Cirrus Clouds near the midlatitude tropopause

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Cirrus Clouds near the mid-latitude
tropopause from CALIPSO Steven T
Massie ACD/NCAR January 8, 2008
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Outline
How likely is it to observe cirrus between
double tropopauses? Data Lidar observations
over France FNL (NCEP) analyses of multiple
tropopauses CALIPSO observations over North
America
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April May double tropopauses occur 25 of
the time (Paris)
Apr
30 25 20
May
Noel and Haeffeln, Midlatitude cirrus clouds and
multiple tropopauses from a 2002 2006
climatology over the SIRTA observatory, JGR, 112,
D13206, doe10.1029/2006JD007753, 2007.
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Lidar observations for a single day Double
tropopause layers are 1.5 km thick
Altitude (km)
Time ?
15 14 13 12 11 10 9 8 7 6
Noel and Haeffeln, Midlatitude cirrus clouds and
multiple tropopauses from a 2002 2006
climatology over the SIRTA observatory, JGR, 112,
D13206, doe10.1029/2006JD007753, 2007.
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Most cirrus cloud tops are below the tropopause
Z (cloud top) Z (tropopause)
Noel and Haeffeln, Midlatitude cirrus clouds and
multiple tropopauses from a 2002 2006
climatology over the SIRTA observatory, JGR, 112,
D13206, doe10.1029/2006JD007753, 2007.
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Statistical Summary of SIRTA Clouds
Frequency of Cirrus case occurrence 83 Clo
ud top 0.5 km below the tropopuase 10 Cloud
top at or above the tropopause 2 Cirrus is between
a double tropopause values are for instances
when clouds are observed
Noel and Haeffeln, Midlatitude cirrus clouds and
multiple tropopauses from a 2002 2006
climatology over the SIRTA observatory, JGR, 112,
D13206, doe10.1029/2006JD007753, 2007.
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2nd Tropopuase Heights from FNL Analyses
2nd trop heights are mostly at 16 - 17 km
altitudes Some are between 13-14 km
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Calipso Example May 28
Altitude (km)
30 20 10 0
56 50 45 38
32 N lat 920 935 UTC
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Calipso Example May 25
T tropopause height from FNL analyses
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CALIPSO and FNL Analyses in 2007
Month multiple of time clouds
are tropopauses between multiple
tropopause April 16 2 May 10 1
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Summary
Based upon lidar observations over France
CALIPSO/ FNL (NCEP) data clouds are between
double tropopauses 2 of the time If you know
that a double tropopause will occur, then you
have a roughly 1 in 10 chance of observing cirrus
above the 1st (lowest) tropopause.