Why does the itcz shift seasonally

The most important consequence of this shifting is the annual alteration of wet and dry seasons in tropical Africa. Annual movement of the intertropical convergence zone ITCZ. Areas near the equator in western and southern Africa have a single intense rainy season from July to September. In eastern Africa S. Ethiopia to central Tanzania , however, there are two rainy seasons.

Since the distance covered by the ITCZ is quite large in this part of the continent, the rainy seasons are less intense than those of western Africa. That is, the ITCZ dumps the same amount of rain in the east as it does in the west, but that rain gets distributed over a larger area in the east because of the greater movement of the weather system. Farther to the north, along the Mediterranean Sea coast, the climate is not affected directly by the ITCZ and rain falls in the winter.

Intertropical convergence zone ITCZ and rain location. Nigeria, therefore, has two major seasons, the dry season and the wet season, the lengths of which vary from north to south. In southern Nigeria, Lagos averages The four observed seasons are:. In northern Nigeria, Kano averages There are only two seasons since the ITCZ only moves into the region once a year before returning south. The two observed seasons are:. Please Contact Us. Toggle navigation JetStream.

So to understand the large scale weather systems and their seasonal patterns, you must start by understanding how solar energy drives the atmospheric circulation. This causes a specific and typical pattern which is locally disrupted by the distribution of land and oceans on the earth. Land masses can be heated more and more quickly than oceans on a seasonal basis, land masses also includes topography that can impede the atmospheric circulation, so it it perhaps obvious that land masses contribute on regional and local scales.

Winds blow from areas of high pressure cold air masses towards areas of low pressure warm air masses. The difference between the ITCZ and the Monsoon Trough is simply the direction of the winds from both hemispheres when they meet.

During the northern hemisphere summer, the winds from the northern hemisphere sometimes change direction from NE to SW. When this occurs you have a Monsoon Trough. Due to the new movement of winds they favor the genesis of vorticity around very low pressures which in turn could form more easily tropical cyclones.

Seasons are the result of this. ITCZ moves toward the hemisphere with most heat, wich are either hemisphere summers. According to me ITCZ is basically the trough where both the north eastern and south western winds converge or meet. You must know that winds move from high pressure to low pressure, therefore when the winds meet an area of low pressure is created on the landmass which in turn brings in winds with moisture causing rainfall. Sign up to join this community.

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Learn more. Why does the Inter tropical Convergence Zone shift? Swart, N. Recent Southern Ocean warming and freshening driven by greenhouse gas emissions and ozone depletion. Deser, C. The role of ocean—atmosphere coupling in the zonal-mean atmospheric response to Arctic Sea ice loss. Tian, B. Diffenbaugh, N. Climate change hotspots in the CMIP5 global climate model ensemble. Xu, L. Hot spots of climate extremes in the future.

Hill, S. Theories for past and future monsoon rainfall changes. Extratropical forcing and tropical rainfall distribution: energetics framework and ocean Ekman advection. NPJ Clim. Biasutti, M. Seasonal and CO 2 -induced shifts of the ITCZ: testing energetic controls in idealized simulations with comprehensive models. Shonk, J. Bain, C. Hartmann, D. Global Physical Climatology 2nd edn Elsevier, Ashouri, H. Lee, H. Download references. Partial support for this research was provided to E. Moreover, the work of E.

The work of P. A research grant from UCI to advance these research ideas is also acknowledged. We thank the climate modelling groups around the world for producing and making their model outputs available. We also acknowledge the help from O. Adam and B. Lintner in discussing parts of this analysis. James T.

Pritchard, Gudrun Magnusdottir, Paul A. You can also search for this author in PubMed Google Scholar. All authors contributed to the conceptualization and interpretation of the results and to extended discussions in the revising and finalizing stages of the manuscript. Peer review information Nature Climate Change thanks Michael Byrne and the other, anonymous, reviewer s for their contribution to the peer review of this work. Reprints and Permissions. Zonally contrasting shifts of the tropical rain belt in response to climate change.

Download citation. Received : 02 September Accepted : 09 November Published : 18 January Issue Date : February Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Nature Communications Climate Dynamics Advanced search. Skip to main content Thank you for visiting nature. Subjects Climate-change impacts Environmental impact Hydrology Projection and prediction.

Abstract Future changes in the position of the intertropical convergence zone ITCZ; a narrow band of heavy precipitation in the tropics with climate change could affect the livelihood and food security of billions of people. Access through your institution. Buy or subscribe. Rent or Buy article Get time limited or full article access on ReadCube.

Data availability The data we use in our analysis are all freely available. Code availability Upon reasonable request, the code that supports the findings of this study can be provided by the corresponding author. References 1. Google Scholar 3.