Limitations in current capabilities to constrain aerosols adversely impact atmospheric simulations. Typically, aerosol burdens within models are constrained employing satellite aerosol optical properties, which are not available under cloudy conditions. Here we set the first steps to overcome the long-standing limitation that aerosols cannot be constrained using satellite remote sensing under cloudy conditions. We introduce a unique data assimilation method that uses cloud droplet number (Nd) retrievals to improve predicted below-cloud aerosol mass and number concentrations.

Atmospheric models generally assume that aerosol particles are in equilibrium with the surrounding gas phase. However, recent observations that secondary organic aerosols can exist in a glassy state have highlighted the need to more fully understand the kinetic limitations that may control water partitioning in ambient particles. Here, we explore the influence of slow water diffusion in the condensed aerosol phase on the rates of both condensation and evaporation, demonstrating that significant inhibition in mass transfer occurs for ultraviscous aerosol, not just for glassy aerosol.

Black carbon (BC) emissions from China are of global concern. A new BC emission inventory (PKU-BC(China)) has been developed with the following improvements: (1) The emission factor database was updated; (2) a 0.1° × 0.1° gridded map was produced for 2007 based on county-level proxies; (3) time trends were derived for 1949–2007 and predicted for 2008–2050; and (4) the uncertainties associated with the inventory were quantified. It was estimated that 1957 Gg of BC were emitted in China in 2007, which is greater than previously reported.

Volatile organic compounds (VOCs) are ubiquitous atmospheric constituents of both anthropogenic and natural origin. VOCs are important precursors of tropospheric ozone (O3), and can impact air quality and global climate. Most of primary VOCs and their oxidized products makeup a major fraction of secondary pollutants in urbanized regions. Due to fast reaction rates mainly with the hydroxyl radical (OH), the VOCs control the oxidizing capacity of the troposphere. Measurements of VOCs are important to study the photochemical transformation, both qualitatively and quantitatively.

Estimates of climate-change impacts will get less, rather than more, certain. But this should not excuse inaction, say Mark Maslin and Patrick Austin.

Political interests, not scientists or inventors, will be the biggest influence on technologies to counter climate change, says Jason Blackstock.

Investigations of aerosol optical and physical characteristics using the application of Ångström formula and second order polynomial fit were carried out from April 2006 to March 2009 at Mohal in the Kullu valley. The measurements of spectral aerosol optical depths (AODs) were conducted using multiwavelength radiometer (MWR). The AOD at 0.5 μm wavelength on daily basis (mean ± standard deviation) for the entire three-year study period is obtained as 0.24 ± 0.08.