Instruments:mlh

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Millstone IS Radar

Image:madrigal.gif


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Contact Persons

ACKNOWLEDGMENTS

The Millstone Hill incoherent scatter radar is supported by the National Science Foundation.

Virtual Millstone Hill Radar: http://www.haystack.mit.edu/madrigal/vmhr. Plots from the local and regional Millstone Hill models using real-time conditions of the 10.7 cm solar flux and the 3-hr ap magnetic activity index.
Local and Regional Models: http://www.haystack.mit.edu/madrigal/Models.

The regional and local Millstone Hill models are based on data from 1970 to 2001. The regional bins are 1 LT, 1 degree of geodetic latitude from 32 to 55, and every 50 km from 200 to 600 km. The local bins are 1 hour LT and heights with nodes at 100, 110, 120, 130, 140, 160, 180, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, and 1000 km. Only the local model contains the E-region. Values are Ne, Te, Ti, and Vi. There is also a convection model from 1987 and 2000.

Instrument/Model Description

The incoherent scatter transmitter station at Millstone Hill, Massachusetts (42.6N, 71.5W) has been in operation since 1960, although only World Days starting in 1978 are in the CEDAR Data Base. The facility is part of and operated by the Massachusetts Institute of Technology.

The electron densities from the power profile were calibrated with an on-site ionosonde, where recently, this ionosonde has been the University of Massachusetts at Lowell digisonde. Since the Coast Guard uses some of the frequencies needed to properly scan the ionosphere, calibration can sometimes be difficult. The calibrated electron density is then corrected for Te and Ti effects, where Te and Ti come from auto-correlation fits. The calibration and auto-correlation fits now have the same height resolution, although in the past, the auto-correlation fits had lower height resolution.

The ion composition changes from mostly O2+ and NO+ at lower altitudes, to mostly O+, and then to H+ and some He+ at higher altitudes. Above 400 km, the percent H+ is computed along with the major ion O+. At lower altitudes, the ratio of molecular ions to the total number of ions is modeled as specified by the FORTRAN code segment below. 


         REAL FUNCTION PMF(Z)
         Z1=AMIN1(-(Z-120.)/40.,50.)
         H=10.-6.*EXP(Z1)
         Z2=AMIN1(-(Z-180.)/H, 50.)

There are 4 areas in the summary plots for image plots as a function of height and time of the electron density, electron temperature, ion temperature, and either the line-of-sight velocity, or line plots of the perpendicular and parallel ion velocities closest to 300 km. Usually, only the line-of-sight velocity is available, although occasionally parallel and/or perpendicular ion velocities were calculated. The image plots are binned in 45 minutes and 40 km, except for the electron density, which has a height bin of 20 km for corrected densities, and 10 km for uncorrected. The data are averaged above 60 degrees of elevation. There are 2 days per page. More complete summary plots of all the elevation and azimuth scans are at Millstone Hill, along with plots of dates not available at the CEDAR Data Base. More Summary Plots are available at http://www.haystack.edu/cgi-bin/holdings

References

Evans, J. V., Theory and practice of ionosphere study by Thomson scatter radar, Proc. IEEE, 57, 496-530, 1969.
Evans, J. V. Incoherent scatter contributions to studies of the dynamics of the lower thermosphere, Rev. Geophys. Space Phys., 16, 195-216, 1978.
Evans, J. V., W. L. Oliver, Jr. and J. E. Salah, Thermospheric properties as deduced from incoherent scatter measurements, J. Atmos. Terr. Phys., 41, 259-278.

Summary Plots for Millstone Hill IS Radar

E Region neutral wind plots for 13 of 20 LTCS campaigns 1988-2000 are available below or in the LTCS area. The March and October 1996 LTCS campaigns only have LTCS data in the CEDAR DB, and not the regular data.

1970's Plots

1980s Plots

1990s Plots