M. Penning de Vries

Monitoring of atmospheric trace gases, clouds, aerosols and surface properties from UV/vis/NIR satellite instruments

A new generation of UV/vis/near-IR satellite instruments like GOME (since 1995), SCIAMACHY (since 2002), OMI (since 2004), and GOME-2 (since 2006) have allowed one to measure backscattered solar radiance from the Earth with moderate spectral resolution over a large wavelength range (240–790 nm). The SCIAMACHY instrument also includes additional spectral channels in the near-IR. From the measured spectra several important stratospheric and tropospheric trace gases (e.g. O_3, NO_2, OClO, HCHO, SO_2, BrO, H_2O) as well as clouds, aerosols and surface properties can be determined from space. Because of its extended spectral range, the SCIAMACHY instrument also allows the retrieval of greenhouse gases (CO_2, CH_4) and CO in the near-IR. Almost all of the tropospheric trace gases have been observed by these instruments for the first time. From satellite data it is possible to investigate their temporal and spatial variation. Also, different sources can be characterized and quantified. The derived global distributions can serve as input and for the validation of atmospheric models. Here we give an overview of the current status of these new instruments and data products and their recent applications in the investigation of various atmospheric and oceanic phenomena.

Modelled and measured effects of clouds on UV Aerosol Indices on a local, regional, and global scale

Introduction Conclusions References

From Radiation Fields to Atmospheric Concentrations – Retrieval of Geophysical Parameters

Satellite-based atmospheric remote sensing aims at deriving the properties of trace gases, aerosols and clouds, as well as surface parameters from the measured top-of-atmosphere spectral radiance and reflectance. This requires, besides high quality spectra, an accurate modelling of the radiative transfer of solar radiation through the atmosphere to the sensor (forward model) and methods to derive the constituent properties from the measured top-of-atmosphere spectra (inversion methods). Many trace gases have structured absorption spectra in the UV-VIS spectral range serving as the starting point for determining their abundance by applying Differential Optical Absorption Spectroscopy (DOAS) or similar methods. In the UV-VIS-NIR and SWIR spectral regions the solar radiation is strongly scattered by clouds and aerosols. Therefore the presence of clouds and aerosol particles and their properties can also be inferred from the outgoing radiance measured by space-based instruments. Contrary to the forward model, the inversion methods allow to derive characteristics of the atmospheric state based on the measured quantities. A common product of the inversion of satellite measurements in limb, nadir or occultation geometry are total columns or height-resolved profiles of trace gas concentrations and aerosol parameters. Retrieving trace gas amounts in the troposphere constitutes a specific challenge. SCIAMACHY’s unique limb/nadir matching capability provides access to tropospheric columns by combining total columns obtained from nadir geometry with simultaneously measured stratospheric columns obtained from limb geometry.

Global Monitoring of Atmospheric Trace Gases, Clouds and Aerosols from UV/vis/NIR Satellite Instruments: Currents Status and Near Future Perspectives

A new generation of UV/vis/near‐IR satellite instruments like GOME (since 1995), SCIAMACHY (since 2002), OMI (since 2004), and GOME‐2 (since 2006) allows to measure several important stratospheric and tropospheric trace gases like O_3, NO_2, OClO, HCHO, SO_2, BrO, and H_2O as well as clouds and aerosols from space. Because of its extended spectral range, the SCIAMACHY instrument also allows the retrieval of Greenhouse gases (CO_2, CH_4) and CO in the near IR. Almost all of the tropospheric trace gases are observed by these instruments for the first time. From satellite data it is possible to investigate the temporal and spatial variation. Also different sources can be characterised and quantified. The derived global distributions can serve as input and for the validation of atmospheric models. Here we give an overview on the current status of these new instruments and data products and their recent applications to various atmospheric and oceanic phenomena.

Relationship between ATSR fire counts and CO vertical column densities retrieved from SCIAMACHY onboard ENVISAT

SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric ChartographY) is the first instrument to allow retrieval of CO by measuring absorption in the near infrared from reflected and scattered sunlight instead of from thermal emission. Thus, in contrast to thermal-infrared satellites (MOPITT), SCIAMACHY is highly sensitive to the lower layers of the troposphere where the sources, such as biomass burning, are located, and where the bulk of the CO is usually found. In many regions of the world, the burning of vegetation has a repeating seasonal pattern, but the amount of CO emitted from biomass burning varies considerably from place to place. Here we present a study on the relationship between fire counts and CO vertical column densities (VCD) in different regions. These results are compared with the CO VCD from MOPITT, aerosol index, and NO2 tropospheric VCD (TVCD) from SCIAMACHY, and the coupled chemistry climate model (CCM) ECHAM5/MESSY.