Geography
from geo "earth" and graphein "to write"
Geography is
- method not a body of knowledge or collection of facts
-hollistic
-eclectic
also
The science that studies the relationships among
-natural systems
-geographic areas
-society
-cultural activities
-the
spacial analysis
analyzing data that specifically includes info about the location of places and their attributes
bridge discipline
geography spans:
-natural/physical sciences
-social sciences
-humanities
Two broad divisions of the discipline:
-Physical Geography (Physical and life sciences)
-Human Geography (Human and cultural sciences)
themes of Geography
1. Location
(absolute and relative)
2. Region
(portions of the earths surface with uniform characteristics; how they form and change; how they relate to other regions
3. Human Environment Relationships
(resource exploitation, hazard perception, environmen
Physical Geograpy
the spatial analysis of all the physical elements and processes that make up the environment
interests:
-processes that shape the landscapes occupied by humanity
-ways in which humans deliberately and inadvertently change the environment.
-focus on humans
scope of physical geogaphy
ecology
geology
soils
geomorphology
hydrology
climatology
meteorology
biogeography
earths 4 spheres
1. atmosphere
2. hydrosphere
3. lithosphere
4. biosphere
distributional patterns
distribution of phenomena over space and time
the processes responsible for those distributional patterns
investigation of spatial patterns (central to geography)
a pattern springboards hypothesis testing and further inquiry
hazards and resources
shape and impact landscapes
Natural hazards
-floods
-earthquakes
-tsunamis
-wildfires
-tropical storms
Opportunities are natural resources
some locations can present both hazards and resources simultaneously
Lecture 1 summary
Geography
-holistic and eclectic in nature
Spacial analysis
-methodological approach of geographers
Geography draws upon many disciplines
Geography is a science that bridges the natural sciences and the social sciences
Physical Geography
- one of the two
induction
reasoning from the SPECIFIC to the GENERAL
using a LIMITED (SPECIFIC) set of observations to make INFERENCES or GENERALIZATIONS about a population
used in scientific inquiry
deduction
reasoning from the GENERAL (theory) to explain SPECIFIC phenomena, processes, or behaviors
-needs confirmation
used in scientific inquiry
scientific method
Sir Francis Bacon then improved and expanded upon Karl Popper
Popper HYPOTHETICO- DEDUCTIVE method
-advancing knowledge by FALSIFICATION
it is used because a theory or a hypothesis can never be proven true using induction
-there must be evidence to reject
reality, theory, and scientific understanding
understanding= explanation and confirmation
explanation= explaining reality (hypotheses, theories and law, formula)
theory= collection of logical ideas used to explain (testing, refining, retesting hypotheses)
-rarely static
we develop scientific theories
prior approaches to interpreting the world
Before Bacon
-answers to questions were through belief in faith,
-conjectured logic
-both
Science was required to conform to religious orthodoxy
-Bacon, Popper helped free science from constraints
systems concepts
Either opened or closed in terms of energy and/ or materials
matter and energy are stored and converted in systems
Earth can be studied as a set of overlapping systems or spheres
Earth is essentially a closed system with respect to materials
Earth is an o
systems definitions
closed system- transfers energy but not matter. (our planet)
Open system- transfers both matter and energy can cross its boundary in the surrounding environment (ecosystems)
system regulation
environmental systems powered by either solar energy or geothermal energy
all systems are self regulated by feedback
- POSITIVE FEEDBACK: forces that promote changes to systems
-NEGATIVE FEEDBACK-forces that resist changes to systems
maintaining the syste
system equilibrium
self regulation promotes system equilibrium.
Definition: a state in which inputs of energy and/or materials into a system are matched by corresponding outputs of the same.
