The Influence of North Pacific Atmospheric Circulation on Streamflow in the West

2013 ◽  
pp. 375-397 ◽  
Author(s):  
Daniel R. Cayan ◽  
David H. Peterson
Keyword(s):  
Atmospheric Circulation ◽  
North Pacific ◽  
The West

Interannual Variability of North American Winter Temperature Extremes and Its Associated Circulation Anomalies in Observations and CMIP5 Simulations

2020 ◽  
Vol 33 (3) ◽  
pp. 847-865 ◽  
Author(s):  
B. Yu ◽  
H. Lin ◽  
V. V. Kharin ◽  
X. L. Wang
Keyword(s):  
North America ◽  
Surface Temperature ◽  
Atmospheric Circulation ◽  
North American ◽  
North Pacific ◽  
Large Scale ◽  
Temperature Extremes ◽  
Temperature Extreme ◽  
Central Canada ◽  
Leading Mode

AbstractThe interannual variability of wintertime North American surface temperature extremes and its generation and maintenance are analyzed in this study. The leading mode of the temperature extreme anomalies, revealed by empirical orthogonal function (EOF) analyses of December–February mean temperature extreme indices over North America, is characterized by an anomalous center of action over western-central Canada. In association with the leading mode of temperature extreme variability, the large-scale atmospheric circulation features an anomalous Pacific–North American (PNA)-like pattern from the preceding fall to winter, which has important implications for seasonal prediction of North American temperature extremes. A positive PNA pattern leads to more warm and fewer cold extremes over western-central Canada. The anomalous circulation over the PNA sector drives thermal advection that contributes to temperature anomalies over North America, as well as a Pacific decadal oscillation (PDO)-like sea surface temperature (SST) anomaly pattern in the midlatitude North Pacific. The PNA-like circulation anomaly tends to be supported by SST warming in the tropical central-eastern Pacific and a positive synoptic-scale eddy vorticity forcing feedback on the large-scale circulation over the PNA sector. The leading extreme mode–associated atmospheric circulation patterns obtained from the observational and reanalysis data, together with the anomalous SST and synoptic eddy activities, are reasonably well simulated in most CMIP5 models and in the multimodel mean. For most models considered, the simulated patterns of atmospheric circulation, SST, and synoptic eddy activities have lower spatial variances than the corresponding observational and reanalysis patterns over the PNA sector, especially over the North Pacific.

scholarly journals Climate change in the western Antarctic Peninsula since 1945: observations and possible causes

1998 ◽  
Vol 27 ◽  
pp. 571-575 ◽  
Author(s):  
J. C. King ◽  
S. A. Harangozo
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
Antarctic Peninsula ◽  
The West ◽  
Sea Ice Extent ◽  
The North ◽  
Ultimate Cause ◽  
Temperature Records ◽  
High Level ◽  
The Antarctic

Temperature records from slations on the west roast of the Antarctic Peninsula show a very high level of interannual variability and, over the last 50 years, larger warming trends than are seen elsewhere in Antarctica. in this paper we investigate the role of atmospheric circulation variability and sea-ice extent variations in driving these changes. Owing to a lack of independent data, the reliability of Antarctic atmospheric analyses produced in the 1950s and 1960s cannot be readily established, but examination of the available data suggests that there has been an increase in the northerly component of the circulation over the Peninsula since the late 1950s. Few observations of sea-ice extent are available prior to 1973, but the limited data available indicate that the ice edge to the west of the Peninsula lay to the north of recently observed extremes during the very cold conditions prevailing in the late 1950s. The ultimate cause of the atmospheric-circulation changes remains to be determined and may lie outside the Antarctic region.

scholarly journals Variations of U.S. Regional Precipitation and Simulations by the NCEP CFS: Focus on the Southwest

2009 ◽  
Vol 22 (12) ◽  
pp. 3211-3231 ◽  
Author(s):  
Song Yang ◽  
Yundi Jiang ◽  
Dawei Zheng ◽  
R. Wayne Higgins ◽  
Qin Zhang ◽  
...  
Keyword(s):  
United States ◽  
Atmospheric Circulation ◽  
Annual Cycle ◽  
West Coast ◽  
Time Scale ◽  
Gulf Coast ◽  
The United States ◽  
The West ◽  
Western Atlantic ◽  
Precipitation Seasonality

Abstract Variations of U.S. regional precipitation in both observations and free-run experiments with the NCEP Climate Forecast System (CFS) are investigated. The seasonality of precipitation over the continental United States and the time–frequency characteristics of precipitation over the Southwest (SW) are the focus. The differences in precipitation variation among different model resolutions are also analyzed. The spatial distribution of U.S. precipitation is characterized by high values over the East and the West Coasts, especially over the Gulf Coast and southeast states, and low values elsewhere except over the SW in summer. A large annual cycle of precipitation occurs over the SW, northern plains, and the West Coast. Overall, the CFS captures the above features reasonably well, except for the SW. However, it overestimates the precipitation over the western United States, except the SW in summer, and underestimates the precipitation over the central South, except in springtime. It also overestimates (underestimates) the precipitation seasonality over the intermountain area and Gulf Coast states (SW, West Coast, and northern Midwest). The model using T126 resolution captures the observed features more realistically than at the lower T62 resolution over a large part of the United States. The variability of observed SW precipitation is characterized by a large annual cycle, followed by a semiannual cycle, and the oscillating signals on annual, semiannual, and interannual time scales account for 41% of the total precipitation variability. However, the CFS, at both T62 and T126 resolution, fails in capturing the above feature. The variability of SW precipitation in the CFS is much less periodic. The annual oscillation of model precipitation is much weaker than that observed and it is even much weaker than the simulated semiannual oscillation. The weakly simulated annual cycle is attributed by the unrealistic precipitation simulations of all seasons, especially spring and summer. On the annual time scale, the CFS fails in simulating the relationship between the SW precipitation and the basinwide sea surface temperature (SST) and the overlying atmospheric circulation. On the semiannual time scale, the model exaggerates the response of the regional precipitation to the variations of SST and atmospheric circulation over the tropics and western Atlantic, including the Gulf of Mexico. This study also demonstrates a challenge for the next-generation CFS, at T126 resolution, to predict the variability of North American monsoon climate.

