EESA09H3 Lecture Notes - Lecture 8: Minimax, Migraine, Toronto Pearson International Airport
EESA09 Lecture 8 – Local Wind Circulation & Thermal Winds
THERMAL WINDS
- Land/sea Breeze
SEA BREEZE
oThermally induced circulation
oCauses pressure differences – association w/temperature difference
oOften associated w/day + night contrasts
Diurmal variation
DAY Land is warmer than water
NIGHT water is warmer than land, surface moving towards water
oSea breeze frequency – sea breeze analysis along New Jersey coast of USA
- clear bias for summer time sea breezes when land/sea contrasts are greatest
oSea breeze front
As sea breeze develops the advancing on-shore breeze forms a front
Land air = forced up + can generate sea breeze frontal clouds
find more resources at oneclass.com
find more resources at oneclass.com
Shallower than fronts produced by midlatitude cyclones
LAND BREEZE
oDay & night phenomenon; 1-5km span max
oThermal breezes from the Great Lakes Regions
- Monsoon
oCame from Arabic word “mausim“ meaning season happens most in Asia, others
occur in Africa, Australia, S_N America (Mexico + SW USA) but not as pronounced as
South Asian Monsoons
oSeasonally scale (NOT Diurmal scale)
SUMMER Land warmer; comparable to lake/sea breeze. Low pressure land
(warmer air rising), sinking over ocean bringing in moist air towards land;
causing big precipitation
WINTER Land breeze; air is warmer over ocean, and sinking over land. Dry air
is moving towards ocean
oTemporal + spatial scale; both are much larger than land/sea breeze
find more resources at oneclass.com
find more resources at oneclass.com
o Rain lasts for weeks at a time can be critical for crops + drinking water (but
excess=floods)
- Valley Breeze
oSmaller scale wind (important for hikers)
DAY ‘upslope winds’ are induced; land warms faster than the air
NIGHT ‘downslope winds’ are induced
- Katabatic wind – another mountain wind associated w/glaciers
o Air passing over a glacier/ice sheet becomes very cold + dense
oCold air funnels into valleys producing cold strong winds (important for hikers)
- Foehn/Chinook
oCanadian term – used in Calgary, AB
oWind on the lee side of mountains – foehn wind
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Eesa09 lecture 8 local wind circulation & thermal winds. Sea breeze: thermally induced circulation, causes pressure differences association w/temperature difference, often associated w/day + night contrasts. Day land is warmer than water. Night water is warmer than land, surface moving towards water: sea breeze frequency sea breeze analysis along new jersey coast of usa. Clear bias for summer time sea breezes when land/sea contrasts are greatest: sea breeze front. As sea breeze develops the advancing on-shore breeze forms a front. Land air = forced up + can generate sea breeze frontal clouds. Land breeze: day & night phenomenon; 1-5km span max, thermal breezes from the great lakes regions. Monsoon: came from arabic word mausim meaning season happens most in asia, others occur in africa, australia, s_n america (mexico + sw usa) but not as pronounced as. South asian monsoons: seasonally scale (not diurmal scale) Summer land warmer; comparable to lake/sea breeze.
