Daniel Keyser's Early Career Journey Into the Emerging Discipline of Mesoscale Meteorology

Daniel Keyser’s Early Career Journey into the Emerging Discipline of Mesoscale Meteorology

Louis W. Uccellini

Entering the meteorological research community in the middle 1970’s, Dan Keyser found himself entering a continuous, and often contentious, swirl related to the emergence of what came to be defined as the “Mesoscale” as a separate research discipline. Mesoscale “pertains to atmospheric phenomena with horizontal scales that range from a few to several hundred kilometers” (AMS Glossary of Meteorology), and mesoscale weather events are noted for a more rapid temporal evolution that is measured by hours instead of days. By the early 1970’s a growing mesoscale research community set about to define the atmospheric mesoscale structures and associated dynamic and physical processes that were also being linked to extreme weather events.

This growing interest in Mesoscale Meteorology occurred as the larger international research community was working toward a better understanding of the global general circulation and the prediction and predictability issues associated with the development of a global numerical prediction models. Much of this work was supported through the Global Atmospheric Research Program (GARP) and its field programs (GARP Atmospheric Tropical Experiment – GATE and the First GARP Global Experiment - FGGE) in the 1960’s into the 1970’s. Nevertheless, others were becoming increasingly involved in the research of smaller scale phenomena. These included “Mesoscale Convective Complexes” (MCCs), the role of frontal zones in organizing smaller scale weather patterns, the study of long duration inertia gravity waves initiating convective storms, and a continuing interest in the rapid development phase of extratropical cyclones. These efforts ultimately led to the first research field program with “Mesoscale” in its title, the “Severe Environmental Storms and Mesoscale Experiment” (SESAME) brought forward in 1974. Along with these research efforts came the introduction of mesoscale limited-area numerical models led by the academic community including Mike Kaplan (SUNY-Albany) and Doug Paine (Cornell University), Karl Kreitzberg and Don Perky (Drexel University), Roger Pielke Sr (University of Virginia) and Richard Anthes (Dan Keyser’s PhD advisor; Penn State University), and the National Meteorological Center who were introducing its Limited-area Fine Mesh (LFM) model. As these new mesoscale models showed an increasing ability to resolve the dynamic and physical processes driving the evolution of the rapidly developing extreme weather systems, it was becoming clearer that a new meteorological discipline had arrived. Dan Keyser carefully assessed this new and developing mesoscale community from observation, modeling and mathematical perspectives and launched his career, finishing his PhD in 1981 under Rick Anthes with several published journal articles on the initial assessments of the Penn State mesoscale model. He then moved on to the new Goddard Laboratory for Atmospheric Sciences (at NASA’s Goddard Space Flight Center, under David Atlas), joining the Mesoscale Analysis and Modeling Section which Joanne Simpson (Branch Chief of the Severe Storms Branch) asked me to spin up and staff (“with the best and brightest”) after she arrived in 1979.

In this presentation, I will offer several highlights of the early part of Dan’s career path, describing certain aspects of his early papers: 1) Anthes-Keyser 1979 MWR assessment of the Penn State Mesoscale model including the model sensitivity to the vertical distribution of latent heat release; 2) his taking the chance with an application of the Sawyer-Eliassen 2-dimensional circulation theory to a data/analysis of the upper-level front and developing tropopause fold that ultimately contributed to the subsequent synoptic scale rapid development phase of the 1979 President’s Day Storm (1985 MWR); and 3) his 1987 BAMS paper (for which he invited me as a co-author) describing how the use of regional to mesoscale models could be used for detailed diagnostic studies designed to show how mesoscale physical and dynamical processes could rapidly influence the larger scale circulation systems, essentially revitalizing synoptic-diagnostic studies as an important research and educational tool.

These might seem to be small wins compared to Dan’s accomplishments that would follow at the GSFC and throughout his academic and research career at the University of Albany. But one needs to remember that the importance of the Mesoscale was not readily apparent to those working on global numerical models and related research to gain a better understanding of the global circulation, who discounted the role of fronts and cyclone scale processes in the overall evolution of the general circulation, with one characterizing the Mesoscale to Dan as “embroidery”. Dan’s research efforts said otherwise. And with these initial “wins”, and related journal publications, he gained the confidence he needed to do even greater things with his foundational analytic work on upper-level frontogenesis that he completed (with Michael Pecnick) at GSFC in the middle 1980’s. And his willingness to explore the real world applications with mesoscale analyses and numerical models, and also apply his analytic work to controversial case studies, all contributed mightily to his subsequent groundbreaking work at the University of Albany that includes the development and applications of “Psi Vectors” that provide the analytic foundations for showing the importance of the cross and along-stream contributions to the divergent flows supporting the vertical motions associated with upper-level fronts and jet streaks. Finally, he teamed up with Lance Bosart at the University of Albany to apply basic mesoscale research advances to the daily weather prediction challenges through a 20-year partnership with the collocated NWS Forecast Office in Albany through the NWS Collaborative Science Technology and Applied Research Program (CSTAR; led locally by Gene Auciello, the Albany WFO/MIC). The CSTAR partnership kept Dan well-grounded with a conviction that the mesoscale processes he dedicated his remarkable research career to are indeed fundamental to the circulation patterns that drive the larger scales and greatly influence the evolution of extreme weather events as was being hypothesized across the growing mesoscale community at the start of his career journey.