Energy and Water Cycles in the Climate System ...
400
g 350
~
::l
~ 300
Q)
a.
E Q)
Ig
Q)
....
::l
tlj
.... Q)
a.
E Q)
I250
325
300
275
250
225
(a)
,~
Venus
__ ,'
---------.. ---. Earth
(b)
I ! 2.5x1 0 6 J kg· 1 1
V
·o~
~
~
o''?f ~o
N,' b-' < ~c,'?f
-!2.84x10 6 J kg· 1
o 00
o~
G melting
freezing
! I -! 3.34x1 0 5 J kg .11
10 2
10 3
Water Vapor Pressure (N m· 2 )
7
Figure 1.2: Phases of water: Phase transition (solid curves) and hypothetical climate trajectories for Venus, Earth and Mars (from Webster, 1994). This figure indicates that on Earth
all three phases can conveniently coexist.
Drastic temporary variations of the mixing ratio can, however, also be observed in the lower
troposphere due to the formation of different air masses on their journey over the globe.
The higher layers of the troposhere are much dryer due to lower temperatures, but as the images
of Meteosat and other satellites each day visualize, if made from measurements of the emission
of water vapor in its band 6.3 /-Lm, there are larger dryer and moister regions, mostly due to
larger-scale atmospheric dynamics. These moister regions are important for the formation and
life time of higher clouds systems, such as cirrus and mid-level stratiform layers. Schmetz et
al. (1988) use such measurements to determine the upper tropospheric humidity and also the
horizontal water vapor transports, where winds are estimated from motions of cloud elements
400
g 350
~
::l
~ 300
Q)
a.
E Q)
Ig
Q)
....
::l
tlj
.... Q)
a.
E Q)
I250
325
300
275
250
225
(a)
,~
Venus
__ ,'
---------.. ---. Earth
(b)
I ! 2.5x1 0 6 J kg· 1 1
V
·o~
~
~
o''?f ~o
N,' b-' < ~c,'?f
-!2.84x10 6 J kg· 1
o 00
o~
G melting
freezing
! I -! 3.34x1 0 5 J kg .11
10 2
10 3
Water Vapor Pressure (N m· 2 )
7
Figure 1.2: Phases of water: Phase transition (solid curves) and hypothetical climate trajectories for Venus, Earth and Mars (from Webster, 1994). This figure indicates that on Earth
all three phases can conveniently coexist.
Drastic temporary variations of the mixing ratio can, however, also be observed in the lower
troposphere due to the formation of different air masses on their journey over the globe.
The higher layers of the troposhere are much dryer due to lower temperatures, but as the images
of Meteosat and other satellites each day visualize, if made from measurements of the emission
of water vapor in its band 6.3 /-Lm, there are larger dryer and moister regions, mostly due to
larger-scale atmospheric dynamics. These moister regions are important for the formation and
life time of higher clouds systems, such as cirrus and mid-level stratiform layers. Schmetz et
al. (1988) use such measurements to determine the upper tropospheric humidity and also the
horizontal water vapor transports, where winds are estimated from motions of cloud elements