Strong, low frequency (decadal) environmental fluctuations during the 20th century in the North Pacific Ocean, on the Washington coast, and in Puget Sound

At decadal period (10-20 years), dynamic linkage was evident between atmospheric low pressure systems over the North Pacific Ocean and circulation in a Pacific Northwest fjord (Puget Sound). As the Aleutian low pressure center shifts, storms arriving from the North Pacific Ocean deposit varying amounts of precipitation in the mountains draining into the estuarine system; in turn, the fluctuating addition of fresh water changes the density distribution near the fjord basin entrance sill, thereby constraining the fjord's vertical velocity structure. This linkage was examined using time series of 21 environmental parameters from 1899 to 1987. Covariation in the time series was evident because of the strong decadal cycles compared with long-term averages, interannual variability, and seasonal cycles.

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.

Tropical and subtropical moisture and southerly displaced North Pacific storm track: factors in the growth of late Quaternary lakes in the Mojave Desert

Historical flood events produced lakes in the Mojave River watershed in southeastern California and represent climatic conditions similar to those in the late Quaternary when perennial lakes formed in the Mojave Desert. Historical lakes are related to tropical and subtropical sources of moisture and an extreme southward shift of storm tracks. It is suggested that this atmospheric pattern occurred frequently during earlier periods with perennial lakes in the Mojave River drainage basin.

Wind climate trends in the Pacific Northwest and the implications to renewable energy supply

EXTRACT (SEE PDF FOR FULL ABSTRACT): This paper examines the influence of wind climate variations on new Pacific Northwest renewable energy sources. Wind represents a potentially valuable supplemental source of energy in the region. ... The recent period of weaker winds may be associated with a stronger North Pacific Low in the last decade. This would result in winter storms more often being deflected farther north, to Canada. Also, in the last dozen years, lower SOI values were common. Other investigators have found low SOI to be associated with drier conditions in the Pacific Northwest.

Climate forcing of Pacific herring recruitment and growth in southern British Columbia

Over the last 50 years, much of the variability in ocean climate and herring recruitment has occurred at two dominant periods centered around 5 and 16 years. Herring growth has also exhibited a dominant 5- and 18-year periodicity. A recent analysis of a number of relevant time series suggests that interannual variations in oceanic conditions off the west coast of Vancouver Island affect survival of herring and their principal predator, Pacific hake, which also exhibits a marked 16-year oscillation in abundance. Thus the dynamics of the herring stock are modulated by a combination of climate and predator forcing. Much of the interannual variation in herring growth is centered around the 5-year (moderate ENSO period) and 16-year (strong ENSO period) ocean climate oscillations and the 16-year recruitment oscillation.

Eastern tropical Pacific corals monitor low latitude climate of the past 400 years

EXTRACT (SEE PDF FOR FULL ABSTRACT): We have measured coral growth band thickness and skeletal stable isotopic composition through a 371-year transect (AD 1583-1954) from a massive specimen of Pavona clavus from the Galápagos Islands. ... We observe a general cooling trend during 1860-1954, corresponding to the end of the Little Ice Age, an interval characterized by general warming at many mid-latitude sites. Variance at sunspot cycle frequencies in growth rate, stable isotopic, and trace element composition implies a direct or indirect link between the solar cycle and climate modulation in the eastern Pacific.

The Younger Dryas and millenial-scale oceanographic variability in the Sulu Sea, tropical western Pacific

EXTRACT (SEE PDF FOR FULL ABSTRACT): A high resolution, AMS carbon-14-dated sediment record from the Sulu Sea clearly indicates the Younger Dryas climatic event affected the western equatorial Pacific. Presence of the Younger Dryas in the tropical western Pacific indicates this climatic event is not restricted to the North Atlantic nor to high latitudes, but is global in extent.

Variations in northeast Asian environments over the last 350,000 years reconstructed from pollen records from the northwest Pacific Ocean

EXTRACT (SEE PDF FOR FULL ABSTRACT): Recent analyses of terrestrial (pollen) and marine microfossils (foraminifera and radiolaria) in cores V28-204 and RC14-99 from the northwest Pacific Ocean extend the continuous, chronostratigraphically-controlled records of the regional vegetation of the Pacific coast of Japan and offshore marine environments through three full glacial cycles. The high-resolution pollen time series show systematic relationships between fluctuations in Japanese vegetation and global ice volume over the last 350 kyr. ... Comparison with solar insolation at 30°N and with an index of orbital parameters suggests that variation in northeast Asian summer monsoon intensity is related to orbital forcing.

Tree-ring records as indicators of air-sea interaction in the northeast Pacific sector

Climate conditions in land areas of the Pacific Northwest are strongly influenced by atmosphere/ocean variability, including fluctuations in the Aleutian Low, Pacific-North American (PNA) atmospheric circulation modes, and the El Niño-Southern Oscillation (ENSO). It thus seems likely that climatically sensitive tree-ring data from these coastal land areas would likewise reflect such climatic parameters. In this paper, tree-ring width and maximum lakewood density chronologies from northwestern Washington State and near Vancouver Island, British Columbia, are compared to surface air temperature and precipitation from nearby coastal and near-coastal land stations and to monthly sea surface temperature (SST) and sea level pressure (SLP) data from the northeast Pacific sector. Results show much promise for eventual reconstruction of these parameters, potentially extending available instrumental records for the northeastern Pacific by several hundred years or more.

Evidence from the Pacific Northwest for solar modulation of climate and of northern ecosystems

EXTRACT (SEE PDF FOR FULL ABSTRACT): The 250-year net annual snow accumulation, or mass balance, time series derived from the Mt. Logan (Yukon) ice core has been spectrally analyzed and is found to contain a nominal 11-year waveform. The stable isotope time series contains a significant amount of power between 9 and 13 years, although this record is evidently not a straightforward proxy for air temperatures. The signal in the mass balance time series exhibits a close relationship with the sunspot cycle waveform and is, therefore, assumed to be related to it. Waveforms showing a high correlation with the solar cycle are found in other climate data in the region. ... Taken collectively, the data point to a link between solar variability, atmospheric variability, climate, and selected ecological dynamics in the Pacific Northwest, but other data, not presented, indicate these relationships may hold elsewhere. So far, the evidence is empirical; complete details of the physical mechanisms involved have yet to be synthesized in a satisfactory way.

The relationship of western Pacific monsoon and tropical cyclone activity to North Pacific and North American climate anomalies

This present study investigates the influence of western Pacific tropical cyclone activity as possible centers of anomalous tropical heating on the large-scale circulation over the Pacific region. The characterization of tropical cyclone activity via an index based on anomalous 700 mb zonal wind is described first. Patterns of anomalous large-scale extratropical circulation anomalies based on composites of similar periods of tropical cyclone activity are then presented, followed by general conclusions.

Anomalies in North American climate: the South Asian-tropical west Pacific connection

How do tropical heating fluctuations create North American climate anomalies? We propose some answers using the results from a simplified global atmospheric model. We find that the South Asian-tropical west Pacific area is especially effective at stimulating North American responses. The relatively strong tropical/extratropical interaction between these two areas is the result of two major processes acting on the Rossby wave signal induced by the tropical heating fluctuations. These factors are: 1) Wave guiding by the Asian-north Pacific subtropical jet; and 2) Wave amplification within unstable regions of the jet flank. These factors allow relatively small, remote, and short-term tropical fluctuations to have relatively large impacts on North American climate.