Earth - The Water Planet
Bob Cahalan
NASA/Goddard/913, Greenbelt, MD 20771
301-614-5390; cahalan@gsfc.nasa.gov
Water Cycle
Atmosphere & Ocean Energy Flows
Ice & Fresh Water
ENSO Family
Water Cycle
Oceans - 70% of Earth’s surface
– Evaporation powers weather
– Heat capacity controls climate
– El Nino - Southern Oscillation
Vapor - Atmospheric Greenhouse
Clouds - control energy flows, rain 1 m/yr
Ice & Snow - store 90% of fresh water
Amazing H20 molecule, 2/3 cell volume
– Polar
– Cohesive
– Heat storage
– Ice floats
– Solvent
Earth climate Sun driven, water controlled.
Our Atmospheric Shield
Sea water is “tuned” to
transmit visible light.
Sunlight IN
TSun ~ 6000 K
Visible
Earthlight OUT
TEarth ~ 300 K
H20 Window
Earth’s Energy Budget
H20 clouds = climate control
Earth = only inner planet with
liquid & ice & vapor H20.
Venus
Earth
374 °C = 647 K
Mars
100 °C = 373 K
0 °C = 273 K
Arctic Sea Ice
66 km ~ 40 miles
20 May 1998, Modis Airborne Simulator
Arctic Sea Ice
New Zealand April
Antarctic Melt-down ?
Area - 13,600,000 km2 > US + Mexico
Ronne & Ross Ice Shelves ~ ea 500,000 km2; Larsen Ice Shelves – 2000, 3250 km2
Highest peak – 5 km (16,000 feet); Maximum Ice Thickness – 5 km
Sea Ice Area – 4 X 10 6 km 2 (March); 19 X 10 6 km 2 (September)
Antarctic Melt-down ?
11,800 ± 3,900 km2/yr
Fresh Water: Rivers, Lakes, Aquifers
T. Oki & Y.Sud,
Earth Interactions,
Vol 2, paper 1,
1998.
Fresh Water: Rivers, Lakes, Aquifers
Private
Fresh Water, E. C. Pielou,
U. Chicago Press, c1998,
275 pp.
Chesapeake Watershed
Chesapeake Watershed
Susquehanna (107)
Factors affecting nutrient trends in major rivers
Of the Chesapeake Bay Watershed, USGS Water
Resources Investigations Report 00-4218.
http://water.usgs.gov
Potomac (106)
Patuxent (105)
Water Monitoring from Space
Water Monitoring from Space
AQUA: http://www.aqua.nasa.gov
• Collects information on Earth’s water cycle,
including ocean evaporation, atmospheric
water vapor and clouds, precipitation, soil
moisture, sea and land ice, and snow cover
on land and ice. AQUA successfully launched
on May 4, 2002.
GRACE: http://essp.gsfc.nasa.gov/grace/
• Unravels global climatic issues by measuring
changes in sea-floor pressure, watching the
mass of the oceans change, and monitoring
changes in the storage of water and snow on
the continents. GRACE successfully launched
on March 17, 2002.
ICESAT: http://icesat.gsfc.nasa.gov
• Will measure the ice sheet mass balance,
cloud and aerosol heights, optical densities,
vegetation and land topography. ICESAT is
scheduled to launch in December, 2002.
Intrinsic Modes of Climate Variability
• Anthropogenic vs. Natural
• Climate modes:
- coherent space-time structures
- interactions among atmosphere, ocean,
land, biosphere & cryosphere
- climate predictability
Global Change and Natural Climate Modes
North Atlantic Oscillation
/Arctic Oscillation
Asian-North America Teleconnection
Natural Modes of Climate Variability
Seasonal-toInterannual
El Nino/
Southern Oscillation
(ENSO)
Synoptic
Weather
Madden
Julian
Oscillation
(MJO)
North Atlantic Oscillation
(NAO)
Pacific North /South
Quasi-biennial America Pattern (PNA, PSA)
Oscillations
Asian –North America
Pattern (ANA)
Indian Ocean Zonal Mode
(IOZM)….
Annular Modes : Arctic/
Antarctic Oscillations
DecadalInterdecadal
Cold-OceanWarm-Land
(COWL)
Pacific Decadal
Oscillations
(PDO)
Atlantic DecCen Variability
Indian Ocean
Warming
>100 yrs
GLOBAL WARMING
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Sem Annua
A climate wave is arriving.
Will we wipe out …
… or ride the wave?
Little Drops …
Little drops of water,
little grains of sand,
Make the mighty ocean
and the pleasant land.
So the little minutes,
humble though they be,
Make the mighty ages
of eternity.
Thus our little errors
make a mighty sin;
Drop by drop the evil
floods the heart within.
Little deeds of kindness
little words of love
Make our Earth an Eden
like the heaven above.
Julia A. Fletcher Carney
(1824-1908)