Announcements

1
Announcements
NO CLASS WEDNESDAY! HAPPY THANKSGIVING! No
office hours this week. Missing your lab? See
the TAs. Apologize for the delays in getting
them back
2
NATS 101 Section 4 Lecture 32

• Global Climate

3
Classifying the global climate and Earths
climate record is probably not as exciting as
learning about hurricanes or tornadoes, but it
important prelude before we get to global
warming, the final topic of the course.
4
Some reasons why understanding global climate is
important
The type of climate in an area is a control on an
areas ecosystem. Plant and animal species are
specifically adapted, physically and
behaviorally, to climate. Climate affects how
human civilization has evolved and adapted to
cope in various environments. For
example Agriculture types of crops and
domesticated animals Water supply Types of
dwellings and structures built Clothing Social
structures, like governments and
religions Climate patterns may change due to
anthropogenic (human-related) activitiesand this
is probably already happening. More on that
later
5

• Survey question Which of the following statement
  best represents your position with respect to the
  potential impact of weather and climate on our
  modern American civilization?
• Our civilization is totally resilient to weather
  and climate.
• Our civilization is susceptible to disruption
  from extreme weather and climate events from time
  to time, for example hurricanes and droughts, but
  these events are localized and affect a small
  portion of the population.
• Our civilization, as a whole, is highly
  vulnerable to weather and climate. Changes in
  weather and climate have the potential to cause
  widespread societal disruption, and, in the most
  extreme, dramatically alter or destroy our way of
  life.

6
Ancient civilizations that succumbed to climate
change
ANASAZI Four Corners Region Southwest U.S. ARID
DESERT CLIMATE
MAYA Yucatan Peninsula Mexico TROPICAL WET-DRY
CLIMATE
PROLONGED DROUGHT PERIODS LIKELY LEAD TO FAMINE
AND WAR, AND THESE ANCIENT CIVILIZATIONS WENT
INTO DECLINE.
7
Weve already discussed many of the controls on
global climate in previous lectures.

• Ill briefly review those and then describe a
  formal global climate classification system.

8
Climate control 1 Latitude
What it does Controls the intensity of incoming
solar radiation. Effects Temperatures decrease
with increasing latitude. Effect is more
pronounced in wintertime. Largest annual changes
occur at higher latitudes. Temperature does not
change much in the low-latitude tropics
January Average Temperature
9
Climate Control 2 Land-Sea distribution
What it does Water has a higher heat capacity
than land, so it heats and cools more slowly than
the surrounding land mass Effect on
climate Locations closer to a large water body
will
SIBERIA -60 F
January
SIBERIA 50 F

