why do the itcz subtropical highs and subpolar lows all move throughout the course of the year

by Josephine Hessel IV 10 min read

The sun shines directly on the equator during the equinoxes • The sun shines above the equator during the northern summer • The sun shines below the equator during the northern winter • The ITCZ forms directly under the area where the sun hits directly • Thus, the ITCZ moves above and below the equator depending on the season: The ITZC, as denoted by the clouds that form in it.

Full Answer

What is ITCZ (Intertropical Convergence Zone)?

3 Why does the ITCZ move throughout the year in a regular pattern? 4 Why does the ITCZ shift above and below the equator during the summer in each hemisphere? 5 What happens during ITCZ? 6 Why do surrounding winds move near the equator? 7 How does the location of the ITCZ change over time?

How does the ITCZ shift from north to South?

• ITCZ will always be under the place where the sun hits Earth at a right angle • During the transitional and dry seasons from November to April, the ITCZ is located south of Costa Rica, either at the equator or even further south • When the ITCZ is directly over Costa Rica during July, September and October, rainfall is heaviest

How does the ITCZ affect the formation of tropical storms?

Why do the ITCZ, subtropical highs, and subpolar lows all move throughout the course of the year? _____ _____ 14. How would the movement of the subtropical high affect the weather at places around 35º latitude?

How does the ITCZ follow the Sun?

As the ITCZ migrates to tropical and subtropical latitudes and even beyond during the respective hemisphere's summer season, increasing Coriolis force makes the formation of tropical cyclones within this zone more possible. Surges of higher pressure from high latitudes can enhance tropical disturbances along its axis.

Why does the ITCZ move around throughout the year?

The ITCZ moves throughout the year and follows the migration of the Sun's overhead position typically with a delay of around 1-2 months. As the ocean heats up more slowly than land, the ITCZ tends to move further north and south over land areas than that over water.

Why do you think the subtropical highs and the ITCZ shifted between January and now?

(2006) have revealed one important driver of ITCZ shifts: differential heating or cooling of the hemispheres shifts the ITCZ toward the differentially warming hemisphere. So when the northern hemisphere warms, for example, because northern ice cover and with it the polar albedo are reduced, the ITCZ shifts northward.

What is the meteorological ITCZ equator and why does it move?

The Intertropical Convergence Zone, or ITCZ, is the region that circles the Earth, near the equator, where the trade winds of the Northern and Southern Hemispheres come together. The intense sun and warm water of the equator heats the air in the ITCZ, raising its humidity and making it buoyant.Jul 11, 2000

Why does ITCZ shift north and south of the equator?

The shifting of ITCZ is the result of the Earth's rotation, axis inclination and the translation of Earth around the Sun. Seasons are the result of this. ITCZ moves toward the hemisphere with most heat, wich are either hemisphere summers.Jan 23, 2015

Why is there high pressure in subtropics?

In climatology As the hot air rises it cools, losing moisture; it is then transported poleward where it descends, creating the high-pressure area. This is part of the Hadley cell circulation and is known as the subtropical ridge or subtropical high, and is strongest in the summer.

What is a characteristic of subtropical highs?

They are characterized by sunny skies, calm winds, and very little precipitation. They are also known as subtropical ridges, or highs. It is a high-pressure area at the divergence of trade winds and the westerlies.

Why is the ITCZ low pressure?

Tropical and Sub-Tropical West Africa The ITCZ is characterized by low atmospheric pressures (low intertropical pressures), as a consequence of the upward movement induced by the trade winds convergence. It results in high atmospheric pressure in the upper troposphere.

How does the ITCZ impact the tropical grasslands climate?

Because the ITCZ moves south in January, northern hemisphere Savanna and Monsoon areas see high pressure and therefore a distinct dry season. The opposite happens in July when the ITCZ moves north; there is a wet season in both of these climates.

Why do air parcels warm up when they compress?

It also promotes sinking air, which as you may recall, causes air parcels to warm as they compress because of increasing air pressure at lower altitudes.

What is the difference between the Northern Hemisphere and the warmer continents?

During the Northern Hemisphere's summer, the oceans are generally cooler compared to the warmer continents. In turn, cooler, denser maritime air that overlies the oceans serves to boost surface pressures, paving the way for relatively robust subtropical highs during summer.

What causes Hadley circulation to be obliterated?

For example, the Hadley circulation in the Northern Hemisphere's summer gets nearly obliterated by the intense, uneven heating of continents and oceans at low latitudes (the interruption of the Hadley circulation during the Southern Hemisphere's summer is noticeably less pronounced).

