Abstract:
Since the beginning of CALIPSO observations in June 2006 EARLINET has
performed correlative measurements during nearby overpasses of the satellite at
individual stations following a dedicated observational strategy. The EARLINET-CALIPSO
correlative measurement plan considers the criteria established in the CALIPSO
validation plan (http://calipsovalidation.hamptonu.edu). Participating EARLINET
stations perform measurements, as close in time as possible and for a period of at
least 30 min up to several hours, when CALIPSO overpasses their location within a
horizontal radius of 100 km. Within the 16-day observational cycle of CALIPSO each
station is overpassed within this distance 1-2 times during daytime (typically
between 1100 and 1400 UTC) and 1-2 times during night time (typically between 0000
and 0300 UTC). Additional measurements are performed, mainly on a non-regular basis,
when CALIPSO overpasses a neighboring station in order to study the horizontal
variability of the aerosol distribution. The time schedule for correlative observations
is calculated starting from the high-resolution ground-track data provided by NASA,
and is updated and distributed to whole network weekly.
The EARLINET-CALIPSO correlative dataset represents a statistically significant data
set to be used for the validation and full exploitation of the CALIPSO mission, for
studying the representativeness of cross sections along an orbit against network
observations on a continental scale, and for supporting the continuous, harmonized
observation of aerosol and clouds with remote-sensing techniques from space over long
time periods.