What are the 4 local winds?
Sea breeze, land breeze, mountain breeze, valley breeze, cover relatively small area
Sea Breeze
during day- land heats faster, lower pressure on land than water, air flows from water to land
Land Breeze
at night- land cools off more than water, cool air descends, flows from land to water
Mountain Breeze
mountain air cools at night, descends
Valley Breeze
valleys warm faster during the day, air rises
What are the 2 regional winds?
Katabatic winds, monsoons, cover larger area
Katabatic winds
gravity drainage winds, layers of air at surface flow downslope, cooler air so becomes dense, speed up and heat up
Monsoons
very strong seasonal wind, caused by annual shift in global pressure belts, brings recurring cycle of precipitation
Forces effecting ocean circulation
Main: frictional drag of wind
others: coriolis, density differences, continents, astronomical
Surface currents
Caused by subtropical high pressure cells
Gyres, W intensification, upwelling/downwelling currents all fall under this category
Gyres
circulation systems that dorm circular patterns in oceans
Western intensification
water "piles up" on west side of oceans (about 6 in higher)
Upwelling currents
when surface water swept away from coast
Downwelling currents
excess water gravitates downward
Thermohaline circulation
deep currents flowing along ocean floor, travel full extent of ocean basin - slower speed than surface currents, but much greater volume
Where did most of Earth's water come from?
formed inside Earth, got to surface through outgassing (volcanoes and geysers)
Eustasy
world-wide change in sea level caused by change in volume of ocean water
colder times = more ice, lower sea level, more land area
warm times = less ice, higher sea level, less land exposed
What is dominant cooling process in Earth's energy budget
Evaporation
Latent heat
heat stored within water, released with phase reversal
Humidity
water vapor content in air, depends on temp of both water vapor and air
Relative humidity
(actual water content)/(max capacity) X 100
temperature and RH inversely related
Maximum specific humidity
max mass of water vapor a specific amount of air can hold at a given temp
Saturated air
air holding max capacity of water, RH is 100%
Dew point temp
temperature at which air becomes saturated
Measuring humidity
hair hygrometer, sling psychrometer
Air parcel
body of air with specific temp and moisture characteristics
Air stability
tendency of air parcel to stay in place vs. rising/falling
Unstable air
warmer and less dense that surrounding environment
Adiabatic
when air parcels rise/fall without exchanging heat with surroundings
cools by expanding, density decreases with lower pressure
conversely, heats by compressing
Dry Adiabatic Rate (DAR)
5.5 F per 1000 ft change in altitude
Wet/Moist Adiabatic Rate (MAR)
3.3 F per 1000 ft change
Lifting condensation altitude
elevation at which air becomes saturated as it rises
(DAR->MAR)
Types of air mass moisture
c = continental (dry)
m = maritime (wet)
Types of air mass temperatures
P = polar
T = tropical
E = equatorial
A = (ant)arctic
Condensation
occurs when air is forced to cool below dew point temp
Condensation nuclei
a particle/surface is needed for water vapor to condense, prerequisite for cloud to form
dust, smoke, pollen, salt, etc.
Precipitation
droplets fall dur to gravity, when weight exceeds for of turbulence (force holding particles up)
Clouds
visible groups of liquid/solid water suspended in air classified by form, altitude, function
Preconditions for cloud formation
1) presence of cooling mechanism (which causes)
2) saturated air
3) availability of condensation nuclei
cloud form
Cirriform = wispy
Stratiform = layered
Cumuliform = puffy
Cloud altitude
Cirro = high
Alto = middle
Cloud function
either produces precipitation or not
Nimbo = rainmaking
2 main types of fog
Advection: air in one place migrates to another place where saturated conditions exist
Radiation: radiative cooling chills air layer directly over ground to dew point temp (moist ground, no air moving)
Types of advection fog
Evaporation: "steam fog" when cool air flows over warm water
Upslope: when moist air is forced up to higher elevations, as it rises it cools
Valley: opposite of upslope, cooler/denser air settles in low-lying-chilled areas
4 types of atmospheric lifting
Convergent: air flows from various directions to low pressure system, then ascends
Convectional: stimulated by local surface heating, hot air rises
Orographic: air being forced over a barrier
Frontal: two air masses with different properties meet along le
4 types of weather fronts
Cold, warm, stationary, occluded
Cold front
steep face with ground hugging nature, move faster
forces warm air to rise- wind shift, temp drop, unstable air
Warm front
slowly overtakes cooler air and rises over it at gentle slope
can produce nimbostratus clouds and rain, move slower
Stationary front
when air masses meet but aren't displacing each other
Occluded front
cold front overtakes slower moving warm front
cyclonic system, force warm air up leaving cold air at surface, produce heavy rains at contact point and winds shift
Weather
short term condition of atmosphere
Midlatitude Cyclonic system
dominate our weather patterns
migrating center of L- converges, rises, spins CCW
Life cycle of Midlatitude cyclonic system
Cyclogenesis, open stage, occluded stage, dissolving stage
Cyclogenesis
beginning of MCS, surface air converges and air aloft diverges, happens in Pacific for US
Open stage
low pressure system has developed, CCW flow, draws warm air from the south and cold air from the north
Occluded stage
cold catches warm front, colder/denser/more unified air moves faster than warm air
Dissolving stage
system entering Atlantic, running out of energy (heat)
Thunderstorms
Result of heat energy being exchanged in atmosphere, latent heat released and warm air rises in cloud
Happen in mT air masses, not really in cP
Lightning
electrical discharge in atmosphere, superheats air (27000F)
90% of strikes happen over land, convection is warmer
Severe thunderstorms
really wast wind, really big hail, or possibility of tornado all classify severe
Mesocyclone
spinning, cyclonic, rising column of air
related to energy change during phase change
Funnel clouds
smaller, dark gray pulse at bottom of mesocyclone
if hits ground = tornado
if hits water = water spout
Dryline
warm dry air migrates across plains, converges with warm wet air forcing it up, mesocyclones form in them
Tornadoes
Pressure is 10% lower than surrounding air
Fujita scale: measures wind speed and related damage
F0-F5
Tropical cyclones
form in areas of warm air masses and warm oceans
surface air spins in toward L, ascends, flows outward aloft
Saffir-Simpson Scale: hurricane damage potential, mainly based on windspeed, 1-5
Atlantic hurricanes
hurricane season June 1-Nov 1
begin with warm desert winds/weather of West Africa
warm sea surface gives energy
Azores H system
?
