Anomalous California winters and the Enso phenomena
Climate anomalies in California associated with ENSO episodes between 1910 and 1984 are investigated using Superposed Epoch Analysis techniques tested against randomization for statistical significance of the identified signals. The results indicate
that statistically significant temperature departures from seasonal normals are associated with ENSO events and are characterized by positive anomalies in all seasons but especially in the key season of the event year and in the winter following the key season
. Temperature anomalies associated with ENSO increase inversely with latitude.
Spatial variability of midtropospheric circulation patterns and associated surface climate in the United States during ENSO winters
This study identifies the dominant synoptic circulation patterns and associated temperature and precipitation departures that occur during ENSO winters. Using standardized departures of 500 mbar heights over North America and the North Pacific Ocean
, a subjective classification of the anomaly maps for winter months identified as warm ENSO events identifies three basic categories of 500 mbar standardized anomaly patterns.
Tree-growth response to Enso events in the central Colorado Front Range
The inflence of climate associated with El Niño/Southern Oscillation (ENSO) events on tree growth in the central Colorado Front Range is investigated through the analysis of two high altitude tree-ring chronologies. Dendrochronological techniques
are used to determine if ENSO-related climatic effects are detectable in tree-ring width patterns in the central Colorado Front Range. The form of the tree growth response is identified and the variability of the influence of these events on tree growth
Effect of ENSO events on sediment production in a large coastal basin in northern Peru
The Catamayo-Chira basin is an interesting case study for investigating these geomorphic implications. The aims were: (i) to study the effect of ENSO on stream flow and sediment yields in the basin, (ii) to investigate if ENSO events affect sediment
yields in the post-ENSO period and (iii) to understand which factors control the ENSO and post-ENSO basin response. The analysis indicates the increase of vegetation growth in the lower basin is not the main reason explaining considerable sediment flux
decrease in post-ENSO periods. During strong ENSO events, sediment in alluvial stores in the lower part of the basin is removed due to enlarging and deepening of channels. The decrease in sediment export will last for several years until the equilibrium
The influence of the PDO on winter precipitation during high- and low-index ENSO conditions in the Eastern United States
The AA. analyzed the influence of the PDO (Pacific Decadal Oscillation) on winter precipitation during years of high- and low-index ENSO conditions for 260 climate divisions in the eastern U.S. from 1925 to 1998. When the 33 neutral ENSO years
are split by cold (12 years) and warm (21 years) PDO, the resulting winter precipitation patterns show wetter (drier) than average conditions in nearly all (80%) of the 260 climate divisions during the warm (cold) phase of the PDO. The two ENSO/PDO
combinations with the driest signals for the eastern U.S. are La Niña/warm PDO and neutral ENSO/cold PDO. The modulation effect of the PDO is significant during La Niña in northern Texas and parts of New England and during neutral ENSO in southern Texas
and the northern Plains. The AA. suggest that seasonal forecasters in these regions may use this knowledge to improve long-lead winter forecasts during those ENSO phases, assuming the current PDO phase is well established.
ENSO rainfall variability and impacts on crop production in Indonesia
Using rice production and rainfall data extending back to 1950 for the 27 Indonesian provinces, this paper examines temporal and spatial relationships across Indonesia between El Niño-Southern Oscillation (ENSO) induced rainfall variability and rice
The impacts of ENSO, PDO, and local SSTS on winter precipitation in India
Monthly precipitation data are assembled to analyze the impact of global teleconnections, namely ENSO, PDO, and local sea surface temperature (SSTs) on winter rainfall across the Indian subcontinent from 1925 to 1998. Canonical correlation analysis
Is the ENSO phenomenon changing as a result of global warming ?
This study aims to investigate whether there is any evidence for changes in the behavior of the ENSO phenomenon over the past 122 years that may be attributed to global warming. Cluster analysis is carried out to group warm and cold events
ENSO effects on temperature and precipitation of the Patagonian-Andean region : implications for biogeography
This study documents instabilities in the relationship between El Niño-Southern Oscillation (ENSO) and climate of the Patagonian-Andean region at spatial and temporal scales directly relevant to biogeographical research. Four temperature and four
indices of ENSO, the Southern Oscillaion Index (SOI) and tropical Pacific sea surface temperatures (SSTs). Discussion of the results.
Influence of ENSO on maximum, minimum, and mean temperatures in the Southeast United States
This paper examines the influence of El Niño/Southern Oscillation (ENSO) warm and cold events on the average monthly maximum and minimum as well as mean temperatures at 88 stations across the Southeast during 1931-1994. Composite time series
for the 24-month period from july prior to a warm- or cold-event year (year -1) to june following a warm- or cold-event year (year +1) are examined. The role of cloud cover is studied in relation to the temperature response to ENSO.
of wildfire. One simple way of illustrating the relationship between ENSO and wildfire occurrence is the use of an Analysis of Variance (ANOVA) on wildfire data that has been categorized according to ENSO status (El Niño, La Niña, and neutral years
). This research shows that a statistically significant relationship exists between ENSO conditions and annual wildfire occurrence in Florida when ENSO conditions are treated as a potential precursor to wildfire conditions.
Circulation atmosphérique ; ENSO ; Etats-Unis ; Etats-Unis de l'Ouest ; Hiver ; Interaction océan-atmosphère ; Oscillation climatique ; Précipitation ; Type de temps ; Téléconnexion ; Variabilité climatique
Atmospheric circulation ; Climate oscillation ; Climatic variability ; ENSO ; Ocean atmosphere interaction ; Precipitation ; Teleconnection ; United States of America ; Weather type ; Western United States ; Winter
The AA. examined historical winter-season relationships among precipitation across the western United States, the northern Pacific jet stream (NPJ) across the northern Pacific Ocean basin, and the El Niño-Southern Oscillation (ENSO) phenomenon
to determine if the NPJ significantly adds to the existing ENSO-based understanding of inter-annual variability in precipitation. The results indicate that the NPJ is significantly related to winter precipitation across a much larger area of the western United
States than the ENSO signal. For areas where the ENSO signal is significantly related to precipitation, there generally exists a stronger or more consistent NPJ-precipitation relationship. The results indicate that there is value in considering seasonal
. Ces résultats fournissent une information essentielle sur l'évaluation des changements induits par le phénomène El Niño/oscillation australe (ENSO) dans les parties inférieures des bassins du Chira et du Piura au cours des 30 dernières années.
with the El Niño-Southern Oscillation (ENSO). ENSO can cause floods and droughts in different parts of the country in different seasons. AA. conclude by discussing explanatory mechanisms in rainfall regime in Costa Rica caused by ENSO warm events. - (SLD)