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Academic literature on the topic 'Intraseasonal Oscillation in Atmosphere'

Author: Grafiati

Published: 6 September 2023

Last updated: 7 September 2023

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Journal articles on the topic "Intraseasonal Oscillation in Atmosphere"

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Bellon, Gilles, Adam H. Sobel, and Jerome Vialard. "Ocean–Atmosphere Coupling in the Monsoon Intraseasonal Oscillation: A Simple Model Study." Journal of Climate 21, no. 20 (October 15, 2008): 5254–70. http://dx.doi.org/10.1175/2008jcli2305.1.

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Abstract A simple coupled model is used in a zonally symmetric aquaplanet configuration to investigate the effect of ocean–atmosphere coupling on the Asian monsoon intraseasonal oscillation. The model consists of a linear atmospheric model of intermediate complexity based on quasi-equilibrium theory coupled to a simple, linear model of the upper ocean. This model has one unstable eigenmode with a period in the 30–60-day range and a structure similar to the observed northward-propagating intraseasonal oscillation in the Bay of Bengal/west Pacific sector. The ocean–atmosphere coupling is shown to have little impact on either the growth rate or latitudinal structure of the atmospheric oscillation, but it reduces the oscillation’s period by a quarter. At latitudes corresponding to the north of the Indian Ocean, the sea surface temperature (SST) anomalies lead the precipitation anomalies by a quarter of a period, similarly to what has been observed in the Bay of Bengal. The mixed layer depth is in phase opposition to the SST: a monsoon break corresponds to both a warming and a shoaling of the mixed layer. This behavior results from the similarity between the patterns of the predominant processes: wind-induced surface heat flux and wind stirring. The instability of the seasonal monsoon flow is sensitive to the seasonal mixed layer depth: the oscillation is damped when the oceanic mixed layer is thin (about 10 m deep or thinner), as in previous experiments with several models aimed at addressing the boreal winter Madden–Julian oscillation. This suggests that the weak thermal inertia of land might explain the minima of intraseasonal variance observed over the Asian continent.

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Roundy, Paul E., and Joseph R. Kravitz. "The Association of the Evolution of Intraseasonal Oscillations to ENSO Phase." Journal of Climate 22, no. 2 (January 15, 2009): 381–95. http://dx.doi.org/10.1175/2008jcli2389.1.

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Abstract The Pacific Ocean intraseasonal Kelvin wave is a leading oceanic mode that links intraseasonal tropical atmospheric variations with interannual variations in the coupled ocean–atmosphere system. This study considers the premise that these waves may evolve differently with their associated weather patterns during different phases of El Niño–Southern Oscillation (ENSO). If atmospheric and oceanic intraseasonal modes interact and evolve differently during various stages of ENSO, this result may provide useful information with regard to the role of these intraseasonal processes in ENSO evolution. This work utilizes signals of the oceanic Kelvin wave as a statistical basis for a simple composite averaging technique that is applied during different phases of ENSO to objectively analyze the evolution of oceanic and the associated portions of atmospheric intraseasonal oscillations. Results confirm the above premise and suggest that coupling between Kelvin waves and atmospheric convection evolves differently during different stages of ENSO. Further, intraseasonal zonal wind anomalies across the east Pacific timed with oceanic Kelvin waves are stronger during adjustment toward El Niño than during adjustment away from El Niño. These and other patterns in the composites suggest the possibility that systematic changes in the evolution of intraseasonal variations over the course of ENSO might feed back upon this interannual mode to influence the evolution of ENSO itself.

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Krishnamurthy, V., Cristiana Stan, David A. Randall, Ravi P. Shukla, and James L. Kinter. "Simulation of the South Asian Monsoon in a Coupled Model with an Embedded Cloud-Resolving Model." Journal of Climate 27, no. 3 (January 24, 2014): 1121–42. http://dx.doi.org/10.1175/jcli-d-13-00257.1.

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Abstract The simulation of the South Asian monsoon by a coupled ocean–atmosphere model with an embedded cloud-resolving model is analyzed on intraseasonal and interannual time scales. The daily modes of variability in the superparameterized Community Climate System Model, version 3 (SP-CCSM), are compared with those in observation, the superparameterized Community Atmospheric Model, version 3 (SP-CAM3), and the control simulation of CCSM (CT-CCSM) with conventional parameterization of convection. The CT-CCSM fails to simulate the observed intraseasonal oscillations but is able to generate the atmospheric El Niño–Southern Oscillation (ENSO) mode, although with regular biennial variability. The dominant modes of variability extracted from daily anomalies of outgoing longwave radiation, precipitation, and low-level horizontal wind in SP-CCSM consist of two intraseasonal oscillations and two seasonally persisting modes, in good agreement with observation. The most significant observed features of the intraseasonal oscillations correctly simulated by the SP-CCSM are the northward propagation of convection, precipitation, and circulation as well as the eastward and westward propagations. The observed spatial structure and the periods of the oscillations are also well captured by the SP-CCSM, although with lesser magnitude. The SP-CCSM is able to simulate the chaotic variability and spatial structure of the seasonally persisting atmospheric ENSO mode, while the evidence for the Indian Ocean dipole mode is inconclusive. The SP-CAM3 simulates two intraseasonal oscillations and the atmospheric ENSO mode. However, the intraseasonal oscillations in SP-CAM3 do not show northward propagation while their periods and spatial structures are not comparable to observation. The results of this study indicate the necessity of coupled models with sufficiently realistic cloud parameterizations.

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Rokade, M. V., R. Kondala Rao, S. S. Nikte, R. N. Ghodpage, P. T. Patil, A. K. Sharma, and S. Gurubaran. "Intraseasonal oscillation (ISO) in the MLT zonal wind over Kolhapur (16.8° N) and Tirunelveli (8.7° N)." Annales Geophysicae 30, no. 12 (December 5, 2012): 1623–31. http://dx.doi.org/10.5194/angeo-30-1623-2012.

