Effect of a Pacific sea surface temperature anomaly on the circulation over North America

During the fall and winter of 1976-1977, sea surface temperature (SST) in the north Pacific was characterized by abnormally cold temperatures in the central and western portions of the north Pacific with a warm pool located off the west coast of the U.S. It was suggested that the north Pacific SST anomalies were one of the multiple causes of the abnormally cold temperatures in eastern North America during the 1976-1977 winter. An attempt was made to test this hypothesis by conducting a numerical experiment with the GLAS general circulation model

Ocean distribution of the American shad (Alosa sapidissima) along the Pacific coast of North America

We examined the incidental catches of American shad (Alosa sapidissima) taken during research cruises and in commercial and recreational landings along the Pacific coast of North America during over 30 years of sampling. Shad, an introduced species, was mainly found over the shallow continental shelf, and largest catches and highest frequency of occurrences were found north of central Oregon, along the coasts of Washington and Vancouver Island, and in California around San Francisco Bay. Migrations to the north off Washington and Vancouver were seen during spring to fall, but we found no evidence for large-scale seasonal migrations to the south during the fall or winter. The average weight of shad increased in deeper water. Sizes were also larger in early years of the study. Most were caught over a wide range of sea surface temperatures (11–17°C) and bottom temperatures (6.4–8.0°C). Abundance of shad on the continental shelf north of 44°N was highly correlated with counts of shad at Bonneville Dam on the Columbia River in the same year. Counts were negatively related to average weights and also negatively correlated with the survival of hatchery coho salmon (Oncorhynchus kisutch), indicating that survival of shad is favored by warm ocean conditions. Examining the catch during research cruises and commercial and recreational landings, we concluded that American shad along the Pacific coast have adapted to the prevailing environmental conditions and undertake only moderate seasonal migrations compared with the long seasonal migrations of shad along the Atlantic coast of North America. We suggest that the large spawning populations in the Columbia River and San Francisco Bay areas explain most of the distributional features along the Pacific coast

Influence of teleconnection patterns on global moisture transport during peak precipitation month

Teleconnection patterns are an important feature influencing the variability of moisture transport. This study explores the influence of the Arctic, Antarctic, Pacific-North American, and El Niño–Southern Oscillations on moisture transport from major oceanic and continental moisture sources during the peak precipitation month. The positive phase of the Pacific-North American teleconnection pattern increases the influence of Pacific Ocean moisture on western North America, while the negative phase increases the influence of Atlantic Ocean moisture over eastern North America, with differences between phases higher than 1.5 mm·day−1 over most of the area when the sources are the preferred. The positive phase of the Arctic Oscillation increases the importance of the Mediterranean as a source of moisture for western Europe while the negative phase increases the importance of the North Atlantic as a source with contribution increased in more than 2 mm·day−1 over Europe. The positive phase of the Antarctic Oscillation favours the contribution from the western Indian basin over eastern Africa, while in the negative phase the contribution from the southern Pacific is increased over northwestern Africa. For El Niño–Southern Oscillation, the main influence occurs over South America during El Niño events, increasing the moisture contributions from the South Pacific Ocean over southern South America and from South Atlantic over southeastern Brazil. El Niño events also increase the moisture transport from the North Atlantic over western Europe and from the North Pacific over North America. In contrast, La Niña events increase moisture contributions from the Pacific over Central America and northern South America, being the latter the area when higher differences between phases are observed.Xunta de Galicia | Ref. ED431C 2021/44Xunta de Galicia | Ref. ED481B 2018/062Xunta de Galicia | Ref. ED481D‐2022‐020Agencia Estatal de Investigación | Ref. RTI2018-095772-B-I00Fundação para a Ciência e a TecnologiaFinanciado para publicación en acceso aberto: Universidade de Vigo/CISU

Some effects of Earth's surface on winter jet stream positions in the Northern Hemisphere and rainfall patterns in northern and central California

EXTRACT (SEE PDF FOR FULL ABSTRACT): This report shows that the mean wintertime polar-front jet stream structure consists of three long waves. Prominent ridges in the jet stream flow occur near the longitudes of India, eastern Pacific/west coast of North America, and eastern Atlantic/British Isles; prominent troughs occur near the longitudes of the Middle East, western Pacific, and western Atlantic/east coast of North America. ... One of the climatological ridges occurs along the west coast of North America ... just off the central Oregon coast. The position of the jet stream at this location appears to be the main reason most Pacific storms pass to the north of California. Sustained rainfall in northern and central California occurs only when the storm track is displaced southward of this climatological position

Pre-Pliocene Extension around the Gulf of California and the transfer of Baja California to the Pacific Plate

Late Miocene (12–5 Ma) extension around the edges of the Gulf of California has been alternatively attributed to “Basin and Range” extension, back arc extension, or development of the Pacific-North America plate boundary. This extension was ENE directed and similar in structural style to extension in the Basin and Range province. Timing constraints permit nearly synchronous onset of this deformation in a belt extending SSE from northernmost Baja California to the mouth of the gulf. Where this extensional faulting continued through Pliocene time to the present, synchronous with motion on the modern transform plate boundary in the Gulf of California, no change in direction of extension can be resolved. Revised constraints on Pacific-North America plate motion support the development of this late Miocene extension as a component of Pacific-North America displacement that could not be accommodated by strike-slip displacement along the existing plate boundary west of the Baja California peninsula. This scenario implies that transfer of Baja California from the North America plate to the Pacific plate was a gradual process, beginning about 12–10 Ma, when motion of the Pacific plate relative to North America was partitioned into separate regimes of strike-slip and dip-slip displacement on opposite sides of Baja California

