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BAMED - Balloons over the Mediterranean seaAn experimental campaign part of the HYMEX programBAMED Balloon Technology |
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BAMED Boundary Layer Pressurized Balloons Developed at CNES under the supervision of Nicolas Verdier
Contact: nicolas.verdier@cnes.fr
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Boundary Layer Pressurized Balloons (BLPB) keep a constant volume and thus fly at a nearly constant density level, acting at Lagrangian tracers of air particles and meteorological platforms. Their envelopes are manufactured by ZODIAC Int. under CNES supervision; with a 2.5 m diameter, they are made of three-laminated polyethylene of 120 microns thickness. Balloons are inflated with Helium at a nominal surpressure of 120 hPa at flight level. The balloon flight can be stopped either automatically if the balloon approaches a specific zone or by a remote command. ![]() With a 9 Kg total mass a BLPB can fly between the surface and 830 hPa, depending of its ballast. As long as the surpressure is maintained the volume remains constant; except for small thermal fluctuations, mainly due the diurnal cycle, inducing small altitude oscillations. The most serious problem encountered by BLPB's is due to the water loading under heavy rain or when the envelope temperature is below the dew point temperature, specially by radiative cooling during night; to prevent this the BLPB envelope is treated with a hydrophobic coating. Scientific instrumentation onboard includes pressure, humidity and temperature sensors and a 3D GPS from witch the balloon velocity can be deduced. Helium pressure and temperature are also monitored. Meteorological data are recorded on board every 10 seconds then averaged on a time interval between 10 seconds and a few minutes; this time interval can be fixed either by remote command or automatically as a function of the vertical velocity. Data are transmitted periodically (at flight level every 20 mn) by means of the Iridium communication system. |
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BLBP history shared by CNES and LMD
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In 1972, following the
success of the EOLE experiment, during which 480 pressurized balloons
were deployed at 200 hPa in the southern hemisphere, Daniel Cadet and
Henri Ovarlez from the Dynamic Meteorology Lab. (LMD, Paris, France)
started to study the use of pressurized balloons to analyze the
atmospheric boundary layer, that is to define Boundary Layer
Pressurized Balloons (BLPB).
BLPB were designed and built entirely by the Dynamic Meteorology Lab. (LMD/Paris) up to BOA experiment. Since VASCO they are developed by CNES, envelopes being manufactured by ZODIAC INTERNATIONAL. |