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Abstract. Simultaneous observations of the mean zonal winds at 88 km obtained by the medium-frequency (MF) radars at Kolhapur (16.8° N, 74.2° E) and Tirunelveli (8.7° N, 77.8° E) have been used to study the intraseasonal oscillation (ISO) in the MLT region. The influences of the intraseasonal variations in the lower tropospheric convective activity associated with the Madden-Julian oscillations on the latitudinal behavior of intraseasonal oscillations (ISO) of the zonal winds in the equatorial mesosphere and lower thermosphere (MLT) have been studied. The ISO activity in the lower tropospheric convective activity is examined by employing outgoing long wave radiation (OLR) as a proxy for deep convective activity occurring in the tropical lower atmosphere. The ISO activity in the zonal wind over TIR is more correlated with that in the convective activity compared to the ISO over KOL. The latitudinal and temporal variabilities of the ISO in MLT zonal winds are explained in terms of the intraseasonal variabilities in the convective activity.

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Hu, Qi, Zhaoning Liang, and Michael W. Hoffman. "Detecting Source Regions of Wave Activities in the Tropical Atmosphere by Applying Beamforming to Interpolated Data Grids." Journal of Atmospheric and Oceanic Technology 26, no. 2 (February 1, 2009): 270–80. http://dx.doi.org/10.1175/2008jtecha1121.1.

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Abstract Wave activities are primary sources of weather disturbances and cyclones in the tropical atmosphere. One such activity is the intraseasonal variations in wind, convection, and precipitation in the tropical Indian and western tropical Pacific region. These variations affect the intensity, break and reset, and rainfall in the Indian and the East Asian monsoons. Detecting the source regions of these wave activities is essential for understanding and for prediction of wave development. In this study, a fixed beamforming method is proposed to deduce source regions of some wave activities in the tropical atmosphere. This method is tested with simulations of single and distributed complex sources of waves and, then, fixed beamformers are applied to the ECMWF interpolated data grids to detect and identify source regions of the intraseasonal oscillations–waves in the tropical Indian and tropical Pacific Ocean region. Results show that the fixed beamforming technique can uniquely identify the source regions of the intraseasonal oscillations. Applications of this method have revealed various source regions of all major intraseasonal oscillation (ISO) events in the tropical Indian and western equatorial Pacific region during the 29 yr from 1974 to 2002. Knowing these source regions will make it possible to extract the relevant information and, thus, to better understand the development of the intraseasonal oscillations as well as their effects on the tropical weather and climate.

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Wang, Lu, Tim Li, and Tianjun Zhou. "Intraseasonal SST Variability and Air–Sea Interaction over the Kuroshio Extension Region during Boreal Summer." Journal of Climate 25, no. 5 (March 2012): 1619–34. http://dx.doi.org/10.1175/jcli-d-11-00109.1.

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The structure and evolution characteristics of intraseasonal (20–100 day) variations of sea surface temperature (SST) and associated atmospheric and oceanic circulations over the Kuroshio Extension (KE) region during boreal summer are investigated, using satellite-based daily SST, observed precipitation data, and reanalysis data. The intraseasonal SST warming in the KE region is associated with an anomalous anticyclone in the overlying atmosphere, reduced precipitation, and northward and downward currents in the upper ocean. The corresponding atmospheric and oceanic fields during the SST cooling phase exhibit a mirror image with an opposite sign. A mixed layer heat budget analysis shows that the intraseasonal SST warming is primarily attributed to anomalous shortwave radiation and latent heat fluxes at the surface. The anomalous sensible heat flux and oceanic advection also have contributions, but with a much smaller magnitude. The SST warming caused by the atmospheric forcing further exerts a significant feedback to the atmosphere through triggering the atmospheric convective instability and precipitation anomalies. The so-induced heating leads to quick setup of a baroclinic response, followed by a baroclinic-to-barotropic transition. As a result, the atmospheric circulation changes from an anomalous anticyclone to an anomalous cyclone. This two-way interaction scenario suggests that the origin of the atmospheric intraseasonal oscillation over the KE region may partly arise from the local atmosphere–ocean interaction.

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Klingaman, Nicholas P., Steven J. Woolnough, Hilary Weller, and Julia M. Slingo. "The Impact of Finer-Resolution Air–Sea Coupling on the Intraseasonal Oscillation of the Indian Monsoon." Journal of Climate 24, no. 10 (May 15, 2011): 2451–68. http://dx.doi.org/10.1175/2010jcli3868.1.

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Abstract A newly assembled atmosphere–ocean coupled model, called HadKPP, is described and then used to determine the effects of subdaily air–sea coupling and fine near-surface ocean vertical resolution on the representation of the Northern Hemisphere summer intraseasonal oscillation. HadKPP comprises the Hadley Centre atmospheric model coupled to the K-Profile Parameterization ocean boundary layer model. Four 30-member ensembles were performed that vary in ocean vertical resolution between 1 and 10 m and in coupling frequency between 3 and 24 h. The 10-m, 24-h ensemble exhibited roughly 60% of the observed 30–50-day variability in sea surface temperatures and rainfall and very weak northward propagation. Enhancing only the vertical resolution or only the coupling frequency produced modest improvements in variability and just a standing intraseasonal oscillation. Only the 1-m, 3-h configuration generated organized, northward-propagating convection similar to observations. Subdaily surface forcing produced stronger upper-ocean temperature anomalies in quadrature with anomalous convection, which likely affected lower-atmospheric stability ahead of the convection, causing propagation. Well-resolved air–sea coupling did not improve the eastward propagation of the boreal summer intraseasonal oscillation in this model. Upper-ocean vertical mixing and diurnal variability in coupled models must be improved to accurately resolve and simulate tropical subseasonal variability. In HadKPP, the mere presence of air–sea coupling was not sufficient to generate an intraseasonal oscillation resembling observations.

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Fu, Xiouhua, Bo Yang, Qing Bao, and Bin Wang. "Sea Surface Temperature Feedback Extends the Predictability of Tropical Intraseasonal Oscillation." Monthly Weather Review 136, no. 2 (February 1, 2008): 577–97. http://dx.doi.org/10.1175/2007mwr2172.1.

