Climate October 22, 2012. Lecture learning objectives: You should be able to: Describe the...
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Climate October 22, 2012. Lecture learning objectives: You should be able to: Describe the difference between climate and weather Describe major climate
Lecture learning objectives: You should be able to: Describe
the difference between climate and weather Describe major climate
factors -radiation, albedo, energy budgets, wind and atmospheric
circulation, temperature, and moisture. Explain the differences
between urban and forest microclimates and what drives those
differences. Identify indicators of climate change
Slide 3
Micro, meso, macro and megaclimate ScaleLength AreaLocale
Micro1 m - 1 km 1m - 1 km local Meso 1 - 100 km 1 - 100 km regional
Macro100 - 10 000 km 100 - 10 000 km continental Mega>10 000 km
>10 000 km global
Slide 4
What is the difference between weather and climate? Climate is
what you expect Weather is what you get
Slide 5
Climate factors Radiation and albedo Energy budgets Wind global
circulation, high and low pressure systems Temperature effects of
latitude and elevation, greenhouse effect Moisture types of
precipitation, seasonal distribution, latitudinal distribution,
orographic precipitation
Slide 6
Ecosystems use solar energy to drive processes < 2 % of
solar energy is used for photosynthesis Most goes into evaporating
water. Heat balance, hydrologic cycle and climate are strongly
linked. Forests have 70% of leaf area on the Earth.
Slide 7
Radiation and albedo Forms of radiation Ultraviolet, visible,
infrared (heat) short wave long wave
http://serc.carleton.edu/images/eslabs
/weather/balance_diagram_simple.jp g
Slide 8
www.windows.ucar.edu/earth/Atmosphere/images/...
Slide 9
Albedo Proportion of shortwave radiation that is reflected (0-1
scale) Albedos of different surfaces Vegetation typeAlbedo
Temperate forest (summer) 0.12 (winter) 0.25 Tropical forest 0.07
Savanna0.16 Field, grassland 0.16 (summer) Desert 0.35 Ocean ice
0.5-0.7 Asphalt 0.04-.12 Color of the surface is important white
surfaces have the highest albedos dark surfaces (black) have the
lowest albedos
Slide 10
Species have different leaf strategies with respect to
radiation Species adjust leaf areas to capture light or handle heat
loads. western hemlock (shade tolerant) has greater leaf area (m 2
leaf/m 2 of surface) than Douglas-fir (shade intolerant). Species
like Noble fir have sun and shade needles. Eucalyptus leaves are
vertical to reduce heat load in a hot environment.
http://www.nps.gov/neri/naturescience/images/web_HWA_01.jpg
http://t1.gstatic.com/images?q=tbn:ANd9GcRcUJDJPOFyMWtGLbA-DNCe0QgQX7IC4Hw-mnLvdigIDHtZDFCUAxYAyNafZQ
http://www.cirrusimage.com/Trees/Eucalyptus_leaves.jpg
Slide 11
Global wind and circulation patterns Nasa.gov Broadly predicts
global to continental climate
Slide 12
Local winds
Slide 13
Santa Ana Winds USA Today
Slide 14
Mountain valley winds
http://t3.gstatic.com/images?q=tbn:ANd9GcTRZqSuMV9Rkd9MIIk-FqKXpexuhgPVn8Fiy0O1arw0od_gmz2rP778sCCH
Slide 15
Urban canyons (valleys) Urban structure also affects winds,
albedo and radiation
http://en.wikipedia.org/wiki/File:42nd_st_canyon.jpg
Slide 16
apollo.lsc.vsc.edu Ag.arizona.edu TEMPERATURE INVERSIONS
http://www.stuffintheair.com/images/Inversion_Smoke.jpg
Slide 17
Temperature Global temperatures are highest in tropics and
lowest at the poles Lowest at highest elevation
Slide 18
Temperature at noon on field trip Oct 13, 2012 58 F Seattle 100
feet 64 F Ellensburg 1764 feet 46 F Stampede Pass 3965 feet
Slide 19
Precipitation tends to be highest in tropics and lowest at the
poles Modified by mountain ranges that produce orographic rainfall
on the windward side of mountains and rain shadows on the lee side
of mountains Moisture humidity and precipitation
http://www.whymap.org/whymap/EN/Downloads/Additional_global_maps/precipitation_g.jpg?__blob=normal&v=3
Slide 20
3. Urban and Forest Microclimates Forest and urban trees modify
the climate because of albedo and energy budgets. Trees cool the
environment (low albedo, high evapotranspiration, low sensible
heat) Concrete and dark asphalt surfaces heat the environment (high
albedo, no transpiration, low evaporation, high sensible heat. The
urban heat island effect
Slide 21
Clearcuts are hotter and colder than forests. South slopes,
particularly SW slopes are hotter and drier than north slopes.