2 types:
-steady state equilibrium: fluctuation of a system viable around a stable
complexity
simple rules govern all complex systems
a way of describing complicated, irregular patterns that are random. ex turbulent flow in streams
larger scale is more predictable
chaotic complexity in environmental systems underlies a larger scale order and overl
resilience
ability of s system to recover from or to resist being affected by a disturbance (environmental change
2 definable Dimensions:
-Degree to which a system returns to its original state following a perturbation
-ability of an environmental system to persist
equifinality
different means can create the same end
two or more causes may produce the same effect
end states in open systems are reachable in more than one way
in my own words. different causes can create the same effect
cycles and periods
cycles: events that recur at regular intervals
Period: time between the same points on a cycle
Cyclicity and Periodicity: important in the study of physical geography
Earths various sphere and systems are or are potentially affected by a large number of e
scientific models
models are approximate representations or simulations of real systems.
-highly generalized, include only essential variables or characteristics of systems
models are commonly used by geographers and other environmental scientists
4 types of scientific models
CONCEPTUAL: describes general relationships among the components of a system
GRAPHIC: compiles and displays data in a form or pattern that readily conveys meaning such as map or climograph
PHYSICAL: mini version of a system
NUMERICAL: consists of one or m
Lecture 2 Summary
-Physical Geographers employ the scientific method to guide their investigations on physical/environmental phenomena.
-scientific method was by Sir Francis Bacon
-Earth is studied as a set of overlapping systems or spheres
-System concepts are used by phy
The Geographical Grid
all absolute locations on Earth is found using the geographical grid
2 sets of circles imposed on globe oriented at right angles to each other
-meridian circles: aligned with the earths axis of rotation. 1/2 of a meridian circle is a meridian a true NS li
great and small circles
The geographical grid has 2 types of circles, Great and small
GREAT CIRCLES- formed by planes that pass through the center of the earth
-largest circles that can be drawn on globe
-all meridian circles are great circles
-intersecting great circles bisect
Circle of illumination
border between day and night, sweeping westward
Great circle
Divides earth in a sunlit half and nighttime half
the orientation of the circle of illumination with respect to earths axis systematically varies throughout the year
-0 -23.5 degrees displacemen
rhumb line- loxodrome
loxodrome. Line of constant compass bearing. curved
degrees
in order to reference the parallels and meridians need reference points
the distance values are called degrees
Latitude: Distance from the equator
Latitude is north or south of the equator
-they are parallels
-oriented east west but measure distance north south
Equator is 0d and the poles are 90d N and S
total of 180d of latitude (one half of a circle)
Latitudinal Zones
High latitudes N (55d N to pole
-Arctic and Subarctic
Mid-latitudes 35d N to 55d N
Low Latitudes 35d N to 35d S
-subtropical
-Equatorial/Tropical
-Subtropical
Mid-latitudes 35d S to 55d S
High Latitudes 55d S to South pole
-subantarctic
antarctic
Longitude: Distance from the Prime Meridian
Distance east or west of the Prime Meridian
-longitude are meridians
-oriented north south but measure distance east west
-Prime meridian is 0d and extends 180d E and W
-distance of 360d longitude (full circle
-no natural starting or stopping point for th
Lat and Long rules
Lat N or S always stated first
Long E or W is always second
Degrees can be broken down into minutes and seconds
60 min =1 degree
6- seconds= 1 minute
Time and Time Keeping
Mean solar Day- The time and interval between 2 successive passages of the noon sun over a local meridian
-Approx 24 hours
Earth rotates eastward
Rate of rotation is 15d of longitude per hour
-later in the day to the east
-earlier in the day to the west
S
Longitude and time measurement
Solar time: timekeeping based on the location of the sun in the sky
Standard time: the legal time for a zone 15d of longitude wide
-time based on the average solar time along a designated time meridian
-time zone extends 7.d of longitude east and west of
International Date line
Used to separate one calendar day from another
Follows 180d E and W
when it is 12 noon at the Prime Meridian it is 12 Midnight along the IDL at this instance and only here does the same calendar day exist on both sides of the IDL
at all other time the cal
Lecture 3 summary
-The geographical grid is a mathematical abstract used to reference absolute locations on the Earths Surface
-Grid consists of great and small circles imposed on the earth which intersect each other at right angles
-parallels are east west oriented circle
Maps, Projection and sclae
Cartography: science of art of mapmaking
Map: generalized view of an area as seen from above reduced in size
-principal tool for geographers
Projection: process of transforming spherical Earth to a flat map
-representing a 3D surface of the earth on 2D fl
Map as a model
A map is simplified of generalized rep of graphical model of all or part of the Earths surface
Map designed for a specific purpose or used based upon its scale, projection and theme
-not reality, highlights a limited portion of reality
Convenient form of
large scale map
Covers a small area with a large amount of detail
small scale map
covers a large area with little detail,
-highly generalized
map properties
conformaility: true shape
Equivalence- equal area
^ these 2 are mutually exclusive; mathematically impossible to rpeserve on the same map
Equidistance- true distance
True direction
* A map can maintain two of these properties.
* only globe has all four pr
Map projection facts
Curved surface cannot be projected on a flat surface without distortion of spacial relationships
-all maps are distorted view of world
Map projections chosen based on abilities to
-preserve a desired map property or properties
-minimie ertain types of ist
developable surfaces
cylindrical projection (mercator projection)
Planar projection (gnomonic projection)
conic projection (albers equal area conic projection, two standard parallels)
Oval projection
remote sensing
the indirect observation of the earth via systems that detect and measure electromagnetic energy
monitor and analyze the environment at varied geographical scales
-local, regional, global
Active remote sensing
-systems that direct beams of electromagnetic
global positioning
Network of 24 satellites that orbit the earth every 12 hours
continuously transmit a unique radio signal (pseido random code)
The speed of the incoming signal (base on the position of the satellite and time) is used to determine location
GPS TRIANGULATION
Geographical information Systems
GIS systems combine spatial and attribute data
Maps can contain multiple layers
-physical features
-cultural features
Layers can be added to create a composite overlay
GIS is the marriage of computer graphics, mapping and database management systems
Used
summary lecture 4
Maps are generalized representations of all or part of the earths surface
all maps present distorted views of world
Maps serve as environmental filters and have specific uses that are a function of scale, projection and thematic content
remote sensing pro
radiant energy: solar and terrestrial
Solar energy drives environmental processes operating on the Earths surface and within the atmosphere
Energy from the sun is in the form of electromagnetic waves
-called radiation
Sun radiates mainly shortwave energy
-shorter wavelengths is more concentra
movements of solar radiation in the earth atmosphere system
Transmission: Passage of energy though atmosphere or water
-no change in direction
Scattering: Changing direction of lights movement, without altering its wavelengths
Refraction: change in speed and direction of light
The solar constant
Amount of energy striking the top of the earths atmosphere varies slightly, about 7% through the year
The average amount is the solar constant
Solar constant= 1.96 calories per cm squared per minute
-a calorie is amt of energy required to raise the temper
electromagnetic spectrum
gamma
x ray
ultraviolet (inside is the visible spectrum ROYGBIV)
near infrared
shortwave infrared
middle infrared thermal infrared
microwave
radio waves
short wave vs longwave
Frequency: # of wavess of energy passing a given point over a given period of time
-shortwave has highfrequency
-more concentrated/ intense form of radiation
-Longwave has low frequency, less concentrated/intense radiation
What happens to incomming radiation
reflected by gases and particles within the atmosphere and by vaious earths surfaces
Scattered/ diffused
Absorbed and transformed within the atmosphere and at the earths surface
-when energy is transformed it goes from a concentrated to less concentrated
Aphelion and perihelion
Earth is closer to the sun in January (perihelion) than in july (aphelion)
Slightly more radiation being received from sun in January
-additional energy strikes earth mainly in southern hemisphere (summer in SH)
-about 7% more radiation in January then ju
broad zones of the atmosphere
Heterosphere: outer atmosphere
-80km outwards
Homosphere- inner atmosphere
-surface to 80km
-gases evenly blended
layers based on temperatures
troposphere
-temperature decreases with altitude
(most weather occurs)
stratosphere
-temperature increases with altitude
(airlines and ozone layer)
mesosphere
-zone of lowest temperature
(meteors burn up)
thermosphere
-zone of high thermodynamic temperatu
atmospheric filter: layers based on function
ionosphere
-absorbs cosmic rays, gamma rays, x rays, some UV rays
ozonosphere
-part of stratosphere
-ozone (O3) absorbs UV energy and converts it to heat energy
-CFCs (Chlorofluorocarbons) destroy ozone
Layers of Atmosphere
classified according to
composition
temperature
function
Troposphere
Lowest layer of the atmosphere
-From surface to 15Km
-thickness ranges from 6Kl over the poles to 15km over the equator
Main source of heat energy is the Earths surface
-atmosphere warmed from below not from above
-Temperature decreases with elevation in
constant and variable gases
Constant- remain in the same proportions through time and space up to 80Km
