Class Notes (906,457)
CA (538,611)
UTSC (32,642)
BIOC50H3 (31)
Lecture

lecture note 7

2 Pages
130 Views

Department
Biological Sciences
Course Code
BIOC50H3
Professor
Herbert Kronzucker

This preview shows half of the first page. Sign up to view the full 2 pages of the document.
LECTURE 7:
- Two key factors determine the distribution of ecosystems on Earth more than any other:
(1) precipitation, and (2) temperature
- Tropospheric air masses are circulated by solar energy (~1% of the total average energy
input into Earth creates the global wind movements); this creates the main patterns of
precipitation
- Air circulation occurs via a set of three distinct cells in the two hemispheres: the
Hadley, Ferrell, and Polar cells
- The Hadley cell (active between 0o to 30o N. and S. latitude; here we describe it for the
Northern hemisphere): the sun heats air at the equator, causing it to expand and rise; it
takes with it large quantities of moisture; as air masses rise, they cool adiabatically (the
adiabatic lapse rate: 100C/km for dry air, 60C/km for moist air) and release their
moisture content in the form of precipitation (thisfeeds the tropical rainforests); the
high-altitude air masses move away from the equator to the North, lose energy, and
descend at ~300 N. latitude (they carry almost no moisture at this point; most of the
world’s deserts are located here, in the semi-permanent high-pressure/low-precipitation
zone that results); upon descending, the air masses split to move as surface winds, with
onearm moving North (these are the Westerlies; the jet stream is a part of this) and the
other moving South, back to the equator (as the Northeast trade winds; these are the
winds that brought Columbus to America); the zone where the Hadley cells of the two
hemispheres meet is called the Intertropical Convergence Zone (ITCZ; there is a dead
zone of very little wind at the surface, known as the doldrums, right where the cells meet;
the similarly windstill zones at the 300 latitudes are known as the horse latitudes)
www.notesolution.com

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.

Leah — University of Toronto

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah — University of Toronto
Saarim — University of Michigan

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim — University of Michigan
Jenna — University of Wisconsin

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna — University of Wisconsin
Anne — University of California

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne — University of California
Description
LECTURE 7: - Two key factors determine the distribution of ecosystems on Earth more than any other: (1) precipitation, and (2) temperature - Tropospheric air masses are circulated by solar energy (~1% of the total average energy input into Earth creates the global wind movements); this creates the main patterns of precipitation - Air circulation occurs via a set of three distinct cells in the two hemispheres: the Hadley, Ferrell, and Polar cells - The Hadley cell (active between 0o to 30o N. and S. latitude; here we describe it for the Northern hemisphere): the sun heats air at the equator, causing it to expand and rise; it takes with it large quantities of moisture; as air masses rise, they cool adiabatically (the adiabatic lapse rate: 100C/km for dry air, 60C/km for moist air) and release their moisture content in the form of precipitation (this “feeds” the tropical rainforests); the high-altitude air masses move away from the equator to the North, lose energy, and descend at ~300 N. latitude (they carry almost no moisture at this point; most of the world’s deserts are located here, in the semi-permanent high-pressure/low-precipitation zone that results); upon descending, the air masses split to move as surface winds, with one “arm” moving North (these are the Westerlies; the jet stream is a part of this) and the other moving South, back to the equator (as the Northeast trade winds; these are the winds that brought Columbus to America); the zone where the Hadley cells of the two hemispheres meet is called the Intertropical Convergence Zone (ITCZ; there is a dead zone of very little wind at the surface, known as the doldrums, right where the cells meet; the similarly windstill zones at the 300 latitudes are known as the horse latitudes) www.notesolution.com - The northward-moving component of the surface winds gives rise to the Ferrell cell (Toronto is in this zone); it moves as far as ~600; the Westerlies pick up moisture until they hit the Polar cell at 600, which moves cold surface air from the North; in the collision zone, air masses rise and produce the abundant rainfall of temperate regions (a semi-permanent low-pressure zone); where the Westerlies are intercepted by large mountain chains that run from North to South (e.g. the Coast Mountains, the Columbia Mountains, and the Rocky Mountains of British Columbia), the air masses are forced up vertically, cool adiabatically, and release their moisture on the Western flank of the mountains, leaving rainshadows along the Eastern flanks (e.g. the Okanagan of B.C.; some rainshadows create extremely dry deserts, such as Death Valley, California) - The Polar cell (between 60o to 90o N. latitude) completes the air circulation pattern; it produces the Polar Easterlies (this one is responsible for Arctic cold fronts) - A similar three-cell pattern governs the Southern hemisphere - The vectors of the surface wind components for each tropospheric circulation cell (Hadley, Ferrell, and Polar) are shifted “to the right” in the N. hemisphere and “to the left” in the S. hemisphere by the Coriolis force www.notesolution.comLECTURE 7: - Two key factors determine the distribution of ecosystems on Earth more than any other: (1) precipitation, and (2) temperature - Tropospheric air masses are circulated by solar energy (~1% of the total average energy input into Earth creates the global wind movements); this creates the main patterns of precipitation - Air circulation occurs via a set of three distinct cells in the two hemispheres: the Hadley, Ferrell, and Polar cells - The Hadley cell (active between 0 to 30 N. and S. latitude; here we describe it for the Northern hemisphere): the sun heats air at the equator, causing it to expand and rise; it takes with it large quantities of moisture; as air masses rise, they cool adiabatically (the adiabatic lapse rate: 10 Ckm for dry air, 6 Ckm for moist air) and release their moisture content in the form of precipitation (this feeds the tropical rainforests); the high-altitude air masses move a
More Less
Unlock Document


Only half of the first page are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit