An algorithm for the simultaneous retrieval of aerosol optical thickness (AOT) and normalized water-leaving radiance (nL_w) is proposed using multispectral satellite measurements. Retrieval accuracy is validated by the in situ measurements selected from eight sites over different waters. Results show more accurate spectral AOT and nL_w are derived by current method than the standard atmospheric correction scheme, except nL_w at 488 nm. Optimization of this approach is also required in future work.

The European Brewer Network (EUBREWNET, COST Action ES1207) is comprised of close to 50 instruments and currently provides near-real-time ozone and UV data. Aerosols also play key role in the Earth–atmosphere system and introduce a large uncertainty into our understanding of climate change. In this work we describe and validate a method to incorporate the measurement of aerosols in EUBREWNET. We find that this Brewer network can provide reliable aerosol data across Europe in the UV range.

Karymsky volcano was used as a test case for identifying the underlying geology of a volcano, solely from satellite-based observations. Fifteen volcanic plumes were observed, ranging in length from 30 to 220 km and primarily dispersing at an altitude of 2–4 km. This technique distinguishes plume components and particle evolution using MISR and combines these with lava flow details from MODIS. The results have relevance in global volcanic assessment, particularly in remote regions.

A rapid increase in the PM_2.5 concentration in Beijing, China, on 30 November 2015 was found to be transported from south of Beijing by both turbulent mixing and advection processes. The nighttime relatively clean air was from the downslope flow northwest of Beijing; the rapid increase in the PM_2.5 concentration in the morning resulted from the downward convective turbulent transfer of the polluted air that was rapidly advected over the nighttime stable boundary layer.

Arctic atmospheric particles have important climate impacts via cloud formation and precipitation, particularly in the wintertime. We show that sulfate, formed during atmospheric transport, is within individual sea spray particles and organic particles measured in the Alaskan Arctic. Greater contributions of combustion emissions were observed when the wind direction came from the Prudhoe Bay oil fields, showing its regional influence.

We present a 3-month analysis of submicron aerosols that were measured at 260 m on a meteorological tower in Beijing, China. The sources of organic aerosol (OA) were analyzed by using a multi-linear engine (ME-2). Our results showed significant changes in both primary and secondary OA composition from the non-heating season to the heating season. We also observed a considerable contribution (10–13%) of cooking OA at 260 m and very different OA composition between ground level and 260 m.

We report long-term and spatially resolved hourly measurements of organic carbon (OC) and elemental carbon (EC) concentrations in ambient particulate matter in Riyadh, Saudi Arabia. Our analysis suggests both local vehicular emissions and regional sources (e.g., oil extraction and refining) were strong influences. Our work informs the development of pollution control strategies for Riyadh.

Linkages between the chemical composition of PAH-derived SOA and oxidative potential (OP) were investigated under various atmospheric aging processes. Peroxides were found to be an insignificant OP contributor. Oligomerization and heterogeneous ozonolysis may enhance the OP of SOA. Mixing with Cu reduces the OP of PAH-derived SOA. Binding between redox-active Cu(II) and quinone was proved by NMR. Results highlighted the essential role of aerosol chemical composition in its health impact.

Here we present a quantitative source apportionment of WSOC, isolated from aerosols in China using radiocarbon (¹⁴C) and offline high-resolution time of flight aerosol mass spectrometer measurements. We demonstrate a dominant contribution of non-fossil emissions to WSOC aerosols in the Northern Hemisphere. However, the fossil fraction is substantially larger in aerosols from East Asia and the east Asian pollution outflow, especially during winter, due to increasing coal combustion.

We use the NMMB-MONARCH-ASH model to quantify the systematic errors associated with traditional offline modeling systems used for operational volcanic ash forecast. Evaluation scores indicate that uncertainties credited to offline modeling are of the same order of magnitude as those associated with the source term, failing to reproduce up to 45–70 % of the ash cloud of an online forecast. This work encourages operational groups to consider online dispersal models for real-time aviation advisory.

