Calculation of Cloud Reflectivity in Rain In Cloud over the Ocean: A Study of the First Aerosol Indirect Effect
AuthorNoble, Stephen R.
AdvisorHudson, James G.
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The first indirect aerosol effect creates large uncertainty in climate change. Hudson et al. (2009) showed that more cloud droplets exist when there are more cloud condensation nuclei. By increasing cloud droplet concentration the reflectivity increases. Cloud reflectivity is calculated for 17 flights using the data from FSSP and 260X probes aboard the NCAR C130 collected during the Rain In Shallow Cumulus over the Ocean (RICO) campaign. Regional reflectivity is also calculated using the probes as well as satellite images. Both methods show increasing reflectivity with increasing concentrations. Flights with clouds having similar liquid water paths are compared. Larger droplet concentrations containing smaller droplets exist in flights with higher reflectivity. The range of the difference in reflectivity for clouds with similar liquid water path is from 0.03 to 0.15. Clouds more sensitive to droplet concentration changes create larger changes in reflectivity. These findings support the first indirect aerosol effect.