Automated analysis of the temporal behavior of the double Intertropical Convergence Zone over the east Pacific

Henke, Daniel; Smyth, Padhraic; Haffke, C. M.; Magnúsdóttir, Guðrún

doi:10.1016/j.rse.2012.03.022

Cited by 24 publications

(40 citation statements)

References 20 publications

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“…In addition, when the ITCZ is weak, such as outside of the boreal summer months, it may be difficult to outline the boundaries of the ITCZ in instantaneous data. Henke et al (2012) introduced an alternative approach that requires significantly less labeling effort and that is able to recognize the ITCZ in instantaneous data even at times when it is quite scattered and weak. In this approach a statistical pattern recognition model is trained based on a training set of images classified by human labelers according to their state.…”

Section: Introductionmentioning

confidence: 99%

Daily States of the March–April East Pacific ITCZ in Three Decades of High-Resolution Satellite Data

et al. 2016

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Zonally elongated areas of cloudiness that make up the east Pacific intertropical convergence zone (ITCZ) can take on several configurations in instantaneous observations. A novel statistical model is used to automatically assess the daily state of the east Pacific ITCZ using infrared satellite images from 1980 to 2012. Four ITCZ states are defined based on ITCZ location relative to the equator: north (nITCZ) and south (sITCZ) of the equator, simultaneously north and south of the equator (dITCZ, for double ITCZ), and over the equator (eITCZ). A fifth ITCZ state is used to classify days when no zonally elongated area of cloudiness is present (aITCZ, for absent ITCZ). The ITCZ states can occur throughout the year (except for the eITCZ, which is not present during June–October), with the nITCZ state dominating in terms of frequency of occurrence. Interannual variability of the state distribution is large. The most striking variability in ITCZ states is observed in spring. During March–April, the dITCZ state occurs on average 34% of the time, second only to the nITCZ state (39%). Composites of observed infrared temperature and precipitation by ITCZ state reveal distinct spatial configurations of cloudiness and rainfall. Strong sea surface temperature anomalies are associated only with eITCZ and sITCZ and they correspond to El Niño and La Niña, respectively. However, all five ITCZ states are associated with distinct atmospheric circulation patterns. A connection is found between the ITCZ and the South Pacific convergence zone (SPCZ), such that activity in the SPCZ is enhanced when the ITCZ is absent in the east Pacific.

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Section: Introductionmentioning

confidence: 99%

Daily States of the March–April East Pacific ITCZ in Three Decades of High-Resolution Satellite Data

et al. 2016

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“…This archive goes back to 1980 and represents a collection of satellite images that have been further processed, stitched together, and intercalibrated to form a global dataset that is appropriate for climate studies. The ITCZ states were determined using the statistical model for ITCZ detection described in detail in Haffke et al (2016) and in Henke et al (2012). An overview of the distribution of ITCZ states is shown in Fig.…”

Section: A Datamentioning

confidence: 99%

“…During the austral summer in the eastern Pacific the ITCZ tends to remain to the north of the equator although with much decreased activity compared to boreal summer. Outside of boreal summer there is considerably more variability in the location of the ITCZ with respect to the equator (Henke et al 2012;Haffke et al 2016). On daily time scales the ITCZ may exist in five different states with respect to the equator.…”

Section: Introductionmentioning

confidence: 99%

“…The first four are as follws: simultaneously on both sides of the equator (dITCZ), to the north of the equator (nITCZ), to the south of the equator (sITCZ), or the ITCZ may be absent (aITCZ) when the convection is not organized in a longitudinally elongated structure. These were the original four states of the east Pacific ITCZ that were identified by Henke et al (2012) in five years of daily geostationary satellite data . The fifth state was only identified when Haffke et al (2016) extended the study and analyzed data from 1980 to 2012, years that include strong east Pacific El Niño years such as 1997/98 and 1982/83 and were dominated by a strong east Pacific ITCZ located over the equator (eITCZ, for equatorial ITCZ).…”

Section: Introductionmentioning

confidence: 99%

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Interannual Signature in Daily ITCZ States in the East Pacific in Boreal Spring

