The precipitable water (PW) was examined for the 2013 Colorado flood to determine how climatologically abnormal this event was. The seasonal PW maximum extended into early September and the September monthly mean PW exceeded the 99th percentile of climatology with a value 25% higher than the 40-year climatology. The above-normal, near-saturation PW values during the flood were the result of large-scale moisture transport into Colorado from the eastern tropical Pacific and the Gulf of Mexico.

We combine satellite measurements of ozone and cloud properties from the Aura OMI and MLS instruments for 2004–2016 to measure ozone in the mid–upper levels of deep convective clouds. Our results ascribe upward injection of low boundary layer ozone (varying from low to high amounts) as a major driver of the measured concentrations of ozone in thick clouds. Our OMI/MLS generated ozone product is made available to the public for use in science applications.

The paper focuses on the aerosol microphysical model selection and characterisation of uncertainty in the retrieved aerosol type and aerosol optical depth (AOD). The proposed method is based on Bayesian inference approach and can account for the model error and also include the model selection uncertainty in the total uncertainty budget. The method is applied to OMI measurements but is also applicable to other instruments. The retrieval was evaluated by comparison with ground-based measurements.

One of the gases polluting the air that we measure in the Dutch National Air Quality Monitoring Network is ammonia. We replaced the ageing instruments that we used for the past 20 years by the miniDOAS, an instrument that uses ultraviolet light to measure ammonia. We operated the old and new instruments side by side for more than a year and found them to agree well. The miniDOAS measures faster than the old instrument; this will give us more insight in how ammonia behaves in the atmosphere.

We need satellite observations to characterize the properties of atmospheric aerosols. Those observations have uncertainties associated with them because of assumptions made in their algorithms. We test the assumptions on a part of the aerosol algorithms used with the Ozone Monitoring Instrument (OMI) flying on the NASA Aura spacecraft. We simulate the OMI observations using a global aerosol model, and then compare what OMI tells us about the simulated aerosols with the model results directly.

This paper describes an algorithm to infer the global atmospheric distribution of the greenhouse gas methane, from measurements made by the infrared, nadir-viewing spectrometer IASI, on board the MetOp polar orbiting satellites. The algorithm has been applied to 9 years of data. Results are presented and validated by comparison to independent measurements.

There is a crucial need for adequate data of concentration and wind to close the potential gap in mass balance of CO₂. Ground-based line-integrating remote sensing techniques are an ideal tool as they provide the spatially representative CO₂ concentration together with wind components within the same voxel structure. An integrated method combination of acoustic and optical systems was applied to measure spatially representative CO₂ advection at the grassland Grillenburg site.

This paper describes a novel instrument for the aircraft-borne remote sensing of trace gases and liquid and solid water. Until recently, such measurements could only be evaluated under clear-sky conditions. We present a characterization and error assessment of the novel "scaling method", which allows for the retrieval of absolute trace gas concentrations under all sky conditions, significantly expanding the applicability of such measurements to study atmospheric photochemistry.

In this paper an algorithm for the retrieval of aerosol properties from NASA Research Scanning Polarimeter (RSP) data is presented. An artificial neural network is used to produce a first estimate of the aerosol properties, which is then improved using an iterative retrieval scheme based on Phillips–Tikhonov regularization. Using the neural network retrievals as a first guess for the Phillips–Tikhonov improved the retrieval convergence, confirming results previously found on ground-based data.

CRL lidar in the Canadian High Arctic uses lasers and a telescope to study polar clouds, essential for understanding the changing global climate. Hardware added to CRL allows it to measure the polarization of returned laser light, indicating whether cloud particles are liquid or frozen. Calibrations show that traditional analysis methods work well, although CRL was not originally set up to make this type of measurement. CRL can now measure cloud particle phase every 5 min, every 37.5 m, 24h/day.

We present a comprehensive characterization of a commonly used commercial instrument (WIBS) for the real-time detection of fluorescent bioaerosols and suggest improved analysis and threshold strategies. Summaries of both biological and potential interfering, non-biological particles (70 aerosol types in total) are discussed in detail. The strategies we suggest will minimize interference from non-biological particles and will aid instrument users’ interpretation of ambient particle data.

We characterise the the performance of a set of artificial neural networks used for the remote sensing of cirrus clouds from the geostationary Meteosat Second Generation satellites. The retrievals show little interference with the underlying land surface type as well as with possible liquid water clouds or aerosol layers below the cirrus cloud. We also characterise the retrievals as a funtion of optical thickness and top height and gain better understanding of the retrival uncertainties of CiPS

We present a new approach to model the response of optical particle counters (OPCs) including a simple parametrization for artificial broadening of size spectra induced by the non-ideal behavior of real OPCs. We show a self-consistent way to evaluate calibration measurements and outline how particle number size distributions with realistic uncertainty estimates can be derived. The innovations will improve the accuracy of OPC-derived size distributions and allow to assess their precision.

