Verlag des Forschungszentrums Jülich
JUEL-3796
Since 1994 the chamber is used for the regular (month1y) calibration of water vapor sensing
devices which are flown aboard 5 civil "in-service" aircraft (Airbus-A340) within the
frame of the European project MOZAIC (Measurement of Ozone and Water Vapor on
Airbus In-Service Aircraft) for automatic monitoring of the water vapor distribution in the
troposphere. The facility is also established as World Calibration Facility for Ozone Sondes
(WCFOS) as part of the Global Atmosphere Watch (GAW) program of the World
Meteorological Organization (WMO). In the scope of this frame work several
intercomparison experiments, JOSIE (=Jü1ich Ozone Sonde Intercomparison Experiment),
were conducted to assess the performance of the major types of ozone sondes used within
the global network of ozone sounding stations. Furthermore, the facility serves as platform
to investigate the performance of new developed airborne sensing devices.
Smit, Herman Gerrit Jan; Sträter, Wolfgang; Helten, Manfred; Kley, Dieter
Environmental simulation facility to Calibrate airborne ozone and humidity sensors
31 S., 2000
The Environmental Simulation Facility established at the Forschungszentrum Jülich (FZJ)
is designed to investigate the performance of different types of balloon borne ozone sensors
as well as air borne humidity sensors to measure the vertical distribution of atmospheric
ozone and water vapor, respectively. Key component of the facility is a temperature and
pressure controlled simulation chamber with a test room volume of about 500 liter
(80x80x80 cm) whereby pressure as well as temperature can be dynamically regulated
between 5 and 1000 hPa and between 200 and 300 K ( -2K/min <= rate <= +2K/min)
respectively. The volume mixing ratio of ozone can be dynamically regulated between 5
and 10000 ppbv up to a simulation altitude of about 35 km. The relative humidity in the
chamber can be varied from about 95% down to 2% over a temperature range between
+30°C and -70°C and pressure range between 1000 and 100 hPa. Ozone and humidity
sensing devices can be calibrated against accurate reference instruments. A fast response
dual beam UV-photometer serves as ozone reference. For the calibration of the water vapor
sensors a dew point hygrometer is used for lower/middle tropospheric humidity conditions,
while for middle/upper tropospheric conditions a Lyman (a) fluorescence hygrometer
serves as reference. The entire simulation process is computer controlled to provide
reproducible conditions with respect to pressure, temperature, ozone concentration and
humidity.
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