scostep 2010 (stp12) - Leibniz-Institut für Atmosphärenphysik an der ...

STP12 Abstracts
Berlin, 12 - 16 July 2010
SCOSTEP Symposium 2010
Multi-frequency radar studies of PMSE: statistical properties, microphysical results and
electron densities
Li Qiang , Rapp Markus
Leibniz-Institute of Atmospheric Physics at the Rostock University, Kühlungsborn, Germany
It is now common belief that polar mesosphere summer echoes (PMSE) originate from
turbulence-induced scatter in combination with a large Schmidt number due to the presence of
charged ice particles. It provides us opportunity to achieve deep insight of PMSE to apply this
theory on simultaneous observations of PMSE at two well separated frequencies. In this
study, we first present the statistical properties of PMSE obtained from simultaneous
observations with the EISCAT Svalbard radar and the SOUSY Svalbard radar (collocated
near Longyearbern (78 o N, 16 o E), with frequencies of 500 and 53.5 MHz, respectively) in June
2006 and also with the EISCAT VHF and UHF radars (collocated near Tromso (69 o N, 19 o E),
with frequencies of 224 and 930 MHz, respectively) from the years 2003 through 2007.
According to the above mentioned theory, the ratio of the volume reflectivities of PMSE
simultaneously observed at two frequencies can be used to calculate the Schmidt number and
hence the radii of the charged ice particles involved. The resulting particle radii display
excellent agreement with expectations from microphysical models and independent
observations of microphysical ice parameters using optical techniques. Finally, we use UHFradar
measurements of incoherent scatter in the presence of VHF PMSE to study the electron
density dependence of PMSE. Statistical distributions of the ratio |ZA|NA/ne will be presented
(where ZA is the average aerosol charge, NA the aerosol number density, and ne the free
electron number density) revealing that in the majority of cases |ZA|NA/ne