ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-27-1643-2009 Radar efficiency and the calculation of decade-long PMSE backscatter cross-section for the Resolute Bay VHF radar Swarnalingam N. 1 Hocking W. K. 1 Argall P. S. 2 Department of Physics and Astronomy, University of Western Ontario, London, Ontario, N6A 3K7, Canada School of Manufacturing Science, Fanshawe College, London, Ontario, N5Y 5R6, Canada 07 04 2009 27 4 1643 1656 Copyright: © 2009 N. Swarnalingam et al. 2009 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/27/1643/2009/angeo-27-1643-2009.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/27/1643/2009/angeo-27-1643-2009.pdf

The Resolute Bay VHF radar, located in Nunavut, Canada (75.0° N, 95.0° W) and operating at 51.5 MHz, has been used to investigate Polar Mesosphere Summer Echoes (PMSE) since 1997. PMSE are a unique form of strong coherent radar echoes, and their understanding has been a challenge to the scientific community since their discovery more than three decades ago. While other high latitude radars have recorded strong levels of PMSE activities, the Resolute Bay radar has observed relatively lower levels of PMSE strengths. In order to derive absolute measurements of PMSE strength at this site, a technique is developed to determine the radar efficiency using cosmic (sky) noise variations along with the help of a calibrated noise source. VHF radars are only rarely calibrated, but determination of efficiency is even less common. Here we emphasize the importance of efficiency for determination of cross-section measurements. The significant advantage of this method is that it can be directly applied to any MST radar system anywhere in the world as long as the sky noise variations are known. The radar efficiencies for two on-site radars at Resolute Bay are determined. PMSE backscatter cross-section is estimated, and decade-long PMSE strength variations at this location are investigated. It was noticed that the median of the backscatter cross-section distribution remains relatively unchanged, but over the years a great level of variability occurs in the high power tail of the distribution.

 References Bremer, J., Hoffmann, P., Latteck, R., and Singer, W.: Long-term changes of mesospheric summer echoes at polar and middle latitudes, J. Atmos. Terr. Phys., 68, 1940–1951, 2006. Bridle, A H.: The spectrum of the radio background between 13 and 404 MHz, Mon. Not. R. Astr. Soc., 136, 219–240, 1967. Campistron, B., Despaux, G., Lothon, M., Klaus, V., Pointin, Y., and Mauprivez, M.: A partial 45 MHz sky temperature map obtained from the observations of five ST radars, Ann. Geophys., 19, 863–871, 2001. Campos, E F., Hocking, W K., and Fabry, F.: Precipitation measurement using VHF wind-profiler radars: A multifaceted approach to calibrate radar antenna and receiver chain, Radio Sci., 42, RS3003, https://doi.org/10.1029/2006RS003508, 2007. Cane, H V.: A 30 MHz map of the whole sky, Aust. J. Phys., 31, 561–565, 1978. Cho, J. Y N. and Kelley, M C.: Polar mesosphere summer radar echoes: Observations and current theories, Rev. Geophys., 31, 243–265, 1993. Cho, J. Y N. and Röttger, J.: An updated review of polar mesosphere summer echoes: Observation, theory, and their relationship to noctilucent clouds and subvisible aerosols, J. Geophys. Res., 102, 2001–2020, 1997. Cho, J. Y N., Hall, T M., and Kelley, M C.: On the role of charged aerosols in the polar mesosphere summer echoes, J. Geophys. Res., 97, 875–886, 1992. Cho, J. Y N., Alcala, C M., Kelley, M C., and Swartz, W E.: Further effect of charged aerosols on summer mesospheric radar scatter, J. Atmos. Terr. Phys., 58, 661–672, 1996. Czechowsky, P. and Rüster, R.: Power spectra of mesospheric velocities in polar regions, Handbook of MAP, 18, 207–211, 