Steeper slopes are hotter.
Slide 22
www.arch.hku.hk
Slide 23
Mitigation of Urban Heat Islands Increase vegetative cover Use
porous concrete surfaces Change the albedo of surfaces
Slide 24
Pacific Ocean to the west Mountain ranges that block and
deflect 24 PNW weather and climate are dominated by two
elements:
Slide 25
Average Rain Per Year Seattle: 37 New York City: 47 Miami: 56
25 Number of Cloudy Days Per Year Seattle: 228 (61%) Houston: 166
Miami: 117 (31%)
Slide 26
East vs West Cascades Annual temperature range East side:
varies by 60F between Jan-July West side: varies by 30F
Precipitation range I-84 along Columbia River gorge: Rain forest
near Cascade Locks (80/year) to arid environment near The Dalles
(13/year) in just 45 miles 26
Slide 27
27
Slide 28
Most temperate forests are dominated by broad-leaved deciduous
trees If enough water to support trees vs grasses Dormant during
winter New leaves in spring Photosynthesis in wet summer 28
Slide 29
PNW Ecosystems Why do conifers dominate here? Short, cool
summers Mild winters Precipitation mostly in winter (75% between
Oct- Mar) Dry summers 29
Slide 30
Photosynthesis and Water Conservation are opposites. The
Photosynthesis-Transpiration Compromise: must open stomata to bring
in CO 2 but in so doing, the plant loses water vapor 30
Slide 31
The PNW west-side Challenge Optimum photosynthesis: warm and
bright PNW is warm and bright mid-July to mid-Sept * These are the
driest months * Regulate stomatal opening to reduce water loss
during drought conditions Lose best opportunity for photosynthesis
31
Slide 32
Solution? Retain leaves and do photosynthesis whenever possible
32
Slide 33
West East Precipitation drops off rapidly east of the passes
Drought- tolerant pines and junipers Grassland and desert 33
Slide 34
34
Slide 35
Global Climate Change Thin layer of atmosphere traps some of
the Suns energy and heat Problem = Thickening layer (Greenhouse
gases) Average global temperatures are rising
Slide 36
Instrument Data (thermometer records) Global mean surface
temperature anomaly 1850 to 2006 relative to 19611990
Slide 37
Hotter than normal globally Hottest years on record in USA:
1934, 1998, and 2006 Red=warmer than average 1934: hot in some
areas; 1998 & 2006: globally hotter
Slide 38
Departure from normal temperatures Image credit: U.S. Global
Change Research Program (www.globalchange.gov).
Slide 39
Past warming trends From 1000-2000: 3 little blips (3 between
1000-1400 A.D.) before current trend Shorter duration and smaller
magnitude
Slide 40
Indications of Global Climate Change 1. Glaciers are melting 2.
