Monitoring and characterization of cirrus clouds in Punta Arenas using lidar data. Study of latitudinal and hemispheric differences in cirrus cloud optical properties"

The main objective of the research proposal is to investigate the latitudinal and hemispheric differences in
the optical properties of cirrus clouds. A Raman polarization lidar newly installed in September 2016 at the
southern-midlatitude site of Punta Arenas (Chile) provides the first ever chance to characterize the cirrus
clouds in this region. Also, give a chance to contrast the properties of cirrus clouds in the latitude band
between 60 and 40°S to existing datasets from other regions. Such a study will not only aid to characterize
regional differences in cirrus cloud properties, but also to investigate whether differences in the
background aerosol load contribute to potential contrasts in cirrus cloud optical and geometrical properties.
Southern South America is one of the last regions on Earth that can be considered pristine. If, at all,
anthropogenic aerosols could influence the cirrus morphology in the strongly polluted northern
midlatitudes, contrasts should be visible in the Punta Arenas datasets of pristine clouds.
The relevance of the present proposal will be to study and characterize the cirrus clouds with a long term
and unique dataset in a pristine site of the southern hemisphere. The obtained characteristics of cirrus
clouds will be contrasted with the counterparts from other latitudes in South America and the northern
hemisphere.
The General Goal is Monitoring and characterizes the geometrical and optical properties of cirrus clouds in
a pristine site of Punta Arenas, creating a good quality dataset to compare their properties with cirrus
measured from other regions in South America and Northern Hemisphere. And Specific Goals are
? Adapt and apply existing algorithms for the retrieval of cirrus cloud optical properties to the new Punta
Arenas lidar system described below,
? Adapt and apply previously adapted algorithm for Punta Arenas to process lidar signal of cirrus cloud
from São Paulo and Natal in Brazil,
? Evaluate the acquired cirrus cloud dataset against existing cirrus studies from different regions.
? Perform a first discussion of possible aerosol effects on the observed cirrus properties in different regions.
? to conduct collocated measurements with LACROS lidar system during DACAPO – PESO to evaluate the
quality of the measurements of SAVERNET lidar.
? perform measurements of the lidar parameters, in order to obtain a good quality dataset during the
monitoring of the atmosphere and cirrus clouds.
These objectives will help to answer key questions: Is there an observable difference between the
properties of cirrus clouds in the southern midlatitudes compared against their northern hemisphere
counterparts? Is there an observable difference between the properties of cirrus clouds in the southern
midlatitudes compared against their Southern Hemisphere tropical and subtropical counterparts?
To get these objectives and answer the scientific questions the lidar technique will be used. Aerosols
backscattering and raman Lidar will be used to probe the atmosphere. Two lidars will be used, one installed
permanently in Punta Arenas, SAVERNet lidar and the other will be installed during the measurement
campaign DACAPO – PESO to obtain the properties of cirrus clouds. Also lidar information from Sao Paulo
and Natal sites will be used to obtain the cirrus clouds properties from other sites in South America. Lidar
onboard satellite information also will be used. Data from lidar in satellite will be used too, the lidar CALIOP
onboard CALIPSO satellite. To study where cirrus clouds come from HYSPLIT backtrajectories model will be
used. Inter-comparison between lidar instruments and CALIOP will be conducted to compare the
instruments and cirrus clouds properties. A comparison between the cirrus clouds properties will be
conducted in order to evaluate the differences between cirrus from different geographical regions.
Finally we expect to obtain as results three papers in internationals scientific peer-reviewed, two theses of
master degree and one these in doctoral degree. These results will enhance the promotion and expansion
of the knowledge about cirrus clouds and the atmospheric science in our region and the world.