-N2 and O2
Variable- inconstant in the proportions over space and time
-include water vapor (.02 to nearly 5% total mass of atmosphere)
-ozone (o3)
-Methane
-CFCs
Mass Vs Importance
Total mass of gas does not indicate importance
from CHEMICAL AND BIOLOGICAL VIEWPOINT Dominant gas in atmosphere is O2
-provides reference level of chemical energy within the atmosphere which makes
COMBUSTION
METABOLIC PROCESSES OF LIVING ORGANISM
THINKIN
SUMMARY OF LECTURE 5
Earth receives shortwave electromagnetic energy from the sun and radiates long wave(heat) electromagnetic energy from the surface to the atmosphere and to space
The main source of hear within the atmosphere is the Earths Surface
Solar radiation passing th
solar energy: insolation and Flows
insolation: the amount of solar radiation striking earths surface
-determines relative rates of surface heating
Energy striking surface may be
-reflected unused back to space (ALBEDO)
-transformed into sensible heat
-transformed into latent heat via evapo
heat transfer process
conduction
-molecule to molecular transfer (through touching, also moving throughout a sold)
convection
-energy transferred by vertical movement
(occurs in liquids and gasses, transfers through movement) warm air rises, cool air goes back to bottom
Advect
water and latent heat: Phase Changes
Water vapor plays a major role in transferring heat from the surface to the atmosphere
Water vapor can be transported great distance before condensing and falling to the surface as precipitation.
Latent heat is released as sensible heat
Latent heat:the he
Atmospheric moisture
Relative humidity
-describe the amount of water vapor in the air.
-the amount of water vapor present over the maximum amount of water vapor the air can hold (capacity) at any given temperature. RH= (amount/capacity) X 100
Dew point
- The temperature at wh
Relative Humidity, temperature, capacity and daily RH cycle
warmer air - greater capacity to hold water vapor
Cooler air- lesser capacity to hold water vapor
condensation
process by which water vapor in the atmosphere changes phase from has to tiny liquid droplets or ice crystals
2 conditions needed for condensation
-air must be saturated
-condensation nuclei must be present provides a mechanical surface upon which water v
Precipitation
the collective name for moisture in liquid or solid form that is heavy enough to fall from the atmosphere
-drizzle
-sleet
-rain
-snow
-hail (made several round trips above the freezing level in the vertical currents of a cumulonimbus cloud. Have distincti
adiabatic heating and cooling
Change of temperature within a parcel of vertically moving air is because of expansion and compression
When air parcel expands, it cools
When air parcel compresses it warms
The rate of cooling is influenced by the relative humidity of the air parcel
-unsa
Lapse Rates: Environmental Vs adiabatic
Environmental lapse rate
-Average = -6.4dC/1000m
-apply to stationary air (temperature change within the troposphere)
-varies daily and seasonally
Adiabatic lapse rate
-apply to air parcels that are in vertical motion
Dry adiabatic lapse rate
-applies to
Greenhouse effect
Makes earth habitable
-average global temp would be about 38dC or 50dF
Atmosphere allows visible light (shortwave) radiation to pass through
-shortwave is transformed into heat energy (terrestrial radiation) at earths surface
Atmosphere slows the flow of
Lecture 6 summary
insolation is the amount of solar energy received at the earths surface
Albedo is extent to which a surface reflects incoming solar radiation
-determines relative rates of heating
heat is transferred via 4 processes
water vapor is a principle means by whi
energy in the earths atmosphere system
suns radiation on the earths surface is unevenly distributed
-curvature of the earths surface(sphericity)
-produces latitudinal differences of temperatures
reasons for spatial and temporal variations in insolation
geographical and temporal variations in solar energy received at the surface are a function of sun angles
Daily variations in solar energy received at the surface are due to rotation
Seasonal variations in solar energy received at the surface are due to
-
insolation and sun angles
Tropics receive more concentrated insolation because of earths curvature
-2.5x more solar energy then poles
Surface insolation is a function on sun angles
High sun angles
-energy more concentrated on surface
-temp are warmer at surface
-low albedo (low ov
sub solar point and declination
sub solar point: the point on earths surface being struck by the vertical (direct) rays of the sun