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Abstract The possible impacts of different sea surface temperature (SST) configurations on the predictability of the boreal summer tropical intraseasonal oscillation (TISO) are assessed with a series of ensemble forecasts. The five different lower boundary conditions examined in this study are, respectively, (i) the fully interactive ocean–atmosphere coupling, (ii) “smoothed” SST, which excludes the intraseasonal signal from sea surface forcing, (iii) damped persistent SST, (iv) coupling to a slab mixed-layer ocean, and (v) daily SST from the coupled forecast. The full atmosphere–ocean coupling generates an interactive SST that results in the highest TISO predictability of about 30 days over Southeast Asia. The atmosphere-only model is capable of reaching this predictability if the ensemble mean daily SST forecast by the coupled model is used as the lower boundary condition, which suggests that, in principle, the so-called tier-one and tier-two systems have the same predictability for the boreal summer TISO. The atmosphere-only model driven by either smoothed or damped persistent SSTs, however, has the lowest predictability (∼20 days). The atmospheric model coupled to a slab mixed-layer ocean achieves a predictability of 25 days. The positive SST anomalies in the northern Indo–western Pacific Oceans trigger convective disturbances by moistening and warming up the atmospheric boundary layer. The seasonal mean easterly shear intensifies the anomalous convection by enhancing the surface convergence. An overturning meridional circulation driven by the off-equatorial anomalous convection suppresses the near-equatorial convection and enhances the northward flows, which further intensify the off-equatorial surface convergence and the TISO-related convection. Thus, the boreal summer mean easterly shear and the overturning meridional circulation in the northern Indo–western Pacific sector act as “amplifiers” for the SST feedback to the convection of the TISO.

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Rydbeck, Adam V., Eric D. Maloney, Shang-Ping Xie, Jan Hafner, and Jeffrey Shaman. "Remote Forcing versus Local Feedback of East Pacific Intraseasonal Variability during Boreal Summer." Journal of Climate 26, no. 11 (May 31, 2013): 3575–96. http://dx.doi.org/10.1175/jcli-d-12-00499.1.

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Abstract During boreal summer (June–October), interactions between intraseasonal variability in the Eastern Hemisphere and east Pacific warm pool are often described as a local amplification of the Madden–Julian oscillation (MJO), the dominant mode of tropical intraseasonal variability. The MJO in the Eastern Hemisphere emits eastward-propagating dry Kelvin waves that are a source of rapid communication with the east Pacific. However, the precise mechanism by and degree to which intraseasonal variability in the Eastern Hemisphere interacts with the east Pacific are not well understood. To quantify the relationship, sensitivity tests in two separate models are used: the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM) and the International Pacific Research Center Regional Atmosphere Model (IRAM). Different methods are employed to isolate the east Pacific from outside intraseasonal signals in each model. When isolated from Kelvin wave fronts associated with the MJO, the CAM produces similar east Pacific intraseasonal variability to observations. In the CAM, the communication of intraseasonal signals by Kelvin waves does not appear necessary to the initiation and maintenance of east Pacific intraseasonal variability, suggesting that such events can be independent of the MJO. However, communication by MJO-initiated Kelvin waves provides a possible phase locking mechanism between hemispheres. When the east Pacific is isolated from all remote intraseasonal signals in the IRAM, intraseasonal events there are weak and incoherent. In the IRAM communication across the Pacific appears necessary to the representation of east Pacific intraseasonal variability. However, the IRAM contains an important bias in the climatological low-level winds that may suppress east Pacific intraseasonal events.

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Wang, Xu, and Guang J. Zhang. "Evaluation of the Quasi-Biweekly Oscillation over the South China Sea in Early and Late Summer in CAM5." Journal of Climate 32, no. 1 (December 4, 2018): 69–84. http://dx.doi.org/10.1175/jcli-d-18-0072.1.

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Abstract Low-frequency intraseasonal oscillations in the tropical atmosphere in general circulation models (GCMs) were studied extensively in many previous studies. However, the simulation of the quasi-biweekly oscillation (QBWO), which is an important component of the intraseasonal oscillations, in GCMs has not received much attention. This paper evaluates the QBWO features over the South China Sea in early [May–June (MJ)] and late [August–September (AS)] summer in the National Center for Atmospheric Research (NCAR) Community Atmosphere Model, version 5.3 (CAM5), using observations and reanalysis data. Results show that the major features of the spatial distribution of the QBWO in both MJ and AS are simulated reasonably well by the model, although the amplitude of the variation is overestimated. CAM5 captures the local oscillation in MJ and the westward propagation in AS of the QBWO. Although there are important biases in geographical location and intensity in MJ, the model represents the QBWO horizontal and vertical structure qualitatively well in AS. The diagnosis of the eddy vorticity budget is conducted to better understand the QBWO activities in the model. Both horizontal advection of relative vorticity and that of planetary vorticity (Coriolis parameter) are important for the local evolution of the QBWO in MJ in observations as well as model simulation, whereas advection of planetary vorticity contributes to the westward propagation of QBWO vorticity anomalies in AS. Since the Coriolis parameter f only changes with latitude, this suggests that the correct simulation of anomalous meridional wind is a key factor in the realistic simulation of the QBWO in the model.

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Dissertations / Theses on the topic "Intraseasonal Oscillation in Atmosphere"

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Teng, Haiyan. "Interannual variations of the boreal summer intraseasonal oscillation." Thesis, University of Hawaii at Manoa, 2003. http://proquest.umi.com/pqdweb?index=0&did=765086511&SrchMode=2&sid=2&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1233255418&clientId=23440.

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Burton, Kenneth R. "Influence of Antarctic oscillation on intraseasonal variability of large-scale circulations over the Western North Pacific /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FBurton.pdf.

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Burton, Kenneth R. Jr. "Influence of Antarctic oscillation on intraseasonal variability of large-scale circulations over the Western North Pacific." Thesis, Monterey California. Naval Postgraduate School, 2005. http://hdl.handle.net/10945/2310.

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This study examines Southern Hemisphere mid-latitude wave variations connected to the Antarctic Oscillation (AAO) to establish connections with the 15- to 25-day wave activity in the western North Pacific monsoon trough region. The AAO index defined from the leading empirical orthogonal functions of 700 hPa height anomalies led to seven distinct circulation patterns that vary in conjunction with the 15- to 25-day monsoon trough mode. For nearly one half of the significant events the onset of 15- to 25-day monsoon trough convective activity coincided with a peak negative AAO index and the peak in monsoon trough convection coincided with a peak positive index. The remaining events either occur when the AAO is not significantly varying or when the AAO-related Southern Hemisphere mid-latitude circulations do not match 15- to 25-day transitions. When a significant connection occurs between the Southern Hemisphere mid-latitude circulations related to the AAO and the 15- to 25-day wave activity in the western North Pacific monsoon trough, the mechanism is via equatorward Rossby-wave dispersion. When wave energy flux in the Southern Hemisphere is directed zonally, no connection is established between the AAO and the alternating periods of enhanced and reduced convection in the western North Pacific monsoon trough.
Captain, United States Air Force

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McDaniel, Brent. "Intraseasonal Dynamical Evolution of the Northern Annular Mode." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6965.

