Purpose of the flight and payload description
The balloon carried two instruments FLASH-B and COBALD
The FLASH-B (FLuorescence Advanced Stratospheric Hygrometer for Balloon) instrument is a light-weighted Lyman-alpha hygrometer (~2 kg) developed by the Central Aerological Observatory, Dolgoprudny, Russia. The instrument is based on the fluorescent method, which uses the photodissociation of H2O molecules at a wavelength < 137 nm followed by the measurement of the fluorescence of excited OH radicals. The source of Lyman-alpha radiation (121.6 nm) is a hydrogen discharge lamp, while the detector of OH fluorescence at 308-316 nm is a Hamamatsu R647-P photomultiplier run in photon counting mode with a narrow band interference filter selecting the fluorescencespectral region. The intensity of the fluorescent light sensed by the photomultiplier is directly proportional to the water vapour mixing ratio under stratospheric conditions (10-150 hPa) with small oxygen absorption (3% at 50 hPa). The H2O measurement range is limited to pressures lower than ~300 hPa due to strong Lyman-alpha absorption in the lower troposphere. Measurements are only made at nighttime.
COBALD (Compact Optical Backscatter Aerosol Detector) is a lightweight backscatter sonde developed at ETH Zurich. With a total weight of approximately 550 g including batteries, the instrument can be flown on operational weather balloons. COBALD measures molecular, aerosol and cloud particle backscatter in the atmosphere from the ground to the level of balloon burst. Two LEDs with 250 mW optical power each emit light at wavelengths of 455 and 870 nm in the blue and near infrared spectral range. To register the backscattered light, a photodiode is placed between the LEDs, and the associated optics establishes an overlap region at distances larger than 0.5 m in front of the instrument. So far, the instrument is designed for applications during night-time only as solar radiation saturates the detector. The molecular number density is determined from temperature and pressure recorded simultaneously by the hosting radiosonde.
Details of the balloon flight
Balloon launched on: 2/7/2013
Launch site: Meteorological Research Institute, Baurú, Sao Paulo, Brazil
Balloon launched by:
Balloon manufacturer/size/composition: Weather Balloon
End of flight (L for landing time, W for last contact, otherwise termination time): 2/7/2013
This flight was part of the TRO-Pico campaign performed in Brazil between 2012 and 2013. It aims at studying deep convection in the tropics and more precisely, the impact of overshooting convection in the lower stratosphere on the stratospheric water budget, from the local to the continental scale.