Grography – ITCZ, Doldrums, Horse Latitude
At sea, ITCZ area is called doldrums because sailors in olden days used to get becalmed here.
It’s the region of weak winds (small pressure gradients), High Humidity and High Temperatures occuring heat near equator.
In olden days, Zones at about 30 N/S Degree were known as Horse latitude.
When ships were becalmed, horses were thrown to reduce the load.
Here, the air is comparatively dry and winds are calm and light, because of small pressure gradient force.
It’s the region of descending air currents or wind divergent ie. Anti-Cyclonic condition.
ITCZ – Inter Tropical Convergence Zone
ITCZ is a zone where the trade winds converge. It’s also referred as the Thermal Equator.
ITCZ can be found as much as 20 degree north of equator in July and 10 degree south of equator in January.
The exceptional shift in ITCZ by 20 degree is seen in South Asia during Summer Season. The exceptional shift of ITCZ plays a significant role in the causation of summer monsoon in South ASIA.
ITCZ is a zone of calm, hot, rising air and low pressure area.