Using self-organising maps to explore ozone profile validation results – SCIAMACHY limb compared to ground-based lidar observations
Atmos. Meas. Tech., 8, 1951-1963, doi:10.5194/amt-8-1951-2015, 2015
A model sensitivity study of the impact of clouds on satellite detection and retrieval of volcanic ash
Summary: Water and ice clouds affect detection and retrieval of volcanic ash clouds by satellite instruments. Synthetic infrared satellite images were generated for the Eyjafjallajokull 2010 and Grimsvotn 2011 eruptions by combining weather forecast, ash transport and radiative transfer modelling. Clouds decreased the number of pixels identified as ash and generally increased the retrieved ash-mass loading compared to the cloudless case; however, large differences were seen between scenes.
Atmos. Meas. Tech., 8, 1935-1949, doi:10.5194/amt-8-1935-2015, 2015
On the microwave optical properties of randomly oriented ice hydrometeors
Summary: The optical properties of randomly oriented ice hydrometeors are reviewed from a perspective of microwave mass retrievals. The soft particle approximation is found to be highly problematic, and the alternative approach presented by Geer and Baordo (2014) should instead be used. We present a simplified version of this approach, and point out several critical limitations of existing DDA data.
Atmos. Meas. Tech., 8, 1913-1933, doi:10.5194/amt-8-1913-2015, 2015
Observing crosswind over urban terrain using scintillometer and Doppler lidar
Atmos. Meas. Tech., 8, 1901-1911, doi:10.5194/amt-8-1901-2015, 2015
The Radio Occultation Processing Package, ROPP
Summary: This paper describes the Radio Occultation Processing Package, ROPP, which is a suite of freely available programs provided by EUMETSAT for the processing of radio occultation data. Its capabilities are briefly reviewed, and examples of its use are given. Some current and prospective uses of ROPP are listed.
Atmos. Meas. Tech., 8, 1887-1899, doi:10.5194/amt-8-1887-2015, 2015
Low-level mixing height detection in coastal locations with a scanning Doppler lidar
Atmos. Meas. Tech., 8, 1875-1885, doi:10.5194/amt-8-1875-2015, 2015
Zeeman effect in atmospheric O2 measured by ground-based microwave radiometry
Summary: In this work we study the Zeeman effect on stratospheric O2 using ground-based microwave radiometer measurements. The interaction of the Earth magnetic field with the oxygen dipole leads to a splitting of O2 energy states which polarizes the emission spectra. A special campaign was carried out in order to measure for the first time the polarization state of the radiation due to the Zeeman effect in the main isotopologue of oxygen from ground-based microwave measurements.
Atmos. Meas. Tech., 8, 1863-1874, doi:10.5194/amt-8-1863-2015, 2015
Instrument intercomparison of glyoxal, methyl glyoxal and NO2 under simulated atmospheric conditions
Summary: Measurements of α-dicarbonyl compounds, like glyoxal (CHOCHO) and methyl glyoxal (CH3C(O)CHO), are informative about the rate of hydrocarbon oxidation, oxidative capacity, and secondary organic aerosol (SOA) formation in the atmosphere. We have compared nine instruments and seven techniques to measure α-dicarbonyl, using simulation chamber facilities in the US and Europe. We assess our understanding of calibration, precision, accuracy and detection limits, as well as possible sampling biases.
Atmos. Meas. Tech., 8, 1835-1862, doi:10.5194/amt-8-1835-2015, 2015
Climate intercomparison of GPS radio occultation, RS90/92 radiosondes and GRUAN from 2002 to 2013
Atmos. Meas. Tech., 8, 1819-1834, doi:10.5194/amt-8-1819-2015, 2015
Validation of SCIAMACHY HDO/H2O measurements using the TCCON and NDACC-MUSICA networks
Atmos. Meas. Tech., 8, 1799-1818, doi:10.5194/amt-8-1799-2015, 2015
On the comparisons of tropical relative humidity in the lower and middle troposphere among COSMIC radio occultations and MERRA and ECMWF data sets
Atmos. Meas. Tech., 8, 1789-1797, doi:10.5194/amt-8-1789-2015, 2015
The mechanical and thermal setup of the GLORIA spectrometer
Summary: The paper shows the design and the technics of the GLORIA spectrometer, the dedicated cooling system, and the performance during operation on HALO aircraft.