The lifetime of a chemical in the atmosphere is largely governed by the rate of its reaction with the hydroxyl radical (OH). Measurements of rates for many of the thousands of identified volatile organic compounds (VOCs) have yet to be determined experimentally. We have developed a new technique for the rapid determination of gas-phase rate coefficients for the simultaneous reactions between multiple VOCs and OH. The method is tasted across a range of scenarios and is used to derive new values.

We used CMB and the tracer yield method to apportion organic sources in Beijing. Vehicular emissions served as the dominant source, and the contributions of all the other primary sources decreased. One interesting result is that in contrast to the SOA from other regions in the world where biogenic SOA was dominant, anthropogenic SOA was the major contributor to SOA, implying that deducting anthropogenic VOC emissions is an efficient way to reduce SOA in Beijing.

Anthropogenic halocarbon emissions contribute to stratospheric ozone depletion and global warming. We measured atmospheric halocarbons for 6 months on Crete to extend the coverage of the existing observation network to the Eastern Mediterranean. The derived emission estimates showed a contribution of 16.8 % (13.6–23.3 %) and 53.2 % (38.1–84.2 %) of this region to the total HFC and HCFC emissions of the analyzed European domain and a reduction of the underlying uncertainties by 40–80 %.

This work presents the analysis of a special event with high biomass burning emissions, named Bonfire Night. Nitrogen chemistry was observed and it was possible to study the night time chemistry. It was possible to quantify particulate organic oxides of nitrogen (PON) concentrations of 2.8 µg m⁻³ using 46 : 30 ratios from aerosol mass spectrometry measurements. The use of the receptor model positive matrix factorization (PMF) allowed to separate organic aerosols into different sources.

We present 1 year of ozone measurements form two ground-based microwave radiometers located at Ny-Ålesund, Svalbard. The ozone measurements cover an altitude range of 25–70 km altitude and have a high time resolution of 1–2 h. With these datasets and model data a comprehensive analysis of the ozone diurnal cycle in the Arctic is performed for the different insolation conditions throughout the year. In the stratosphere we find a diurnal cycle which persists over the whole polar day.

This paper highlights the first multi-year ground-based climatology of aerosol direct radiative effect (DRE) in the southeastern US Aerosol DRE at the co-located NOAA and NASA aerosol monitoring sites at Appalachian State University is approximately five times more negative during summer than winter. Aerosol DRE is most sensitive to aerosol optical depth (AOD). Use of MODIS-measured increases DRE uncertainty by a factor of 2.5 to 5.

Recent measurements of the potent greenhouse gas HFC-23, a by-product of HCFC-22 production, show a 28 % increase in the atmospheric mole fraction from 2009 to 2016. A minimum in the atmospheric abundance of HFC-23 in 2009 was attributed to abatement of HFC-23 emissions by incineration under the Clean Development Mechanism (CDM). Our results indicate that the recent increase in HFC-23 emissions is driven by failure of mitigation under the CDM to keep pace with increased HCFC-22 production.

We used ground measurements from the recently developed air quality monitoring network in China to validate modeling surface NO₂ concentrations from the regional chemical transport model (CTM). The CTM simulations driven by satellite-derived and bottom-up inventories show negative and positive differences against the ground measurements, respectively. Our study suggests an improvement of the distribution of emissions between urban and rural areas in the satellite-derived inventory.

This study investigates orbital sampling biases and evaluates the additional impact caused by data quality screening for the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the Aura Microwave Limb Sounder (MLS).

Fine dust (< 2.5 microns) is an important component of the total PM_2.5 mass in the western and central US in spring and summer and has positive trends. However, the causes of the trends have not been thoroughly discussed by previous studies. This work identified key local factors controlling the variations in fine dust in the US and found that the increase in fine dust in the central Great Plains in summer is associated with increasing atmospheric stability.

