Observing Clouds and Contrails for GLOBE and NASA · shortened name for condensation trails....
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Observing Clouds and Contrails for GLOBE and NASA Dr. Lin Chambers NASA Langley Research Center Hampton,VA
Transcript of Observing Clouds and Contrails for GLOBE and NASA · shortened name for condensation trails....
Observing Clouds andContrails for GLOBE and
NASA
Dr. Lin ChambersNASA Langley Research Center
Hampton,VA
Our Objectives
• Obtain contrail and other cloudinformation from the largest possiblenetwork of ground observers
• Use to:– Validate satellite retrieval algorithms– Improve contrail prediction methods
Outline
• What are contrails?• Why is NASA involved?• Why and how are students important to
this study?
Outline
• What are contrails?• Why is NASA involved?• Why and how are students important to
this study?
What are Contrails?• Contrails are
CLOUDS that formin the wake ofaircraft.
• Contrail is ashortened name forcondensation trails.
• Also known as vaportrails, jet trails,“chemtrails”
Contrails have been aroundfor a long time!
• They were firstdescribed in thescientific literature in1919.
• During WWII,contrails sometimeslittered the skiesduring aerialcombat.
What is a Mixing Cloud?
The cloud that formson your breath duringa cold day is a mixing
cloud
B. Cold, dry air inupper atmosphere
A. Hot, moistair from planeexhaustC. If you cross
the line …contrail!
Do Contrails Affect Cloud Cover?
Outline
• What are contrails?• Why is NASA involved?• Why and how are students important to
this study?
Global Cloud CoverAugust 26, 1993
EARTH'S ENERGY BUDGET
Incoming
solar energy
100%
Reflected by
atmosphere
6%
Reflected
by clouds
20%
Reflected from
earth's surface
4%
Absorbed by
atmosphere 16%
Conduction and
rising air 7%
Absorbed by
clouds 3%
Radiated to space
from clouds and
atmosphere
64% 6%
Radiated
directly
to space
from earth
Carried to clouds
and atmophere by
latent heat in
water vapor 23%
Radiation
absorbed by
atmosphere
15%
Absorbed by land
and oceans 51%
Derived Product
Requires CloudDetection andCloud PropertyRetrieval
When the upperatmosphere ismoist enough,the contrailscontinue to grow.
Under theseconditions, thecontrails becomepersistent.
Why Do We Study Contrails?
We currentlyestimate thatcontrails addan additional0.5 to 5 %warming tothegreenhousegas effect.
Persistentcontrailsoccasionallycover largeareas.Like cirrusclouds,contrailslikelycontribute toglobalwarming.
Air traffic and persistent contrail coveragewill continue to increase.
By 2050, warming due to contrails may be 2.5to 25 % of the current greenhouse gas warming.
Outline
• What are contrails?• Why is NASA involved?• Why and how are students important
to this study?
Our estimates ofthe climaticeffects ofpersistentcontrails are stilluncertain.We still havetrouble estimatingcontrail coverage.
Why can students help?
Most contrails are still smaller than the resolutionof most satellites.
Why can students help?
Data Sheet
Initial GLOBEContrail Data
AnalysisDr. Dave Duda,
Hampton University
Method•Compare GLOBE obs to:
• RUC (Rapid Update Cycle;Benjamin et al.)• ARPS (Advanced RegionalPrediction System; Xue et al.)
• Initial comparison for April 2004• 1500 GLOBE observations ofcontrails
Website & Activities
http://asd-www.larc.nasa.gov/GLOBE/
• Some other things you may see…
Inverse contrails (distrails)
Aircraft sometimes make holes in clouds!
Contrail Cousins
Cloud “zippers” on Father’s Day, 2004