Speleothem Paleoclimatology for the Caribbean, Central America, and North America

Speleothem oxygen isotope records from the Caribbean, Central, and North America reveal climatic controls that include orbital variation, deglacial forcing related to ocean circulation and ice sheet retreat, and the influence of local and remote sea surface temperature variations. Here, we review these records and the global climate teleconnections they suggest following the recent publication of the Speleothem Isotopes Synthesis and Analysis (SISAL) database. We find that low-latitude records generally reflect changes in precipitation, whereas higher latitude records are sensitive to temperature and moisture source variability. Tropical records suggest precipitation variability is forced by orbital precession and North Atlantic Ocean circulation driven changes in atmospheric convection on long timescales, and tropical sea surface temperature variations on short timescales. On millennial timescales, precipitation seasonality in southwestern North America is related to North Atlantic climate variability. Great Basin speleothem records are closely linked with changes in Northern Hemisphere summer insolation. Although speleothems have revealed these critical global climate teleconnections, the paucity of continuous records precludes our ability to investigate climate drivers from the whole of Central and North America for the Pleistocene through modern. This underscores the need to improve spatial and temporal coverage of speleothem records across this climatically variable region

Celebrating the Portuguese Communities in America: A Cartographic Perspective (Exhibit Guide)

Celebrating the Portuguese Communities in America: A Cartographic Perspective. June 10 - November 29, 1997 Although numerous countries and individuals were involved in the exploration and mapping of the Americas, it was the Portuguese who set the stage during the fifteenth century for the ensuing discoveries in the New World. Portuguese-born and sponsored explorers played a significant role, especially in charting a route around the southern tip of South America; in exploring and exploiting the waters bordering the northeast coast of North America; and in exploring the Pacific Coast of North America, particularly the area that today is the state of California.https://digitalcommons.usm.maine.edu/oml_miscellaneous/1007/thumbnail.jp

Uncertainties and implications of the Late Cretaceous and Tertiary position of North America relative to the Farallon, Kula, and Pacific Plates

We present updated global plate reconstructions and calculated uncertainties of the Pacific, Kula, and Farallon/Vancouver plates relative to North America for selected times since 68 Ma. Improved magnetic data from the Indian Ocean decrease the uncertainties in. the global plate circuit approach; these uncertainties are now considerably smaller than those inherent in equivalent reconstructions based on the assumption of fixed hotspots. Major differences between these results and those of others are due to our use of more detailed Africa-North America reconstructions, separate Vancouver and Farallon plate reconstructions, and the assumption of a rigid Antarctica plate during Cenozoic time. The uncertainties in the relative positions of the Pacific and North America plates since the time of anomaly 7 (26 Ma) range up to ±100 km in position, or from 1 to 3 m.y. in time. If the Mendocino triple junction initiated at about 28.5 Ma, its position would have been at 31.3°N ± 130 km relative to fixed North America. Unacceptable overlap of oceanic crust of the Pacific plate with continental crust of western North America in the anomaly 10 (30 Ma) reconstruction is a minimum of 340±200 km along an azimuth of N60°E and may be accounted for by Basin and Range extension. Pacific-North America displacement in the past 20 Ma is found to be considerably less than that calculated by fixed hotspot reconstructions. Farallon (Vancouver)-North America convergence velocity decreased greatly between the times of anomalies 24 and 21 (56 to 50 Ma), prior to the 43 Ma age of the Hawaiian-Emperor bend and the often quoted 40 Ma “end” of the Laramide orogeny. A change in direction of Farallon-North America convergence occurred sometime between 50 and 42 Ma and also may not correlate with the time of the Hawaiian-Emperor bend. The lack of data from subducted parts of the Farallon and Kula plates permits many possibilities regarding the position of the Kula-Farallon ridge, the age of subducted crust, or the position of oceanic plateaus during the Laramide orogeny, leaving open the question of the relationship between plate tectonic scenarios and tectonic style during Laramide time. Displacements of points on the various oceanic plates along the west coast of an arbitrarily fixed North America during the interval between anomalies 30/31 and 18 (68 to 42 Ma) are found to be: Pacific plate, 1700±200 km northward; Farallon plate, 3200±400 km northeastward; Vancouver plate, 3000±400 km northeastward; Kula plate, if attached to the Pacific plate after A24 time, 2500±400 km northward

Stanford University’s John Otterbein Snyder: Student, Collaborator, and Colleague of David Starr Jordan and Charles Henry Gilbert

John Otterbein Snyder (1867–1943) was an early student of David Starr Jordan at Stanford University and subsequently rose to become an assistant professor there. During his 34 years with the university he taught a wide variety of courses in various branches of zoology and advised numerous students. He eventually mentored 8 M.A. and 4 Ph.D. students to completion at Stanford. He also assisted in the collection of tens of thousands of fish specimens from the western Pacific, central Pacific, and the West Coast of North America, part of the time while stationed as “Naturalist” aboard the U.S. Fish Commission’s Steamer Albatross (1902–06). Although his early publications dealt mainly with fish groups and descriptions (often as a junior author with Jordan), after 1910 he became more autonomous and eventually rose to become one of the Pacific salmon, Oncorhynchus spp., experts on the West Coast. Throughout his career, he was especially esteemed by colleagues as “a stimulating teacher,” “an excellent biologist,” and “a fine man