Pacific sea surface temperature associations with southwestern United States summer rainfall and atmospheric circulation

Pacific sea surface temperatures (SSTs) are examined for their associations with (1) summer rainfall, and (2) the latitude location of the mid-tropospheric subtropical high pressure ridge (STR) in the southwestern United States during 1945 to 1986. Extreme northward (southward) displacements of STR are associated with wet (dry) summers over Arizona and an enhanced (weakened) gradient of SST off the California and Baja coasts. These tend to follow winters marked by positive (negative) phases of the PNA, Pacific/North America, teleconnection pattern. Recent decadal variations of Arizona summer rainfall (1950s wet; 1970s dry) appear similarly related to southwestern United States synoptic circulation and eastern Pacific SSTs.

Simulation and diagnosis of large-scale atmospheric moisture and surface hydrology over North America

We describe a preliminary investigation into large-scale atmospheric and surface moisture variations over North America. We compare large-scale hydrologic budgets in the Los Alamos general circulation model (GCM) to observed precipitation and vertically integrated atmospheric moisture fluxes derived from the National Meteorological Center's operational analyses. THe GCM faithfully simulates the integrated flux divergence and P-E differences. However, the integrated moisture content is too low, and precipitation and evaporation are too high. The model produces summertime soil moisture dryness, which supports previous studies showing increased droughts under warmer conditions.

Anomalous atmospheric circulation and large winter floods in six subregions of the southwestern United States

EXTRACT (SEE PDF FOR FULL ABSTRACT): We examined atmospheric circulation conditions conducive to occurrence of winter floods that exceed the 10-year peak discharge on rivers in six hydroclimatic subregions in Arizona, southern Utah, Nevada, and California. ... This relationship between flooding and broad-scale atmospheric patterns in the modern record will aid in paleoclimatic interpretations of paleoflood records over the last few thousand years.

ENSO influences on atmospheric circulation and precipitation in the western United States

EXTRACT (SEE PDF FOR FULL ABSTRACT): The influence of ENSO on atmospheric circulation and precipitation over the western United States is presented from two perspectives. First, ENSO-associated circulation patterns over the North Pacific/North America sector were identified using an REOF (rotated empirical orthogonal function) analysis of the 700-mb height field and compositing these for extreme phases of the Southern Oscillation Index. ... Second, we examine the variability of precipitation during the warm and cool phases of ENSO for different locations in the western United States.

Near and distant connection of atmospheric systems to ocean temperature change in the coastal California Current region

In studying hydrosphere, atmosphere, and biosphere interactions, it is useful to focus on specific subsystem processes and energy exchanges (forcing). Since subsystem scales range over ten orders of magnitude, it may be difficult to focus research on scales that will yield useful results in terms of establishing causal and predictive connections between more easily and less easily observed subsystems. In an effort to find pertinent scales, we have begun empirical investigations into relationships between atmospheric, oceanic, and biological systems having spatial scales exceeding 10^3 kilometers and temporal scales of six months or more.

Multivariate climate reconstruction for the last 14,000 years in southernmost South America

Comparison between past changes in pollen assemblages and stable isotope ratios (deuterium and carbon) analyzed in the same peat core from Tierra del Fuego at latitude 55°S permitted identification of the relative contribution of precipitation versus temperature responsible for the respective change. Major steps in the sequence of paleoenvironmental changes, such as at 12700, 9000, 5000, and 4000 years ago are apparently related only to increase in precipitation, reflecting the latitudinal location and intensity of the westerly storm tracks. On the other hand, high paleoenvironmental variability, which is characteristic for the late-glacial and the latest Holocene, is related to temperature variability, which affects the relative moisture content. Comparison with other paleoenvironmental records suggests that the late-glacial temperature variability is probably related to variability in the extent of Antarctic sea-ice, which in turn appears to be related to the intensity of Atlantic deep-water circulation. Temperature variability during the latest Holocene, on the other hand, is probably related to the dynamics of the El Niño/Southern Oscillation.

Neogene through Pleistocene paleoclimate of the Great Salt Lake region, northeastern Great Basin, USA

In a cooperative agreement between Amoco Production Company and the University of Arizona Geosciences Department, extensive data and resources associated with 15 deep wells drilled in the Great Salt Lake are currently on loan at the University of Arizona. Seismic data, electric and lithologic logs, cuttings and previously-prepared pollen slides will eventually permit a thorough study of both the tectonic and climatic history of the Great Salt Lake region. The preliminary study presented here concentrates on the Late Tertiary and Pleistocene climatic reconstruction of the eastern Great Basin through examination of fossil pollen.