1. Have less of a seasonal temperature range.
2. Have a later occurrence of annual maximum and
   minimum temperature.

July
Maximum Temperature
10
Climate control 3 Ocean Currents
What they do Giant convective circulations
(gyres) transport heat from equator to pole. The
warm side of a gyre is typically along the east
coast of a continent. The cold side of a gyre is
typically along the west coast of a continent.
Gulf Stream
California
Kuroshio
Canary
Alguhas
Bengulas
Brazil
Humbolt
E. Australia
Effect on climate Climates on east and west
coasts of continents margins are respectively
modulated by the presence of warm and cold ocean
currents.
11
Climate control 4 the general circulation
What it does Governs the locations where air
converges or diverges on a global scale. Effect
on climate It is the primary control on the
global distribution of rainfall.
12
SAHEL
SAHARA DESERT
SAHARA DESERT
SAHEL
CONGO RAIN FOREST
SARENGETI
CONGO
KALAHARI DESERT
SARENGETI
(UNC Charlotte)
KALAHARI DESERT
13
Climate control 5 Terrain
What it does Mountain valley circulations. Monso
ons Orographic uplift Effect on climate All of
these factors can be potentially very significant
controls on the precipitation occurring at a
regional scale. As we discussed earlier, these
factors are really important for understanding
Arizonas climate!
Example of rain shadow effect
14
Köppen climate classification system
Developed a climate classification system based
on common vegetation types observed throughout
the world. Goal was to explain climate in areas
that had few or no station observations. Basic
Types A Tropical moist B Dry C Moist
temperate D Moist cold E Polar H
Highland Notations for subtypes derive from
German.
Wladimir Köppen German climatologist
15
Climates of the world in Köppen system
Rest of the lecture is taking the tour of this
map
16
Type A Moist Tropical Climates
Characteristics Year-round warm temperatures
(above an average of 64 F) Abundant rainfall
(about 60 inches a year) Wet and dry seasons
controlled by the position of the ITCZ. Where
located Equator to about 15 25
latitude. Subtypes Af Tropical wet Am
Tropical monsoon Aw Tropical wet and dry
17
Tropical Wet (Af)
These regions are tropical rainforests. Typically
near the equator. Wettest time of the year is
typically during the equinoxes when the ITCZ is
nearest to the equator. Temperature hardly
varies through the year. Tropical monsoon (Am)
climates similar, but have a bit more variation
in rainfall.
18
Example RegionsTropical Wet (Af) Climates
CONGO
AMAZON
INDONESIA
\
19
Tropical Wet-Dry (Aw)
About 5 - 20 latitude, on the periphery of the
ITCZ. Strong annual variation in rainfall,
controlled by ITCZ position Summer wet
season Winter dry season Savannahs, or large
grasslands with scattered trees, like the
Sarengeti in Africa.
20
Example RegionsTropical Wet-Dry (Aw) Climates
SAHEL
SARENGETI
BRAZILIAN HIGHLANDS
\
21
Type B Dry Climates
Characteristics Low precipitation most of the
year (less than 20 inches). Located under the
subtropical high most of the time. Favored on the
west side of continents because of cold sea
surface temps. Where located About 20 - 40
latitude Subtypes BW Arid Desert BS
Semi-arid or steppe
22
Arid desert (BW)
Receives less than 13 inches of rain per
year Hottest temperatures on Earth (e.g. greater
than 120 F) Plants that live in these areas are
xerophytes, capable of living long periods
without rain. THIS IS THE CLIMATE FOR MOST OF
ARIZONA
23
Example RegionsArid Desert (BW) Climates
GOBI DESERT
SONORAN DESERT
SAHARA
ARABIAN DESERT
ATACAMA DESERT
AUSTRALIAN DESERT
KALAHARI DESERT
\
24
The driest spot on Earthwhere is this??
25
Semi-arid or Steppe (BS)
Receive about 8 to 16 inches of rainfall. Short
grasses and scattered low bushes and trees. Can
get cold in the winter, if in the
mid-latitudes. Areas typically are good for
grazing animals. In the tropics, typically the
transition zone from tropical-wet dry to arid
desert.
26
Example Regions(Mid-latitude) Steppe (BS)
Climates
CENTRAL ASIA
GREAT PLAINS
PAMPAS
\
27
Type C Moist Temperate Climates
Characteristics Humid with mild winters About 20
to 40 inches of precipitation per year Very
different subtypes depending on continental
position. Where located About 25 - 40