-due to surface curvature, only one point at a given time experiences the direct (vertical) rays of the sun
-no shadows when sun is directly overhead
Declin
analemma
finding the latitude of the sub solar point
vertical noon sun angle
seasonal changes in the noon sin at angle 40dN
spring equinox
march 21-22
day and night equal
sub solar point located on equator
fall equinox
September 22-23
Day and night equal
sub solar point located on equator
Summer solstice
June 21-22
longest day
sub solar point located on the tropic of cancer
Wi
rotation and daily sun angle cycles
solar noon: sun at its highest daily position in the sky (above horizon)
-highest daily sun angle
-time of greatest insulation
-peak temperature lags behind peak insolation
Global energy imbalance
surplus energy to redress energy imbalances is transported pole ward by
-winds transporting sensible and latent heat in water vapor
-ocean currents transporting sensible heat
axial tilt and parallelism
axial tilt is perpendicular to the plane of ecliptic
lecture 7 summary
solar energy is unevenly distributed over the earths surface due to sphericity
the sun angle determines the quantity and the quality of heating at the earths surface
-sin angles vary throughout the day due to rotation
-sun angles vary seasonal due to revo
Drivers of atmospheric circulation
Uneven distribution of suns radiation on the earths surface
Pressure differences
-air glows from high to low pressure (creates wind) this is pressure gradient force
Coriolis effect
friction at the surface slows down winds
Earths rotation
-Coriolis effect:
geographical air pressure variations
air pressure: force exerted on the surface by the weight of the atmosphere
- in Millibars (mb)
Average atmospheric pressure at sea level is 1013.2 mb
Isobar: a line connecting points of equal atmospheric pressure on a map
air pressure varies not only vert
geographic differences in air pressure rules of thumb
cold air is more dense than warm air
dry air is more dense than moist air
-when water vapor is added to the air, the weight of a unit volume of air decreases
-avogadros law: a unit volume of gas always contains the same number of molecules
-lighter molecu
cyclone and anticyclone
a cyclone is a low pressure cell and is associated with UNSTABLE WEATHER CONDITIONS
-northern hemisphere, air spirals into a cyclone counterclockwise
-southern hemisphere spiral is clockwise
anticyclone is a high pressure cell and is associated with STABL
seasonal variations in air pressure
land heats rapidly and cools rapidly
-limited capacity to store heat
water heats slowly and cools slowly
-high capacity to store heat
Summer
Lland masses heat rapidly
-pump heat into atmosphere
-creates low pressure
Water bodies heat slowly
-overlying air
air flow and the pressure gradient force
air drifts down the pressure gradient
-this is called the PGF
The steeper the gradient, the higher the wind velocity
the earths rotation and the Coriolis eddet
air does not flow straight down the pressure gradient because of the Coriolis effect
The apparent deflection of objects, including winds, moving freely over the earths surface
-deflection is to the right in NH
-deflection to let in SH
caused by rotation o
idealized distribution of global pressure systems
The pressure systems are dynamic
-produced by the convergence and divergence of air at surface and aloft
-shift positions seasonally in response to changing locations of the sub solar point
-polar highs and sub polar lows weaken the summer and strengthen
convergence and divergence
the general circulation of the atmosphere can be explained by these
convergence: exists when air currents are moving on intersecting paths
Divergence: occurs when there is an outflow of air and air streams are separating
Hadley, Ferrel ad polar cells
Hadley:
The Hadley cells are formed by rising air near the equator which ?ows towards the poles and then sinks at about 30� north and south before returning at low levels back to the equatorial regions. As air rises it cools then forms clouds and rains ne
rossby waves and Jet streams
rossby waves: greatly undulating (wavelike) westerly air flows patterns
-help redress global energy imbalances
-in fall winter and spring these deliver tropical air into the higher latitudes and enable polar air to flow towards the equator (polar outbreak
factors controlling large scale oceanic circulation
water salinity
-source: chemical weathering of rocks on land
-carried by runoff into oceans
-concentrations vary by location
-diluted by glacial melt water and precipitation