Atmos. Meas. Tech., 8, 1773-1787, doi:10.5194/amt-8-1773-2015, 2015
Bayesian cloud detection for MERIS, AATSR, and their combination
Summary: Cloud detection is one of the key components for the exploitation of Earth observation images. We discuss the use of probabilistic algorithms for MERIS and AATSR on-board the ENVISAT satellite. As a new approach, we used an automated search to find the best combination of channels for the algorithm, which led to a number of unusual combinations that have not been used in the past. We show how very small samples of manually classified cloud truth images can be used to set up efficient algorithms.
Atmos. Meas. Tech., 8, 1757-1771, doi:10.5194/amt-8-1757-2015, 2015
Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations
Summary: Formaldehyde (HCHO) amounts are obtained from ground-based Fourier transform infrared solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded at the Jungfraujoch station (46.5°N, 8.0°E, 3580m a.s.l.). Using HCHO amounts simulated by the chemical transport models GEOS-Chem and IMAGES as intermediates, comparisons reveal that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval.
Atmos. Meas. Tech., 8, 1733-1756, doi:10.5194/amt-8-1733-2015, 2015
Synergistic angular and spectral estimation of aerosol properties using CHRIS/PROBA-1 and simulated Sentinel-3 data
Summary: We develop a method to derive aerosol properties over land surfaces using simulated data from the ESA Sentinel-3 mission. The method aims to improve the estimation of aerosol optical depth and to explore the estimation of other aerosol properties using models. The method is tested using hyperspectral, multi-angle Compact High Resolution Imaging Spectrometer images, and validated using ground-based sun-photometer measurements. Results show an improvement over the previous method.
Atmos. Meas. Tech., 8, 1719-1731, doi:10.5194/amt-8-1719-2015, 2015
Assessment of the sensitivity of core / shell parameters derived using the single-particle soot photometer to density and refractive index
Summary: When using the SP2 to report black carbon core/shell coating thickness, the core density and refractive index must be estimated from literature values. We systematically vary the assumed parameters and the instrument calibration, and quantify the effects in the derived coatings. The technique is highly sensitive to the core refractive index but has only a minor sensitivity to the core density and coating refractive index. We identify the most appropriate values to use in future analysis.
Atmos. Meas. Tech., 8, 1701-1718, doi:10.5194/amt-8-1701-2015, 2015
Improved spectral fitting of nitrogen dioxide from OMI in the 405–465 nm window
Summary: The paper describes improvements to the algorithm for the retrieval of nitrogen dioxide (NO2) concentration from measurements of the Ozone Monitoring Instrument (OMI), launched on board NASA's EOS-Aura satellite in 2004. With these improvements - updates of the wavelength calibration and the reference spectra - the OMI results are consistent with independent NO2 measurements and the overall quality of the spectral fit is improved considerably.
Atmos. Meas. Tech., 8, 1685-1699, doi:10.5194/amt-8-1685-2015, 2015
Techniques for analyses of trends in GRUAN data
Summary: This paper discusses, and demonstrates, the methodology for reliably determining long-term trends in upper air climate data records and how measurement uncertainties should be used in trend analyses. A pedagogical approach is taken whereby numerical recipes for key parts of the trend analysis process are explored. The paper describes the construction of linear least squares regression models for trend analysis and the boot-strapping approach to determine the uncertainty on the derived trends.
Atmos. Meas. Tech., 8, 1673-1684, doi:10.5194/amt-8-1673-2015, 2015
How well do tall-tower measurements characterize the CO2 mole fraction distribution in the planetary boundary layer?
Atmos. Meas. Tech., 8, 1657-1671, doi:10.5194/amt-8-1657-2015, 2015
Estimating bias in the OCO-2 retrieval algorithm caused by 3-D radiation scattering from unresolved boundary layer clouds
Atmos. Meas. Tech., 8, 1641-1656, doi:10.5194/amt-8-1641-2015, 2015