ARM’s Aerosol–Cloud–Precipitation Research (Aerosol Indirect Effects) Meteorological Mongraphs

The conception of the Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program over 20 years ago demonstrated prescience on the part of a number of astute scientists, many of whose words fill the pages of this monograph. The early years focused on a handful of cloud and radiation measurements and activities of relatively limited scope. The intervening decades have seen these efforts expanded to some of the finest instrumentation in the world to measure aerosol, clouds, radiation, and precipitation, accompanied by a substantial modeling effort. Together these have allowed the United States and international communities to tackle one of the thorniest problems associated with climate change, namely the influence of aerosol particles on cloud microphysics, precipitation, and cloud radiative properties (aerosol indirect effects). ARM research was at the forefront of aerosol indirect efforts from the outset, but because instrumentation was not readily in place and retrieval methodologies were still in their infancy, these were necessarily modeling efforts (e.g., Ghan et al. 1990; Feingold and Heymsfield 1992; Kim and Cess 1993) that addressed subsets of the problem. These early endeavors joined other key studies highlighting the climate forcing potential of tropospheric aerosol (e.g., Charlson et al. 1992) in setting the stage for a research effort that is, to this day, one of the cornerstones of ARM and the Atmospheric System Research Program (ASR).