-concentrated by evaporation
water temperature
-absorbs solar energy, gains and s
surface ocean currents
driven by planetary winds
deflected approx 45d from wind direction due to Coriolis effect
broad circularity systems called gyres
-driven by wind and deflected by land masses
five subtropical gyres
-results in:
-warm currents off east coasts of continents
deep ocean currents
circulate slowly
-moves only a few centimeters per second
-transfers water between the oceans
-estimated that one complete cycle takes 1000 years
-moves vast amounts of water (100x the flow of the amazon)
Driven by the differences in water density
-thermo
summary of lecture 8
air pressures varies geographically and seasonally
-differences due to:
-temperature
-water vapor
-behavior of air aloft and at the surface
global air pressure differences and the Coriolis effect generate large scale atmospheric circulation patterns that
weather vs climate
weather is the short term condition of the atmosphere
-meteorology: the study of short term atmospheric phenomena that constitute day to day weather
-day to day changes in weather are not isolated events but controlled bu larger scale systems such as
Air
factors affecting climate
Latitude (sun angle)
-intensity of radiation and length of day have direct impact on air temp
Seasonality
-annual variation of sun angle influences seasonal temperature change
Land and water distribution
-impacts temp and precip
-land and water respond di
summary of climatic factors
earth sun relationship
-position of earth in orbit influences amount of radiation received
Latitude
-influence sun angle and length of day
air circulation
influences flow of air and position of high and low pressure systems
marine continental
-large water
heat capacity and specific heat of substances
heat capacity: the ability of a substance to store heat energy
-water has a high heat capacity
-land has low head capacity
specific heat: the ratio of energy loss or gain to the corresponding fall or rise of temperature
-water has high spec heat
-land low
Earths temperature patterns
thermal equator: imaginary line connecting points of highest average temperatures for lines of longitude
January temp mat
=movement of thermal equator southward.
-more pronounced over large continents
July temperature map
=movement of thermal equator nort
air masses
large bodies of air that have uniform temp and humidity characteristics at any given elevation
-cover 100,000s of square miles
-the boundary between two air masses is called a FRONT (usually the site of pronounced weather changes)
temperature and humidity
classes of air masses
A,AA- arctic and antarctic
-bitterly cold and dry
P- polar
-seasonal changes in temperatures
=cool to warm in summer
-cold to bitterly cold in winter
T-tropical
-warm to hot
C-continental
-dry
M-maritime
-moist
teleconnections and inter annual climate variability
teleconnections: links between environmental events, particularly between climatic variations separated in time and geographically
Ex: North atlantic oscillation- oscillation of air and ocean masses that affect a large part of europe and western asia
El n
north Atlantic oscillation
oscillation of air and ocean masses that affect a large part of Europe and western Asia, as well as eastern north America
Function of the relative strengths of the Icelandic low and the Azores high
Stronger pressure gradient (high index) leads to more nor
North Atlantic oscillation index
expresses the constant shifts in the oscillation from year to year and decade to decade
High index- westerlies deliver heat from the Atlantic to Europe along with powerful storms
-mild winter temp
-more rainfall in northern europe
-dry conditions in south
El nino - souther oscillation and La nina
El nino- southern oscillation
-reversal of the normal pressure and wind pattern in the southern pacific ocean
-occur on average every 5 years (range 2 to 8 years)
-caused drought in Indonesia and Australia
-heavy rains and flooding to coastal south americ
summary lecture 9
weather concerns short term conditions of the atmosphere whereas climate concerns long term average weather conditions for given geographic areas
different combinations of factors produce very different types of climates
these factors include but not limi
polar weather charracteristics
weather dominated by Arctic and Antarctic air masses
-cold and dry year round
Polar highs generate the Polar easterlies winds during winter
-directs cold air toward equator to warm up
-polar easterlies cease blowing during the summer
