Issue 10 Volume 41 May 16, 2003

20030032417 NASA Goddard Space Flight Center, Greenbelt, MD, USA
Gyrophase-bunched Electrons: Cluster Observations and Simulations
Gurgiolo, C.; Vinas, A. F.; Goldstein, Melvyn L.; [2003]; 1 pp.; In English; Yosemite 2003 Conference, 2003, CA, USA;
Copyright; Avail: Other Sources; Abstract Only
The interaction of the solar wind with the Earth’s bow shock is responsible for a number of phenomena both upstream
and downstream. One of the least understood and studied of these is the generation of gyrophase-bunched electrons. We will
describe initial work searching for and analyzing such events in (Plasma Electron And Current Experiment (PEACE) data from
CLUSTER. Plasma simulations will complement the data analysis. Recent analyses suggest that gyrophase-bunched electrons
are present rather frequently in the upstream region, due either to energization in the reflection off the shock front or, more
likely, to phase trapping in locally produced whistler wave fields.
Author
Solar Wind; Electrons; Shock Waves; Electron Plasma; Simulation
20030032480 NASA Langley Research Center, Hampton, VA, USA
Comparison of Stratus Cloud Properties Deduced from Surface, GOES, and Aircraft Data during the March 2000
ARM Cloud IOP
Minnis, Patrick; Smith, William L., Jr.; Dong, Xiquan; Mace, Gerald G.; Poellot, Michael; Marchand, Roger T.; Rapp, Anita
D.; Journal of the Atmospheric Sciences; December 2002; 59, 23, pp. 3265-3284; In English; Original contains color
illustrations; Copyright; Avail: Other Sources
Low-level stratus cloud microphysical properties derived from surface and Geostationary Operational Environmental
Satellite (GOES) data during the March 2000 cloud intensive observational period (IOP) at the Atmospheric Radiation
Measurement (ARM) program Southern Great Plains (SGP) site are compared with aircraft in situ measurements. For the
surface retrievals, the cloud droplet effective radius and optical depth are retrieved from a delta2-stream radiative transfer
model with the input of ground-based measurements, and the cloud liquid water path (LWP) is retrieved from ground-based
microwave-radiometer-measured brightness temperature. The satellite results, retrieved from GOES visible, solar-infrared,
and infrared radiances, are averaged in a 0.5 deg x 0.5 deg box centered on the ARM SGP site. The forward scattering
spectrometer probe (FSSP) on the University of North Dakota Citation aircraft provided in situ measurements of the cloud
microphysical properties. During the IOP, four low-level stratus cases were intensively observed by the ground- and
satellite-based remote sensors and aircraft in situ instruments resulting in a total of 10 h of simultaneous data from the three
platforms. In spite of the large differences in temporal and spatial resolution between surface, GOES, and aircraft, the surface
retrievals have excellent agreement with the aircraft data overall for the entire 10-h period, and the GOES results agree
reasonably well with the surface and aircraft data and have similar trends and magnitudes except for the GOES-derived
effective radii, which are typically larger than the surface- and aircraft-derived values. The means and standard deviations of
the differences between the surface and aircraft effective radius, LWP, and optical depth are -4\% +/- 20.1\%, -1\% +/- 31.2\%,
and 8\% l+/- 29.395, respectively: while their correlation coefficients are 0.78, 0.92, and 0.89, respectively, during the 10-h
period. The differences and correlations between the GOES-8 and aircraft results are of a similar magnitude, except for the
droplet sizes. The averaged GOES-derived effective radius is 23\% or 1.8 microns greater than the corresponding aircraft
values. resulting in a much smaller correlation coefficient of 0.18. Additional surface-satellite datasets were analyzed for time
periods when the aircraft was unavailable. When these additional results are combined with the retrievals from the four in situ
cases, the means and standard deviations of the differences between the satellite-derived cloud droplet effective radius, LWP,
and optical depth and their surface-based counterparts are 16\% +/- 31.2\%, 4\% +/- 31.6\%, and -6\% +/- 39.9\%, respectively.
The corresponding correlation coefficients are 0.24, 0.88, and 0.73. The frequency distributions of the two datasets are very
similar indicating that the satellite retrieval method should be able to produce reliable statistics of boundary layer cloud
properties for use in climate and cloud process models.
Author
Cloud Physics; Radiation Measurement; Atmospheric Radiation; Radiative Transfer; Particle Size Distribution; Infrared
Radiation; Water
20030032987 NASA Goddard Space Flight Center, Greenbelt, MD, USA
A New Estimate of the Extragalactic Gamma-ray Background from EGRET Data
Moskalenko, I. V.; Strong, A.; Reimer, O.; March 12, 2003; 1 pp.; In English; 28th ICRC Meeting, 31 Jul - 7 Aug. 2003,
Japan; Copyright; Avail: Other Sources; Abstract Only
We use the GALPROP model for cosmic-ray propagation to obtain our best prediction of the Galactic component of
gamma rays, and show that away from the Galactic plane it gives an accurate prediction of the observed Energetic Gamma
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