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The dual-field-of-view polarization lidar technique: a new concept in monitoring aerosol effects in liquid-water clouds – theoretical framework

A novel lidar method to study cloud microphysical properties (of liquid water clouds) and to study aerosol–cloud interaction (ACI) is developed and presented in this paper. In Part 1, the theoretical framework including an error analysis is given together with an overview of the aerosol information that the same lidar system can obtain. The ACI concept based on aerosol and cloud information is also explained. Applications of the proposed approach to lidar measurements are presented in Part 2.

Sensitivity of the Southern Hemisphere circumpolar jet response to Antarctic ozone depletion: prescribed versus interactive chemistry

Ozone depletion over Antarctica was shown to influence the tropospheric jet in the Southern Hemisphere. We investigate the atmospheric response to ozone depletion comparing climate model ensembles with interactive and prescribed ozone fields. We show that allowing feedbacks between ozone chemistry and model physics as well as including asymmetries in ozone leads to a strengthened ozone depletion signature in the stratosphere but does not significantly affect the tropospheric jet position.

Long-term historical trends in air pollutant emissions in Asia: Regional Emission inventory in ASia (REAS) version 3

A long historical emission inventory of major air pollutants in Asia during 1950–2015 was developed as Regional Emission inventory in ASia version 3 (REASv3). Trends of emissions and changes in source contributions in countries and regions in Asia during these 6 decades were analyzed. REASv3 provides monthly gridded data with 0.25° by 0.25° resolution for major source categories as well as table of emissions by countries and sub-regions for major sectors and fuel types.

REAS) version 3">Read more

Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017

Airborne measurements of highly aged biomass burning aerosols (BBAs) over the remote southeast Atlantic provide unique aerosol parameters for climate models. Our observations demonstrate the persistence of strongly absorbing BBAs across wide regions of the South Atlantic. We also found significant vertical variation in the single-scattering albedo of these BBAs, as a function of relative chemical composition and size. Aerosol properties in the marine BL are suggested to be separated from the FT.

CLARIFY-2017">Read more

A microphysics guide to cirrus – Part 2:Climatologies of clouds and humidity from observations

To improve the representations of cirrus clouds in climate predictions, extended knowledge of their properties and geographical distribution is required. This study presents extensive airborne in situ and satellite remote sensing climatologies of cirrus and humidity, which serve as a guide to cirrus clouds. Further, exemplary radiative characteristics of cirrus types and also in situ observations of tropical tropopause layer cirrus and humidity in the Asian monsoon anticyclone are shown.

The Aarhus Chamber Campaign on Highly Oxygenated Organic Molecules andAerosols (ACCHA): particle formation, organic acids, and dimer esters fromα-pinene ozonolysis at different temperatures

Atmospheric particles are important in relation to human health and the global climate. As the global temperature changes, so may the atmospheric chemistry controlling the formation of particles from reactions of naturally emitted volatile organic compounds (VOCs). In the current work, we show how temperatures influence the formation and chemical composition of atmospheric particles from α-pinene: a biogenic VOC largely emitted in high-latitude environments such as the boreal forests.

ACCHA): particle formation, organic acids, and dimer esters fromα-pinene ozonolysis at different temperatures">Read more

Large contribution of organics to condensational growth and formation of cloud condensation nuclei (CCN) in the remote marine boundary layer

Condensational growth of Aitken-mode particles is a major source of cloud condensation nuclei in the remote marine boundary layer. It has been long thought that over remote oceans, condensation growth is dominated by sulfate that derives from ocean-emitted dimethyl sulfide. In this study, we present the first long-term observational evidence that, contrary to conventional thinking, organics play an even more important role than sulfate in particle growth over remote oceans throughout the year.

CCN) in the remote marine boundary layer">Read more

Global modeling of cloud water acidity, precipitation acidity, and acidinputs to ecosystems

Cloud water pH affects atmospheric chemistry, and acid rain damages ecosystems. We use model simulations along with observations to present a global view of cloud water and precipitation pH. Sulfuric acid, nitric acid, and ammonia control the pH in the northern midlatitudes, but carboxylic acids and dust cations are important in the tropics and subtropics. The acid inputs to many nitrogen-saturated ecosystems are high enough to cause acidification, with ammonium as the main acidifying species.

Impacts of future land use and land cover change on mid-21st-century surface ozone air quality: distinguishing between the biogeophysical and biogeochemical effects

We investigate the effects of future land use and land cover change (LULCC) on surface ozone air quality worldwide and find that LULCC can significantly influence ozone in North America and Europe via modifying surface energy balance, boundary-layer meteorology, and regional circulation. The strength of such “biogeophysical effects” of LULCC is strongly dependent on forest type and generally greater than the “biogeochemical effects” via changing deposition and emission fluxes alone.

Absorption closure in highly aged biomass burning smoke

Every year, huge plumes of smoke hundreds of miles wide travel over the south Atlantic Ocean from fires in central and southern Africa. These plumes absorb the sun’s energy and warm the climate. We used airborne optical instrumentation to determine how absorbing the smoke was as well as the relative importance of black and brown carbon. We also tested different ways of simulating these properties that could be used in a climate model.

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