Figure 1. Bin-averaged measurements of atmospheric properties from 4 PACS monitoring cruises. Upper pane: low-cloud fraction; lower panel: integrated cloud liquid water content when clouds are present. Red circles for are fall and blue diamonds are spring.

Figure 2. Daily-averaged measurements of atmospheric properties from 4 PACS monitoring cruises. Upper pane: low cloud base height; lower panel: ratio of MBL specific humidity, q, to total column integrated water vapor, IV. Red circles for are fall and blue diamonds are spring.

Figure 3. Daily averaged downward solar (upper panel) and IR (lower panel) flux time series for 10 N 95 W. The blue lines are TAO buoy data; the green line clear sky model values based on ETL PACS cruise information. The difference in the two lines is the cloud radiative forcing at the surface. Strong forcing in the May-October period is caused by migration of the ITCZ to 10 N.

Figure 4. Stratocumulus cloud characteristics on Oct. 18, 2001. Upper panel: total liquid water path (LWP) from two microwave radiometer systems (green line and red dots) and cloud fraction from a ceilometer (blue circles). Lower panel: cloud radar backscatter intensity (color contours) and ceilometer cloud base heights (white dots).

Figure 5. Time series from EPIC2001 of stratocumulus cloud droplet concentration inferred from solar radiative flux measurements using the method of Dong et al. 1998. Blue dots are individual half-hour values; red x's are the daily median. Days 286-295 correspond to Ronald H. Brown observations at the WHOI ORS buoy at 20 S 85 W. After day 295 the ship departed the area and headed East toward the coast of Chile. The increase in cloud droplet concentration associated with lower cloud solar transmission coefficient (higher albedo) assumed to be caused by increasing aerosol concentration near the coast.