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.

A numerical simulation of cool/wet and warm/wet episodes in the western United States

Wintertime precipitation in the mountains of the western United States during a warm or cool period has a pronounced influence on streamflow. During a warm year, streamflow at intermediate elevations responds more immediately to precipitation events; during a cold year, much of the discharge is delayed until the snow melts in spring and summer. Previous efforts at studying these extremes have been hampered by a limited number and length of observational analyses. In this study, we augment this limited observational record by analyzing a simplified general circulation model.

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.

Climatology of the seasonal precipitation maximum in the western United States

The western United States is characterized by heterogeneous patterns of seasonal precipitation regimes due to the hierarchy of climatic controls that operate at different spatial scales. A climatology of intermonthly precipitation changes, using data from more than 4,000 stations including high-elevation sites, illustrate how different climatic controls explain the spatial distribution of the seasonal precipitation maximum. These results indicate that smaller-scale climatic controls must be considered along with larger-scale ones to explain patterns of spatial climate heterogeneity over mountainous areas. The results also offer important implications for scholars interested in assessing spatial climatic variations of the western United States at different timescales.

Decadal hydroclimatic variability over western North America [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Variability of precipitation over North America on ENSO and decadal time scales is examined from several decades of precipitation and snow course records.

Terrestrial ecosystem response to interdecadal climate variability in the western United States [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): We argue that the most important climatically-driven terrestrial ecosystem changes are concentrated in annual- to decadal-scale episodic events. These rapid ecosystem responses to climate change are manifested as regionally synchronized disturbance events (eg, floods, fires, and insect outbreaks) and increased drought-caused plant mortality rates.

The terrestrial record of interdecadal climate variability in western North America [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Western North America is particularly rich in natural records of climate that have potential to reveal features of interdecadal climate variability.

Recent winters in the western United States and relationship to ENSO patterns [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): In the mountainous western United States, winter weather has consequences for the entire year, especially with respect to the use of water. For most of the past 6-8 years, drought has been a persistent feature of the climate.

River salinity variations in response to discharge: examples from the western United States during the early 1900s

Major controls on river salinity (total dissolved solids) in the western United States are climate, geology, and human activity. Climate, in general, influences soil-river salinity via salt-balance variations. When climate becomes wetter, river discharge increases and soil-river salinity decreases; when climate becomes drier river discharge decreases and soil-river salinity increases. This study characterizes the river salinity response to discharge using statistical-dynamic methods. An exploratory analysis of river salinity, using early 1900s water quality surveys in the western United States, shows much river salinity variability is in response to storm and annual discharge. Presumably this is because river discharge is largely supported by surface flow.

Oxygen isotope analysis of corals from the Gulf of California and the Gulf of Panama: application and implications for coral-based paleoclimate reconstructions [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Coral-based reconstruction of past variability of sea surface conditions is improving our understanding of the tropical ocean-atmosphere system. We present oxygen isotope records from corals collected near the tip of Baja California (Baja) and the Gulf of Panama (Saboga).

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.