Clouds and precipitation are affected through modifications of the temperature and
water vapour content of near - surface air.
Oh and, while
the water vapour content of air may be dependent on temperature, cloud cover certainly isn't No, not entirely, but increased water vapour is the main contributors to cloud formation, and, as you almost point out, increased temperature increases water vapour in the atmosphere.
Oh and, while
the water vapour content of air may be dependent on temperature, cloud cover certainly isn't
Truth n ° 10
The water vapour content of the air has been roughly constant since more than 50 years but the humidity of the upper layers of the troposphere has been decreasing: the IPCC foretold the opposite to assert its «positive water vapour feedback» with increasing CO2.
If CO2 increases there is more cooling at say 250 mbar and less cooling below: such a setting is likely to be erased by convection; and by a slight reduction of
the water vapour content of the upper troposphere that will restore the OLR.
The water vapour content of the air has been roughly constant since more than 50 years but the humidity of the upper layers of the troposphere has been decreasing: the IPCC foretold the opposite to assert its «positive water vapour feedback» with increasing CO2.
Hence while the bulk of the water vapour in the lowest layers (2.3 km) closely tracks the temperature of the surface, it's
the water vapour content of the high troposphere that controls the outgoing longwave radiation (OLR) and the global balance of the absorbed solar radiation with the OLR.
[44] a reduction of 1/7 of
the water vapour content of the air near 300 mbar pushes down by a factor 1 / (1-1/7) 4.7 = 1.03 the P80 % level and the P80 % temperature increases by a factor 1.030.19 = 1.006 that is by about 1.5 K for the radiation temperature over the far infrared spectral range
*
the water vapour content of upper layer of the air (in blue figure 6 - D) will change by about 12 % / K near the tropopause and is reduced by the enhanced cooling of the 250 mbar layer; hence the water vapour radiation will the be from a «lower and warmer» level, with a very significant spectral leverage of a factor of ten (400 cm - 1 for the water vapour w.r.t to 40 cm - 1 for the CO2).
[41]
The water vapour content of the air between the top of the air and the altitude of pressure P (atm) is decreasing roughly like P4.5 [42]: hence 80 % of the total water vapour is between P = 1 and P = 0.75 near 2.3 km, and the total water content of the air closely follows the surface temperature.
I have made simple calculations with
a water vapour content of 1 % and find that liquid water has less volume than the equivalent number of H2O molecules in gas form.
What is evident from the dust during the cool phase and lack of dust during the warm phase was that
the water vapour content of the air suddenly changed.
Not exact matches
For this reason, telescopes for this kind
of astronomy must be built on high and dry sites, where the atmosphere is rarefied and its
water vapour content minimal.
Given the lower temperatures and lower
water vapour content at higher altitudes and a need for high supercooling to initiate condensation (in the absence
of sufficient normal CCN), wouldn't an increased source
of nuclei, in the form
of GCRs, enhance high - and middle - altitude cloud formation?
Areas with high
water vapour content at the exact same latitude don't cool off nearly as much which is evidence
of the very back radiation you are trying to refute.
To claim that the entire system
of atmospheric temperature moderation has been described by the fluctuations
of atmospheric CO2
content while excluding the other obvious factors such as atmospheric
water vapour content, solar flux and orbital mechanics is just nonsense.
The blue line
of the graph shows the optical depth
of the atmosphere with changing CO2 and
water vapour content.
Water vapour content is largely a function
of temperature, particularly ocean surface and near - surface temperature.
Or what the possible role
of increasing / decreasing
water vapour content in increasing / decreasing the radiative forcing with multi-decadal oscillations?
The numerical experiments are designed to explore the effects
of changing various properties
of the ocean (its size, geometry and diapycnal diffusivity), the atmosphere (its
water vapour content) and the forcing
of the system (the distribution
of incoming solar radiation and the rotation rate
of the planet).