«While low clouds have a predominantly cooling effect due to their shading of sunlight,
most cirrus clouds have a net warming effect on the Earth,» Spencer said.
The
most significant changes in the new D - series
cloud datasets are: 1) revised radiance calibrations to remove spurious changes in the long - term record, 2) increased
cirrus detection sensitivity over land, 3) increased low - level
cloud detection sensitivity in polar regions, 4) reduced biases in
cirrus cloud properties using an ice crystal microphysics model in place of a liquid droplet microphysics model, and 5) increased detail about the variations of
cloud properties.
Emissions, they discovered, increased the fraction of
cirrus clouds where vapor trails were
most prevalent but decreased the fraction in some areas by increasing the temperature and consequently decreasing the relative humidity in the lower atmosphere.