HR: 0830h
AN: SA41B-0437    [PDF]
TI: Equatorial, Daytime ExB Drift Velocities Inferred From GUVI 1356 A Radiance Observations
AU: * Anderson, D N
EM: david.anderson@noaa.gov
AF: CIRES/Univ. of Colorado, NOAA/SEC 325 Broadway, Boulder, CO 80303 United States
AU: Anghel, A
EM: adela.anghel@noaa.gov
AF: CIRES/Univ. of Colorado, NOAA/SEC 325 Broadway, Boulder, CO 80303 United States
AB: Currently, there does not exist a way of estimating low latitude, ionospheric daytime vertical ExB drifts, day-to-day, around the globe. In this talk we present a promising, new technique that would enable us to estimate the day-to-day variability in daytime ExB drift velocities using the nighttime 1356 � radiance observations from the GUVI instrument -Global UltraViolet Imager- on the TIMED satellite. It is well known that the greater the upward, daytime ExB drift velocity in the low latitude ionospheric F region, the greater the latitude separation of the crests in maximum electron density, Nmax, known as the equatorial anomaly. At night, the observed 1356 � GUVI radiance observations can be primarily attributed to the radiative recombination reaction, O+ + e = O* + hv. This means that the 1356 � intensity is proportional to the height integral of Ne2, with most of the radiation originating near Hmax. In this talk we describe the procedures that have been carried out to estimate the post-sunset latitude crest separation in Nmax inferred from GUVI observations for a significant number of nights in the low latitude Peruvian longitude sector and how these crest separations are directly related to the observed strength of the daytime ExB drift velocities on these days in this longitude sector. In addition to presenting the derived Crest Separation vs Average Daytime ExB Drift Velocity relationship, we discuss the importance of these findings as they relate to the recently developed Global Assimilation of Ionospheric Measurements -GAIM- model.
DE: 0310 Airglow and aurora
DE: 0933 Remote sensing
DE: 2411 Electric fields (2712)
DE: 2415 Equatorial ionosphere
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting