8
E. Raschke
but also other observable structures in the upper-tropospheric water vapor fields. Their analysis
is based on principles which were developed already 25 years ago (e.g. Moller, 1961).
30
""
i
"I
";i
"- "/'
".: :. -l.O3
LC02- ",
,..
"\
: :
i
"\
"'~, :
"0 '
ZO
\
I ' v '
i
\j
IL "':
~
...
I ' ~ :'
0
, I ,
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! :, \
;::
't""
10
/
I \
I
~2:' ~\
j J
0
-15
-1.0
-0.5
05
1.0
l5
2 .0
2.5
RATE Of TEMPERATURE CHAHGE ("c/doy)
Figure 1.3: Radiative heating and cooling of the atmosphere, computed for the greenhouse
gases water vapor, carbon dioxide and ozone (from Manabe and Moller, 1961). This figure
arose in one of the earliest studies of the effects of radiative energy transfer on dynamical
processes computed in numerical models for the atmosphere.
In the lower layers of the stratosphere the water vapor mixing ratio assumes already low values
around 2 to 5 X 10- 6 gH,O/gair' Read et al. (1995) confirmed the many direct soundings
with analyses of microwave limbsounding data from the UARS (Upper Atmosphere Research
Satellite). Convection from below causes that most portions of the water vapor freeze out,
when air penetrates through the tropopause into the stratosphere (see also details in Webster,
1995).
In the upper stratosphere and even more in the, the water vapor participates also in many photochemical processes, which are responsible for the maintenance of the ozone layer. It originates
there to some part from the methane, which is steadily penetrating from the troposphere below
into the middle atmosphere. Presently observed increases of the number of annual occurances
of noctilucent clouds, and also an apparent increase of their areal extent, are attributed to this
water vapor source.
Direct measurements of the atmospheric water vapor with operational sondes show large and
often also systematic errors in all layers above about 400 hPa, where mostly too dry values
are obtained. Other sensors for direct measurements, such as the complex Lyman-a probes or
cryogenically cooled mirrors, measure higher moistures, but they are too expensive for world
wide operational use in the operational "throw-away sondes".
E. Raschke
but also other observable structures in the upper-tropospheric water vapor fields. Their analysis
is based on principles which were developed already 25 years ago (e.g. Moller, 1961).
30
""
i
"I
";i
"- "/'
".: :. -l.O3
LC02- ",
,..
"\
: :
i
"\
"'~, :
"0 '
ZO
\
I ' v '
i
\j
IL "':
~
...
I ' ~ :'
0
, I ,
~
...
! :, \
;::
't""
10
/
I \
I
~2:' ~\
j J
0
-15
-1.0
-0.5
05
1.0
l5
2 .0
2.5
RATE Of TEMPERATURE CHAHGE ("c/doy)
Figure 1.3: Radiative heating and cooling of the atmosphere, computed for the greenhouse
gases water vapor, carbon dioxide and ozone (from Manabe and Moller, 1961). This figure
arose in one of the earliest studies of the effects of radiative energy transfer on dynamical
processes computed in numerical models for the atmosphere.
In the lower layers of the stratosphere the water vapor mixing ratio assumes already low values
around 2 to 5 X 10- 6 gH,O/gair' Read et al. (1995) confirmed the many direct soundings
with analyses of microwave limbsounding data from the UARS (Upper Atmosphere Research
Satellite). Convection from below causes that most portions of the water vapor freeze out,
when air penetrates through the tropopause into the stratosphere (see also details in Webster,
1995).
In the upper stratosphere and even more in the, the water vapor participates also in many photochemical processes, which are responsible for the maintenance of the ozone layer. It originates
there to some part from the methane, which is steadily penetrating from the troposphere below
into the middle atmosphere. Presently observed increases of the number of annual occurances
of noctilucent clouds, and also an apparent increase of their areal extent, are attributed to this
water vapor source.
Direct measurements of the atmospheric water vapor with operational sondes show large and
often also systematic errors in all layers above about 400 hPa, where mostly too dry values
are obtained. Other sensors for direct measurements, such as the complex Lyman-a probes or
cryogenically cooled mirrors, measure higher moistures, but they are too expensive for world
wide operational use in the operational "throw-away sondes".