Comparison of satellite based retrieved atmospheric profiles of temperature and water vapor with other, more traditional, ground based measurements, like radiosondes, is not trivial. There are many issues, like collocation, spatial inhomogeneities of the atmospheric parameters or others, that may render the comparison of little use. In this paper a method is presented to asses if the comparison is adequate.

This research explores, through simulations, how a realistically shaped snowflake aggregate begins the melting process and how microwave-based satellite observations are sensitive to those initial stages of melting. Using highly detailed physical models, and high-precision numerical models, we can accurately simulate the sensitivity of observations to this critical transition from dry snow to melting snow. This research improves on existing models, providing an accurate measurement basis.

In this study, we developed an offline technique using the AMS for the characterization of the chemical fingerprints of aerosols collected on quartz filters, and evaluated the suitability of the organic mass spectral data for source apportionment. This technique may be used to enhance the AMS capabilities in measuring size-fractionated, spatially resolved long-term data sets.

Formaldehyde is the most abundant aldehyde in the atmosphere and plays an important role in photochemistry. Broadband cavity-enhanced absorption spectroscopy uses a high finesse cavity to obtain effective path lengths of kilometers. We use a diode-pumped plasma lamp and custom cavity mirrors to extend this technique further into the ultraviolet spectral region, and we achieve detection limits of hundreds of parts per trillion in 1 min for formaldehyde and nitrogen dioxide.

This paper presents the reconstruction of a 73-year time series of the aerosol optical depth (AOD) at 500 nm at the subtropical high-mountain Izaña Atmospheric Observatory (IZO) located in Tenerife (Canary Islands, Spain). For this purpose, we have combined AOD estimates from artificial neural networks (ANNs) from 1941 to 2001 and AOD measurements directly obtained with a precision filter radiometer (PFR) between 2003 and 2013.

We present details of an Aerodyne quantum cascade laser absorption spectrometer (QCLAS) used to make airborne measurements of N₂O and CH₄, including its configuration for use on board an aircraft. Two different methods to correct for the influence of water vapour on the measurements are evaluated. We diagnose a sensitivity of the instrument to changes in pressure, introduce a new calibration procedure to account for this effect, and assess its performance.

Integrated water vapour (IWV) obtained from GNSS is to be developed into a GRUAN data product. In addition to the actual measurement, this data product needs to provide an estimate of the measurement uncertainty at the same time resolution as the actual measurement. The method developed in the paper fulfils the requirement by assigning a specific uncertainty to each data point. The method is also valuable for all applications of GNSS IWV data in atmospheric research and weather forecast.

The small-scale gravity waves are the least understood processes in the middle-atmospheric variability. Using airglow imaging, we provide new measurements of gravity wave propagation over equatorial latitudes in India. We find that propagation of waves is often in the opposite direction to the tropospheric convective regions. These waves are found to have horizontal wavelengths ranging from 12 to 42 km, with the phase velocities in the 20 to 90 km range.

A method for the measurement of the nonvolatile atmospheric particle size distribution is developed and tested. The tests include laboratory experiments with biogenic and anthropogenic secondary organic aerosol as well as nucleation experiments with ambient air. The method is then further tested during an ambient campaign.

This study investigates the sensitivity of TIR satellite nadir observations to the chemical composition and the size distribution of idealized UTLS sulfate aerosol layers. The dependence of the sulfate spectral signature, between 700 and 1200 cm⁻¹, on the sulfuric acid mixing ratio, effective number concentration and radius, as well as the role of interfering parameters, is analysed. The information content of broadband and high-spectral-resolution observations is finally discussed.

The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) aboard the Envisat satellite provided measurements between 2002 and 2012 with different viewing geometries. The limb viewing geometry allows the retrieval of water vapour profiles in the UTLS (upper troposphere and lower stratosphere) from the near-infrared spectral range (1353–1410 nm). Here, we present data version 3.01 and compare it to other water vapour data.

To study clouds constituting of liquid droplets as well as ice particles we used the latest versions of the Small Ice Detector which record high resolution scattering patterns of individual small cloud particles. In the case of a droplet its precise size is obtained and for ice particles its shape is deduced from the scattering pattern.We present results from artificial clouds at the AIDA cloud chamber and natural clouds probed at a mountain top station as well as from an aircraft in the arctic.

We present the characterization and application of a new gas chromatography time-of-flight mass spectrometry instrument, with focus on quantitative analysis of halocarbons in air samples. The applicability of the TOFMS technique, e.g. to form the basis of a "digital air archieve", is supported by the findings of this work: very high sensitivity, high measurement precision, a large dynamical range and an open data format which allows in-depth analysis of the data.

Changes to measurement methods over Canada's 48-year ozonesonde record have been characterized and corrections applied. An estimate of the altitude-dependent uncertainty is added to each profile. The re-evaluated time series show negative trends in the lower stratosphere of up to 5 % per decade for the period 1966–2013. In the troposphere trends for the 48-year period are generally not significant. This suggests that free tropospheric ozone levels over Canada have not changed in nearly 50 years.

Langley plots are plots of the ln(V₀) vs. air mass m used to calibrate sun radiometers, mainly, to determine the aerosol component of the atmosphere assuming attenuation follows V = V₀·exp(−τ·m). This is simple if the atmosphere is stable since the intercept of this plot is ln(V₀), which can then be used to solve for tau for any measured V. The atmosphere is not stable; therefore, 11 methods to measure V₀s and determine robust estimates of V₀s for interesting field sites are discussed.

This paper presents a comparison of operational vertical ozone profiles retrieved by OPERA algorithm from the GOME-2 measurements on board Metop-A with space borne high-vertical-resolution ozone profiles by GOMOS, OSIRIS and MLS. The overall agreement of ozone profiles from GOME-2 and reference instruments is within 15 % below 35–40 km depending on latitude. The GOME-2 ozone profiles from non-degradation corrected radiances have a tendency to underestimate the ozone concentration above 30 km.

We present a newly developed field-deployable, autonomous platform simultaneously measuring the three most abundant isotopologues of methane using mid-infrared laser absorption spectroscopy. The instrument consists of a compact quantum cascade laser absorption spectrometer (QCLAS) coupled to a preconcentration unit, called TRace gas EXtractor (TREX). The performance of this new in situ technique was investigated during a 2-week measurement campaign and compared to other techniques.

A process to characterize a ground-based microwave radiometer by comparing measured radiance with a reference data, prepared by the radiative transfer simulation with the input of temperature and humidity profiles from NWP model is introduced. When the data affected by clouds and erroneous absolute calibration is compared, the data show a better than 0.97 and 0.5 K of regression coefficient and bias, respectively. However, there is unresolved discrepancy of about 2 K at the lower frequencies.

An algorithm has been developed for the retrieval of sodium atom (Na) number density on a latitude and altitude grid from SCIAMACHY limb measurements of the Na resonance fluorescence (multiannual means 2008–2012). The Na layer peaks at 90 to 93 km altitude and has a FWHM of 5 to 15 km. A summer minimum in peak density and width is observed at high latitudes. At low latitudes, a semiannual oscillation is found. The results are compared with other measurements and models and agree well with these.