Browsing by Author "Sulzer, M. P."
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Item Open Access An upper bound on the solar radar cross section at 50 MHz(American Geophysical Union, 2006-04) Coles, W.A.; Harmon, J. K.; Sulzer, M. P.; Chau Chong Shing, Jorge Luis; Woodman Pollitt, Ronald FranciscoWe have made 16 unsuccessful attempts, in February and October 2003, and February 2004, to observe solar echoes using the 50 MHz radar at Jicamarca in Peru. The upper bound that we have determined on the solar cross section is significantly lower than the average of earlier reported observations. In this paper we will describe the observations, discuss the noise and interference from solar bursts, and suggest possible reasons why the echo might be weaker than expected.Item Restricted Fine structure in midlatitude sporadic E layers(Elsevier, 2013-01-03) Hysell, D. L.; Nossa, E.; Aveiro, H. C.; Larsen, M. F.; Munro, J.; Sulzer, M. P.; González, S. A.Fine structure in midlatitude sporadic E layer patches or “clouds” is apparent in incoherent scatter observations from the Arecibo Radio Telescope. The fine structure is wavelike with predominant horizontal wavelengths as large as about 2–3 km. We attribute the structure to a drift wave instability operating in the collisional regime. A linear, local dispersion relation for the waves is described which predicts growth driven by polarization electric fields in the cloud. A numerical simulation produces wave growth and other features consistent with the dispersion relation, including finite parallel wavenumbers. The kilometric irregularities are thought to be the primary waves from which secondary, meter-scale waves in the layers can form.Item Restricted Pulse compression hardware decoding techniques for MST radars(American Geophysical Union, 1985-11) Sulzer, M. P.; Woodman Pollitt, Ronald FranciscoThe techniques for decoding in hardware received signals transmitted by phase‐coded mesosphere‐stratosphere‐troposphere (MST) radars are reviewed. The designs consist of digital and analog types which resemble filters or correlators in their operation. A new analog design is presented, and a discussion of the choice between hardware and software decoding is given. The number of bits required for digital coherent integrators and decoders is discussed, and the use of fast Fourier transforms for decoding is described.Item Restricted Quasi-complementary codes: A new technique for MST radar sounding(American Geophysical Union, 1984-01) Sulzer, M. P.; Woodman Pollitt, Ronald FranciscoThe binary phase complementary code set has been used in stratospheric radar sounding. The quasi-complementary code technique presented here has nearly complementary properties and offers significant reduction of side lobes caused by imperfections in the radar transmitter. The new technique and its application are described; a simulation of the performance of the two techniques when certain imperfections are present in the transmitter is presented. The results are compared with the actual performance of the Arecibo 430-MHz radar transmitter.Item Open Access Quiet time ionospheric variability over Arecibo during sudden stratospheric warming events(American Geophysical Union, 2010-09-11) Chau Chong Shing, Jorge Luis; Aponte, N. A.; Cabassa, E.; Sulzer, M. P.; Goncharenko, L. P.; González, S. A.We present observations of the F‐region ionosphere over Arecibo, Puerto Rico (18.34°N, 66.75°W), during the January–February 2008 and January–February 2009 sudden stratospheric warming (SSW) events. For the first period (2008), we have used incoherent scatter radar (ISR) electron density and temperature measurements from the Arecibo Observatory (AO), as well as relative total electron content (TEC) derived from a dual‐frequency GPS receiver. For the second event (2009), during which we observed the largest recorded stratospheric warming, we have used the relative GPS TEC. Our analysis indicates that the ionosphere over Arecibo exhibits perturbations after the SSW, the effects are most visible during the daytime. The strongest signatures are observed in the TEC measurements, represented by large enhancements (with respect to non SSW days), particularly during daytime hours. However, the local time dependence of these enhancements is not the same in the two events. In addition, the data show that our results are consistent with the larger than normal daytime vertical drift differences observed at the magnetic equator over Jicamarca. The electron temperature is also affected during the daytime due to changes in electron density, indicating that the electron temperatures is influenced, indirectly, by changes in planetary wave activity in the lower altitudes.Item Open Access Quiet time variability over Arecibo and Jicamarca during SSWs(Instituto Geofísico del Perú, 2010) Chau Chong Shing, Jorge Luis; Aponte, N. A.; Cabassa, E.; Sulzer, M. P.; Goncharenko, L. P.; González, S. A.Diapositivas presentadas en el 2010 CEDAR Workshop, University of Colorado, Boulder, CO, 20-25 June 2010.