Some features of electron density behaviour in the high latitude D-region derived from in situ measurements

Abstract. The first aerosol indirect effect over a clean, northern high-latitude site was investigated by determining the aerosol cloud interaction (ACI) using three different approaches; ground-based in situ measurements, combined ground-based in situ measurements and satellite retrievals and using only satellite retrievals. The obtained values of ACI were highest for in situ ground-based data, clearly lower for combined ground-based and satellite data, and lowest for data relying solely on satellite retrievals. One of the key findings of this study was the high sensitivity of ACI to the definition of the aerosol burden. We showed that at least a part of the variability in ACI can be explained by how different investigators have related different cloud properties to "aerosol burden".

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Aerosol-cloud interaction determined by both in situ and satellite data over a northern high-latitude site

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-10987-2010 ◽

2010 ◽

Vol 10 (22) ◽

pp. 10987-10995 ◽

Cited By ~ 25

Author(s):

H. Lihavainen ◽

V.-M. Kerminen ◽

L. A. Remer

Keyword(s):

Satellite Data ◽

High Latitude ◽

High Sensitivity ◽

In Situ Measurements ◽

Aerosol Cloud ◽

Cloud Properties ◽

Satellite Retrievals ◽

Northern High Latitude ◽

Definition Of

Abstract. The first aerosol indirect effect over a clean, northern high-latitude site was investigated by determining the aerosol cloud interaction (ACI) using three different approaches; ground-based in situ measurements, combined ground-based in situ measurements and satellite retrievals and using only satellite retrievals. The obtained values of ACI were highest for in situ ground-based data, clearly lower for combined ground-based and satellite data, and lowest for data relying solely on satellite retrievals. One of the key findings of this study was the high sensitivity of ACI to the definition of the aerosol burden. We showed that at least a part of the variability in ACI can be explained by how different investigators have related different cloud properties to "aerosol burden".

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Meteor smoke influences on the D-region charge balance – review of recent in situ measurements and one-dimensional model results

Annales Geophysicae ◽

10.5194/angeo-31-2049-2013 ◽

2013 ◽

Vol 31 (11) ◽

pp. 2049-2062 ◽

Cited By ~ 13

Author(s):

C. Baumann ◽

M. Rapp ◽

A. Kero ◽

C.-F. Enell

Keyword(s):

Negative Ions ◽

Dissociative Recombination ◽

In Situ Measurements ◽

Ionospheric Model ◽

Charge Balance ◽

Faraday Cup ◽

One Dimensional ◽

Positive Ions ◽

D Region

Abstract. This work investigates the influence of meteoric smoke particles (MSP) on the charge balance in the D-region ionosphere. Both experimental in situ measurements and a one-dimensional ionospheric model reveal a clear impact of MSP on the ionospheric composition of the D-region. The study reviews rocket-borne in situ measurements of electron and positive ion density, which show a distinct deficit of electrons in comparison to positive ions between 80 and 95 km. This deficit can be explained by the ambient negatively charged MSP measured simultaneously with a Faraday cup. The influence of MSP on the D-region charge balance is addressed with a simplified ionospheric model with only six components, i.e. electrons, positive and negative ions and neutral and charged MSP (both signs). The scheme includes reactions of plasma captured by MSP and MSP photo reactions as well as the standard ionospheric processes, e.g. ion-ion recombination. The model shows that the capture of plasma constituents by MSP is an important process leading to scavenging of electrons. Since Faraday cup measurements are biased towards heavy MSP because of aerodynamical filtering, we have applied an estimate of this filter on the modelled MSP densities. By doing that, we find good qualitative agreement between the experimental data and our model results. In addition, the model study reveals an increase of positive ions in the presence of MSP. That is primarily caused by the reduced dissociative recombination with electrons which have been removed from the gas phase by the MSP.

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