The atmospheric circulation on the synoptic scale during the culmination phase of the El-Niño − Southern Oscillation events (1997−1998)

Sokolikhina, E. V.; Semenov, E. K.; Sokolikhina, N. N.

doi:10.5194/adgeo-6-17-2006

Cited by 5 publications

(3 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, the MJO-C positive regression pattern over the Southern Hemisphere matches the South Pacific convergence zone (SPCZ) location, suggesting an MJO amplification within the SPCZ during the CP event. This is consistent with the increase in tropical cyclone number within the SPCZ during the fall-winter of El Niñ o (Sokolikhina et al 2006), the latter being associated with the positive MJO phase as suggested by Liebmann et al (1994). Note also the positive regression pattern during the CP event (1965/66, 1972/73, 1976/77, 1982/83, 1997/98), (b),(f),( j) CP El Niñ o (1968/69, 1990/91, 1994/95, 2002/03, 2004/05, 2006/07), (c),(g),(k) La Niñ a (1970/71, 1973/74, 1975/76, 1984/85, 1988/89, 1998/99, 1999/2000, 2007/08), and (d),(h),(l) mean seasonal cycle (averaged over 1960-2008).…”

Section: A Mjo Activitysupporting

confidence: 86%

Intraseasonal Tropical Atmospheric Variability Associated with the Two Flavors of El Niño

Gushchina

Dewitte

2012

Monthly Weather Review

View full text Add to dashboard Cite

The characteristics of intraseasonal tropical variability (ITV) associated with the two flavors of El Niño [i.e., the canonical or eastern Pacific (EP) El Niño and the Modoki or central Pacific (CP) El Niño] are documented using composite and regression analysis. Double space–time Fourier analysis is applied to the NCEP–NCAR zonal wind at 850 hPa (U850) to separate the different components of the ITV in the tropical troposphere, which is then used to define indices of wave activity, and document the spatial pattern of the waves. It is shown that the ITV characteristics are altered during CP El Niño compared to the typical seasonal dependence of the ITV–ENSO relationship. In particular, while EP El Niño is characterized by enhanced MJO and equatorial Rossby (ER) wave activity during spring–summer prior to the ENSO peak, during CP El Niño, the ITV activity is increased during the mature and decaying phases. It is suggested that ITV is more propitious to the triggering of the EP event; while during the CP event, it contributes mostly to the persistence of positive SST anomalies. The oceanic response of these ITV anomalous patterns is further investigated in the Simple Ocean Data Assimilation (SODA) reanalysis by documenting the seasonal evolution of the intraseasonal equatorial oceanic Kelvin wave (IEKW) activity during the two flavors of El Niño. It is shown that anomalous westerlies associated with ITV may generate the corresponding response in the ocean in the form of anomalous IEKW activity.

show abstract

Section: A Mjo Activitysupporting

confidence: 86%

Intraseasonal Tropical Atmospheric Variability Associated with the Two Flavors of El Niño

Gushchina

Dewitte

2012

Monthly Weather Review

View full text Add to dashboard Cite

show abstract

“…Despite the large amount of oceanographic climate information existing on this phenomenon (Philander 1990;Escribano et al 2004;Dijkstra 2006;Nyenzi and Lefale 2006;Santos 2006, Sokolikhina et al 2006, and its known impacts on the diversity of marine soft-bottom benthic communities of shallow zones in the HCS (Peru-Chile, e.g., Tarazona et al 1985Tarazona et al , 1988aTarazona et al , 1996Gallardo 1985;Salzwedel et al 1988;Arntz et al 1991;Gutiérrez et al 2000;Laudien et al 2007), our knowledge of the mechanism and processes driving community structure during EN is still scarce.…”

Section: Introductionmentioning

confidence: 99%

Subtidal macrozoobenthos communities from northern Chile during and post El Niño 1997–1998

et al. 2007

View full text Add to dashboard Cite

Despite a large amount of climatic and oceanographic information dealing with the recurring climate phenomenon El Niño (EN) and its well known impact on diversity of marine benthic communities, most published data are rather descriptive and consequently our understanding of the underlying mechanisms and processes that drive community structure during EN are still very scarce. In this study, we address two questions on the effects of EN on macrozoobenthic communities: (1) how does EN affect species diversity of the communities in northern Chile? and (2) is EN a phenomenon that restarts community assembling processes by affecting species interactions in northern Chile? To answer these questions, we compared species diversity and co-occurrence patterns of soft-bottoms macrozoobenthos communities from the continental shelf off northern Chile during (March 1998) and after (September 1998) the strong EN event 1997-1998. The methods used varied from species diversity and species cooccurrence analyses to multivariate ordination methods. Our results indicate that EN positively affects diversity of macrozoobenthos communities in the study area, increasing the species richness and diversity and decreasing the species dominance. EN represents a strong disturbance that affects species interactions that rule the species assembling processes in shallow-water, sea-bottom environments.

show abstract

“…According to previous studies (Hendon et al 2007;Gushchina and Dewitte 2011), interaction between ENSO and MJO is also robust during boreal spring; however, the HF-LF relation is strongest during boreal winter, possibly due to the increase of synoptic-scale wind variability (Sokolikhina et al 2006). In addition, there is the possibility that the degree of the HF-LF relationship can be different when the SST forcing is changed to the boreal spring season.…”

Section: Summary and Discussionmentioning

confidence: 79%

Rectification Feedback of High-Frequency Atmospheric Variability into Low-Frequency Zonal Flows in the Tropical Pacific

2012

View full text Add to dashboard Cite

In this study, the rectification process of high-frequency (HF) zonal-wind variability on the low-frequency (LF) zonal wind is investigated through an idealized experiment using an atmospheric general circulation model (AGCM). Through an idealized AGCM experiment with a fixed SST boundary forcing, it is shown that there is positive (negative) correlation between HF (2-90-day period) zonal-wind variance and LF (3-month average) zonal wind where the HF zonal-wind variance is positively (negatively) skewed because the stronger HF westerly (easterly) wind events than HF easterly (westerly) wind events induce a residual westerly (easterly), and it results in an additional rectified LF westerly (easterly) anomaly. This means that, over regions with positively skewed HF zonal winds, LF westerly anomalies are generated due to the residuals of the HF zonal winds. It implies that the LF zonal wind can be generated through internal processes of the atmosphere without external forcing and the interaction between LF and HF is not a one-way process from LF to HF but, rather, a two-way interaction process.

show abstract

The atmospheric circulation on the synoptic scale during the culmination phase of the El-Niño − Southern Oscillation events (1997−1998)

Cited by 5 publications

References 2 publications

Intraseasonal Tropical Atmospheric Variability Associated with the Two Flavors of El Niño

Intraseasonal Tropical Atmospheric Variability Associated with the Two Flavors of El Niño

Subtidal macrozoobenthos communities from northern Chile during and post El Niño 1997–1998

Rectification Feedback of High-Frequency Atmospheric Variability into Low-Frequency Zonal Flows in the Tropical Pacific

Contact Info

Product

Resources

About