Mass analysis of charged aerosol particles in NLC and PMSE during the ECOMA/MASS campaign

Abstract

Abstract. MASS (Mesospheric Aerosol Sampling Spectrometer) is a multichannel mass spectrometer for charged aerosol particles, which was flown from the Andøya Rocket Range, Norway, through NLC and PMSE on 3 August 2007 and through PMSE on 6 August 2007. The eight-channel analyzers provided for the first time simultaneous measurements of the charge density residing on aerosol particles in four mass ranges, corresponding to ice particles with radii <0.5 nm (including ions), 0.5-1 nm, 1-2 nm, and >3 nm (approximately). Positive and negative particles were recorded on separate channels. Faraday rotation measurements provided electron density and a means of checking charge density measurements made by the spectrometer. Additional complementary measurements were made by rocket-borne dust impact detectors, electric field booms, a photometer and ground-based radar and lidar. The MASS data from the first flight showed negative charge number densities of 1500-3000 cm −3 for particles with radii >3 nm from 83-88 km approximately coincident with PMSE observed by the ALWIN radar and NLC observed by the ALOMAR lidar. For particles in the 1-2 nm range, number densities of positive and negative charge were similar in magnitude (∼2000 cm −3 ) and for smaller particles, 0.5-1 nm in radius, positive charge was dominant. The occurrence of positive charge on the aerosol particles of the smallest size and predominately negative charge on the particles of largest size suggests that nucleCorrespondence to: S. Knappmiller (knappmil@colorado.edu) ation occurs on positive condensation nuclei and is followed by collection of negative charge during subsequent growth to larger size. Faraday rotation measurements show a bite-out in electron density that increases the time for positive aerosol particles to be neutralized and charged negatively. The larger particles (>3 nm) are observed throughout the NLC region, 83-88 km, and the smaller particles are observed primarily at the high end of the range, 86-88 km. The second flight into PMSE alone at 84-88 km, found only small number densities (∼500 cm −3 ) of particles >3 nm in a narrow altitude range, 86.5-87.5 km. Both positive (∼2000 cm −3 ) and negative (∼4500 cm −3 ) particles with radii 1-2 nm were detected from 85-87.5 km.

Spatial and temporal variability in MLT turbulence inferred from in situ and ground-based observations during the WADIS-1 sounding rocket campaign

“…Figure 5 shows NLC observations by the RMR lidar. The vertical dashed line marks the WADIS-1 launch and one can see that the NLC was co-located with the lower PMSE layer, which is a common feature (see e.g., von Zahn and Bremer, 1999;Lübken et al, 2004;She et al, 2006;Taylor et al, 2009;Robertson et al, 2009;Kaifler et al, 2011). Figure 6 also shows EISCAT measurements in terms of radar reflectivity.…”

A comparison of overshoot modelling with observations of polar mesospheric summer echoes at radar frequencies of 56 and 224 MHz

“…This is also needed in the models of Biebricher and Havnes (2012) to produce a sufficiently large recovery for VHF during the heater-on phase. We have no strong candidates for this but wonder whether this can have any connection to the surprising amount of positively charged nanometer-sized particles found within and near to NLCs and PMSEs by the dust probe MASS (Robertson et al, 2009).…”

Small-scale structures in neutrals and charged aerosol particles as observed during the ECOMA/MASS rocket campaign

“…In August 2007 the joint European-American ECOMA/MASS sounding rocket campaign took place at the North-Norwegian Andøya Rocket Range (69 • N, see Robertson et al, 2009, for details). The European part ECOMA stands for "Existence and Charge state Of meteoric smoke particles in the Middle Atmosphere" and is a sounding rocket program lead by the Leibniz-Institute of Atmospheric Physics (IAP) in Germany and the Norwegian Defense Research Establishment (FFI) with contributions from Sweden, Austria and the US.…”