The SAGE-III instrument was launched in February 2017. As with any new instrument, a significant post-launch activity is planned to validate the data products. Validation of trace gases with short photolytic lifetimes is challenging, though careful use of Pandora-type instruments may prove beneficial. A careful intercomparison of Pandora and NIWA's M07 instrument was carried out. Results show Pandora to be well correlated with M07, showing its viability as a validation tool for SAGE science.

This paper verifies and corrects the Ozone Mapping and Profiler Suite (OMPS) nadir mapper (NM) level 1B v2.0 measurements to retrieve reliable ozone profile and tropospheric ozone using an optimal estimation inversion with the fitting window of 302.5–340 nm. We apply "soft calibration" and "common mode correction" to OMPS radiances to eliminate systematic errors in the fitting residuals and derive random-noise measurement errors accounting for both OMPS radiances and forward model calculation.

NO₂ (a gas that plays an important role in air quality) can be measured by satellite-based instruments. These measurements require a best guess of the vertical distribution of NO₂ and are very sensitive to the changes in that distribution near the top of the troposphere (~ 12 km). NO₂ concentrations at this altitude are strongly influenced by lightning; therefore, we study how different representations of lightning in models that provide that best guess affect the NO₂ measured by satellites.

Microwave radiometry is a suitable technique to measure atmospheric temperature profiles during clear sky and cloudy conditions. However clouds can influence the temperature measurements. In this study we analyse the influence of clouds on temperature measurements in the troposphere from a microwave radiometer. We found that the effect of clouds on the temperature measurements is important and that the measurements can be improved substantially by considering clouds in the retrieval process.

In this study, vertical profiles and column integrated aerosol properties retrieved by GRASP (Generalized Retrieval of Atmosphere and Surface Properties) algorithm are evaluated with in situ airborne measurements made during the ChArMEx-ADRIMED field campaign in summer 2013. Differences between GRASP retrievals and airborne extinction profiles are in the range of 15 to 30 %. Also, the total volume concentration differences between in situ data and GRASP retrieval ranges from 15 to 36 %.

This study presents the first-time attempt at using time-of-flight single particle mass spectrometry (SPMS) as an emerging online technique for measuring insoluble particles in glacial snow and ice. Using samples from two Greenlandic ice cores, we show that SPMS can constrain the aerodynamic size, composition, and relative abundance of most particulate types on a per-particle basis, reducing the preparation time and resources required of conventional, filter-based particle retrieval methods.

Long-term measurement series are the pillars of all climate change analysis. The Arosa total ozone series is the world's longest record, starting in 1926. To secure the future of these measurements, it is foreseen to move the instruments in Davos. To ascertain that the series will not be affected by this change, a multiyear campaign of parallel measurements on both sites has been done. The analysis of these data is presented and it is concluded that no discernible difference can be identified.

Results of the temperature characterization of the global UV spectral measurements of eight different Brewer spectrophotometers operating in Greece, Finland, Germany and Spain are presented. Different temperature characterization methods are evaluated and an improved methodology for the correction of the measurements for the effects of temperature is presented.

Cavity ring-down spectroscopy (CRDS) is an increasingly popular technology for isotope analysis of trace gases. However, most commercial CRDS instruments are designed for continuous gas sampling and cannot reliably measure small discrete samples. We present a novel technical adaptation that allows routine analysis of 50 mL syringed samples on an isotopic-CO₂ CRDS unit. Our method offers excellent accuracy and precision, fast sample throughput, and is easily implemented in other CRDS instruments.

Water vapour is one of the most important gases in the Earth’s atmosphere and plays a unique role in climate and weather forming. Cross-comparison of different systems for monitoring the atmospheric integrated water vapour (IWV) measurements is an essential part of their testing and validation protocol. We compare coincident measurements of IWV by different techniques over Saint Petersburg (Russia), assess their quality in various atmospheric conditions, and give recommendation for data users.

Here we present the instrument characteristics and field applicability of the newly developed Delta Ray analyzer for stable isotope measurements in CO₂. We used this analyzer to measure the concentration and the isotopic composition of CO₂ exchange in a managed beech forest for 3 months in autumn 2015. During this period an early frost event occurred and our measurements suggest that this short event strongly influenced the measured isotopic composition of CO₂ exchange.

Lightning data as observed by the European Cooperation for Lightning Detection network EUCLID are used in combination with radar data to retrieve the temporal and spatial behavior of lightning outliers, i.e. discharges located in a wrong place, over a 5-year period from 2011 to 2016 in Belgium and Austria.