Search Results

You are looking at 11 - 12 of 12 items for

  • Author or Editor: Piotr J. Flatau x
  • Refine by Access: All Content x
Clear All Modify Search
Jerome M. Schmidt
,
Piotr J. Flatau
,
Paul R. Harasti
,
Robert. D. Yates
,
David J. Delene
,
Nicholas J. Gapp
,
William J. Kohri
,
Jerome R. Vetter
,
Jason E. Nachamkin
,
Mark G. Parent
,
Joshua D. Hoover
,
Mark J. Anderson
,
Seth Green
, and
James E. Bennett

Abstract

Descriptions of the experimental design and research highlights obtained from a series of four multiagency field projects held near Cape Canaveral, Florida, are presented. The experiments featured a 3 MW, dual-polarization, C-band Doppler radar that serves in a dual capacity as both a precipitation and cloud radar. This duality stems from a combination of the radar’s high sensitivity and extremely small-resolution volumes produced by the narrow 0.22° beamwidth and the 0.543 m along-range resolution. Experimental highlights focus on the radar’s real-time aircraft tracking capability as well as the finescale reflectivity and eddy structure of a thin nonprecipitating stratus layer. Examples of precipitating storm systems focus on the analysis of the distinctive and nearly linear radar reflectivity signatures (referred to as “streaks”) that are caused as individual hydrometeors traverse the narrow radar beam. Each streak leaves a unique radar reflectivity signature that is analyzed with regard to estimating the underlying particle properties such as size, fall speed, and oscillation characteristics. The observed along-streak reflectivity oscillations are complex and discussed in terms of diameter-dependent drop dynamics (oscillation frequency and viscous damping time scales) as well as radar-dependent factors governing the near-field Fresnel radiation pattern and inferred drop–drop interference.

Full access
John H. Seinfeld
,
Gregory R. Carmichael
,
Richard Arimoto
,
William C. Conant
,
Frederick J. Brechtel
,
Timothy S. Bates
,
Thomas A. Cahill
,
Antony D. Clarke
,
Sarah J. Doherty
,
Piotr J. Flatau
,
Barry J. Huebert
,
Jiyoung Kim
,
Krzysztof M. Markowicz
,
Patricia K. Quinn
,
Lynn M. Russell
,
Philip B. Russell
,
Atsushi Shimizu
,
Yohei Shinozuka
,
Chul H. Song
,
Youhua Tang
,
Itsushi Uno
,
Andrew M. Vogelmann
,
Rodney J. Weber
,
Jung-Hun Woo
, and
Xiao Y. Zhang

Although continental-scale plumes of Asian dust and pollution reduce the amount of solar radiation reaching the earth's surface and perturb the chemistry of the atmosphere, our ability to quantify these effects has been limited by a lack of critical observations, particularly of layers above the surface. Comprehensive surface, airborne, shipboard, and satellite measurements of Asian aerosol chemical composition, size, optical properties, and radiative impacts were performed during the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) study. Measurements within a massive Chinese dust storm at numerous widely spaced sampling locations revealed the highly complex structure of the atmosphere, in which layers of dust, urban pollution, and biomass- burning smoke may be transported long distances as distinct entities or mixed together. The data allow a first-time assessment of the regional climatic and atmospheric chemical effects of a continental-scale mixture of dust and pollution. Our results show that radiative flux reductions during such episodes are sufficient to cause regional climate change.

Full access