Polar Ozone and Aerosol Measurement (POAM III)
POAM III iis a 99--channel
h
l visible/near
i ibl /
infrared
i f
d photometer
h t
t for
f making
ki
measurements of stratospheric constituents using solar occultation
techniques.
The POAM measurements:
Ozone (5(5-60 km)
Aerosol Extinction (5(5-30 km)
Nitrogen Dioxide (20(20-45 km)
Water Vapor (5(5-50 km)
Atmospheric Density (30(30-60 km)
Launched on SPOT 4 spacecraft March 1998
Ceased operations in December 2005
POAM III is the successor to POAM II which operated from Oct. 1993 to Nov. 1996.
P=POAM
H=HALOE
S SAGE
S=SAGE
r=sunrise
s=sunset
2001-2004 ozone hole changes
Is the ozone hole
recovering? Reduced
ozone loss found at top
edge of ozone hole in
2001-2004
Hoppel et al. [GRL, 2005]
POAM III Measurement Location
Vortex edge
POAM latitude
POAM equivalent latitude
POAM III Antarctic Vortex Water Vapor
M
Measurements
t
IMPACT
model
results
Benson
et al.,
al
2006
Inside-the-vortex
water vapor
parcels starting at
500K on June 1
and descending
and dehydrating
until Sept
Sept. 29
29,
1998.
IMPACT model runs for various reasonable
dehydration mechanisms
•Saturation
S t ti =>
> Dehydrate
D h d t tto saturation
t ti
•Ice freezing => homogeneous pathway
•HomFrz => homogeneous NAT freezing
•HetFrzA => heterogeneous NAT freezing
with
ith poor SAT
SAT-NAT
NAT nucleation
l ti
•HetFrzB => heterogeneous NAT freezing
with improved SAT-NAT nucleation.
Daily minimum parcel temperature for the
POAM latitude band.
Comparison of POAM measured
d h d ti with
dehydration
ith IMPACT model
d l run with
ith
different temperature biases
Inside the vortex temperatures,
p
, South Pole,, 30 hPa
UKMO
REAN
Temperatures at 490K on
June 15,
15 1998
1998.
NCEP-CPC
ECMWF
490K is potential
temperature to which
parcels
l starting
i at 500K
00K
on June 1 have
descended
POAM measurement locations
Compare POAM
dehydration
de
yd at o with
t
IMPACT model
dehydration run
with several
weather models.
UKMO
NCEP CPC
NCEP-CPC
REAN
ECMWF
POAM
measurements
REAN-POAM
REAN
POAM
comparison looks
good in all years.
Unusual descent?
Minimum water vapor from
POAM and 4 IMPACT
model calculations
500K descending surface
500K descending
surface
Sonde, GPSRO
Sonde
GPSRO, and dehydration
data show similar results
JJAS grand average temperature
South Pole
So why was there less ozone loss
in 2003?
At least with REAN temperatures
2003 is not an unusually cold
year.
Neumayer
end