Evidence gleaned from the instrumental record of climate data identifies a robust, recurring pattern ocean–atmosphere variability centered over midlatitude North Pacific basin. Over past century, amplitude this has varied irregularly at interannual-to-interdecadal timescales. There is evidence reversals in prevailing polarity oscillation occurring around 1925, 1947, and 1977; last two correspond to dramatic shifts salmon production regimes Ocean. This also affects coastal sea continental...

Contemporaneous correlations between geopotential heights on a given pressure surface at widely separated points earth, referred to as teleconnections in this paper, are studied an attempt identify and document recurrent spatial patterns which might be indicative of standing oscillations the planetary waves during Northern Hemisphere winter, with time scales order month or longer. A review existing literature subject reveals existence least four such patterns: North Atlantic Pacific...

The leading empirical orthogonal function of the wintertime sea‐level pressure field is more strongly coupled to surface air temperature fluctuations over Eurasian continent than North Atlantic Oscillation (NAO). It resembles NAO in many respects; but its primary center action covers Arctic, giving it a zonally symmetric appearance. Coupled strong at 50‐hPa level on intraseasonal, interannual, and interdecadal time scales, this “Arctic Oscillation” (AO) can be interpreted as signature...

The leading modes of variability the extratropical circulation in both hemispheres are characterized by deep, zonally symmetric or “annular” structures, with geopotential height perturbations opposing signs polar cap region and surrounding zonal ring centered near 45° latitude. structure dynamics Southern Hemisphere (SH) annular mode have been extensively documented, whereas existence a Northern (NH) mode, herein referred to as Arctic Oscillation (AO), has only recently recognized. Like SH...

A number of recent studies have reported an ENSO-like EOF mode in the global sea surface temperature (SST) field, whose time variability is marked by abrupt change toward a warmer tropical eastern Pacific and colder extratropical central North 1976–77. The present study compares this pattern with structure interannual associated ENSO cycle documents its history back to 1900. analysis primarily based on leading EOFs SST anomaly “anomaly deviation” fields various domains expansion coefficient...

Preface. Units and Numerical Values. A brief Survey of the Atmosphere. Atmospheric Thermodynamics. Extratropical Synoptic-Scale Disturbances. Aerosol Cloud Microphysical Processes. Clouds Storms. Radiative Transfer. The Global Energy Balance. Dynamics. General Circulation. Index.

Atmospheric phenomena associated with the Southern Oscillation are examined, emphasis on vertical structure and teleconnections to middle latitudes. This paper is specifically concerned interannual variability of seasonal means for Northern Hemisphere winter during period 1951–78. Among variables considered sea surface temperature in equatorial Pacific, precipitation at selected Pacific stations, a “Southern Index” level pressure, 200 mb height tropospheric mean stations throughout tropics,...

This paper introduces a conceptual framework for comparing methods that isolate important coupled modes of variability between time series two fields. Four specific are compared: principal component analysis with the fields combined (CPCA), canonical correlation (CCA) and variant CCA proposed by Barnett Preisendorfer (BP), one single field followed its amplitudes second (SFPCA), singular value decomposition covariance matrix (SVD). SVD CPCA easier to implement than BP, do not involve...

The authors systematically investigate two easily computed measures of the effective number spatial degrees freedom (ESDOF), or independently varying patterns, a time-varying field data. first measure is based on matching mean and variance time series spatially integrated squared anomaly to chi-squared distribution. second measure, which equivalent for long sample normally distributed values, partitioning between EOFs. Although these were proposed almost 30 years ago, this paper aims provide...

The authors exploit the remarkable similarity between recent climate trends and structure of “annular modes” in month-to-month variability (as described a companion paper) to partition into components linearly congruent with independent annular modes. index Northern Hemisphere (NH) mode, referred as Arctic Oscillation (AO), has exhibited trend toward high polarity over past few decades. largest most significant are observed during “active season” for stratospheric planetary wave–mean flow...

Data collected by the International Arctic Buoy Programme from 1979 to 1998 are analyzed obtain statistics of sea level pressure (SLP) and ice motion (SIM). The annual seasonal mean fields agree with those obtained in previous studies climatology. data show a 3-hPa decrease decadal SLP over central Ocean between 1979–88 1989–98. This drives cyclonic trend SIM, which resembles structure Oscillation (AO). Regression maps SIM during wintertime (January–March) AO index 1) an increase advection...

The single most prominent signal in year-to-year climate variability is the Southern Oscillation, which associated with fluctuations atmospheric pressure at sea level tropics, monsoon rainfall, and wintertime circulation over North America other parts of extratropics. Although meteorologists have known about Oscillation for more than a half-century, its relation to oceanic El Niño phenomenon was not recognized until late 1960's, theoretical understanding these relations has begun emerge only...

The Northern Hemisphere annular mode (NAM) (also known as the North Atlantic Oscillation) is shown to exert a strong influence on wintertime climate, not only over Euro-Atlantic half of hemisphere documented in previous studies, but Pacific well. It affects mean conditions, also day-to-day variability, modulating intensity mid-latitude storms and frequency occurrence high-latitude blocking cold air outbreaks throughout hemisphere. recent trend NAM toward its high-index polarity with stronger...

