CRISTA-NF measurements during the AMMA-SCOUT-O3 aircraft campaign

Abstract

The Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere – New Frontiers (CRISTA-NF) instrument participated in the AMMA-SCOUT-O3 measurement campaign in July and August 2006. The instrument is mounted on the high-flying Russian research aircraft M55-Geophysica and measures limb-emissions in the mid-infrared region in the tangent altitude range of about 6 to 21 km. We present a new retrieval setup which is based on 9 integrated spectral windows allowing to retrieve an extended set of trace gases and temperature fields with high vertical resolution (up to 500 m). Retrieval results are shown for temperature, water vapor (H<sub>2</sub>O), ozone (O<sub>3</sub>), nitric acid (HNO<sub>3</sub>), peroxyacetyl nitrate (PAN), carbon tetrachloride (CCl<sub>4</sub>), and aerosol extinction. Comparisons of temperature, O<sub>3</sub>, and H<sub>2</sub>O observations with corresponding in situ measurements on-board M55-Geophysica show reasonable agreement. In particular, CRISTA-NF observations in the vicinity of the aircraft resemble horizontal variations found in the in situ measurements better than corresponding ECMWF fields

Volcanic ash detection with infrared limb sounding: MIPAS observations and radiative transfer simulations

“…It was used in several studies for the infrared limb sounders MIPAS (Hoffmann et al, 2005, CRISTA-NF Weigel et al, 2010), the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) (Ungermann et al, 2010) and the nadir instrument Atmospheric Infrared Sounder (AIRS) (Hoffmann and Alexander, 2009;Grimsdell et al, 2010).…”

“…For fast simulations, it applies pre-calculated look-up tables of spectral emissivities and approximations to radiative transfer calculations, such as the emissivity growth approximation (EGA) (Weinreb and Neuendorffer, 1973;Gordley and Russell, 1981;Marshall et al, 1994) and the CurtisGodson approximation (CGA) (Curtis, 1952;Godson, 1953). The look-up tables were calculated with the Reference Forward Model (RFM) (Dudhia et al, 2002;Dudhia, 2013), which is an exact line-by-line model specifically developed for MIPAS.…”

Towards a 3-D tomographic retrieval for the air-borne limb-imager GLORIA

“…Even at this reduced spectral resolution, infrared emission features of important atmospheric constituents are clearly visible (e.g. Weigel et al (2010) successfully retrieved using the CRISTA-NF instrument).…”

“…As an example for the spectral resolution of the dynamics ra for mid-latitude atmospheric conditions and 12 km tangent altitude Even at this reduced spectral resolution, infrared emission features of constituents are clearly visible (e.g. CO 2 , CFC11, CFC12, CCl 4 , H 2 O, , or PAN, which Weigel et al (2010) successfully retrieved using the t). er is to describe a methodology that enables 3-D tomographic retrievals IA measurements and to show the principal feasibility of this via simplients.…”

“…We perform both simulations with and without added noise according to this specification as presented below. The simulations use only a single channel at 778.5 cm −1 , which was previously used by Weigel et al (2010) to derive ozone from CRISTA-NF measurements. This channel is optically thin in the troposphere, close to the CO 2 Q-branch at 12.6 µm usually employed for deriving temperature, and relatively unaffected by water vapor.…”