Sonia Kreidenweis made her mark on cloud physics early in her career with the definition of “kappa,” a single parameter that captures the process transforming dry particles into cloud droplets via action as cloud condensation nuclei (CCN). Her work reaches far beyond cloud microphysics to include aerosol optical properties, atmospheric chemistry, bioaerosols, visibility, and ice nucleation. Her research has spanned laboratory, field, and theoretical work, and remote sensing, each time bringing exceptional fresh ideas and new understanding.

Prof. Kreidenweis is dedicated to sharing her experience through teaching and mentoring. She demands the best, never cutting corners on rigor in research, but always approaches the students with a deeply humble attitude. This is not a lordly professor dictating a research agenda, but a fellow traveler seeking the truth.

While most of us consider a balance between research and teaching sufficient to define a career, Prof. Kreidenweis unselfishly gives her time to service. She is an active member of the American Meteorological Society (AMS) and American Association for Aerosol Research (AAAR), serving on many committees, associate editor of journals, and as secretary, vice president, and president of AAAR. She sits on numerous advisory committees for such organizations as the National Center for Atmospheric Research and the Karlsruhe Institute of Technology (KIT) in Germany. In addition, since 2015 she has served Colorado State University as an associate dean in various roles in the College of Engineering and been one of the five founding members of the interdisciplinary Partnership for Air Quality, Climate and Health. As with teaching, Prof. Kreidenweis approaches these leadership roles with humility. For her, the work is never about glory, only service, and an opportunity to create a better professional environment for all of us.

The humble qualities that empower her protégés and colleagues are especially significant given the era in which Prof. Kreidenweis came of age. When she was starting in science, being a woman in physical science was still a novelty. Prof. Kreidenweis has served as a role model for countless women entering the field. From her example we understood that yes, women can succeed as scientists, and yes, they can do so without braggadocio and swagger.

It is for all of the above that Sonia M. Kreidenweis is deserving of the Yoram J. Kaufman Outstanding and Unselfish Cooperation in Research Award.

—Lorraine Remer, University of Maryland, Baltimore County, Catonsville

I am humbled to receive the Yoram J. Kaufman Outstanding and Unselfish Cooperation in Research Award, and honored to be in the company of the distinguished scientists who are prior recipients. I am also deeply grateful to my nominators for considering me for this recognition, as this award in Yoram’s memory is especially meaningful to me. Yoram cosponsored (with Anne Thompson) my first sabbatical from Colorado State University. In addition to generating cherished memories and lifelong friendships, my visit to the NASA Goddard Space Flight Center, on the eve of the deployment of the first Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, had a profound influence on my scientific life. It provided a glimpse into the importance of Yoram’s dedication to international collaboration and unselfish cooperation in bringing such a complex mission to fruition. It is uniquely appropriate to honor Yoram’s legacy with particular attention to these attributes. I feel very fortunate to have started my career at a time when atmospheric chemistry was blossoming, and to have been a part of the growth of this wonderful community that embraces interdisciplinary science and collaboration. I sincerely thank the many colleagues who have shared this journey and have made it so fun and rewarding, especially Paul DeMott, who introduced me to new areas of research and whose achievements exemplify the power of cooperative research. Special thanks to the outstanding current and former graduate students, postdocs, and research scientists who have been the driving force of our research group; your success brings me joy. My deepest gratitude goes to my Ph.D. advisers, John Seinfeld and Rick Flagan; my postdoctoral mentor, Joyce Penner; and my colleagues at Colorado State University, for sharing their knowledge, for setting high standards, and for their encouragement throughout my career. Finally, my heartfelt thanks to my husband and son for their love and support that bring meaning to everything else. —Sonia Kreidenweis, Department of Atmospheric Science, Colorado State University, Fort Collins

For elucidating aerosols’ role in climate and visibility by quantifying their hygroscopic growth and cloud-condensation/ice nuclei activity.