Resumen
Individual tropospheric particles (0.03 to several um in diameter) were sampled using wire impactors on a DC-8 64 aircraft along and within Pacific Rim, from 125ºE to 120ºW and 70ºS to 70ºN, during the November 1989 and May 1990 Global Backscattering Experiment (GLOBE) deployments of NASA. A simple radiative balance model was used to determine the first order radiative effect of this aerosol layer at the surface. The results indicate that: (i) The background (optical thickness of ?0.005) tropospheric aerosols between 2.4 - 12.2 km exert a warming tendency on surfaces with albedos > ?0.02 in both the visible and infrared, (ii) There is an apparent increase in the coarse mode sulfur containing aerosol abundance compared to ?15 years ago, suggesting that the background aerosol layer exerted a stronger tendency of planetary warming ?15 years ago.