
Fig.1: Instrumentation of LACROS at TROPOS. Besides MARTHA (4) and SAEMS (5) all instruments are mobile or at least available in a mobile version.
The Leipzig Aerosol and Cloud Remote Observations System LACROS
Motivation
The large number of unsolved questions concerning the interaction between aerosol particles and clouds and corresponding indirect effects on precipitation and radiative transfer demand new measurement strategies to resolve the atmospheric processes involved. In this regard, obtaining synergistic information about cloud and aerosol properties from multi–instrument and hence multi–sensor observations is a key approach to overcome the current lack of knowledge. Motivated by these needs, the novel mobile multi–instrument platform Leipzig Aerosol and Cloud Remote Observations System — LACROS — has been set up at TROPOS.
Instrumentation
LACROS comprises a unique set of active and passive remote-sensing instruments which are to a large extent containerized and available for application in field campaigns. The instruments of LACROS are shown in Fig. 1.
The active-remote-sensing branch now spans the wavelength range from the UV to microwave radiation which is covered with
Passive instrumentation which helps to interpret the active remote measurements consists of an Aerosol Robotic Network (AERONET) Sun photometer, the microwave radiometer HATPRO that includes also two infrared radiometers, and an all-sky imager.
Meteorological surface data and radiosondes are available in addition. Measurements of a radiation-balance station that fullfills the criteria of the the Baseline Surface Radiation Network (BSRN) are available. For the determination of precipitation properties an optical disdrometer records the velocity and size distributionof falling hydrometeors in the size range from 0.1 to 10 mm at 4 m above ground.
In addition to the ground-based remote sensing instrumentation, TROPOS is acquiring growing expertise in the managenemt and analysis of spaceborne observationswith passive sensors as the Spinning Enhanced Visible Infrared Imager (SEVIRI) aboard the Meteosat Second Generation (MSG) satellite or the Moderate Resolution Imaging Spectroradiometer MODIS.
Fig.1: Instrumentation of LACROS at TROPOS. Besides MARTHA (4) and SAEMS (5) all instruments are mobile or at least available in a mobile version.
Fields of Application
The available lidar systems measure the optical and microphysical properties of aerosols and optically thin clouds, vertical winds within aerosol layers and at cloud base, as well as temperature and humidity profiles. The integration of the cloud radar into LACROS overcomes the limitation of the lidar systems to observe only cloud-free and thincloud (cirrus, altocumulus) scenarios. It enables extensive insights into the microphysical and dynamical processes of thick stratiform and convective clouds, and thus the investigation of droplet activation and precipitation formation in convective cloud systems. This achievement will facilitate novel links between atmospheric measurements, laboratory studies, and modeling activities. The future application of LACROS concentrates on four main subjects:
Dr. Patric Seifert
Scientific staff
Dr. Johannes Bühl
Scientific staff
Dr. Ronny Engelmann
Scientific staff