Is the subtropical high dry?

As a result, the region of subtropical highs tends to be very dry. For example, the desert landscape of Monument Valley.

What happens when the intertropical convergence zone is narrow?

Longer term changes in the intertropical convergence zone can result in severe droughts or flooding in nearby areas. In some cases, the ITCZ may become narrow, especially when it moves away from the equator; the ITCZ can then be interpreted as a front along the leading edge of the equatorial air.

Where does the ITCZ migrate?

As the ITCZ migrates to tropical and subtropical latitudes and even beyond ( Shandong province of the People's Republic of China) during the respective hemisphere's summer season, increasing Coriolis force makes the formation of tropical cyclones within this zone more possible.

How does the intertropical convergence zone affect rainfall?

Variation in the location of the intertropical convergence zone drastically affects rainfall in many equatorial nations, resulting in the wet and dry seasons of the tropics rather than the cold and warm seasons of higher latitudes. Longer term changes in the intertropical convergence zone can result in severe droughts or flooding in nearby areas.

What is the ITCZ?

Meteorological phenomenon. The ITCZ is visible as a band of clouds encircling Earth near the Equator. The Intertropical Convergence Zone ( ITCZ, pronounced "itch" ), known by sailors as the doldrums or the calms because of its monotonous windless weather, is the area where the northeast and the southeast trade winds converge.

Why is the ITCZ called the Doldrums?

As trans-equator sea voyages became more common, sailors in the eighteenth century named this belt of calm the doldrums because of the calm, stagnant, or inactive winds.

How is ITCZ formed?

The ITCZ is formed by vertical motion largely appearing as convective activity of thunderstorms driven by solar heating, which effectively draw air in; these are the trade winds. The ITCZ is effectively a tracer of the ascending branch of the Hadley cell and is wet. The dry descending branch is the horse latitudes .

Why is migration more prominent over land?

As the heat capacity of the oceans is greater than air over land, migration is more prominent over land. Over the oceans, where the convergence zone is better defined, the seasonal cycle is more subtle, as the convection is constrained by the distribution of ocean temperatures. Sometimes, a double ITCZ forms, with one located north ...

How does the ITCZ shift?

It shifts from north and south seasonally according to the movement of the Sun. For Example- when the ITCZ is shifted to north of the Equator, the southeast trade wind changes to a southwest wind as it crosses the Equator. The ITCZ shifts only between 40° to 45° of latitude north or south of the equator based on the pattern of land and ocean.

What causes the ITCZ?

What causes ITCZ (Intertropical Convergence Zone)? ITCZ (Intertropical Convergence Zone) is caused by the convergence of northeast and southeast trade winds in the area encircling Earth near the Equator. For better understanding, we must know about the trade winds and air masses. 1.

What is the ITCZ?

The ITCZ (Intertropical Convergence Zone) play important role in the global circulation system and also known as the Equatorial Convergence Zone or Intertropical Front. It is a basically low pressure belt encircling Earth near the Equator. It is a zone of convergence where the trade winds meet.

Why is the ITCZ important?

It helps in the formation of cyclone because it is a zone of wind change and speed. The ITCZ is a narrow zone where trade winds of two hemispheres collide which causes erratic weather patterns with stagnant calms and violent thunderstorms.

What are trade winds?

Trade Winds: Easterly winds that circle the Earth near the equator. 2. Air Masses: A volume of air defined by its temperature and water vapour content. In tropical latitudes this air mass is hot to very hot, with high relative humidity, bringing unstable weather.

What is the ITCZ?

The intertropical convergence zone (ITCZ) is a belt of calm air where northeast trades and southeast trades converge, generally in the vicinity of the equator. The ITCZ is also known as the equatorial front, intertropical front, and the doldrums. The ITCZ's thunderstorms provide the updrafts where all the rising air of the tropics ascends.

What is a subtropical high?

The subtropical highs (STHs) are large semi-permanent high-pressure (anticyclone) cells centered at about 30° latitude over the oceans; have average diameters of 3,200 kilometers (2,000 miles) and are usually elongated east-west. They develop from the descending air of the Hadley cells.

What is the low pressure belt?

There is weak pressure gradient in the equatorial low pressure belt.This is a region of calm winds known as the Doldrums. The high pressure belts at about 30 degree N and S are called 'Horse latitudes'.This belt is characterised by calm or light variable winds and clear weathe.