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Recent observational and modeling studies indicate a robust dynamical coupling between the stratosphere and troposphere during boreal winter. This coupling occurs in association with the Northern Annular Mode (NAM), which itself accounts for a significant fraction of the variability of the extratropical circulation. While monthly NAM dynamics have been studied previously, the mechanisms that give rise to NAM variability on short intraseasonal timescale are still unclear. We perform regression analyses, case studies, and composites based on periods of dynamical growth/decay to investigate the roles of the different proposed mechanisms in driving the atmospheric variability observed in association with the NAM on short intraseasonal timescales. More specifically, lag-regression analyses are used to identify the mean canonical structures present during the evolution of a typical NAM event. Illustrative case studies of robust stratospheric NAM events but with different tropospheric signals are contrasted in order to identify the underlying dynamical reasons for the observed differences. Finally, composite analyses of NAM tendencies are performed to isolate the structural and dynamical evolution of NAM events. Zonal-mean and three-dimensional eddy-flux diagnoses are used to examine the role of eddy-mean flow interaction in driving the wind tendencies characteristic of the NAM. In particular, Plumb flux analyses are employed to quantify the contribution of regional stationary wave anomalies toward the zonal mean wind tendency field. Potential vorticity inversions are also used to determine the role of stratospheric anomalies in inducing tropospheric circulations. The case study analyses indicate that preexisting tropospheric PV anomalies can mask the downward penetration of an initial stratospheric NAM signal into the troposphere. PV inversions further suggest that a minimum requirement for a direct downward stratospheric influence is that the stratospheric NAM signal be robust in the lower stratosphere. The dynamical composites show a remarkable degree of reverse symmetry between the zonal-mean dynamical evolution of positive and negative NAM events. Anomalous Eliassen-Palm fluxes are observed in the troposphere and stratosphere, consistent with index of refraction considerations and an indirect downward influence of the stratosphere on the troposphere. The patterns of anomalous wave driving, primarily due to low-frequency planetary scale waves, provide the main forcing of the zonal mean wind tendency field. Regional wave activity fluxes indicate that the wave driving pattern represents the manifestation of planetary scale anomalies over the North Atlantic.

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Agudelo, Paula A. "Role of Local Thermodynamic Coupling in the Life Cycle of the Intraseasonal Oscillation in the Indo-Pacific Warm Pool." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19834.

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Intraseasonal oscillations (ISOs) are important elements of the tropical climate with time-scales of 20-80 day. The ISO is poorly simulated and predicted by numerical models. This work presents a joint diagnostic and modeling study of the ISO that examines the hypothesis that local coupling between the ocean and the atmosphere is essential to the existence and evolution of the ISO in the Indo-Pacific warm pool region. Low-level moistening during the transition phase preconditions the atmosphere for deep convection. The vertical structure of ISO from the ECMWF coupled model during different phases of the oscillation as well as the skill of the model in simulating the processes that occur during the transition phase were studied. The forecast skill of the vertical structure associated with the ISO is greater for winter than for summer events. Predictability of the convective period is poor when initialized before the transitional phase. When initialized within the transition period including lower tropospheric moistening, predictability increases substantially, although the model parameterizations appears to trigger convection quickly without allowing an adequate buildup of CAPE during the transition. The model tends to simulate a more stable atmosphere compared to data, limiting the production of deep convective events. Two different one-dimensional coupled models are used to analyze the role of local ocean-atmosphere coupling in generating ISO. The ocean component is a one-dimensional mixed layer model. In the first model the atmospheric component corresponds to the SCCM. Results suggest that convection in the model tends to be "overactive," inhibiting development of lower frequency oscillations in the atmosphere. In the second case, the atmospheric component is a semi-empirical model that allows reproducing the coupled ISO over long integration periods including only local mechanisms. In the semi-empirical scheme the rate of change of atmospheric variables is statistically related to changes in SST. The stable state of this model is a quasi-periodic oscillation with a time scale between 25 and 80 days that matches well the observed ISO. Results suggest that the period of the oscillation depends on the characteristics of the ocean mixed layer, with a higher frequency oscillation for a shallow mixed layer.

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Zuluaga-Arias, Manuel D. "Spatial and temporal distribution of latent heating in the South Asian monsoon region." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31753.

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Thesis (M. S.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2010.
Committee Chair: Peter J. Webster; Committee Member: Judith A. Curry; Committee Member: Robert X. Black. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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Matthews, Adrian John. "The intraseasonal oscillation." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358464.

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Hoyos, Carlos D. "Intraseasonal Variability: Processes, Predictability and Prospects for Prediction." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-04102006-135125/.

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Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2006.
Dr. Peter J. Webster, Committee Chair ; Dr. Judith A. Curry, Committee Member ; Dr. Robert Dickinson, Committee Member ; Dr. Robert X. Black, Committee Member ; Dr. Predrag Cvitanovic, Committee Member.

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Charlesworth, Oliver. "Intraseasonal European climate variability and interactions with the Madden-Julian Oscillation." Thesis, University of East Anglia, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490613.

