Transcript METO112-extremes - Department of Meteorology and Climate

Observations of Our Changing Planet:
Weather EXTREMES
Professor Menglin Jin
METR112: Global Climate Change
The Weather Extremes and Climate Change
Video
• http://www.met.sjsu.edu/metr112videos/MET%20112%20Video%20LibraryMP4/weather%20extremes/
• Global Warming-1.mp4
Meehl et al. 2005 Science
GCM simulated
sea surface temperature
and sea Level rise
under different CO2 conditions
Surface Air Temperature
Surface will keep warming
Sea level rise
Sea level will keep rise
Definitions
• Climate Change:
– Changes in climate of the past, present or future associated
with natural or anthropogenic (human) factors
• Global Warming:
– Warming of the 20th and 21st century associated with
anthropogenic activities.
Weather VS Climate
• Weather describes whatever is
happening outdoors in a given place
at a given time.
• Weather is what happens from
minute to minute.
• can change a lot within a very
short time
• Weather includes daily changes in
precipitation, barometric pressure,
temperature, and wind conditions
in a given location.
• Climate describes the total of all
weather occurring over a period of
years in a given place.
• Climate tells us what it's usually
like in the place where you live
NASA Earth Satellite Provide tremendous
Observations
TRMM
11/27/97
Terra
Landsat 7
4/15/99
Aqua
5/4/02
12/18/99
Weather can be measured from space. Average of weather can get climate
Weather Extremes
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Hurricane
Flood
Snowfall
Drought
fire
etc
what are the frequency and
in a changing climate
strength of extreme weather events
What does it mean by extreme?
Extreme value distributions are often used to model the smallest or
largest value among a large set of independent, identically distributed
random values representing measurements or observations.
frequency
Extremes
Climate value
Where are the extremes here?
NOAA Extreme Weather and Climate Events
http://www.ncdc.noaa.gov/oa/climate/severeweather/extremes.html
Landsat 7 Observes Flooding in New Orleans
Hurricane Katrina
September 7, 2005
September 15, 2005
TRMM: Unprecedented Views of Hurricanes
Hurricane Ike was the third most destructive hurricane to
ever make landfall in the United States. It was the ninth
named storm, fifth hurricane and third major hurricane of the
2008 Atlantic hurricane season
Category 4
Hurricane and SST Change
Webster et al. report
that the number of category 4 and 5
hurricanes has almost doubled globally
over the past three decades
(Webster et al, 2005, Science)
Hurricane and SST Change
Emanuel, K. A. (2005), Nature
Emanuel, K. A. (2005) reports that a measure of the power dissipated by tropical cyclones
(proportional to the cube of wind speeds accumulated over the North Atlantic and
western North Pacific basins) has approximately doubled since about 1950, with most
of the increase occurring over the past 30 years.
According to Emanuel, increases in both intensity and duration of tropical cyclones
have contributed to this apparent increase. Emanuel's power dissipation index (PDI)
is strongly correlated with sea surface temperatures in these basins,
which have increased markedly over the same period.
http://www.gfdl.noaa.gov/~tk/glob_warm_hurr.html
Be careful
• Hurricanes are natural events, and are not linearly related to
climate change
• Climate change, by increase SST, indeed makes it more possible to
have strong hurricane occur
Saharan Dust Front - Ground View
Saharan Dust Front - Algeria
Arctic sea ice coverage, 1979 and 2003
NASA http://www.learner.org/channel/courses/envsci/unit/text.php?unit=12&secNum=7
20-Year Trends in Arctic Sea Ice Coverage
Yearly and Seasonal Ice Coverage Trends
Yearly
–2.8%/decade
Winter
–2.2%/decade
Spring
–3.1%/decade
Summer
–4.5%/decade
Autumn
–1.9%/decade
 37,000 km2/year decrease of sea ice area
over a 19.4 year period observed from satellite
Parkinson et al. (1999) and Vinnikov et al. (1999)
Deviation of Monthly Arctic Sea Ice Area
22 years from Nimbus 7 to DMSP
Seasonal Cycle Removed
Sea Ice Area (106 km2)
1.0
0.5
0.0
-0.5
-1.0
-1.5
79
81
83
85
87
89
91
93
95
97
99
Year
DMSP: Defense Meteorological Satellite program
Parkinson et al. (1999)
MODIS Flyby of the Himalayas & Ganges Valley
Glaciers as a Harbinger of Global Change
 Glacier National Park
– 110 glaciers have disappeared in the past 150 years
– 37 remaining glaciers expected to disappear within 25 years
 Mt. Kilimanjaro
– All glaciers likely to disappear within 20 years
 160,000 glaciers worldwide being monitored by satellites (especially Landsat
7/ETM+ and Terra/ASTER)
Gangotri Glacier, Himalaya
Bhutan-Himalaya
Seasonal Snow Coverage from MODIS
Flood
Flood occurs all over the globe
China
Land Cover Change in Florida
1900 vs 1992
 Human influence has transformed southern Florida
 Land converted to cropland and cities
 Everglades transformed from deep-water sloughs and bog marsh into drier sawgrass
marshes
 Mangroves have shrunk dramatically
Crop and Property Damages from Natural Hazards
1960 – June 2004
$/Square mile
$14.5-$500
$500-$1,250
$1,250-$2,500
$2,500-$5,000
$5,000-$545,000
 San Francisco County ($26.8 million/square mile)
 Los Alamos ($16.5 million/square mile)
Hazards Research Lab, U of South Carolina
Summary and Resources
Satellites have played a crucial role in understanding
and documenting global change
– sources and sinks of carbon in the oceans and land
– global surface and atmospheric temperature
– sea ice extent and change
– glacial retreat
– hurricanes
Resource on Earth science, including news stories,
images of the day, data sets, and natural hazards
– earthobservatory.nasa.gov
The only way to have real success in science ... is to describe
the evidence very carefully without regard to the way you feel
it should be. If you have a theory, you must try to explain
what's good about it and what's bad about it equally. In
science you learn a kind of standard integrity and honesty.
— Richard Feynman
What does it mean by extreme?
Extreme value distributions are often used to model the smallest or
largest value among a large set of independent, identically distributed
random values representing measurements or observations.
frequency
Extremes
Climate value
Where are the extremes here?
NOAA Extreme Weather and Climate Events
http://www.ncdc.noaa.gov/oa/climate/severeweather/extremes.html