| An Alternative Method of Computing Altitude Adjustment Corrected Geomagnetic Coordinates as Applied to IGRF Epoch 2005 |
20-Jul-2007 |
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| Authors:
William Heres; Nelson A Bonito; ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC LEXINGTON MA
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 | An updated set of altitude adjusted corrected geomagnetic coordinates has been calculated. The coordinates are based on the 10th generation IGRF model coefficients for Epoch 2005. The corrected geomagnetic coordinates at ground level are available as a lookup table, and a corresponding set of spherical harmonic coefficients for use in computing altitude adjusted corrected geomagnetic coordinates at various altitudes (after Baker and Wing [1998]) are also available. Both products are ... |
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| Aspects of Spacecraft Charging in Sunlight |
OCT 2006 |
10 pages |
| Authors:
Shu T. Lai; Maurice F. Tautz; ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC LEXINGTON MA
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 | This paper is an overview of spacecraft charging in sunlight. The daylight photoelectron flux emitted from spacecraft surfaces normally exceeds the ambient electron flux. As a result, charging of spacecraft surfaces to positive voltage is expected to occur in sunlight. Indeed, spacecraft are often observed to charge to low positive voltages in sunlight. However, spacecraft can charge to high-level (kilo-electron-volts) negative voltages in sunlight. Why do spacecraft charge negatively in ... |
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| Analytic Models for a Spherical Satellite Charging in Sunlight at any Spin Rate |
OCT 2006 |
13 pages |
| Authors:
Maurice F. Tautz; Shu T. Lai; ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC LEXINGTON MA
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| We present analytic models for the steady state potential distributions surrounding a spinning, dielectric-coated, spherical spacecraft charging in sunlight. The sun direction is assumed to lie in the satellite bellyband plane, perpendicular to the spin axes. The models are based on a multipole expansion of Laplacian potentials external to the spacecraft surface. The combination of monopole potentials along with the dipole or quadrupole contributions produce potential barriers which form at ... |
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| Gravity Waves in Idealized MM5 Simulations |
15 APR 2006 |
29 pages |
| Authors:
Susan A. Triantafillou; ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC LEXINGTON MA
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| Propagation and dissipation of gravity waves in the NCAR/Penn State Mesoscale Model (MM5) are studied using numerical experiment, numerical analysis, and established theory. The waves, which are due to a small, fixed-frequency disturbance in an idealized atmosphere, form beams in an X shaped pattern known as St. Andrew's Cross. This choice of problem is accompanied by a theory, supported by physical experiment, and it allows the MM5 wave propagation by ... |
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| Satellite Radiance Data Assimilation: Code Migration to Scalable Architectures |
09 JUL 2004 |
42 pages |
| Authors:
George Modica; Thomas Nerkhorn; ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC LEXINGTON MA
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| We developed a highly scalable version of the MM5 4d-Var application. The application consists of a meteorological analysis code that provides accurate depictions of the state of the atmosphere, has been applied successfully to a large number of cases, and the results have been documented in peer reviewed forums. Prior to this project, this code was optimized for vector computer architectures. By rewriting this code in order to make it ... |
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| Advanced Analysis of the Influence of Clouds, Precipiation and Surface Emissivity on DMSP/NPOESS Satellite Microwave Channels |
15 MAY 2002 |
5 pages |
| Authors:
R. G. Isaacs; ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC LEXINGTON MA
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| This contract was for a basic research program to investigate the effects of clouds, precipitation and surface emissivity on microwave satellite sensors and their influence on atmospheric retrievals using the Unified Retrieval (UR) technique. The work consisted of the following tasks: development of databases of brightness temperatures from various satellite sensors; development databases of conventional analysis to verify the presence and amount of clouds and precipitation and for verification of ... |
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| Biogeochemical Variability in the Upper Ocean |
19 JAN 2001 |
4 pages |
| Authors:
A. Mahadevan; ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC LEXINGTON MA
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| Differences in the response times of different biogeochemical tracers to upper ocean forcing processes can lead to substantial differences in their patterns of variability. An idealized tracer with a steep vertical concentration gradient is modeled in a flow field representative of an upper ocean front. The surface distribution of the tracer is studied as a function of its response or restoration time scale. |
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| Strategic High Altitude Infrared Backgrounds |
15 JAN 2001 |
8 pages |
| Authors:
W. O. Gallery; H. E. Snell; J. -l. Moncet; ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC LEXINGTON MA
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| The purpose of this contract was to "...provide models and codes to predict infrared background phenomenon to be encountered by advanced space based systems operating in natural and disturbed backgrounds." The three specific tasks of the contact were: (1) analysis data from the Mid Course Space Experiment (MSX), (2) development of advanced radiance inversion techniques, and (3) enhancement of the radiative transfer program FASCODE Environment (FASE). Under (1), AER developed ... |
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| Development and Validation of Improved Techniques for Cloud Property Retrieval from Environmental Satellites |
17 NOV 2000 |
53 pages |
| Authors:
Gary B. Gustafson; Robert P. d'Entrement; ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC LEXINGTON MA
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| A basic research program was conducted for the Air Force Research Laboratory, consisting of three tasks: (1) develop extensible cloud property retrieval algorithms suitable for expanding existing cloud analysis capabilities to utilize data from new and future environmental satellite sensing systems; (2) develop advanced algorithms for retrieval of cloud properties that are insufficiently resolved to satisfy Air Force requirements using existing techniques; and (3) validate cloud property retrieval algorithms using ... |
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