1985. Czechowsky, P., Singer, W., Schmidt, G., and Keuer, D.: Technical design of a VHF radar for MST investigations at Andenes, Proceedings of the sixth workshop on technical and scientific aspects of MST radar, Solar-Terrestrial Energy Program, 310–314, 1993. Dolph, C L.: A Current Distribution for Broadside Arrays Which Optimizes the Relationship between Beam Width and Side-Lobe Level, Proceedings of the IRE, 34, 335–348, 1946. Ecklund, W L. and Balsley, B B.: Long-term observations of the Arctic mesosphere with the MST radar at Poker Flat, Alaska, J. Geophys. Res., 86, 7775–7780, 1981. Green, J L., Clark, W L., Warnock, J M., and Ruth, K J.: Absolute calibration of MST/ST radars, Preprints 21st Conf. on Radar Meteorology, Edmonton, Alberta, Canada, Published by American Meteorol. Society, 114–147, 1983. Havnes, O., Trøim, J., Blix, T., Mortensen, W., Næsheim, L I., Thrane, E., and Tønnesen, T.: First detection of charged dust particles in the Earth's atmosphere, J. Geophys. Res., 101, 10829–10847, 1996. Hill, R. J R.: Nonneutral and quasi-neutral diffusion of weakly ionized multiconstituent plasma, J. Geophys. Res., 83, 989–998, 1978. Hocking, W K.: Measurement of turbulent energy dissipation rates in the middle atmosphere by radar techniques: A review, Radio Sci., 20, 1403–1422, 1985. Hocking, W K.: Observation and measurement of turbulence in the middle atmosphere with a VHF radar, J. Atmos. Terr. Phys., 48, 655–670, 1986. Hocking, W K.: Radar studies of small scale structure in the upper middle atmosphere and lower ionosphere, Adv. Space. Res., 7, 327–338, 1987. Hocking, W K.: System design, signal-processing procedures, and preliminary results for the Canadian (London, Ontario)VHF atmospheric radar, Radio Sci., 32, 687–706, 1997. Hocking, W K. and Röttger, J.: Studies of polar mesosphere summer echoes over EISCAT using calibrated signal strengths and statistical parameters, Radio Sci., 32, 1425–1444, 1997. Hocking, W K. and Vincent, R A.: A comparison between HF partial reflection profiles from the D-region and simultaneous Langmuir probe electron density measurements, Rev. Sci. Ins., 87, 7615–7624, 1982. Hocking, W K., Schmidt, G., and Czechowsky, P.: Absolute calibration of the SOUSY VHF stationary radar, MPAE Report MPAE-W-00-83-14, Max-Planck-Institut für Aeronomie, Katlenburg-Lindau,Germany, 1983. Hocking, W K., Kelley, M., Rogers, R., Maurice, J.-P S., and Moorcroft, D.: Resolute Bay VHF radar: A multi-purpose tool for studies of tropospheric motions, middle atmosphere dynamics, meteor physics and ionospheric physics, Radio Sci., 36, 1839–1857, 2001. Hoppe, U P., Hall, C., and Röttger, J.: First observation of summer polar mesosphere backscatter with a 224 MHz radar, Geophys. Res. Lett., 15, 28–31, 1988. Huaman, M M., Kelley, M C., Hocking, W K., and Woodman, R F.: Polar mesosphere summer echo studies at 51.5 MHz at Resolute Bay, Canada: Comparison with Poker Flat results, Radio Sci., 36, 1823–1837, 2001. Inhester, B., Ulwick, J C., Cho, J. Y N., Kelley, M C., and Schmidt, G.: Consistency of rocket and radar electron density observations: Implication about the anisotropy of mesospheric turbulence, J. Atmos. Terr. Phys., 52, 855–873, 1990. Kelley, M C., Farley, D T., and Röttger, J.: The effect of cluster ions on anomalous VHF backscatter from the summer polar mesosphere, Geophys. Res. Lett., 14, 1031–1034, 1987. Kirkwood, S., Wolf, I., Nilsson, H., Dalin, P., Mikhaylova, D., and Belova, E.: Polar mesosphere summer echoes at Wasa, Antarctica (73°S): First observations and comparison with 68° N, Geophys. Res. Lett., 34, 9–10, 2007. La Hoz, C., Havnes, O., Næsheim, L I., and Hysell, D L.: Observations and theories of polar mesospheric summer echoes at a Bragg wavelength of 16 cm, J. Geophys. Res., 111, D04203, https://doi.org/10.1029/2005JD006044, 