Initial observations with the Global Ultraviolet Imager (GUVI) in the NASA TIMED satellite mission

[1] The Global Ultraviolet Imager (GUVI) instrument carried aboard the NASA TIMED satellite measures the spectral radiance of the Earth’s far ultraviolet airglow in the spectral region from 120 to 180 nm using a cross-track scanning spectrometer design. Continuous operation of the instrument provides images of the Earth’s disk and limb in five selectable spectral bands. Also, spectra at fixed scanning mirror position can be obtained. Initial results demonstrate the quantitative functionality of the instrument for studies of the Earth’s dayglow, aurora, and ionosphere. Moreover, through forward modeling, the abundance of the major constituents of the thermosphere, O, N2, and O2 and thermospheric temperatures can be retrieved from observations of the limb radiance. Variations of the column O/N2 ratio can be deduced from sunlit disk observations. In regions of auroral precipitation not only can the aurora regions be geographically located and the auroral boundaries identified, but also the energy flux Q, the characteristic energy Eo, and a parameter fo that scales the abundance of neutral atomic oxygen can be derived. Radiance due to radiative recombination in the ionospheric F region is evident from both dayside and nightside observations of the Earth’s limb and disk, respectively. Regions of depleted F-region electron density are evident in the tropical Appleton anomaly regions, associated with so-called ionospheric ‘‘bubbles.’’ Access to the GUVI data is provided through the GUVI website www.timed.jhuapl.edu\guvi. INDEX TERMS: 0310 Atmospheric Composition and Structure: Airglow and aurora; 0355 Atmospheric Composition and Structure: Thermosphere—composition and chemistry; 0358 Atmospheric Composition and Structure: Thermosphere—energy deposition; 2407 Ionosphere: Auroral ionosphere (2704); KEYWORDS: airglow, aurora, ultraviolet, imaging, satellite, atmosphere

[1]  L. C. Gentile,et al.  DMSP observations of equatorial plasma bubbles in the topside ionosphere near solar maximum , 2001 .

[2]  R. E. Huffman,et al.  Satellite vacuum ultraviolet airglow and auroral observations , 1980 .

[3]  M. Larsen,et al.  Gravity wave initiation of equatorial spread F: A case study , 1981 .

[4]  John D. Craven,et al.  Six days of thermospheric‐ionospheric weather over the Northern Hemisphere in late September 1981 , 2001 .

[5]  R. Eastes,et al.  Modeling the N2 Lyman-Birge-Hopfield bands in the dayglow : Including radiative and collisional cascading between the singlet states , 2000 .

[6]  Larry J. Paxton,et al.  SSUSI - Horizon-to-horizon and limb-viewing spectrographic imager for remote sensing of environmental parameters , 1993, Optics & Photonics.

[7]  Robert R. Meier,et al.  Determination of atmospheric composition and temperature from the u.v. airglow , 1983 .

[8]  J. A. Whalen,et al.  Appleton anomaly increase following sunset: Its observed relation to equatorial F layer E × B drift velocity , 1998 .

[9]  Robert R. Meier,et al.  Deducing composition and incident electron spectra from ground-based auroral optical measurements: Theory and model results , 1989 .

[10]  Larry J. Paxton,et al.  Validation of remote sensing products produced by the Special Sensor Ultraviolet Scanning Imager (SSUSI): a far UV-imaging spectrograph on DMSP F-16 , 2002, SPIE Optics + Photonics.

[11]  R. Daniell,et al.  Dependence of auroral middle UV emissions on the incident electron spectrum and neutral atmosphere , 1983 .

[12]  David N. Anderson,et al.  Model studies of the latitudinal extent of the equatorial anomaly during equinoctial conditions , 1991 .

[13]  Larry J. Paxton,et al.  Global ultraviolet imager (GUVI): measuring composition and energy inputs for the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission , 1999, Optics & Photonics.

[14]  Larry J. Paxton,et al.  Design and performance of the Global Ultraviolet Imager (GUVI) , 1998, Optics & Photonics.

[15]  J. Craven,et al.  A Survey of Large-Scale Variations in Thermospheric Oxygen Column Density with Magnetic Activity as Inferred from Observations of the FUV Dayglow , 1997 .

[16]  W. Menke.  Geophysical data analysis : discrete inverse theory , 1984 .

[17]  J. M. Picone,et al.  Retrieval of absolute thermospheric concentrations from the far UV dayglow: An application of discrete inverse theory , 1994 .

[18]  Robert R. Meier,et al.  Global Ultraviolet Imager (GUVI) for the NASA Thermosphere-Ionsphere-Mesosphere Energetics and Dynamics (TIMED) mission , 1994, Optics & Photonics.

