An analysis on the mid-latitude scintillation and coherence frequency bandwidth using transionospheric VHF signals

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Radio Science

OSTI ID:956624

Juang, Zhen ^[1]; Roussel-dupre, Robert ^[1]

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1. Los Alamos National Laboratory

An analysis was perfonned on the mid-latitude scintillation and coherence frequency bandwidth (Fcoh) using transionospheric VHF signal data. The data include 1062 events spanning from November 1997 to June 2002. Each event records FORTE satellite received VHF signals from LAPP located at Los Alamos, New Mexico. Fcohs were derived to study scintillation characteristics on diurnal and seasonal variations, as well as changes due to solar and geomagnetic activities. Comparisons to the VHFIUHF coherence frequency bandwidth studies previously reported at equatorial and mid-latitude regions are made using a 4th power frequency dependence relationship. Furthennore, a wideband ionospheric scintillation model, WBMOD, was used to estimate Fcohs and compared with our VHF Fcoh values. Our analysis indicates mid-latitude scintillation characteristics that are not previously revealed. At the VHF bottom frequency range (3035 MHz), distinguished smaller Fcohs are found in time period from sunset to midnight, in wann season from May to August, and in low solar activity years. The effects of geomagnetic storm activity on Fcoh are characterized by a sudden transition at a Kp index of 50-60. Comparisons with median Fcohs estimated from other studies validated our VHF Fcohs for daytime while an order of magnitude larger Fcohs are found for nighttime, implying a time-dependent issue in applying the 4th order power relationship. Furthermore, comparisons with WBMOD-estimated Fcohs indicated generally matched median scintillation level estimates while differences do exist for those events undergoing high geomagnetic stonn activity which may imply underestimates of scintillation level by the WBMOD in the mid-latitude regions.

• Research Organization: Los Alamos National Laboratory (LANL)
• Sponsoring Organization: DOE
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 956624
• Report Number(s): LA-UR-08-07826; LA-UR-08-7826
• Journal Information: Radio Science, Journal Name: Radio Science; ISSN RASCAD; ISSN 0048-6604
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
DATA
FREQUENCY DEPENDENCE
FREQUENCY RANGE
LEVELS
LOS ALAMOS
MAGNETIC STORMS
MHZ RANGE
NEW MEXICO
POWER
SATELLITES
SCINTILLATIONS
SEASONAL VARIATIONS
SEASONS
SIGNALS
SOLAR ACTIVITY