2006. Landecker, T L. and Wielebinski, R.: The galactic metre wave radiation: A two-frequency survey between declinations +25 deg and −25 deg and the preparation of a map of the whole sky, Aust. J. Phys. Suppl., 16, 1–30, 1970. Latteck, R., Singer, W., Morris, R. J., Hocking, W. K., Murphy, D. J., Holdsworth, D. A., and Swarnalingam, N.: Similarities and differences in polar mesosphere summer echoes observed in the Arctic and Antarctica, Ann. Geophys., 26, 2795–2806, 2008. Maronna, R A., Martin, D R., and Yohai, V J.: Robust Statistics: Theory and Methods, Wiley Series in Probability and Statistics, John Wiley and sons Ltd, 2006. Morris, R J., Terkildsen, M B., Holdsworth, D A., and Hyde, M R.: Is there a casual relationship between cosmic noise absorption and PMSE?, Geophys. Res. Lett., 32, L24809, https://doi.org/10.1029/2005GL024568, 2005. Rapp, M. and Lübken, F J.: On the nature of PMSE: Electron diffusion in the vicinity of charged particles revisted, J. Geophys. Res., 108, 8437–8449, 2003. Rapp, M. and Lübken, F J.: Polar mesosphere summer echoes (PMSE): Review of observations and current understanding, Atmos. Chem. Phys, 4, 2601–2633, 2004. Roger, H V., Costain, C H., Landecker, T L., and Swerdlyk, C M.: The radio emission from the Galaxy at 22 MHz, Astron. Astrophys. Suppl. Ser., 137, 7–11, 1999. Röttger, J.: Reflection and scattering of VHF radar signals from atmospheric reflectivity structures, Radio Sci., 15, 259–276, 1980. Röttger, J.: Investigation of lower and middle atmopshere dynamics with spaced antenna drifts radars, J. Atmos. Terr. Phys., 43, 277–292, 1981. Röttger, J.: Observations of the polar D-region and the mesosphere with the EISCAT Svalbard Radar and SOUSY Svalbard Radar, Mem. Nat. Inst. Pol. Res, 54, 9–20, 2001. Sarango, M. and Woodman, R.: Further observations of PMSE in Antartica, CEDAR Workshop, Colorado, USA, 2003. Schmidt, G., Ruster, R., and Czechowsky, P.: Complementary Code and Digital Filtering for Detection of Weak VHF Radar Signals from the Mesosphere, IEEE Trans. Geosci. Electron., GE-17, 154–161, 1979. Sironi, G.: The spectrum of the galactic non-thermal background radiation - I, Mon. Not. R. Astr. Soc, 166, 345–353, 1974. Swarnalingam, N.: Studies of Polar Mesosphere Summer echoes at multiple sites using calibrated radars, Ph.D. thesis, University of Western Ontario, Canada, 2007. Swarnalingam, N. and Hocking, W K.: Calibration and calculation of absolute backscatter cross-section using sky noise and calibrated noise source for Resolute Bay radar, The Eleventh Workshop on Technical and Scientific Aspects of MST Radar, December 2006, Tirupati, India, 2006. Swarnalingam, N. and Hocking, W K.: Calibration and calculation of absolute backscatter cross-section using sky noise and calibrated noise source for Resolute Bay radar, Proceedings of the Eleventh Workshop on Technical and Scientific Aspects of MST Radar, December 2006, edited by: Anandan, V. K., 328–333, 2007. Swarnalingam, N., Hocking, W K., and Argall, P S.: Observations and comparisons of polar mesosphere summer echoes in the northern magnetic polar cap region with two calibrated MST radars, COSPAR-2008, Montreal, Canada, 2008. Thomas, G., Russell III, J. M. R., and Bailey, S.: Polar Mesospheric Cloud properties derived from the NASA Aeronomy of Ice in the Mesosphere Mission (2007–2008), COSPAR-2008, Montreal, Canada, 2008. Turtle, A J. and Baldwin, J E.: A survey of galactic radiation at 178 Mc/s, Mon. Not. R. Astr. Soc., 124, 459–476, 1962. Webster, A S.: The spectrum of the galactic non-thermal background radiation – II, Mon. Not. R. Astr. Soc., 166, 355–371, 1974. Woodman, R F. and Guillen, A.: Radar Observations of Winds and Turbulence in the Stratosphere and Mesosphere, J. Atmos. Sci., 31, 493–505, 1974.