Heat waves 3. Ocean temperature is rising 4. More powerful storms
5. Increased flooding 6. Drought (relocalization of precipitation)
7. Melting ice caps 8. Melting tundra 9. Tropical plants moving
north 10. Insect infestations 11. Sea level is rising And more
Slide 41
1. Glaciers are melting Upsala Glacier in South American Andes
in Argentina - Retreating 180 feet per year 1928 2004
Slide 42
The total surface area of glaciers worldwide has decreased by
50% since the end of the 19th century
Slide 43
What controls glacier changes? Accumulation (snowfall,
rainfall) Temperature (summer/winter) Dr. Michelle Koutnik (UW PhD
07)
Slide 44
2. Heat waves Heat wave in Europe 2003- killed 35,000
Record-breaking heat in 2005 in many American cities Hottest and
longest duration above 100F Of the 21 hottest years on record
(global), 20 within last 25 years
Slide 45
3. Ocean temperature is rising Cannot get the long history of
temperature data Warming trend Since 1960s, more warm temperature
anomalies
Slide 46
4. More powerful storms Increased frequency 2004: Japans
typhoons (10) U.S. severe hurricanes (Katrina) 2005: First time
World Meteorological Society ran out of names (27)
Slide 47
4. More powerful storms (cont.) Unusual places 2004: first
hurricane in Brazil Previously thought impossible in South
Atlantic
Slide 48
Power of hurricanes correlates with sea surface
temperature
Slide 49
5. Increased flooding Number of Major Flood Events Source:
Millennium Ecosystem Assessment
Slide 50
6. Relocalization of precipitation Global precipitation
increased by 20% in last century But not evenly distributed Severe
droughts
Slide 51
Slide 52
Changes in precipitation Amount, intensity, frequency, and type
More in E North America, S South America, N Europe Less in
Mediterranean, Africa, and S Asia More rain and less snow in
mountains
Slide 53
7. Melting ice caps Antarctica- frozen desert Losing land ice
at rate of 31 billion tons of water per year Ice shelves are
breaking up Emperor penguin population declined 70% in last 50
years Depends on stable sea ice
Slide 54
Slide 55
8. Melting Tundra Western Siberia is thawing for the first time
in 11,000 years Size of France + Germany Started to thaw only
recently Western Siberia temp increasing faster than anywhere
else
Slide 56
9. Subtropical plants moving North Overwintering plants that
normally dont survive Subtropical camellias in Pennsylvania Kudzu
(fast-growing vine) moving north State Flowers of 28 states soon
cant grow there
Slide 57
9. Plant zones are changing (cont.) Gardening maps are changing
Many areas are a full zone warmer Some are two zones warmer than in
1990
Slide 58
10. Insects Beetles wiping out forests in Canada Pine beetles
kept in check by cold 14 million acres of bark beetle-infested
spruce trees
Slide 59
11. Sea level is rising 2000 years of little change Rose 8 in
last 100 years Water expands as it warms Melting glaciers and ice
sheets
Climate Change in the PNW? Local simulations: largest warming
on lower and middle mountain slopes More cloudiness in spring in
west side More rain and less snow 64 Impacts of these changes?
Slide 65
The 2007 IPCC report Conclusions Warming of the climate system
is unequivocal, as is now evident from observations of increases in
global average air and ocean temperatures, widespread melting of
snow and ice, and rising global average sea level. Eleven of the
last 12 years (1995-2006) rank among the 12 warmest years in the
instrumental record since 1850.
Slide 66
Slide 67
Temperature trends WA, ID WA ID
Slide 68
Modeled predicted species changes Ponderosa pine will expand,
Douglas-fir and lodgepole pine will increase range Tree line in
mountains will be much higher shrinking alpine zone. Engelmann
spruce, Mt. hemlock and Pacific silver ranges will be reduced. Some
desert species will expand
Slide 69
Slide 70
Lecture learning objectives: You should be able to: Describe
the difference between climate and weather Describe major climate
factors -radiation, albedo, energy budgets, wind and atmospheric
circulation, temperature, and moisture. Explain the differences
between urban and forest microclimates and what drives those
differences. Identify indicators of climate change
