Microphysical properties of boundary-layer mixed-phase clouds observed in Ny-Alesund, Svalbard: observed cloud microphysics and calculated optical properties

 

Authors

Akihiro Uchiyama — Meteorological Research Institute
Akihiro Yamazaki — Meteorological Research Institute
Masataka Shiobara — National Institute of Polar Research
Hiroshi Kobayashi — University of Yamanashi

Category

Aerosol-Cloud-Radiation Interactions

Description

The cloud-radiation interaction plays an important role in the global climate system and has been investigated by many researchers. However, the understanding of mixed-phase boundary-layer clouds in the Arctic has remained one of the unknown factors. During the period of May to June, 2011, in situ measurement of mixed-phase boundary-layer clouds were carried out at Zeppelin Station of Norwegian Polar Institute (NPI) in Ny-Alesund (78.9N, 11.9E), Svalbard.

The instruments consist of Cloud, Aerosol and Precipitation Spectrometer (CAPS), PVM-100 (Gerber Particulate Volume Monitor), and Cloud Particle Microscope imager (CPM). CAPS is composed of Cloud and Aerosol Spectrometer (CAS) and Cloud Imaging Probe (CIP). CAPS-CAS and CAPS-CIP have the same measurement capabilities of the Forward Scattering Spectrometer Probe (FSSP) models 100 and 300 and two-dimensional optical imaging probe (2D-OAP), respectively. PVM-100 measures liquid water content and effective radius of water droplet clouds. CPM, which was newly developed by one of the authors, consists of a CCD camera and microscope and takes an image of cloud particles. These instruments were installed on the roof of Zeppelin Station of NPI, which is near the top of Mt. Zeppelin and is at an altitude of 474 m.

During the observation period, the clouds associated with cyclonic disturbance and the clouds associated with outbreak of westerly cold air mass from the sea were observed. The atmospheric temperature during all the measurements is from 0° to -5°C. In every case, the large part of cloud particles that were measured by CAPS-CIP consisted of column type. We show the cloud microphysical properties on June 9, 2011: cloud particle size spectrum, liquid water content, ice water content, and so on. We also show the optical properties calculated based on the observed cloud microphysical properties.