Structure and Properties of Synoptic-Scale Wave Disturbances in the Intertropical Convergence Zone of the Eastern Atlantic

1979 ◽  
Vol 36 (1) ◽  
pp. 53-72 ◽  
Author(s):  
Robert M. Thompson ◽  
Steven W. Payne ◽  
Ernest E. Recker ◽  
Richard J. Reed
Keyword(s):  
Intertropical Convergence Zone ◽  
Convergence Zone ◽  
Structure And Properties ◽  
Synoptic Scale ◽  
Wave Disturbances

scholarly journals African monsoons, Part 2: Synoptic-scale wave disturbances in the intertropical convergence zone over north Africa

MAUSAM ◽  
2022 ◽  
Vol 53 (2) ◽  
pp. 197-214
Author(s):  
KSHUDIRAM SAHA ◽  
SURANJANA SAHA
Keyword(s):  
North Africa ◽  
Stationary Wave ◽  
Life Cycles ◽  
Intertropical Convergence Zone ◽  
Vertical Shear ◽  
Dynamical Instability ◽  
Convergence Zone ◽  
Nile Valley ◽  
Tropical Zone ◽  
Wave Disturbances

In this part, the paper discusses several aspects of the origin, structure, development and movement of wave disturbances over the North African tropical zone during the northern summer. Analyzing the cases often actual wave disturbances which later in their life cycles developed into hurricanes over the Atlantic, it finds that though the horizontal and vertical shear of the mean zonal wind associated with the mid-tropospheric easterly jet over Africa satisfies the condition of dynamical instability under certain restrictive boundary conditions, it is the influence of a large-amplitude baroclinic wave in mid-latitude westerlies upon a stationary wave in the mountainous region of the east-central north Africa that appears to trigger the birth of a wave disturbance in the intertropical convergence zone over the Nile valley of Sudan between the Marra and the Ethiopian mountains. Physical processes likely to be important in the formation, development and movement of the disturbances are pointed out.

OH measurement near the Intertropical Convergence Zone in the Pacific

1987 ◽  
Vol 92 (D2) ◽  
pp. 2020 ◽  
Author(s):  
L. I. Davis ◽  
John V. James ◽  
Charles C. Wang ◽  
Chuan Guo ◽  
Peter T. Morris ◽  
...  
Keyword(s):  
Intertropical Convergence Zone ◽  
Convergence Zone ◽  
The Pacific

scholarly journals Dynamics of the Intertropical Convergence Zone of the East Pacific

2006 ◽  
Vol 63 (2) ◽  
pp. 582-597 ◽  
Author(s):  
David J. Raymond ◽  
Christopher S. Bretherton ◽  
John Molinari
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Deep Convection ◽  
Intertropical Convergence Zone ◽  
Surface Fluxes ◽  
Balance Model ◽  
Convergence Zone ◽  
East Pacific ◽  
Layer Flow ◽  
Sst Gradient

Abstract The dynamical factors controlling the mean state and variability of the east Pacific intertropical convergence zone (ITCZ) and the associated cross-equatorial boundary layer flow are investigated using observations from the East Pacific Investigation of Climate (EPIC2001) project. The tropical east Pacific exhibits a southerly boundary layer flow that terminates in the ITCZ. This flow is induced by the strong meridional sea surface temperature (SST) gradient in the region. Away from the equator and from deep convection, it is reasonably well described on a day-to-day basis by an extended Ekman balance model. Variability in the strength and northward extent of this flow is caused by variations in free-tropospheric pressure gradients that either reinforce or oppose the pressure gradient associated with the SST gradient. These free-tropospheric gradients are caused by easterly waves, tropical cyclones, and the Madden–Julian oscillation. Convergence in the boundary layer flow is often assumed to be responsible for destabilizing the atmosphere to deep convection. An alternative hypothesis is that enhanced total surface heat fluxes associated with high SSTs and strong winds act to produce the necessary destabilization. Analysis of the moist entropy budget of the planetary boundary layer shows that, on average, surface fluxes generate over twice the destabilization produced by boundary layer convergence in the east Pacific ITCZ.

The Intertropical Convergence Zone

2013 ◽  
pp. 35-46
Author(s):  
T. N. Krishnamurti ◽  
Lydia Stefanova ◽  
Vasubandhu Misra
Keyword(s):  
Intertropical Convergence Zone ◽  
Convergence Zone

scholarly journals Three distinct Holocene intervals of stalagmite deposition and nondeposition revealed in NW Madagascar, and their paleoclimate implications

2017 ◽  
Vol 13 (12) ◽  
pp. 1771-1790 ◽  
Author(s):  
Ny Riavo Gilbertinie Voarintsoa ◽  
Loren Bruce Railsback ◽  
George Albert Brook ◽  
Lixin Wang ◽  
Gayatri Kathayat ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
High Resolution ◽  
Late Holocene ◽  
Intertropical Convergence Zone ◽  
Convergence Zone ◽  
High Resolution Data ◽  
The Holocene ◽  
Middle Holocene ◽  
Resolution Data

Abstract. Petrographic features, mineralogy, and stable isotopes from two stalagmites, ANJB-2 and MAJ-5, respectively from Anjohibe and Anjokipoty caves, allow distinction of three intervals of the Holocene in NW Madagascar. The Malagasy early Holocene (between ca. 9.8 and 7.8 ka) and late Holocene (after ca. 1.6 ka) intervals (MEHI and MLHI, respectively) record evidence of stalagmite deposition. The Malagasy middle Holocene interval (MMHI, between ca. 7.8 and 1.6 ka) is marked by a depositional hiatus of ca. 6500 years. Deposition of these stalagmites indicates that the two caves were sufficiently supplied with water to allow stalagmite formation. This suggests that the MEHI and MLHI intervals may have been comparatively wet in NW Madagascar. In contrast, the long-term depositional hiatus during the MMHI implies it was relatively drier than the MEHI and the MLHI. The alternating wet–dry–wet conditions during the Holocene may have been linked to the long-term migrations of the Intertropical Convergence Zone (ITCZ). When the ITCZ's mean position is farther south, NW Madagascar experiences wetter conditions, such as during the MEHI and MLHI, and when it moves north, NW Madagascar climate becomes drier, such as during the MMHI. A similar wet–dry–wet succession during the Holocene has been reported in neighboring locations, such as southeastern Africa. Beyond these three subdivisions, the records also suggest wet conditions around the cold 8.2 ka event, suggesting a causal relationship. However, additional Southern Hemisphere high-resolution data will be needed to confirm this.

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