-least consistent of
polar climates
cold to extremely cold year round, relatively dry
-refferd to as polar deserts
Tundra climate
-at least one month where temp average above freezing but under 10dC 50dF
--permafrost underlies many areas
-short summers lead to surface thawing (ponded and st
mid latitude weather
most precip in the middle latitude starts as snow because clouds form at altitudes where temperatures are below freezing
- if temp near surface are below freezing it remains snow
-if temp near surface above freezing it melts and its rain
Mid latitude weat
fronts
best describes are transition zones from the surface and extending up into the atmosphere
Surface of discontiunity
Cold fronts: cold ai masses advance against warm air masses
-cold air forces warm air aloft
abrupt warm air lifting
-400km wide (250 miles)
violent weather of the mid latitudes and beyond
thunderstorms
-most common type in the world
-caused by convergent, frontal and convectional lifting
-approx 1800 in progress at any given time
tornadoes
-smallest but most violent storms known to humanity
characteristics of continental climates
located from 35d to 60dN and S
found only in northern hemisphere
-except in highland areas in southern hemisphere
-no large land masses in south hemisphere
Large annual ranges of temperature
Annual moisture surpluses
-most precipitation is due to cyclonic
mid latitude western continental edge climates
Two major types
Marine: called marine west coast climates
Mediterranean or dry summer subtropical climates
marine climates
temperatures influenced by maritime air masses
under the influence of the westerlies year round
no dry season with mild to cool summers and moderate winter temperatures
Low evaporation rates
Precip is mainly cyclonic with a winter maxima
Stormiest of clim
Mediterranean climates
summer drought associated with subtropical pressure
-desert like during dry season
winter rainy season caused by westerly flow of air from water to land
located on the western sides of major land masses with cold currents offshore
-marine climates are fou
summary of lecture 10
polar climates are dominated by cold dry air masses year round.
-tundra, and ice cap climates
mid latitude locations are dominated by interactions of different air masses
precip in mid latitudes typically start as snow
mid latitude cyclones are the major
tropical and subtropical weather
tropical weather involves only one air mass
subtropical weather involves two air masses
-especially in winter
thunderstorms occur frequently in the tropics and humid subtropics
tornadoes occur frequently in subtropics
tropical cyclones
-powerful regional
stages of thunderstorm
early, mature, dissipating
tropical cyclones
form in trade wind zones
-between 8d to 20d N and S
-do not form along equator
-Coriolis effect too weak
warm tropical ocean surfaces
water temp at least 27dC to depth of 73 meters
sources of energy:
-sensible hear from ocean
-latent heat from condensatio
storm surge
greatest property damage loss of life by a tropical cyclone is from storm surge
monsoon
term that is derived from Arabic word for a wind that reverses direction seasonally
true monsoon experiences 180d reversal
operates on a regional scale (second order circulation)
summer monsoon associated with rain
winter monsoon is usually dry in most lo
humid tropical climates
humid- have annual moisture surpluses
-precip exceeds evapotranspiration
occupy almost all of the land area from 25dN or S of equator
interrupted by mountains and zones of aridity
temperatures are generally high
-consistently warm average temperatures
ann
characteristics of tropical humid climates
tropical rainforest
-equatorial in location, small land area
-under the influence around of the ITCZ
-windward coastal rainforest climates up to 25th parallel north and south (also an orographic effect)
-annual temp range is slight never more than 3dC
-no
Humid hot summer subtropical
hot simmer mild winter
snow is of short duration
high summer temperatures 90-100 and more
daily temp ranges small
high humidity
no dry season
-mac precip in the summer due to convectional storms
-cyclonic precip in winter
support forests
-broad leaf everg
dry winter subtropical climates
winter drought
hot rainy summers
found in three locations:
-in tropical latitudes where elevation causes the average temp of one or more months to drop below 18dC (africa and latin america)
-sub tropical latitudes bordering tropical savanna climates (wint
summary of lecture 11
Tropical weather involves only one air mass
subtropical weather involves 2 air masses
