Accession Number:

ADA443529

Title:

A Potential Remote-Sensing Technique for Thermospheric Temperature with Ground-Based Resonant Atomic Oxygen Raman Lidar

Descriptive Note:

Journal article

Corporate Author:

AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE

Personal Author(s):

Report Date:

2005-01-01

Pagination or Media Count:

10.0

Abstract:

We propose a remote-sensing technique to measure temperature in the lower thermosphere with a resonant Raman lidar. A ground-based pulsed laser operating at 630.0304 636.3776 nm excites exp-3 P sub-2 exp-3 P sub-1 multiplet level of the ground electronic state of atomic oxygen in the atmosphere to the electronically excited exp-1 D sub-2 state and the back-scattered photons at 636.3776 630.0304 nm, while the atom transitions to exp-3 P sub-1 exp-3 P sub-2, are detected. Using the backscattering Raman cross sections calculated here we show 1 For the range of altitudes in the lower thermosphere where the fine-structure multiplets of atomic oxygen are in thermodynamic equilibrium with the local translational temperature LTE and the electronically excited intermediate state exp-1 D sub-2 remains relaxed primarily by collisions with Nsub-2 and Osub-2, the ratio of the backscattered signal can be used to obtain temperature. 2 Higher up, for the range of altitudes where the fine-structure multiplets of atomic oxygen are in LTE and the electronically excited intermediate state exp-1 D sub-2 is relaxed primarily by spontaneous emission of a photon, the Stokes and anti-Stokes backscattered signal can be used to obtain the atomic oxygen density and local temperature. 3 Still higher up, for the range of altitudes where the fine-structure multiplets of atomic oxygen are not in LTE and the electronically excited intermediate state exp-1 D sub-2 is relaxed primarily by spontaneous emission of a photon, the Stokes and anti-Stokes backscattered signal can be used to obtain the density of the exp-3 P sub-2 and exp-3 P multiplet levels of the ground electronic state of atomic oxygen.

Subject Categories:

  • Atmospheric Physics
  • Meteorology
  • Optical Detection and Detectors
  • Active and Passive Radar Detection and Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE