WMOD00311

• Title: Harold D. Orville Symposium - Forty Years of Modeling Clouds and Weather Modification
• Date: 4/26/2003
• Weather Modification - Doc Type: Report

(GSFC). Since May 2000, most of my research in
the Environmental Modeling Center (EMC) at the
National Center for Environmental Prediction
(NCEP) has been to improve cloud and radiation
parameterizations in operational forecast models,
particularly the operational Eta model (Black, 1994;
Rogers et a/., 1996).

3. BROAD USE OF MICROPHYSICS MODELS

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CLOUD MICROPHYSICS MODELING: THE LASTING LEGACY OF HAROLD D. ORVILLE

Brad S. Ferrier',1,2

1NOAA/NWS/NCEP/EMC, Camp Springs, MD 20746-4304
2SAIC/GSO, Beltsville, MD 20705-2675

1. INTRODUCTION

Cloud microphysics is an important area of
study in atmospheric sciences that impacts our
lives in so many ways, serving the central role in
the atmospheric water cycle. Some of the most
important environmental issues, such as global
warming and air quality, are strongly impacted by
our understanding (or lack thereof) of cloud
microphysics. Some within the cloud physics
community may view their work through more
narrowly defined areas of specialization. What is
remarkable about Professor Harold D. Orville is
the international recognition of his contributions to
so many different aspects of cloud microphysics in
particular, but also in atmospheric sciences in
general.

This contribution will highlight Prof. Orville's
contributions to the field of cloud microphysics
modeling by providing some background of
microphysical models, my personal perspective of
the current state of cloud microphysics modeling,
and finally suggestions for future research. But
before doing so, I'm going to provide a little
background of my recent activities, because they
shape my perspective and my biases on the state
of cloud microphysical modeling and research.

2. RECENT ACTIVITIES

I also cannot help but feel a little
uncomfortable, because I have not kept pace with
advances during the past year or two in cloud.
microphysics modeling, particularly at cloud
resolving scales of motion where the horizontal
re$olution is several km or less. I have not
worked on microphysics packages in these
models since the mid 1990s. In late 1996 lied the
Ground Validation operational data processing in
support of the Tropical Rainfall Measuring Mission
(TRMM) at NASNGoddard Space Flight Center

'Corresponding author address: Brad S. Ferrier,
NOAA/NWS/NCEP/EMC W/NP2, 5200 Auth Rd.,
Rm. 207, Camp Springs, MD 20746-4304;
E-mail: [e-mail]

The interdisciplinary nature of cloud physics
research has grown exponentially during the past
few decades. As in other areas of specialization
within the Atmospheric Sciences, cloud physics
research is primarily in the form of observational
studies, numerical modeling studies, and
theoretical (laboratory) studies. But unlike most
other atmospheric fields of study, advancements in
cloud microphysics continue to rely heavily on
knowledge gained from laboratory experiments. In
some ways, the fundamental nature of cloud
microphysics is similar to turbulent fluid flows, in
that both are incredibly complicated and far
beyond our ability to comprehend. Like with
numerical models of turbulent fluid flows, state-of-
the-art cloud microphysical models can be
exceedingly detailed and complex. Taken
together, it is no wonder that even the "best" cloud
numerical models, which are the collective
repositories of our knowledge of turbulent fluids
and thermodynamics, are still quite flawed. And
yet, we have made great strides during the past
several decades in improving our understanding of
how clouds work and in representing their effects
in numerical models.

Cloud microphysical models are used in a wide
variety of research areas, such as advertent and
inadvertent weather modification; atmospheric
electrification and lightning; atmospheric chemistry
and air quality monitoring; developing improved
remote sensing techniques from radars, lidars,
profilers, and satellites, involving a large portion of
the electromagnetic spectrum; numerical weather
prediction (NWP) forecasts of mid latitude systems,
hurricanes, severe and non-severe local storms,
squall lines, and other mesoscale convective
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