latitude Subtypes Cfa Humid subtropical Cfg
West coast marine Cs Mediterranean
28
Humid Subtropical (Cfa)
Typically along east coasts of continents, on the
western side of the subtropical ridge. Wet all
year round, but slightly more rain in the
summer. Hot, muggy summers Supports thick
forests or agriculture.
29
Example RegionsHumid Subtropical (Cfa) Climate
SOUTHEAST CHINA AND JAPAN
SOUTHEAST U.S.
EASTERN ARGENTINA AND URUGUAY
NORTHEAST SOUTH AFRICA
EASTERN AUSTRALIA
\
30
West coast marine (Cfb)
Located at 40 60 latitude Rain throughout the
year, especially in winter. More so if on the
windward side of mountain range. Receive rain
from mid-latitude cyclones hitting west
coasts. Proximity to water moderates the climate
31
Example RegionsWest Coast Marine (Cfb) Climate
NORTHERN EUROPE
PACIFIC NORTHWEST
SOUTHERN CHILE
NEW ZEALAND
\
32
Mediterranean (Cs)
Located equatorward of the west coast marine
climates (30 - 40 latitude) Under the subsiding
branch of the eastern side of the subtropical
high in summer, so hot and dry then. Wet, mild
winters. Short scrubby vegetation with a few
trees. Good climate for winemaking!
33
Example RegionsMediterranean (Cs) Climate
MEDITERRANEAN
CALIFORNIA
SOUTHWEST AUSTRALIA
CAPE TOWN AREA
CENTRAL CHILE
\
34
Mediterranean Climate and the Roman Empire
Relatively similar and agriculturally productive
climate conditions exist throughout much of the
Mediterranean. Same crops that grew in one place
would also grow in a another place. FACILITATING
FACTOR IN THE EXPANSION OF THE ROMAN EMPIRE AND
DEVELOPMENT OF WESTERN CIVILIZATION!
35
Type D Moist Cold Climates
Characteristics Warm to cool summers Cold
winters with snow Large seasonal temperature
range About 30 - 40 inches of precipitation per
year. Where located About 25 - 70
latitude Subtypes Dfa and Dfb Humid
continental Dfc Subpolar
36
Humid continental (Dfa and Dfb)
Typically more toward the eastern side of a
continent, poleward of moist subtropical
areas. Regular precipitation throughout the
year. Summer precipitation maximum. Summers can
be sometimes hot. Favorable for deciduous
forests and agriculture
37
Example RegionsMoist cold (Df) Climate
EASTERN EUROPE AND SOUTHEAST RUSSIA
MIDWEST AND NORTHEAST U.S.
NORTHEAST ASIA
\
38
Subpolar or Boreal (Df)
Very cold winters Fairly low precipitation (less
than 20 inches per year) Typically supports
large evergreen boreal forests, or taiga.
39
Example RegionsBoreal Forests (Df)
NORTHERN SCANDANAVIA AND SIBERIA
NORTHERN CANADA AND ALASKA
\
40
Type E Polar Climates
Characteristics Cold temperatures year
round. Tundra, permafrost, or ice cap. Very
little precipitation. Where located Poleward
of boreal forest
THESE REGIONS ARE CHANGING RAPIDLY DUE TO RECENT
GLOBAL WARMING.
41
Type H Highland Climates
Climate changes experienced with increasing
altitude. Farther up, the typically more polar
the climate gets. THESE REGIONS ARE ALSO
CHANGING RAPIDLY DUE TO THE RECENT GLOBAL
WARMINGPARTICULARLY MOUNTAIN GLACIERS.
42
Example RegionsHighland Climates (H)
ROCKY MOUNTAINS
CENTRAL ASIA AND TIBET
ANDEAN ALTIPLANO
WELL SEE WHAT HAS HAPPENED TO MOUNTAIN GLACIERS
IN THESE PLACES LATER
43
Summary of Lecture 32
The major controls on climate are latitude,
land-sea distribution, ocean currents, the
general circulation, and terrain. Climate is
classified by the Köppen system. TROPICAL MOIST
(A) Either rainforest near the equator or
savannah farther polward. Precipitation
influenced by the ITCZ. DRY (B) Deserts
typically located under the subtropical ridge
and/or near the west coast of continents.
Steppes are grassland transition zones. MOIST
TEMPERATE (C) Specific subtype depends on
continental position (east vs. west). Moist
subtropical on eastern side, west coast marine
and Mediterranean on the western side. MOIST
COLD (D) Poleward of moist temperate climates,
with large seasonal shifts in temperature.
Includes boreal forest. POLAR (E) Tundra,
permafrost, or ice cap. HIGHLAND (H) Colder
climate due to higher elevation.
44
Reading Assignment and Review Questions
Reading Chapter 16 (last Chapter to be
covered) Chapter 17 Questions Questions for
Review 1,2,3,4,5,7,8,9,10,11,12,13,19 (8th ed.)

1,2,3,4,5,6,7,8,9,10,11,12,13,14,20 (9th
ed.) Questions for Thought 2,3,5,6