Accession Number:

ADA592195

Title:

Assimilative Modeling of Observed Postmidnight Equatorial Plasma Depletions in June 2008 (Postprint)

Descriptive Note:

Interim rept. 12 Feb 2010-31 Dec 2012

Corporate Author:

AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE

Report Date:

2011-09-22

Pagination or Media Count:

16.0

Abstract:

The CommunicationsNavigation Outage Forecasting System CNOFS satellite observed large-scale density depletions at postmidnight and early morning local times in the Northern Hemisphere summer during solar minimum conditions. Using electric field data obtained from the vector electric field instrument VEFI as input, the assimilative physics-based model PBMOD qualitatively reproduced more than 70 of the large-scale density depletions observed by the Planar Langmuir Probe PLP onboard CNOFS. In contrast, the use of a climatological specification of plasma drifts in the model produces no plasma depletions at night. Results from a one-month statistical study found that the large-scale depletion structures most often occur near longitudes of 60 deg, 140 deg, and 330 deg, suggesting that these depletions may be associated with nonmigrating atmospheric tides, although the generation mechanisms of eastward electric fields at postmidnight local times are still uncertain. In this paper, densities obtained from both assimilation and climatology for the entire month of June 2008 are compared with PLP data from CNOFS and the Challenging Minisatellite Payload CHAMP, as well as special sensor ionospheric plasma driftscintillation meter SSIES measurements from the Defense Meteorological Satellite Program DMSP satellites. Our statistical study has shown that, on average, the densities obtained by the PBMOD, when it assimilates VEFI electric fields, agree better with observed background densities than when PBMOD uses climatological electric fields.

Subject Categories:

  • Atmospheric Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE