Nadir Jeevanjee received the 2019 James R. Holton Award at AGU’s Fall Meeting 2019, held 9–13 December in San Francisco, Calif. The award recognizes “outstanding scientific research and accomplishments of early-career scientists” who are no more than 3 years past receiving the Ph.D. degree.  

Nadir Jeevanjee is awarded the James R. Holton Award for his groundbreaking contributions to atmospheric sciences, in particular, to the fundamental understanding of convection.

Although the notion of Archimedean buoyancy is among the classics in science, the idealized concept of buoyant accelerations as driven by local density variations suffers important limitations. First, the motion of a buoyant plume induces a response in the environment through which the plume moves, establishing a nonhydrostatic vertical pressure gradient. Second, environmental fluid surrounding the plumes is mixed, or entrained, into the plume. Both reduce the acceleration of the plume. Nadir’s studies of effective buoyancy have provided a robust interpretation of the environmental pressure gradients associated with buoyant plumes. The roles of buoyancy and turbulence in entrainment are a more recent focus of these studies.

Nadir has connected his findings on plume dynamics with cold pools and convective organization, both areas currently receiving extensive attention in studies of convection. His incisive analysis of the sources of acceleration in convection showed the importance of mechanical forcing to the initiation of deep convection. As with his results on the effective buoyancy of plumes, these results have important implications for the parameterization of convection in complex Earth system models. Nadir’s powerful application of analytic methods in his studies has imbued these results with physical intuition, but he has also explored numerical models of convection. In addition to proving consistent with analytic results, these studies have produced important results in their own right, for example, by illuminating the “gray zone,” where models begin to resolve motions parameterized at coarser resolutions. Other innovative studies are providing new insights on fundamentals of radiative transfer, including its relationship to precipitation changes in warming climates as well as cooling to space.

—Leo Donner, Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration, Princeton, N.J.

I am honored to receive this year’s James R. Holton Award. It is humbling and inspiring to consider how deeply Holton shaped our field, not only through his influential books and papers, but also through the many younger scientists whom he mentored and who continue to shape the field today. This honor adds to the extraordinarily good fortune I’ve already had in being mentored myself. At University of California, Berkeley, I was privileged to work with David Romps, a fellow physicist by training who inspired me with his incisive thinking, clever use of numerical models and analytical methods, and simultaneous emphasis on simplicity and rigor. Whatever I have accomplished, I owe much of it to him. After transitioning to Princeton and the Geophysical Fluid Dynamics Laboratory for postdoctoral work, I was quickly taken in by Leo Donner, Isaac Held, Stephan Fueglistaler, and Rob Socolow, each of whom have broadened my thinking, opened doors, and generally made an intellectual home for me here in Princeton. Perhaps the biggest benefit of receiving an award like this is the sense that one’s research is valued, and the encouragement that follows. This is all the more meaningful for me, given the unconventional path I have taken thus far. I would not have made it without the support of loved ones, especially my parents, Kamila and Mushtaq, and my wife, Erika. I hope to pay my good fortune forward in the future and follow Holton’s example as a scholar and community member. —Nadir Jeevanjee, Princeton University, Princeton, N.J.