A new method of inferring the size, number density, and charge of mesospheric dust from its in situ collection by the DUSTY probe

Ove Havnes,Gerd Baumgarten,Tarjei Antonsen,Jonas Hedin,Martin Friedrich,Åshild Fredriksen,Thomas W Hartquist,Alexander Biebricher

doi:10.5194/amt-12-1673-2019

Abstract

Abstract. We present a new method of analyzing measurements of mesospheric dust made with DUSTY rocket-borne Faraday cup probes. It can yield the variation in fundamental dust parameters through a mesospheric cloud with an altitude resolution down to 10 cm or less if plasma probes give the plasma density variations with similar height resolution. A DUSTY probe was the first probe that unambiguously detected charged dust and aerosol particles in the Earth's mesosphere. DUSTY excluded the ambient plasma by various biased grids, which however allowed dust particles with radii above a few nanometers to enter, and it measured the flux of charged dust particles. The flux measurements directly yielded the total ambient dust charge density. We extend the analysis of DUSTY data by using the impact currents on its main grid and the bottom plate as before, together with a dust charging model and a secondary charge production model, to allow the determination of fundamental parameters, such as dust radius, charge number, and total dust density. We demonstrate the utility of the new analysis technique by considering observations made with the DUSTY probes during the MAXIDUSTY rocket campaign in June–July 2016 and comparing the results with those of other instruments (lidar and photometer) also used in the campaign. In the present version we have used monodisperse dust size distributions.

Highlights

The Earth’s mesosphere has for a long time been the least known part of the Earth’s atmosphere, and it probably still is
In the last panel we show the RMR lidar observations of noctilucent clouds (NLCs) brightness for 30 s around 09:44:36 UT compared with two model lidar profiles computed for dust parameters inferred from the DUSTY observations and for the assumptions that the particles are pure ice or ice contaminated with 5 % FeO, which is the upper limit used by Hervig et al (2012)
The first is that the RMR lidar in the region at and slightly below 83 km finds particles of half of or less than the size that DUSTY finds

Summary

Introduction

The Earth’s mesosphere has for a long time been the least known part of the Earth’s atmosphere, and it probably still is. 3 we show the values for dust density and dust radius from this new method, used for the observations by the DUSTY probe on the payload MXD-1, which was launched on 30 June 2016 at 09:43:18 UT in the MAXIDUSTY rocket campaign (Havnes et al, 2019).

Results

Conclusion