of the North Pacific and over the eastern North Pacific/southwestern United States and, thus, a northward displacement of the jet stream and storm track over the western United States (Livezey et al 1997). These conditions favor below-(above-) normal precipitation across the Southwest (Pacific Northwest), consistent with that observed during October-May 1995/96.…”

Section: Oct Nov Dec Jan Feb Mar Apr May Oct-maysupporting

confidence: 77%

“…These conditions favor below-(above-) normal precipitation across the Southwest (Pacific Northwest), consistent with that observed during October-May 1995/96. Farther east, below-normal heights are favored across Canada and the northern tier of the United States during cold-episode conditions (Livezey et al 1997), reflecting an overall amplification of the climatological-mean Hudson Bay trough.…”

Section: Oct Nov Dec Jan Feb Mar Apr May Oct-maymentioning

confidence: 99%

See 1 more Smart Citation

Climate Assessment for 1996

Halpert

Bell

1997

Bulletin of the American Meteorological Society

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The climate of 1996 can be characterized by several phenomena that reflect substantial deviations from the mean state of the atmosphere persisting from months to seasons. First, mature cold-episode conditions persisted across the tropical Pacific from November 1995 through May 1996 and contributed to large-scale anomalies of atmospheric circulation, temperature, and precipitation across the Tropics, the North Pacific and North America. These anomalies were in many respects opposite to those that had prevailed during the past several years in association with a prolonged period of tropical Pacific warm-episode conditions (ENSO). Second, strong tropical intraseasonal (Madden–Julian oscillations) activity was observed during most of the year. The impact of these oscillations on extratropical circulation variability was most evident late in the year in association with strong variations in the eastward extent of the East Asian jet and in the attendant downstream circulation, temperature, and precipitation patterns over the eastern North Pacific and central North America. Third, a return to the strong negative phase of the atmospheric North Atlantic oscillation (NAO) during November 1995–February 1996, following a nearly continuous 15-yr period of positive-phase NAO conditions, played a critical role in affecting temperature and precipitation patterns across the North Atlantic, Eurasia, and northern Africa. The NAO also contributed to a significant decrease in wintertime temperatures across large portions of Siberia and northern Russia from those that had prevailed during much of the 1980s and early 1990s. Other regional aspects of the short-term climate during 1996 included severe drought across the southwestern United States and southern plains states during October 1995–May 1996, flooding in the Pacific Northwest region of the United States during the 1995/96 and 1996/97 winters, a cold and extremely snowy 1995/96 winter in the eastern United States, a second consecutive year of above-normal North Atlantic hurricane activity, near-normal rains in the African Sahel, above-normal rainfall across southeastern Africa during October 1995–April 1996, above-normal precipitation for most of the year across eastern and southeastern Australia following severe drought in these areas during 1995, and generally nearnormal monsoonal rains in India with significantly below-normal rainfall in Bangladesh and western Burma. The global annual mean surface temperature for land and marine areas during 1996 averaged 0.21°C above the 1961–90 base period means. This is a decrease of 0.19°C from the record warm year of 1995 but was still among the 10 highest values observed since 1860. The global land-only temperature for 1996 was 0.06°C above normal and was the lowest anomaly observed since 1985 (−0.11°C). Much of this relative decrease in global temperatures occurred in the Northern Hemisphere extratropics, where land-only temperatures dropped from 0.42°C above normal in 1995 to 0.04°C below normal in 1996. The year also witnessed a continuation of near-record low ozone amounts in the Southern Hemisphere stratosphere, along with an abnormally prolonged appearance of the “ozone hole” into early December. The areal extent of the ozone hole in November and early December exceeded that previously observed for any such period on record. However, its areal extent at peak amplitude during late September–early October was near that observed during the past several years.

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Section: Oct Nov Dec Jan Feb Mar Apr May Oct-maysupporting

confidence: 77%

Section: Oct Nov Dec Jan Feb Mar Apr May Oct-maymentioning

confidence: 99%

Climate Assessment for 1996

Halpert

Bell

1997

Bulletin of the American Meteorological Society

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“…Recently, Livezey et al (1997), Hu et al (1998), and Berger et al (1999) have noted ENSO related variability in mid-western U.S. precipitation. Hu et al (1998) also showed variability in mid-western precipitation on longer time scales as well as a general upward trend in precipitation amounts.…”

Section: Introductionmentioning

confidence: 97%

A Climatology of Northwest Missouri Snowfall Events: Long-Term Trends and Interannual Variability

et al. 2002

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The goal of this study was to develop a 50-year statistical climatology of snowfall occurrences using data from a dense network of cooperative station observations covering northwest and central Missouri, and these records were provided by the Missouri Climate Center.This included a study of the long term trends and interannual variability in snowfall occurrence as related to sea surface temperature variations in the Pacific Ocean basin associated with the El Nin o and Southern Oscillation (ENSO) and the North Pacific Oscillation (NPO). These trends and variations were then related to four synoptic-scale flow regimes that produce these snowfalls in the Midwest. The results demonstrate that during the snowfall season (Oct -April) the northwest Missouri region can expect about eight snowfall events which produce three or more inches of accumulation. While no significant long-term trend in overall snowfall occurrence was found, a decrease in the number of extreme events (10 or more inches) was noted. Also, fewer snowfall events were found during El Nin o years, while more heavy snowfall events occurred during "neutral" years, and these results could be related to synoptic-scale variability. A closer examination of the results demonstrated that El Nin o/La Nin a related variability in snowfall occurrence was superimposed on longer-term NPO-related variability. [Interannual Variability, snowfalls, climatology, El Nin o]

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“…Leetma (1998) concluded that CPC climate outlooks generally have higher accuracy during extremely warm ENSO conditions because recent analogs in the historic record, including a decadal signal in precipitation records, are similar to El Niño precipitation patterns; numerical models work well under El Niño's strong and persistent SST signal as well. Livezey et al (1996Livezey et al ( , 1997 concluded winter season forecasts during warm and cold ENSO phases have moderate skill over the U.S., but not otherwise. The Salt River Project (SRP, 1998) found CPC climate outlooks unusable for predicting summer peak power loads.…”

Section: Forecast Performancementioning

confidence: 96%

“…Additionally, the SST signal is strong and persistent, and numerical models seem to seem to work well under El Nino conditions. Livezey et al (1996Livezey et al ( , 1997 conclude that forecasts for the winter seasons during both warm and cold ENSO phases (El Nino and La Nina, respectively) have moderate skill over the U.S., but no skill during non-ENSO winters.…”

Section: Cpc Forecast Qualitymentioning

confidence: 99%