Relationships between climate and atmospheric circulation in the Sonoran Desert region

The goal of this research is to identify key features of atmospheric circulation that influence winter climate variability in the Sonoran Desert region. This relationship between winter climate and atmospheric circulation is investigated through the use of indices, which describe the principal features of circulation patterns.

Decadal patterns in atmospheric carbon dioxide as indicators of changing growth and decay of terrestrial vegetation [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Large-scale changes in the growth and decay of land plants can be deduced from trends in the concentration of atmospherics [sic] carbon dioxide, after removing signals in the recorded data caused by oceanic and industrial disturbances to the concentration.

Offshore coho salmon populations near the Pacific Northwest and large-scale atmospheric events

EXTRACT (SEE PDF FOR FULL ABSTRACT): Catch of coho salmon off the coast of Washington and Oregon since 1925 appears to be related to large-scale events in the atmosphere, which in turn affect ocean currents and coastal upwelling intensities in the northeastern Pacific. At least two time scales of variations can be identified. The first is that of the El Nino/Southern Oscillation phenomenon giving rise to an irregular cycle of between 3 to 7 years. ... The second time scale of variation seems to have a periodicity of about 20 years, although this is based on a limited dataset. ... This paper endeavors to describe how, if real, these atmospheric/oceanic effects are integrated and might affect the salmon catch. The possibility must also be considered that the atmospheric events are symbiotically related to the oceanic events and, further, that both may be enmeshed in even longer-term variability of climate.

Synoptic dendroclimatology: a process-based approach for linking tree-ring information to atmospheric circulation over the Pacific and western North America [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Synoptic dendroclimatology uses dated tree rings to study and reconstruct climate from the viewpoint of the climate's weather components and their relationship to atmospheric circulation. This approach defines a connection between large-scale circulation and ring-width variation at local sites using correlation fields, composite maps, indexing, and other circulation-based methodologies.

Atmospheric circulation patterns associated with tree growth anomalies in the central and southern Sierra Nevada mountains [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): In this work, I examine patterns of atmospheric circulation associated with tree growth anomalies at mid-to-high latitudes (2000-3500 meters).

Quantifying global terrestrial carbon influx and storage as stimulated by an increase in atmospheric carbon dioxide concentration

EXTRACT (SEE PDF FOR FULL ABSTRACT): Measurements of spatial and temporal distributions of carbon dioxide concentration and carbon-13/carbon-12 ratio in the atmosphere suggest a strong biospheric carbon sink in terrestrial ecosystems. Quantifying the sink, however, has become an enormous challenge for Earth system scientists because of great uncertainties associated with biological variation and environmental heterogeneity in the ecosystems. This paper presents an approach that uses two driving parameters to bound terrestrial carbon sequestration associated with an increase in carbon dioxide concentration.

A new deep-sea crab, genus Chaceon, from the Arabian Sea (Crustacea, Decapoda, Geryonidae)

The sixth nominal species of Chaceon to be recorded from the western Indian Ocean is named from a specimen collected off Somalia in 504-506 meters. Chaceon somaliensis, n. sp., resembles C. macphersoni (Manning and Holthuis, 1988) and differs from the other four species known from the area in having the dactylus of the walking legs dorsoventrally depressed. It differs from C. macphersoni in having slenderer legs, a smoother body, and a much deeper, evenly curved orbit.

Seasonal and spatial distribution of Chlorophyll a in the north Arabian Sea bordering Pakistan

The average integrated chlorophyll a values for a 30-m deep surface layer in the north Arabian Sea bordering Pakistan ranged from negligible amounts to as high as 0.53μg chl. a 1ˉ¹(15.9mg mˉ²) during the period January 20, 1977 to June 4, 1977. The values, in general, decreased offshore except for the westernmost part of the Makran shelf, where unexpectedly high values were recorded over deep water. Seasonal distribution showed very high values in January (northeast monsoon season) which, with a few exceptions, gradually decreased to very low values in May, and then increased in June. The January peak may be related to winter cooling of surface waters resulting in convection and the June peak to the onset of southwest monsoon season in May. Coastal water shallower than 30m showed no seasonality and were often sites of intense phytoplankton blooms.