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Arecibo IS Radar



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The incoherent scatter radar at the National Astronomy and Ionosphere Center (NAIC) at Arecibo, Puerto Rico (18.3N, 66.75W), has made ionospheric measurements since 1963. The radar facilities are shared with radio astronomers.

The most recent analysis solves between 3 (Ne, Ti, Ti) and 5 parameters (Ne, Ti, Te, H+/Ne, He+/Ne) simultaneously. The line-of-sight velocity is found in a separate fit to the slope of the auto-correlation function (ACF). There are several corrections that are applied to the data. These include a chirp correction for the velocities, eliminating bad data records due to satellites or ground based radio communication (some outliers remain), and calibration of electron densities with ionosonde data in post processing.

In the lower altitudes, a molecular ion model is assumed. The model was determined by looking for consistency in the other parameters. The molecular ion mass is assumed to be 30 amu and the assumed molecular ion composition is:

Alt(km)        145     182     219     256     > 293.
[M. ion]/[Ne]  1.      0.3     0.2     0.07    0.

There are 4 areas in the summary plots. There are image plots as a function of height and time of the electron density (Ne), electron temperature (Te), and ion temperature (Ti). If available, the electron density which is uncorrected for temperature effects (from the Barker code measurements instead of the ACFs) is plotted since the height resolution is better. The bin sizes are 45 min in time, and 40 km in height for ACF records, and 10 km in height for Barker data. For the period when there are scan averaged ACF records, then there are line plots of the ion drift in the perpendicular east, north and parallel directions at the altitude closest to 300 km. Where there are no scan averaged data, the line-of-sight velocity is plotted, which is roughly the vertical velocity since all azimuths are binned together. There are 2 days per page.


Sulzer, M. P., A phase modulation technique for a sevenfold statistical improvement in incoherent scatter data-taking, Radio Sci., 21, 737-744, 1986.
Erickson, P. and W. Swartz, Mid-latitude incoherent scatter observations of helium and hydrogen atoms, Geophys. Res. Lett., 21, 2745-2748, 1994.

Summary Plots for Arecibo IS Radar

E Region neutral wind plots for some LTCS campaigns are available in the LTCS area, along with descriptions of other LTCS Arecibo data.

Other IS Radars

Daily Listing for IS/HF Radars

-Revised 09 December 2002 by Barbara Emery