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The seasonally-varying interaction between the Madden-Julian Oscillation (MJO) and .the northern extratropics, specifically the North Atlantic and Europe region, on intraseasonal timescales is studied. When the MJO is observed using composite and Monte-Carlo significance testing, a direct response to the tropical dynamics is found over the North Atlantic and Europe. When the MJO convection is active over the Indian Ocean, significant anticyclonic anomalies at the 95% confidence level are frequently found over the UK and eastern North Atlantic region. Approximately 10 to 20 days later, when the MJO convection is active over Indonesia, the extratropical anomalies occur in similar locations with opposite sign. Using a systematic two-month sliding season approach to investigate the interaction, the anomalies are present for the majority of the year, favouring the boreal spring. The relationship between the MJO and the North Atlantic Oscillation (NAO) for each of the 12 seasons throughout the year is quantified for the first time using regression analysis. Although correlations between the MJO and NAO are weak, further regressions between the MJO and a North Atlantic 1000 hPa geopotential height index just east of the UK gives very strong boreal springtime correlations of up to r=0.50 and anti-correlations of r=-0.53. An Intermediate Global Circulation Model (IGCM) is used to model the MJO to investigate the mechanisms behind the strong tropical-extratropical interactions. Various stages of representing the MJO in the model are presented using fixed and time dependent heating profiles and many of the observed extratropical features are reproduced as a response to the forcing. Direct comparisons between the observations and the model results are made and the level at which it is able to reproduce the North Atlantic and European anomalies is discussed.

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Valad?o, Cati Elisa de Avila. "Impacts of the Madden-Julian oscillation on intraseasonal precipitation over northeast Brazil." Universidade Federal do Rio Grande do Norte, 2015. http://repositorio.ufrn.br/handle/123456789/20695.

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The impacts of the Madden?Julian Oscillation (MJO) on precipitation over Northeast Brazil (NEB, also known as Nordeste) are evaluated based on daily raingauge data from 492 stations over 30-year period (1981-2010). Composites of precipitation, outgoing longwave radiation and moisture-flux anomalies are performed for each phase of the MJO based on the Jones?Carvalho MJO index. To distinguish the MJO signal from other patterns of climate variability, daily data are filtered using a 20 - 90 day band-pass filter; only days classified as MJO events are considered in the composites. A preliminary analysis based on precipitation data was conducted for a small scale area located in NEB?s semiarid interior, in an area known as Serid?. The Serid? is one of the driest regions in NEB, and is recognized by the United Nations Convention to Combat Desertification as particularly vulnerable to desertification. Composites of rainfall anomalies were computed for each of the eight phases of the MJO during February-May, which is Serid??s main rainy season. Results showed that the rainfall patterns in Serid? undergo substantial changes (from enhancement to suppression) as the convective center of the MJO propagates eastward. When combining the MJO signals for wet and dry phases, the difference represents about 50 - 150% modulation of the mean rainfall over Serid?. Then a comprehensive analysis of the role of the MJO in modulating the spatiotemporal variation of NEB?s precipitation was performed, considering all four seasons. The results showed strong seasonality of the MJO impact on precipitation. The most spatially coherent signals of precipitation anomalies occurred in the austral summer, when about 80% of the raingauge stations showed increased precipitation during phases 1 - 2 and suppressed precipitation in phases 5 - 6 of the oscillation. Although the MJO impacts precipitation on intraseasonal timescales in all seasons in most locations, these impacts vary in magnitude and depend on the phase of the oscillation. Precipitation anomalies over NEB are explained by the interaction of convectively coupled Kelvin-Rossby waves with the dominant climatic features in each season. During the austral summer and spring, westerly regimes increased precipitation over most NEB. In the austral winter and fall, precipitation anomalies exhibited more complex spatial variability. In these seasons precipitation anomalies in eastern coastal areas depended on the strength of the South Atlantic anticyclone, which is largely modulated by Rossby waves. The strengthening of the anticyclone intensified the convergence of the trade winds in coastal areas and precipitation windward of the coastal range. Conversely, the intensification of the subsidence was responsible for precipitation deficits in the lee side of the range. These conditions were typically observed when easterly regimes dominate over tropical South America and NEB, decreasing moisture flow from the Amazon.
Este estudo tem como objetivo investigar os impactos da oscila??o de Madden-Julian (OMJ) na precipita??o da regi?o Nordeste do Brasil (NEB). Para tanto foram utilizados dados di?rios de precipita??o baseados em 492 pluvi?metros distribu?dos na regi?o e cobrindo um per?odo de 30 anos (1981 ? 2010). As an?lises atrav?s de composi??es de anomalias de precipita??o, radia??o de onda longa e fluxo de umidade, foram obtidas com base no ?ndice da OMJ desenvolvido por Jones-Carvalho. Para distinguir o sinal da OMJ de outros padr?es de variabilidade clim?tica, todos os dados di?rios foram filtrados na escala de 20 ? 90 dias; portanto somente dias classificados como eventos da OMJ foram considerados nas composi??es. Uma an?lise preliminar baseada apenas nos dados de precipita??o foi feita para uma pequena ?rea localizada no interior semi?rido do NEB, conhecida como Serid?. Essa microrregi?o ? uma das ?reas mais secas do NEB e foi reconhecida pela Conven??o das Na??es Unidas para o Combate ? Desertifica??o e Mitiga??o dos Efeitos das Secas como particularmente vulner?vel ? desertifica??o. Composi??es de anomalias de precipita??o foram feitas para cada uma das oito fases da OMJ durante Fevereiro-Maio (principal per?odo chuvoso da microrregi?o). Os resultados mostraram a exist?ncia de varia??es significativas nos padr?es de precipita??o (de precipita??o excessiva ? deficiente) associados ? propaga??o da OMJ. A combina??o dos sinais de precipita??o obtidos durantes as fases ?midas e secas da OMJ mostrou que a diferen?a corresponde cerca de 50 ? 150% de modula??o das chuvas na microrregi?o. Em seguida, uma investiga??o abrangente sobre o papel da OMJ sobre toda a regi?o Nordeste foi feita considerando-se as quatro esta??es do ano. Os resultados mostraram que os impactos da OMJ na precipita??o intrassazonal do NEB apresentam forte sazonalidade. A maior coer?ncia espacial dos sinais de precipita??o ocorreram durante o ver?o austral, quando cerca de 80% das esta??es pluviom?tricas apresentaram anomalias positivas de precipita??o durante as fases 1 ? 2 da OMJ e anomalias negativas de precipita??o nas fases 5 ? 6 da oscila??o. Embora impactos da OMJ na precipita??o intrassazonal tenham sido encontrados na maioria das localidades e em todas as esta??es do ano, eles apresentaram varia??es na magnitude dos sinais e dependem da fase da oscila??o. As anomalias de precipita??o do NEB observadas s?o explicadas atrav?s da intera??o existente entre as ondas de Kelvin-Rossby acopladas convectivamente e as caracter?sticas clim?ticas predominantes sobre a regi?o em cada esta??o do ano. O aumento de precipita??o observado sobre a maior parte do NEB durante o ver?o e primavera austrais encontra-se associado com o fluxo de umidade de oeste (regime de oeste), o qual favorece a atividade convectiva em amplas ?reas da Am?rica do Sul tropical. Por outro lado, as anomalias de precipita??o durante o inverno e outono austrais apresentaram uma variabilidade espacial mais complexa. Durante estas esta??es, as anomalias de precipita??o observadas nas esta??es localizadas na costa leste do NEB dependem da intensidade do anticiclone do Atl?ntico Sul, o qual ? modulado em grande parte por ondas de Rossby. As caracter?sticas topogr?ficas do NEB parecem desempenhar um papel importante na variabilidade observada na precipita??o, principalmente nestas ?reas costeiras. A intensifica??o do anticiclone aumenta a converg?ncia dos ventos al?sios na costa contribuindo para a ocorr?ncia de precipita??o observada ? barlavento do planalto da Borborema. Por outro lado, o aumento da subsid?ncia parece ser respons?vel pelos d?ficits de precipita??o observados ? sotavento. Tais condi??es mostraram-se t?picas durante o predom?nio do regime de leste sobre a regi?o tropical da Am?rica do Sul e o NEB, durante o qual ocorre uma diminui??o no fluxo de umidade proveniente da Amaz?nia.

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Books on the topic "Intraseasonal Oscillation in Atmosphere"

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Lau, William K. M., and Duane E. Waliser. Intraseasonal Variability in the Atmosphere-Ocean Climate System. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-13914-7.

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Lau, William K. M. Intraseasonal Variability in the Atmosphere-Ocean Climate System. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012.

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E, Waliser Duane, ed. Intraseasonal variability in the atmosphere-ocean climate system. Berlin: Springer-Verlag, 2005.

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G, Vincent Dayton, and United States. National Aeronautics and Space Administration., eds. Relationship between intraseasonal oscillation and subtropical wind maxima over the South Pacific Ocean. [Washington, DC: National Aeronautics and Space Administration, 1991.

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Allan, Robert J. El Niño, southern oscillation & climatic variability. Collingwood, Vic., Australia: CSIRO, 1996.

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Wright, Peter B. Relationships between surface observations over the global oceans and the southern oscillation. Seattle, Wash: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, 1985.

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F, Diaz Henry, and Markgraf Vera, eds. El Niño: Historical and paleoclimatic aspects of the southern oscillation. Cambridge [England]: Cambridge University Press, 1992.

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El Niño, La Niña, and the southern oscillation. San Diego: Academic Press, 1990.

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Kikuchi, Kazuyoshi. Data analysis studies on the propagation characteristics of the Madden-Julian Oscillation (MJO). [Tokyo]: Center for Climate System Research, University of Tokyo, 2006.

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Allan, Rob. El Niño Southern Oscillation and climatic variability. Collingwood, Vict: CSIRO PUblishing, 1996.

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Book chapters on the topic "Intraseasonal Oscillation in Atmosphere"

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Lau, William K. M., and Duane E. Waliser. "El Niño Southern Oscillation connection." In Intraseasonal Variability in the Atmosphere-Ocean Climate System, 297–334. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-13914-7_9.

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Lau, William K. M., Duane E. Waliser, K. R. Sperber, J. M. Slingo, and P. M. Inness. "Modeling intraseasonal variability." In Intraseasonal Variability in the Atmosphere-Ocean Climate System, 399–431. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-13914-7_11.

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Pawson, Steven, Karin Labitzke, Barbara Naujokat, Risheng Wang, and Klaus Fraedrich. "Intraseasonal Tropical—Extra-Tropical Interactions Observed in the Stratosphere." In Coupling Processes in the Lower and Middle Atmosphere, 35–47. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1594-0_3.

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Lau, William K. M., Duane E. Waliser, Roland A. Madden, and Paul R. Julian. "Historical perspective." In Intraseasonal Variability in the Atmosphere-Ocean Climate System, 1–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-13914-7_1.

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Lau, William K. M., Duane E. Waliser, and Bin Wang. "Theories." In Intraseasonal Variability in the Atmosphere-Ocean Climate System, 335–98. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-13914-7_10.

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Lau, William K. M., Duane E. Waliser, and Duane Waliser. "Predictability and forecasting." In Intraseasonal Variability in the Atmosphere-Ocean Climate System, 433–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-13914-7_12.

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Lau, William K. M., Duane E. Waliser, and Mathew Barlow. "Africa and West Asia." In Intraseasonal Variability in the Atmosphere-Ocean Climate System, 477–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-13914-7_13.

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Lau, William K. M., Duane E. Waliser, and Paul E. Roundy. "Tropical–extratropical interactions." In Intraseasonal Variability in the Atmosphere-Ocean Climate System, 497–512. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-13914-7_14.

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Lau, William K. M., Duane E. Waliser, and Jean Philippe Duvel. "Oceans and air–sea interaction." In Intraseasonal Variability in the Atmosphere-Ocean Climate System, 513–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-13914-7_15.

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Lau, William K. M., Duane E. Waliser, and Chidong Zhang. "Vertical structure from recent observations." In Intraseasonal Variability in the Atmosphere-Ocean Climate System, 537–48. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-13914-7_16.

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Conference papers on the topic "Intraseasonal Oscillation in Atmosphere"

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Zhou, Qun, and Lixin Wei. "Impacts of the Madden-Julian Oscillation on South China Sea Monsoon." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-19301.

