Mathematisch-Naturwissenschaftliche Fakultät

Institut für Atmosphärenphysik

Fachgebiet: Atmosphärenphysik

Betreuer: Prof. Dr. Markus Rapp

Diplom Physikerin Irina Strelnikova
(e-mail: )

Mesospheric aerosol particles: Evidence from rocket and radar techniques

Every day, the Earth’s atmosphere is hit by ~50 tons of meteoric material witch vaporizes between ~70 and 100 km. This evaporated material forms metal layers in the upper mesosphere and can recondense forming solid nanometer-scale meteor smoke particles (MSP). Under conditions of the polar summer mesopause MSP are thought to act as nuclei for ice particles which are observed as noctilucent clouds (NLC) and polar mesosphere summer echoes (PMSE).

In this work two new techniques for aerosol measurements in the mesosphere were developed and successfully applied. The first method employs a new rocket-borne instrument for in situ measurements and the second is a radar technique for ground-based remote soundings.

The rocket-borne instrument is a combination of a Faraday-Cup and a xenon-flashlamp for active photoionization of the aerosols. The measurements with this instrument delivered the first experimental confirmation for the existence of MSPs in the entire mesosphere as it was previously only predicted by models. This new instrument was also applied for measurements of ice particles and yielded the first direct in situ data of mesospheric ice volume densities at unprecedented height resolution. It also allows to measure both MSP and ice particles simultaneously.

Using powerful incoherent scatter radars it was further demonstrated that MSP can in fact be observed from the ground making use of the spectral characteristics of observed signals. Corresponding measurements constitute the first ground based detection of MSP and hence open a new observing window for the study of these particles. This new technique allows the derivation of mean radii and number densities of the aerosols particles. Application of this method to measurements with the Arecibo incoherent scatter radar in Puerto Rico yields good agreement with experimental data obtained by rocket techniques and with model results.

Finally, the current standard theory of PMSE was confirmed by two new and independent radar experiments.