Yang

Magnúsdóttir

2016

Journal of Climate

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The intertropical convergence zone (ITCZ) in the east Pacific is located north of the equator during most of the year. In daily data it is most variable in March-April when it may be located north of the equator (nITCZ), on both sides of the equator (dITCZ), or south of the equator (sITCZ), or it may be absent (when convection does not take on a zonally elongated form). Additionally, in strong El Niño years it is located on the equator during the boreal winter half-year. Here the focus is on conditions when the ITCZ has a presence south of the equator (dITCZ, sITCZ) and composites of various fields are compared to ''normal conditions'' [i.e., when the ITCZ is north of the equator (nITCZ)]. Composites of sea surface temperature (SST), precipitation, outgoing longwave radiation, and the upper-level circulation show very similar patterns for dITCZ and sITCZ days, where the latter cases have almost double the amplitude of the former. The sITCZ state is viewed as an extreme case of the dITCZ state. Both are found to be related to the central Pacific (CP) La Niña with anomalous positive SST and atmospheric heating over the western tropical Pacific and anomalous negative SST and cooling over the central tropical Pacific. Ocean-atmosphere interaction plays an important role in developing the dITCZ and sITCZ anomalies. These daily composite patterns can be reproduced by the regression of monthly fields on the cold CP El Niño-Southern Oscillation mode, suggesting that the interannual rather than day-to-day variability dominates in contributing to the patterns of the composites.

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“…Also genetic algorithms, self-organized mapping systems and techniques of nearest neighbor were used by Henke, Sieglaff and Parikh in [3]- [5]. Furthermore, tracking techniques have been implemented using satellite image processing and neural networks (NN) in Chandan [5].…”

Section: Introductionmentioning

confidence: 99%

Técnicas inteligentes para la identificación y el seguimiento de fenómenos meteorológicos que podrían afectar la seguridad de vuelo

Zuluaga

Vargas²,

Reina³

2017

Ciencia y Poder Aéreo

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Resumo: Na aviação, os fenômenos meteorológicos são um dos aspectos mais importantes a ter em conta em todas as etapas do vôo, do planejamento ao pouso. O desenvolvimento de sistemas de previsão do tempo aplicados à aviação pode apoiar o processo de tomada de decisão de controladores e pilotos de tráfego aéreo, facilitando a análise de variáveis meteorológicas e fornecendo uma primeira interpretação disponível para todos os usuários do sistema de ar . Por esta razão, o Centro de Desenvolvimento Tecnológico para a Defesa (CETAD) tem como objetivo principal neste documento descrever os resultados do desenvolvimento de uma metodologia sistematizada que utiliza técnicas inteligentes para a detecção, identificação e monitoramento de qualquer tipo de treinamento que, devido às suas características pode representar um risco para a aviação, gerando, por sua vez, informações de suporte para o controlador de tráfego aéreo. Para isso, é necessário primeiro identificar as formações convectivas, classificá-las, filtrar o ruído e individualizá-las. Este tipo de processo pode ser automatizado através da análise inteligente Resumen: en la aviación, los fenómenos meteorológicos son uno de los aspectos más importantes para tener en cuenta en todas las etapas de vuelo, desde la planificación hasta el aterrizaje. El desarrollo de sistemas de predicción meteorológica aplicados a la aviación puede apoyar el proceso de toma de decisiones de los controladores de tráfico aéreo y los pilotos, facilitando el análisis de las variables meteorológicas y proporcionando una primera interpretación a disposición de todos los usuarios del sistema aéreo. Por esta razón el Centro de desarrollo Tecnológico para la Defensa (CETAD) tiene como principal objetivo en este documento describir los resultados del desarrollo de una metodología sistematizada que utiliza técnicas inteligentes para la detección, identificación y seguimiento de cualquier tipo de formación que por sus características pueda representar un riesgo para la aviación, generando a su vez información de soporte al controlador aéreo. Para esto es necesario primero identificar las formaciones convectivas, clasificarlas, filtrar el ruido e individualizarlas. Este tipo de procesos pueden ser automatizados a través del análisis inteligente de productos disponibles en cualquier sistema aéreo como las imágenes satelitales multiespectrales. Posterior a una identificación, se deben determinar un grupo de características que permitan desarrollar algoritmos eficientes capaces de realizar un seguimiento del comportamiento de la formación convectiva, que permita generar pronósticos de las características de los sistemas convectivos en el corto plazo, para lo que se requiere conocer otras variables como el viento en las áreas de análisis. Este tipo de aplicaciones integradas a los sistemas de control de tráfico aérea disminuirían los riesgos debidos factores meteorológicos.Palabras clave: sistemas de control de aire, análisis meteorológico, inteligencia artificial, imá-genes satelitales, sistemas de p...

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Automated analysis of the temporal behavior of the double Intertropical Convergence Zone over the east Pacific

Cited by 24 publications

References 20 publications

Daily States of the March–April East Pacific ITCZ in Three Decades of High-Resolution Satellite Data

Daily States of the March–April East Pacific ITCZ in Three Decades of High-Resolution Satellite Data

Interannual Signature in Daily ITCZ States in the East Pacific in Boreal Spring

Técnicas inteligentes para la identificación y el seguimiento de fenómenos meteorológicos que podrían afectar la seguridad de vuelo

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