Prof. Pavlos Kollias

Pavlos Kollias

Radar Applications for Weather and Climate Research

Adjunct Professor
pavlos.kollias [at] (E-mail)

Research interests

The cloud problem

The “cloud problem”, i.e., the understanding of the microphysical, dynamical and radiative processes that act at the cloud scale and their accurate representation in numerical models is the central theme of my research. In particular, boundary layer clouds, precipitation initiation, cloud entrainment and turbulence are focus areas of current and future research. Synergetic remote sensing observations from both space and ground-based sensors and their clever use through the development of new retrieval algorithms and sampling strategies constitute our approach for probing clouds and precipitation in their natural environment.

3D observations of clouds and precipitation

The life cycle of clouds is not well understood; not least because the cloud and precipitation communities have remained staunchly separate. A seemingly simple process such as the rapid formation of warm rain is still not understood, and remains far from having a community-consensus explanation or model. Many other examples of fundamental gaps in understanding of clouds could be cited. Cloud lifecycle studies require detailed observations of all phases of cloud evolution, from initiation, to development of updrafts and downdrafts, to hydrometeor evolution in time and space, to partitioning of condensate into precipitation and outflow anvils. The temporal and spatial scales of both Large-Eddy Simulation (LES) and Cloud Resolving Models (CRM) are suitable for studying cloud lifecycles and cloud-aerosol interactions. LES domains are typically 10 km with grids as small as 20 m. 3D observations of clouds and precipitation over a 50-100 km domain could play a vital role in testing and improving LES models and CRM’s. Such observations would allow us to follow the life cycle of individual clouds or even cloud systems, and thus provide a way to evaluate the net result of the various aerosol indirect effects, each of which operates at different stages of a cloud’s lifetime.

Radar Applications in Weather and Climate Research Group

Our goal is to promote the use of radars in weather and climate research, from severe weather nowcasting to cloud climatology. Starting with the instrument, we are interested in the optimization of radar systems and networks though hardware and software innovations. The translation of radar observables to physical parameters of interest to the modeling community using both forward and inversion methods is a key area of research for our group. Our scientific curiosity focuses on the physical understanding of the atmospheric component of the hydrological cycle (e.g., cloud, precipitation, radiation and thermodynamics) and the improved representation of cloud and precipitation processes in global, regional and storm scale numerical models.

Read more about our research at


Time Lapse of the Research Flight on May 20, 2012 as part of the Key West Aerosol and Cloud Experiment which our group is participating


Some recent publications

McLaughlin D, Pepyne D, Chandrasekar V, Philips B, Kurose J, et al. (2009) Short-Wavelength Technology and the Potential for Distributed Networks of Small Radar Systems. Bulletin of the American Meteorological Society: In Press.

Kollias, P., B. A. Albrecht, 2009: Vertical Velocity Statistics in Fair Weather Cumuli at the ARM TWP Nauru Climate Research Facility. Submitted to J. of Climate.

Kollias P., M. A. Miller, K. L. Johnson, M. P. Jensen, D. T. Troyan (2009), Cloud, thermodynamic, and precipitation observations in West Africa during 2006, J. Geophys. Res., 114, D00E08, doi:10.1029/2008JD010641.

Giangrande, S. E., E. Luke and P. Kollias, 2009: Retrievals of Precipitation Parameters Using Non-Rayleigh Scattering at 95-GHz. Submitted to J. Atmos. Oceanic Tech.

Luke, E., P. Kollias, and M. D. Shupe, 2009: Detection of Supercooled Liquid in Mixed-Phase Clouds using radar Doppler spectra. Submitted to J. Atmos. Oceanic Techn.

Remillard, J., P. Kollias, M. D. Shupe and E. Eloranda, 2009: Three Years of Cloud Climatology and Phase at Eureka Using Synergetic Radar/Lidar Measurements. Submitted to J. Geoph. Res.

Serpetzoglou E, Albrecht BA, Kollias P, Fairall CW, 2009: Boundary Layer, Cloud, and Drizzle Variability in the Southeast Pacific Stratocumulus Regime. J. Climate, 21, 6191–6214.

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