Twilight tropospheric and stratospheric photodissociation rates derived from balloon borne radiation measurements

[摘要] A new ligthweight multichannel moderate bandwidth filter instrumentdesigned to be flown on balloons, is described. The instrument measures the radiation field within the short UV (center wavelength at312 nm) and long UV (center wavelength at 340 nm). The angular and spectral characteristics of theinstrument are discussed and the calibration procedure outlined. Measurements made during a stratospheric balloon flightat twilight conditions fromGap-Tallard, France, are presented and compared with state-of-the-art radiative transfer modelsimulations. The model simulations and the measurements agree within ±10%(±20%) for solar zenith angles smaller than 93° (90°) for the 340 (312)nm channel. Based on the model simulations of the measured radiation, actinic flux spectra are reconstructed. These are used to calculatevarious photodissociation rates.

[学科分类] 大气科学