In this study, we investigate the role of the winter residual circulation in the summer mesopause region using the Whole Atmosphere Community Climate Model. In addition, we study the role of the summer stratosphere in shaping the conditions of the summer polar mesosphere. We strengthen the evidence that the variability in the summer mesopause region is mainly driven by changes in the summer mesosphere rather than in the summer stratosphere.

This paper assesses the potential of atmospheric ¹⁴CO₂ observations and a global inversion system to solve for fossil fuel CO₂ (FFCO₂) emissions in Europe. The estimate of monthly emission budgets is largely improved in high emitting regions. The results are sensitive to the observation network and the prior uncertainty. Using a high-resolution transport model and a systematic evaluation of the uncertainty in current emission inventories should improve the potential to retrieve FFCO₂ emissions.

Imported African ozone peaks in the Asian middle and upper troposphere in March. The seasonality of African ozone influence on Asia is mainly driven by the seasonal swing of the ITCZ, the Hadley circulation, and the northern subtropical westerlies. The stronger the ITCZ over Africa in a boreal winter is, the more African ozone is transported to Asia that winter. The convective divergence over the ITCZ and the Somali jet are drivers of interhemispheric transport of African ozone.

While oceanic air is generally thought to be clean, the air pollution over waters in proximity to the coasts is not well recognized. This research indicated that ozone was higher over South China Sea (SCS) than that in the adjacent continental area, while continental anticyclone, tropical cyclone and land breeze favored O₃ formation over SCS. In addition, weaker NO titration and stronger atmospheric oxidative capacity led to higher O₃ production efficiency over SCS.

The ocean takes up about 25 % of emitted anthropogenic emitted carbon dioxide and thus plays a significant role in the regulation of climate. In order to accurately calculate this uptake, a quantity known as the air–sea gas transfer velocity needs to be determined. This is typically parameterised with mean wind speed, the most commonly used velocity scale for calculating air–sea transfer coefficients. In this article, we propose an alternative velocity scale known as the friction velocity.

Ice production in atmospheric clouds is important for global water cycle and radiation budget. Active satellite remote sensing measurements are analyzed to quantitatively study primary ice particle production in stratiform mixed-phase clouds on a global scale. We quantify the geographic and seasonal variations of ice production and their correlations with aerosol, especially mineral dust activities. The results can be used to evaluate mixed-phased clouds simulations by global climate models.

Dry deposition at the Earth’s surface is an important sink of atmospheric ozone. A new parameterisation for ozone dry deposition to the ocean that accounts for relevant chemical and physical processes is developed and tested. It results in an ocean deposition loss that is only about a third of the current model estimates and corresponds to an increase of 5 % in the tropospheric ozone burden. This is important for tropospheric ozone budget, associated radiative forcing, and ozone mixing ratios.

This study presents concentrations, variation characteristics, sources and secondary formations of nitrated phenols, a major component of brown carbon, in typical seasons at four sites in northern China. The results highlight the strong influences and contributions of anthropogenic activities, in particular coal combustion and the aging processes, to the atmospheric nitrated phenols in this region.

The emission of volatile elemental mercury by the sea is an important source of atmospheric mercury. The light-induced biotic and abiotic transformation of deposited ionic mercury to elemental mercury in surface water is highly variable. On research campaigns in the Baltic Sea a new method was applied to measure elemental mercury at high resolution. The Baltic Sea's mercury emission was subsequently calculated based on the new data and the current knowledge of mercury gas exchange parameters.

This study examines how different aerosol optical properties determine the dust longwave radiative effects at the surface, in the atmosphere and at the top of the atmosphere, based on the combination of remote sensing and in situ observations from the ground, from airborne sensors, and from space, by means of radiative transfer modelling. The closure experiment is based on longwave irradiances and spectral brightness temperatures measured during the 2013 ChArMEx–ADRIMED campaign at Lampedusa.