Hurricane structure
Rain bands: moisture being pulled in toward L
Eye: center, where L is
Eye wall: two closest rain bands to eye, fastest winds and heaviest rains
Climate
daily and seasonal weather regime for a place over long periods of time, weather patterns over time
no two places have exact same climate
Order: recognizing patterns and grouping similar "things"
Disorder: recognizes individuality we see in world
Climate components
Insolation: uneven over Earth's surface, varies w/ latitude
Temperature: varying daily and seasonally
Air pressure/masses: areas of consistency, like ITCZ
Precipitation: varies depending upon local conditions
Climate classifications
Tropical, mesothermal, microthermal, polar, arid/semiarid
Tropical climates
-36% Earth's surface, most extensive
-Generally straddle equator, consistent day length and insolation
-ITCZ brings rain and wind seasonally
-Warm ocean temps and unstable maritime air masses (higher energy)
- Amazon, central Africa, Indonesia, etc.
Mesothermal climate
- midlatitude, mild winters
- warm temp climate with seasons
- 27% of land but 55% population, relatively consistent weather
- shifting air masses, changeable weather conditions as air masses conflict
- SE US, Europe, China, S Brazil, coastal Aus. etc.
Microthermal climate
- mid to high latitudes, cold winters
- winter season with some summer warmth
- 7% Earth's surface
- greater temp ranges related to continentality and air mass conflicts
- continental interiors serve as source regions for intense cP air masses
- habitable
Polar climates
- polar regions
- don't have true summer, daily temps never get above 50 F
- 19% Earth's surface
- Extremes in daylight related to insolation, low humidity leads to low precipitation
- northern Canada/Russia, tundra and ice caps
Arid/Semiarid climates
- permanent moisture deficits
- 35% Earth's surface
- water demand exceeds supply, dry subsiding air in subtropical H
- deserts form in rain shadows of mountains, usually far from moisture anyway (continental)
- mainly along tropics
Effects of climate change
Physical: droughts, melting ice, earlier snow melts, rising sea levels
Ecological: spread by insects/pests, earlier migration of animals, coral bleaching
El Ni�o
warm surface water shifts East toward S and central American coasts b/c trade winds weaken or stop, waters warm above average
involves unstable air in atmosphere interacting with ocean and planetary-scale wave
La Ni�a
opposite of el ni�o, when surface waters in central/east Pacific cool below average
Mechanisms of climate fluctuation
Eccentricity: change in orbit around sun, orbit goes through cyclical change about every 100,000 years
Precision: wobble in axis, every 26,000 years
Obliquity: variation in Earth's tilt, varies between 22-24, changes every 40,000 years
Tectonics effects
land masses migrate over millions of years, experience various climate conditions
as ocean basins open/close, large climate effect over time
Hydrologic cycle
evaporation, condensation, precipitation.....
surface runoff, subsurface flow, etc also part
Percolation
water moving within the ground
Infiltration
movement of surface water to subsurface
Water budget
Losses: runoff evaporation, transportation (loss from plants)
Stored: lakes, ice caps, groundwater
losses > gains/stored, rapid depletion
Deficit = more demand on water than what is supplied
Surplus = more water exists than needed, stored in reservoirs/da
Soil moisture
Gravitational, capillary, hygroscopic water
Gravitational water
percolated through soil, exits as runoff
soil is at "field capacity" when it is holding max amount possible, after gravitational water is gone
Capillary water
held by surface tension and hydrogen bonding, available for plants
wilting point = when all capillary water has been used
Hygroscopic water
bonded to soil/rock, too strong for plant to break, not available for plant to use
Groundwater
water that lies beneath surface but is tied to surface supplies, largest potential source of freshwater, from surface to about 2 miles below (22%)
Zone of aeration
soil is less than saturated, capillary/hygroscopic water
Zone of saturation
soil is saturated, where gravitational water collects/stored
Water table
contact point between zones
above is aeration, below is saturated
Aquifer
storing groundwater, high porosity and permeability
Confined: not open, bounded by aquiclude
Unconfined: water table is top, easy to get to
Aquiclude
impermeable layer, low porosity or permeability or both
Porosity
ratio of void space to solid in an object
depends of arrangement of pores and how much it has been compacted, not necessarily related to permeability
Permeability
ability for water to run through, not necessarily related to porosity
Aquifer characteristics
Recharge area: surface area where water enters aquifer
Potentiometric surface: only exist with confined aquifers - pressure level caused by aquifer's own weight
Drawdown: when pumping rate exceeds horizontal flow
Dry well: when depth of well is shallower
Streams
gaining stream: receive groundwater when water table is high
losing stream: contribute to groundwater reserves when water table is low
Groundwater mining
When water is extracted faster than it can be replenished, like squeezing out a sponge, but once aquifers are "squeezed" they can't be filled again so lose that resource
can result in land subsidence and other ecological problems