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Abstract It is of great practical importance to understand the variability of the South China Sea (SCS) monsoon on intraseasonal time scales, since the anomalous enhancement of the SCS monsoon may exert serious impacts on the safety of offshore engineering and marine transportation. Our composite analysis shows that the SCS surface wind anomalies are considerably varying with the Madden-Julian Oscillation (MJO) eastward propagation. The SCS summer southwest monsoon tends to be stronger (weaker) in phases 5–8 (1–4) of MJO with the largest positive (negative) wind-speed anomalies when the MJO convection is centered in the western Pacific (far western Indian Ocean), suggesting the highest (lowest) probability of the gale over the SCS. The variation of the western Pacific Subtropical High (WPSH), induced by the variations of the local meridional circulation, is shown to play a crucial role in the MJO-SCS summer monsoon linkage. The SCS winter monsoon is also shown to be modulated by the MJO with strengthened (weakened) surface northeasterly in phases 5–6 (1–2). The extra-tropical East Asian trough and East Asian westerly jet associated with the local meridional circulation can well explain the changes of the MJO-SCS winter monsoon relationship. The opposite responses of the wind direction during the same phases of the MJO between summer and winter may be attributed to the discrepancy of meridional circulation related to the wintertime equatorward shift of the MJO convection. The present study indicates that the MJO could be taken into consideration when applying extended-range weather forecast over the SCS as the predictability of the MJO activity is up to 15–20 day currently.

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Feng, Jianying, Yuanpu Liu, and Zhilan Wang. "Application of atmospheric low-frequency oscillation on meteorological drought forecast in Eastern part of the Northwest China." In Remote Sensing of the Atmosphere, Clouds, and Precipitation VII, edited by Eastwood Im and Song Yang. SPIE, 2018. http://dx.doi.org/10.1117/12.2324833.

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Watanabe, Masahiro. "Sensitivity of convectively coupled modes to basic state: implication to the Madden-Julian Oscillation under the Walker circulation." In Third International Asia-Pacific Environmental Remote Sensing Remote Sensing of the Atmosphere, Ocean, Environment, and Space, edited by Zhaobo Sun, Fei-Fei Jin, and Toshiki Iwasaki. SPIE, 2003. http://dx.doi.org/10.1117/12.466585.

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Hegyi, Bradley M., and Patrick C. Taylor. "Seasonal clear-sky flux and cloud radiative effect anomalies in the Arctic atmospheric column associated with the Arctic Oscillation and Arctic Dipole." In RADIATION PROCESSES IN THE ATMOSPHERE AND OCEAN (IRS2016): Proceedings of the International Radiation Symposium (IRC/IAMAS). Author(s), 2017. http://dx.doi.org/10.1063/1.4975524.

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Hou, Xiaofan, Zhongning Sun, Guangming Fan, Jiguo Tang, and Jiqiang Su. "Flow Characteristics in an Open Two-Phase Natural Circulation Loop." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30549.

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The flow characteristics of an open single-tube (Φ38×2000 mm), two-phase natural circulation (TPNC) loop was investigated, under the condition of constant saturated temperature at the atmosphere (99±0.5°C) at the inlet of heating tube. Five typical circulation modes are observed in the range of experiment heating power (from 2.8 kW to 34.8kW), namely intermittent flashing oscillation, geysering and flashing induced oscillation, flashing boiling eruption and flashing induced oscillation, sustained flashing and steady two-phase flow. It was shown that flashing and geysering or boiling eruption are predominant factors influencing flow characteristics. Moreover, a calculation model is developed to investigate the static flow characteristics of the TPNC system. The calculation results show a good agreement with the experiments. In addition, the calculation results show that the static flow excursion phenomenon may occurs in the open TPNC system, under the higher heating powers.

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Liu, Xunwei, Weiwei Shao, Yong Tian, Yan Liu, Bin Yu, Zhedian Zhang, and Yunhan Xiao. "Investigation of H2/CH4-Air Flame Characteristics of a Micromix Model Burner at Atmosphere Pressure Condition." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-76276.

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For high-hydrogen-content fuel, the Micromix Combustion Technology has been developed as a potential low NOx emission solution for gas turbine combustors, especially for advanced gas turbines with high turbine inlet temperature. Compared with conventional lean premixed flames, multiple distributed slim and micro flames could lead to a lower NOx emission performance for shortening residence time of high temperature flue gas and generally a more uniform temperature distribution. This work aims at micromix flame characteristics of a model burner fueled with hydrogen blending with methane under atmosphere pressure conditions. The model burner assembly was designed to have six concentrically millimeter-sized premixed units around a same unit centrally. Numerical and experimental studies were conducted on mixing performance, flame stability, flame structure and CO/NOx emissions of the model burner. OH radical distribution by OH-PLIF and OH chemiluminescence (OH*) imaging were employed to analyze the turbulence-reaction interactions and characters of the reaction zone at the burner exit. Micromix flames fueled with five different hydrogen content H2-CH4 (60/40, 50/50, 40/60, 30/70, 0/100 Vol.%) were investigated, along with the effects of equivalence ratio and heat load. Results indicated that low NOx emissions of less than 10 ppm (@15% O2) below the exhaust temperature of 1920 K were obtained for all the different fuels. Combustion oscillation didn’t occur for all the conditions. It was found that at a constant flame temperature, the higher the hydrogen content of the fuel, the higher the turbulent flame speed and the weaker the flame lift effect. Combustion noise and NOx emissions also increase with increasing hydrogen content. The OH/OH* signal distribution indicated that a pure methane micromix flame showed a lifted and weaken distributed feature.

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Morimoto, Yuichiro, Kenji Kawamata, Haruki Madarame, and Koji Okamoto. "Bifurcation of Water Column Oscillator Behavior Simulating Reactor Safety System: 1st Report, Experiment." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32555.

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The non-periodical oscillation was reported in Water Column Oscillator, which simulates a passive safety system of a future nuclear reactor, however, the mechanism of the oscillation is not clarified. The objective of this study is to elucidate the mechanism of non-periodical oscillation in Water Column Oscillator experimentally and analytically. The U-type rectangular duct is filled with the water in a certain degree of height. An end of the duct is sealed and the other is open to the atmosphere. The electromagnetic valve is installed at the top of the sealed side. A cover gas simulating vapor generation by residual heat is injected constantly into the gas phase of the sealed side. The water column oscillation with its natural frequency continues until the free surface in the sealed side, pushed by the gas, reaches at a certain height. When the height of the water level reaches HL, the electromagnetic valve is open and the cover gas flows out from the U-type duct. The gas is ejected rapidly, and thus, the cover gas pressure decreases almost to the atmospheric pressure. The water level in the sealed side of the duct rises with water supply from the open side and reaches a certain height HU. Then the valve is closed again and the increasing gas pressure pushes down the water surface of the sealed side. The water level oscillates repeating the above process. The analytical model which agrees well with the experiment is derived. The bifurcation-like phenomenon is shown in experiment, however, it can be clear that the phenomenon is not bifurcation but noise effects by the numerical simulation with noise effects. The variation of characteristics of oscillation are investigated in detail by using Poincare´ section (Y2(N), U2(N)), which indicate cover gas pressure and water level velocity at the beginning of the Nth valve-open instant. The parameter region where the system shows bifurcation can be discovered by the numerical simulation. The bifurcation is confirmed in the experiment.

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Aristizabal, Jaime, Carlos Motta, Nelson Obregon, Carlos Capachero, Leonardo Real, and Julian Chaves. "Supervised Learning Algorithms Applied in the Zoning of Susceptibility by Hydroclimatological Geohazards." In ASME-ARPEL 2021 International Pipeline Geotechnical Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/ipg2021-65003.

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Abstract Cenit Transporte y Logística de Hidrocarburos (CENIT), operator of about 7000 km of hydrocarbon transport systems, which constitutes it the largest operator in Colombia, has developed a strategic alliance to structure an adaptive geotechnical susceptibility zoning using supervised learning algorithms. Through this exercise, has been implemented operational decision inferences with simple linguistic values. The difficulties proposed by the method considers the hydroclimatology of Colombia, which is conditioned by several phenomena of Climate Variability that affect the atmosphere at different scales such as the Oscillation of the Intertropical Convergence Zone - ITCZ (seasonal scale) and the occurrence of macroclimatic phenomena such as El Niño-La Niña Southern Oscillation (ENSO) (interannual scale). Likewise, it considers the geotechnical complexity derived from the different geological formation environments, the extension and geographical dispersion of the infrastructure, and its interaction with the climatic regimes, to differentiate areas of interest based on the geohazards of hydrometeorological origin, when grouped into five clusters. The results of this exercise stand out the importance of keep a robust record of the events that affect the infrastructure of hydrocarbon transportation systems and using data-guided intelligence techniques to improve the tools that support decision-making in asset management.

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Navia, Diaz Juan, Diaz Juan Navia, Bolaños Nancy Villegas, Bolaños Nancy Villegas, Igor Malikov, and Igor Malikov. "EXTREME VALUES OF SEA SURFACE TEMPERATURE ASSOCIATED WITH LONG-PERIOD PHENOMENA OCCURRED DURING 1960-2015 IN THE COLOMBIAN PACIFIC OCEAN." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b943a9e4336.75393991.

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Sea Surface Temperature Anomalies (SSTA), in four coastal hydrographic stations of Colombian Pacific Ocean, were analyzed. The selected hydrographic stations were: Tumaco (1°48'N-78°45'W), Gorgona island (2°58'N-78°11'W), Solano Bay (6°13'N-77°24'W) and Malpelo island (4°0'N-81°36'W). SSTA time series for 1960-2015 were calculated from monthly Sea Surface Temperature obtained from International Comprehensive Ocean Atmosphere Data Set (ICOADS). SSTA time series, Oceanic Nino Index (ONI), Pacific Decadal Oscillation index (PDO), Arctic Oscillation index (AO) and sunspots number (associated to solar activity), were compared. It was found that the SSTA absolute minimum has occurred in Tumaco (-3.93°C) in March 2009, in Gorgona (-3.71°C) in October 2007, in Solano Bay (-4.23°C) in April 2014 and Malpelo (-4.21°C) in December 2005. The SSTA absolute maximum was observed in Tumaco (3.45°C) in January 2002, in Gorgona (5.01°C) in July 1978, in Solano Bay (5.27°C) in March 1998 and Malpelo (3.64°C) in July 2015. A high correlation between SST and ONI in large part of study period, followed by a good correlation with PDO, was identified. The AO and SSTA have showed an inverse relationship in some periods. Solar Cycle has showed to be a modulator of behavior of SSTA in the selected stations. It was determined that extreme values of SST are related to the analyzed large scale oscillations.

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Navia, Diaz Juan, Diaz Juan Navia, Bolaños Nancy Villegas, Bolaños Nancy Villegas, Igor Malikov, and Igor Malikov. "EXTREME VALUES OF SEA SURFACE TEMPERATURE ASSOCIATED WITH LONG-PERIOD PHENOMENA OCCURRED DURING 1960-2015 IN THE COLOMBIAN PACIFIC OCEAN." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b431547291f.

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Sea Surface Temperature Anomalies (SSTA), in four coastal hydrographic stations of Colombian Pacific Ocean, were analyzed. The selected hydrographic stations were: Tumaco (1°48'N-78°45'W), Gorgona island (2°58'N-78°11'W), Solano Bay (6°13'N-77°24'W) and Malpelo island (4°0'N-81°36'W). SSTA time series for 1960-2015 were calculated from monthly Sea Surface Temperature obtained from International Comprehensive Ocean Atmosphere Data Set (ICOADS). SSTA time series, Oceanic Nino Index (ONI), Pacific Decadal Oscillation index (PDO), Arctic Oscillation index (AO) and sunspots number (associated to solar activity), were compared. It was found that the SSTA absolute minimum has occurred in Tumaco (-3.93°C) in March 2009, in Gorgona (-3.71°C) in October 2007, in Solano Bay (-4.23°C) in April 2014 and Malpelo (-4.21°C) in December 2005. The SSTA absolute maximum was observed in Tumaco (3.45°C) in January 2002, in Gorgona (5.01°C) in July 1978, in Solano Bay (5.27°C) in March 1998 and Malpelo (3.64°C) in July 2015. A high correlation between SST and ONI in large part of study period, followed by a good correlation with PDO, was identified. The AO and SSTA have showed an inverse relationship in some periods. Solar Cycle has showed to be a modulator of behavior of SSTA in the selected stations. It was determined that extreme values of SST are related to the analyzed large scale oscillations.

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Reports on the topic "Intraseasonal Oscillation in Atmosphere"

1

Straus, David M., and Jagadish Shukla. Predictability of the North Atlantic Oscillation on Intraseasonal Time Scales. Fort Belvoir, VA: Defense Technical Information Center, September 2013. http://dx.doi.org/10.21236/ada597695.

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