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Geophysical Turbulence Program

		This image shows a snapshot of the temperature field in a direct numerical simulation of penetrative convection. This figure reveals effects of molecular diffusion that may act to alter the widely accepted convective entrainment law. This result is part of a program of investigation to understand the convective atmospheric boundary layer. (Figure courtesy of Peter Sullivan (NCAR/MMM) and H. Jonker (Delft University, Netherlands).

Research on turbulence has been a significant part of the NCAR scientific program since its beginning in the early 1960s. The original scientific leaders of NCAR recognized that to understand the dynamics of the atmosphere, the oceans, the climate, the sun, and solar-terretrial interactions, it would be essential to understand the relevant turbulent processes. A number of scientific appointmens in the first 10-15 years of NCAR's existence reflected this view and provided an in-house base from which to productively interact and collaborate with the world turbulence community. From these beginnings has emerged a sustained emphasis on geophysical turbulence at NCAR in research, visitors, seminars, and workshops that continues to this day. This emphasis can be found today in the Geophysical Turbulence Program (GTP).

GTP is by construction an interdiscplinary group of about 40 members that spans many divisions and laboratories at NCAR with a few external affiliates. It encompasses research at NCAR on multiscale nonlinear processes with an array of applications in a broad variety of areas. GTP is also the outreach arm of this research.

In FY2007, GTP sponsored 13 seminars and hosted 7 long-term visitors (with an average stay of 25 days) and a one-year visitor. The topics covered in collaboration with NCAR staff represent a broad variety of interests: studies of semi-Lagrangian fluid numerics, collision coalescence of cloud droplets, the entrainment law of the atmospheric boundary layer, spectral element methods for turbulence, turbulence in a rotating sphere with global spectral models, magnetospheric and space physics, and fundamental turbulence scaling laws. A collection of these collaboration summaries appears at GTP contributions by visiting collaborators.

GTP activities advance NCAR's strategic priorities of "Conducting computer science, computational science, applied mathematics, statistics, and numerical methods R&D" and "Engaging a broader and more diverse community in the atmospheric and geosciences." This work is supported by NSF Core funding.