Our last flight was a successful sampling of a small cu (photo attached). We first climbed to 22 kfeet northbound to do a sounding. The aerosol models suggested that we were on the western edge of a dust event, so we wanted to get a profile of it. We then turned south to intercept a line of small, mostly non precipitating cumulus west of Denver. Tops of the cloud were about -15 C, we sampled in mid cloud at -14 (19 kfeet), then at cloud base at 18 kfeet, followed by below base at 17.5. The air was rather dirty today with CN over 10,000 in lower levels and a rather smooth decrease with altitude. At cloud base the CN was 6000 and then decreased to around 2000 at the same altitude away from the cloud region. Drop concentrations were very continental (500 to 700 cm-3). The cloud had only a little ice in it and liquid water concentrations of up to 0.3 g m-3. We had a few shutdowns of the data system that were inconvenient, but we were able to make a fair case study of this small cloud.

Jeff Stith