[19]  Qian Wu,et al.  TIMED Doppler interferometer (TIDI) , 1999, Optics & Photonics.

[20]  D. Drob,et al.  Similarity transformation‐based analysis of atmospheric models, data, and inverse remote sensing algorithms , 2001 .

[21]  D. Shemansky,et al.  A reexamination of important N2 cross sections by electron impact with application to the dayglow: The Lyman-Birge-Hopfield Band System and N I (119.99 nm) , 1985 .

[22]  G. Thomas,et al.  Global atomic oxygen density derived from OGO-6 1304 Å airglow measurements , 1976 .

[23]  Joseph J. Tansock,et al.  Overview of the SABER experiment and preliminary calibration results , 1999, Optics & Photonics.

[24]  Christopher D. Martin,et al.  WEDGE-AND-STRIP ANODES FOR CENTROID-FINDING POSITION-SENSITIVE PHOTON AND PARTICLE DETECTORS. , 1981 .

[25]  Stefan E. Thonnard,et al.  An optical remote sensing technique for determining nighttime F region electron density , 1997 .

[26]  John D. Craven,et al.  Variations in the FUV dayglow after intense auroral activity , 1994 .

[27]  D. Anderson,et al.  A theoretical study of the ionospheric F region equatorial anomaly—I. Theory☆ , 1973 .

[28]  Gary J. Rottman,et al.  TIMED solar EUV experiment , 1998, Optics & Photonics.

[29]  G. Crowley,et al.  Dayside enhancements of thermospheric O/N2 following magnetic storm onset , 2001 .

[30]  B. M. Reddy,et al.  Equatorial electric field versus neutral wind control of the equatorialanomaly under quiet and disturbed conditions , 1990 .

[31]  R. Moffett,et al.  Effect of Ionization Transport on the Equatorial F-Region , 1965, Nature.

[32]  R. J. Moffett,et al.  The Equatorial Anomaly in the Electron Distribution of the Terrestrial F-Region , 1979 .

[33]  John D. Craven,et al.  Negative ionospheric storm coincident with DE 1-observed thermospheric disturbance on October 14, 1981 , 2001 .

[34]  W. B. Hanson.  RADIATIVE RECOMBINATION OF ATOMIC OXYGEN IONS IN THE NIGHTTIME F REGION. , 1969 .

[35]  John Hayes,et al.  Performance of the wedge-and-strip microchannel plate detectors and electronics for the Global Ultraviolet Imager , 1999, Optics & Photonics.

[36]  P. Richards,et al.  Determination of ionospheric conductivities from FUV auroral emissions , 1994 .

[37]  Brian E. Smith,et al.  Special sensor ultraviolet spectrographic imager: an instrument description , 1992, Optics & Photonics.

[38]  R. Cohen,et al.  On the nature of equatorial spread F , 1961 .

[39]  R. Heelis,et al.  Interhemispheric plasma flows in the equatorial topside ionosphere , 2000 .

[40]  Larry J. Paxton,et al.  Optical calibration of the Global Ultraviolet Imager (GUVI) , 1999, Optics & Photonics.

[41]  Larry J. Paxton,et al.  Satellite remote sensing of thermospheric O/N2 and solar EUV: 1. Theory , 1995 .

[42]  Ronald F. Woodman,et al.  Radar observations of F region equatorial irregularities , 1976 .

[43]  J. Craven,et al.  Ionospheric conductances derived from DE-1 auroral images , 1991 .

[44]  P. Feldman,et al.  The ultraviolet dayglow at solar maximum 1. Far UV spectroscopy at 3.5 Å resolution , 1985 .

[45]  Robert R. Meier,et al.  The ultraviolet dayglow at solar maximum. III: Photoelectron-excited emissions of N2 and O , 1985 .

[46]  P. D. Feldman,et al.  The ultraviolet spectrum of an aurora 530–1520 Å , 1982 .

[47]  Larry J. Paxton,et al.  Interactive interpretation and display of far ultraviolet data , 1998 .

[48]  D. Drob,et al.  Nrlmsise-00 Empirical Model of the Atmosphere: Statistical Comparisons and Scientific Issues , 2002 .

[49]  Larry J. Paxton,et al.  On-orbit calibration of the Special Sensor Ultraviolet Scanning Imager (SSUSI): a far-UV imaging spectrograph on DMSP F-16 , 2002, SPIE Optics + Photonics.

[50]  R. R. Meier,et al.  Ultraviolet spectroscopy and remote sensing of the upper atmosphere , 1991 .