A global barotropic model, linearized about the 300 mb climatological mean January flow, is perturbed by applying a series of localized forcings distributed throughout tropics and subtropics. Structures which resemble observed "Pacific/North American" "East Atlantic" teleconnection patterns noted Wallace Gutzler (1981) tend to recur in responses. Similar are found result from dispersion isolated initial perturbations placed at variety locations midlatitudes. It shown that these structures...

Single field principal component analysis (PCA), direct singular value decomposition (SVD), canonical correlation (CCA), and combined (CPCA) of two fields are applied to a 39-winter dataset consisting normalized seasonal mean sea surface temperature anomalies over the North Pacific concurrent 500-mb height same region. The CCA solutions obtained by linear transformations SVD solutions. Spatial patterns various measures variances covariances explained modes derived from different types...

BACKGROUND. This paper reports racial/ethnic differences in the use of licit and illicit drugs by high school seniors United States. METHODS. The study uses questionnaire data from annual, nationally representative surveys 1976 through 1989. Combined sample sizes were 57,620 for 1976-79; 75,772 1980-84; 73,527 1985-89. RESULTS. Native American had highest prevalence rates cigarettes, alcohol, most drugs; White students next drugs. Asian Americans lowest rates, Black levels nearly as low...

The dynamical coupling between the stratospheric and tropospheric circulations yields a statistically significant level of potential predictability for extreme cold events throughout much Northern Hemisphere (NH) mid–high latitudes on both month-to-month winter-to-winter timescales. Pronounced weakenings NH wintertime polar vortex tend to be followed by episodes anomalously low surface air temperatures increased frequency occurrence densely populated regions such as eastern North America,...

Hourly data on the frequencies of all types precipitation events, heavy trace events and thunderstorms for more than 100 stations in United States were processed to generate statistics amplitude phase diurnal semidiurnal cycles at each station. Results are displayed seasonal maps a vectorial format that emphasizes large scale geographical consistency variations. During summer four parameters listed above displays distinctive pattern Thunderstorm frequency tends be most strongly modulated by...

Twice-daily synoptic analyses are statistically analyzed for a sample of nine individual winters. Temporal variance and covariance quantities at each grid point partitioned into “low-pass” (approximately 10–90 day) “band-pass” 2.5–6 components by means conventional filtering procedures. The time-filtered fields displayed in terms hemisphere maps. Included the analysis sea level pressure, 300 mb height, 500 wind statistics, 850 temperature poleward heat flux. most definitive results study...

Improved observations in the tropical Pacific during Tropical Ocean‐Global Atmosphere (TOGA) program have served to corroborate preexisting notions concerning seasonally dependent relationships between sea surface temperature, level pressure, wind stress, rainfall, upper tropospheric circulation, and ocean thermal structure anomalies El Niño‐Southern Oscillation (ENSO) phenomenon. However, paradigm of a quasiperiodic “ENSO cycle,” phase locked with annual march, does not capture complexity...

The climate of the eastern Pacific exhibits a pronounced equatorial asymmetry. Boundary layer air originating in Southern Hemisphere trades crosses equator and flows into intertropical convergence zone (ITCZ), whose southern limit is nearly always located at least 4° to north equator. sea-surface temperature (SST) distribution characterized by prominent “cold tongue” centered ∼ 1°S, strong frontal 2°N, warm eastward current near 5°N. surface wind field horizontal divergence as northward...

Midlatitude atmospheric variability is identified as a particularly effective component of the stochastic forcing ENSO. This realized via seasonal footprinting mechanism (SFM), in which tropical atmosphere forced during spring and summer by SST anomalies generated midlatitude previous winter. The strong relationship between SFM ENSO may serve to enhance predictability supports view that linearly stable nature.

Three of the past six summers have exhibited record low sea‐ice extent on Arctic Ocean. These minima may been dynamically induced by changes in surface winds. Based results a simple model that keeps track age ice as it moves about Ocean, we show areal coverage thick multi‐year decreased precipitously during 1989–1990 when Oscillation was an extreme “high index” state, and has remained since time. Under these conditions, younger, thinner anomalies recirculate back to Alaskan coast more...

Abstract The North Atlantic Oscillation (NAO), as defined in the studies of Sir Gilbert Walker ca . 1930, and zonal‐index cycle, elaborated by investigators at Massachusetts Institute Technology some twenty years later, are different interpretations same entity, whose time variations well represented leading principal component northern hemisphere sea‐level pressure field. NAO paradigm envisions this phenomenon involving a unique teleconnection pattern sector that varies on interannual...

Although past research has long documented religion's salutary impact on adult health-related behaviors and outcomes, relatively little examined the relationship between religion adolescent health. This study uses large, nationally representative samples of high school seniors to examine behavioral predictors morbidity mortality. Relative their peers, religious youth are less likely engage in that compromise health (e.g., carrying weapons, getting into fights, drinking driving) more behave...