thunderstorms are most common storm type
tornadoes occur frequently in subtropics
tropical cyclones involve one air mass and form over warm tropical oceans in the trade
overview of dry climates
consists of desert and steppe climates
-polar climates also dry
steppe (semi arid) is transitional between desert and humid climates
dry climates are dominated by high pressure that produces extreme atmospheric stability
Deserts and steppes have :
Annual
types of dry climates
low latitude deserts
-average temp above 64.4F (sahara desert of north africa)
Mid latitude (cold deserts)
-average temp below 18C (gobi desert of mongolia)
Low latitude steppe (grassland)
-sahal region of North africa
mid latitude (cold) steppe (short gr
conditions favorable to development of dry climates
location on leeward side of mountains (rain shadows)
presence of subsiding air masses (STH)
prevailing wind direction from land to water
locations off the path of moisture laden winds
cold currents offshore
great distances from water bodies (interior loca
characteristics of dry climates
evaporation exceeds precip
skies are generally clear with abundant sunshine
daily temp ranges are excessive due to lack of cloud cover
insolation proceeded rapidly during the day causing temp to be high
ground radiation proceeds rapidly at night causing t
distribution and influence of topography on dry climates
the heart of low latitude dry climates lies near the tropics of cancer and Capricorn on the west sides of continents
-low latitude deserts occupy more land space than any other type of climate*
throughout dry climates elevation has an influence on precip
mountains in deserts
mountains may have relatively moist climates in desert regions due to
-orographic lifting and precip
-lower temp leading to lower evapotranspiration rates
-may contain relict plant and animal populations isolated due to climate change (refugia)
(dwarf cro
summary of lecture 12
Dry climates have annual moisture deficits
experience large daily ranges of temp
a number of factors contribute to the formation of low latitude and mid latitude dry climates
dry climates cover more land area than any other climatic type
-low lat dry clim
mountain temperatures
higher altitude locations have lower annual temp averages
within the troposphere temp decrease with increasing altitude
-atmosphere is thinner, therefore less heat gets conducted
higher elevations experience large daily ranges of temp
-insolation is high
mountain climates
mnts produce complex patterns of climate
climate varies dramatically within relatively short distances due to:
-temp drops with altitude
-slope aspects and insolation, south vs north facing slopes
-differences in precip and temp between windward and leewa
fohn winds (chinooks)
dry winds that flow down the leeward sides of mnts
-warm acrobatically due to compression
-can raise temp significantly over a period of a few mins to few hours
-causes low relative humidity
called chinooks (snoweater) in Pacific northwest
called santa an
local circulation systems
land sea breezes
-land breezes at night
-sea breezes during day
mountain valley breezes
-valley breeze during the day
-mountain breeze at night
katabatic winds
-occur in mnts and polar regions
-very cold dense air drains off the sides of the mnts, plateau
vegetation and climate
different plants have different albedos
-affect local radiation budgets
vegetation roughens surface
-increased friction with wind, decreases wind speed, reduces evap, wind breaks for crops
plants transpire moisture to the atmosphere
-water is released fro
urban climate
most pollutants/ particulates in the air over cities
lower wind speeds due to higher friction
-pollutants are not dispersed quickly, poorer air quality
tall buildings can have a canyon effect in funneling winds, producing strong gusts of air
less water an
review of conduction, heat capacity, and specific heat
conduction: transfer of heat from molecule to molecule
heat capacity- the ability of a substance to store heat energy
-water has a high heat capacity
-land has a low heat capacity
specific heat
-ratio of energy loss or gain to the corresponding fall or ri
urban air circulation
solar radiation is reflected downward by buildings
-concentrates solar energy at street level and raises temp
summary of lecture 12!
altitude is a profound influence on climate
mountains complicate patterns of climate and lead to climate variability over relatively short distances
-produces distinct climatic and vegetation zones based on::
-elevation
-aspect (orientation of slope towar