Absorbing aerosols have significant influences on tropospheric photochemistry and regional climate change. Here, the direct radiative effects of absorbing aerosols at the major AERONET sites in East Asia and corresponding impacts on near-surface photochemical processes were quantified by employing a radiation transfer model. The average annual aerosol optical depth (AOD) of sites in China, Korea, and Japan was 1.15, 1.02 and 0.94, respectively, and the corresponding proportion of absorbing aerosol optical depth (AAOD) was 8.61%, 6.69%, and 6.49%, respectively. The influence of absorbing aerosol on ultraviolet (UV) radiation mainly focused on UV-A band (315-400 nm). Under the influence of such radiative effect, the annual mean near-surface J[NO2] (J[(OD)-D-1]) of sites in China, Korea, and Japan decreased by 16.95% (22.42%), 9.61% (13.55%), and 9.63% (13.79%), respectively. In Beijing-Tianjin-Hebei (BTH) and Yangtze River Delta (YRD) region, the annual average AOD was 1.48 and 1.29, and the AAOD was 0.14 and 0.13, respectively. The UV radiative forcing caused by aerosols dominated by black carbon (BC-dominated aerosols) on the surface was -3.19 and -2.98 W m(-2), respectively, accounting for about 40% of the total aerosol radiative forcing, indicating that the reduction efficiency of BC-dominated aerosols on solar radiation was higher than that of other types of aerosols. The annual mean J[NO2] (J[(OD)-D-1]) decreased by 14.90% (20.53%) and 13.71% (18.20%) due to the BC-dominated aerosols. The daily maximum photolysis rate usually occurred near noon due to the diurnal variation of solar zenith angle and, thus, the daily average photolysis rate decreased by 2-3% higher than that average during 10:00-14:00.

Ozone is known to be present within the surface ice of Jupiter's moon Ganymede as well as Saturn's moons Dione and Rhea. Given the ubiquity of solar photons incident on these water-ice-dominated surfaces, experiments were conducted to better understand the photochemistry of ozone-water ice mixtures. Samples were deposited as thin films in a vacuum chamber under temperature and pressure conditions relevant to satellites in the outer solar system. Chemical changes in the ices were monitored with infrared spectroscopy as they were exposed to ultraviolet light at 116.5/123.6, 147, and 254 nm emitted from Kr, Xe, and Hg resonant lamps, respectively. In all instances, hydrogen peroxide formed after ultraviolet irradiation, while the amount of ozone present decreased. Of the wavelengths tested, irradiation at 254 rim induced the most rapid change both in terms of irradiation time and number of incident photons. This work emphasizes the importance of wavelengths longer than the vacuum ultraviolet in the chemical evolution of ozone on Ganymede, Dione, and Rhea.

H2O (v = 0) and O(P-3(J=2,1,0)) desorbates were measured with resonance-enhanced multiphoton ionization following 157-nm irradiation of amorphous solid water (ASW) deposited on a lunar mare basalt. Both H2O photodesorption and O(P-3(J)) photodissociation products of ASW were studied in the attempt to better understand the competition between photodesorption and photodissociation of water in the condensed phase on a lunar surface. The oxygen atom time-of-flight (TOF) spectrum was measured as a function of spin-orbit state, H2O exposure, and 157-nm irradiation time. Maxwell-Boltzmann distributions with translational temperatures of 10,000 K, 1800 K, 400 K, and 89 K fit the four TOF components. For high H2O exposures, diffusion out of pores in the lunar substrate made a large portion of the O(P-3(J)) signal appear to be sub-thermal. Water depletion cross sections were measured at exposures between 0.1 and 10 Langmuir (1 L = 10(-6) Torr s). These cross sections decreased with increasing coverage and matched previously measured cross sections from a lunar impact melt breccia. Additionally, non-resonant ionization was employed to detect vibrationally excited water indirectly through its fragments. The OH+ fragment of H2O (v*) and the O(P-3(J)) photodissociation product increased in intensity during prolonged irradiation as hydroxyl groups accumulated on the surface and then recombined. For an initial exposure of 5 L H2O, after reaching maximum signal, the cross sections for H2O (v*) and O((3)P4(2)) depletion were measured to be 1.2 x 10(-19) cm(2) and 6.7 x 10(-20) cm(2), respectively. (c) 2014 Elsevier Inc. All rights reserved.

Three global chemistry-transport models (CTM) are used to quantify the radiative forcing (RF) from aviation NOx emissions, and the resultant reductions in RF from coupling NOx to aerosols via heterogeneous chemistry. One of the models calculates the changes due to aviation black carbon (BC) and sulphate aerosols and their direct RF, as well as the BC indirect effect on cirrus cloudiness. The surface area density of sulphate aerosols is then passed to the other models to compare the resulting photochemical perturbations on NOx through heterogeneous chemical reactions. The perturbation on O-3 and CH4 (via OH) is finally evaluated, considering both short- and long-term O-3 responses. Ozone RF is calculated using the monthly averaged output of the three CTMs in two independent radiative transfer codes. According to the models, column ozone and CH4 lifetime changes due to coupled NOx/aerosol emissions are, on average, +0.56 Dobson Units (DU) and -1.1 months, respectively, for atmospheric conditions and aviation emissions representative of the year 2006, with an RF of +16.4 and -10.2 mW/m(2) for O-3 and CH4, respectively. Sulphate aerosol induced changes on ozone column and CH4 lifetime account for -0.028 DU and +0.04 months, respectively, with corresponding RFs of -0.63 and +0.36 mW/m(2). Soot-cirrus forcing is calculated to be 4.9 mW/m(2).