scholarly journals California Central Valley Summer Heat Waves Form Two Ways*

2016 ◽  
Vol 29 (3) ◽  
pp. 1201-1217 ◽  
Author(s):  
Yun-Young Lee ◽  
Richard Grotjahn
Keyword(s):  
North Pacific ◽  
Heat Waves ◽  
Central Valley ◽  
Maximum Temperature ◽  
Northern California ◽  
Long Distance ◽  
The West ◽  
California Coast ◽  
The North ◽  
The North Pacific

Abstract California Central Valley (CCV) heat waves are grouped into two types based on the temporal and spatial evolution of the large-scale meteorological patterns (LSMPs) prior to onset. The k-means clustering of key features in the anomalous temperature and zonal wind identifies the two groups. Composite analyses show different evolution prior to developing a similar ridge–trough–ridge pattern spanning the North Pacific at the onset of CCV hot spells. Backward trajectories show adiabatic heating of air enhanced by anomalous sinking plus horizontal advection as the main mechanisms to create hot lower-tropospheric air just off the Northern California coast, although the paths differ between clusters. The first cluster develops the ridge at the west coast on the day before onset, consistent with wave activity flux traveling across the North Pacific. Air parcels that arrive at the maximum temperature anomaly (just off the Northern California coast) tend to travel a long distance across the Pacific from the west. The second cluster has the ridge in place for several days prior to extreme CCV heat, but this ridge is located farther north, with heat anomaly over the northwestern United States. This ridge expands south as air parcels at midtropospheric levels descend from the northwest while lower-level parcels over land tend to bring hot air from directions ranging from the hot area to the northeast to the desert areas to the southeast. These two types reveal unexpected dynamical complexity, hint at different remote associations, and expand the assessment needed of climate models’ simulations of these heat waves.

scholarly journals IV. On the Connection between the Crag Formations and the Recent North Pacific Faunas

1865 ◽  
Vol 2 (10) ◽  
pp. 152-154
Author(s):  
P. Carpenter
Keyword(s):  
North Pacific ◽  
West Indies ◽  
The West

All facts from stray sources bearing on the connection between the Newer Tertiaries and existing faunas are worth placing on record, as they may hereafter unexpectedly throw light on important points of inquiry. The existing faunas radiating from the Boreal districts may, indeed, be expected to have much in common, together with species peculiar to each ocean, and to each side of each ocean; and the correspondence extends to species living in the Temperate and even the Sub-tropical districts. Kellia suborbicularis, Lasea rubra, and Saxicava pholadis of the Coralline Crag are now living along the whole coast from Vancouver to the Acapulcan district: and Erato Maugeriw, whose head-quarters are now in the West Indies, appeared in the Coralline, did not disappear in the Red Crag, is now living in the Bay of Panama, and is nearly, if not quite, identical with E. columbella of the Gulf and the Temperate shores of California.

scholarly journals Holocene atmospheric circulation in the central North Pacific: A new terrestrial diatom and δ18O dataset from the Aleutian Islands

2018 ◽  
Vol 194 ◽  
pp. 27-38 ◽  
Author(s):  
Hannah L. Bailey ◽  
Darrell S. Kaufman ◽  
Hilary J. Sloane ◽  
Alun L. Hubbard ◽  
Andrew C.G. Henderson ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
North Pacific ◽  
Aleutian Islands ◽  
Central North Pacific

Atmospheric Control on the Thermohaline Circulation

2009 ◽  
Vol 39 (1) ◽  
pp. 234-247 ◽  
Author(s):  
Arnaud Czaja
Keyword(s):  
Atmospheric Circulation ◽  
North Atlantic ◽  
North Pacific ◽  
Thermohaline Circulation ◽  
High Surface ◽  
Subpolar Gyre ◽  
Atlantic Sector ◽  
The North ◽  
The North Atlantic ◽  
The North Pacific

Abstract In an attempt to elucidate the role of atmospheric and oceanic processes in setting a vigorous ocean overturning circulation in the North Atlantic but not in the North Pacific, a comparison of the observed atmospheric circulation and net surface freshwater fluxes over the North Atlantic and Pacific basins is conducted. It is proposed that the more erratic meridional displacements of the atmospheric jet stream over the North Atlantic sector is instrumental in maintaining high surface salinities in its subpolar gyre. In addition, it is suggested that the spatial pattern of the net freshwater flux at the sea surface favors higher subpolar Atlantic salinity, because the geographical line separating net precipitation from net evaporation is found well south of the time-mean gyre separation in the North Pacific, whereas the two lines tend to coincide in the North Atlantic. Numerical experiments with an idealized two-gyre system confirm that these differences impact the salinity budget of the subpolar gyre. Further analysis of a coupled climate model in which the Atlantic meridional overturning cell has been artificially weakened suggests that the more erratic jet fluctuations in the Atlantic and the shift of the zero [net evaporation minus precipitation (E − P)] line are likely explained by features independent of the state of the thermohaline circulation. It is thus proposed that the atmospheric circulation helps “locking” high surface salinities and an active coupling between upper and deep ocean layers in the North Atlantic rather than in the North Pacific basin.

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