International audienceAn interactive system coupling the Beijing Climate Center atmospheric general circulation model (BCC_AGCM2. 0. 1) and the Canadian Aerosol Module (CAM) with updated aerosol emission sources was developed to investigate the global distributions of optical properties and direct radiative forcing (DRF) of typical aerosols and their impacts on East Asian climate. The simulated total aerosol optical depth (AOD), single scattering albedo, and asymmetry parameter were generally consistent with the ground-based measurements. Under all-sky conditions, the simulated global annual mean DRF at the top of the atmosphere was -2. 03 W m-2 for all aerosols including sulfate, organic carbon (OC), black carbon (BC), dust, and sea salt; the global annual mean DRF was -0. 23 W m-2 for sulfate, BC, and OC aerosols. The sulfate, BC, and OC aerosols led to decreases of 0. 58° and 0. 14 mm day-1 in the JJA means of surface temperature and precipitation rate in East Asia. The differences of land-sea surface temperature and surface pressure were reduced in East Asian monsoon region due to these aerosols, thus leading to the weakening of East Asian summer monsoon. Atmospheric dynamic and thermodynamic were affected due to the three types of aerosol, and the southward motion between 15°N and 30°N in lower troposphere was increased, which slowed down the northward transport of moist air carried by the East Asian summer monsoon, and moreover decreased the summer monsoon precipitation in south and east China. © 2011 Springer-Verlag

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The analysis of weather phenomenon plays a crucial role in various applications, for example, environmental monitoring, weather forecasting, and the assessment of environmental quality (Cai et al., 2018). Besides, different weather phenomena have diverse effects on agriculture (Przybylska-Balcerek et al., 2019). Therefore, accurately distinguishing weather phenomena can improve agricultural planning. Furthermore, weather phenomena not only strongly influences vehicle assistant driving systems (by snow, sandstorm, haze, etc.;Yan et al., 2009) but also affects us in our daily lives, such as the wearing, traveling, and solar technologies (Lu et al., 2014;Zhao et al., 2018). Meanwhile, the functionality of many visual systems like outdoor video surveillance is also affected by weather phenomena (Elhoseiny et al., 2015). Additionally, the weather phenomena (haze, snow, sandstorm, and so on) that occurred the day before will also affect weather conditions for the next few days. Local or regional weather conditions such as sandstorms, heavy rain, rime, snow, haze, and agglomerate fog are dangerous weather conditions that could be partly responsible for a large number of traffic accidents on expressways (Lin et al., 2005;Tan et al., 2019). Therefore, we can come to the simple conclusion that the classification of weather phenomena is essential and can help meteorologists to understand climatic conditions as well as improve weather forecasting.Generally, traditional classification methods of weather phenomena rely on human observation. However, the traditional artificial visual distinction between weather phenomena takes a lot of time and is prone to errors. Hence, there is an urgent need to develop high-precision, efficient, and automated technologies for weather phenomena classification. In recent years, Lu et al. (2014) used a collaborative learning approach for the two-class weather classification (sunny and cloudy). Besides, Pavlic et al. (2013) successfully classified fog and fog-free scenes by using a simple linear classifier. Nowadays, machine learning is developing rapidly, enabling researchers to apply machine learning to various academic fields. For weather phenomena recognition, Song et al. ( 2014) achieved weather condition

Although single-layer solutions have been obtained for the d-four-stream discrete ordinates method (DOM) in radiative transfer, a four-stream doubling-adding method (4DA) is lacking, which enables us to calculate the radiative transfer through a vertically inhomogeneous atmosphere with multiple layers. In this work, based on the Chandrasekhar invariance principle, an analytical method of d-4DA is proposed.When applying d-4DA to an idealized medium with specified optical properties, the reflection, transmission, and absorption are the same if the medium is treated as either a single layer or dividing it into multiple layers. This indicates that d-4DA is able to solve the multilayer connection properly in a radiative transfer process. In addition, the d-4DA method has been systematically compared with the d-two-stream doubling-adding method (d-2DA) in the solar spectrum. For a realistic atmospheric profile with gaseous transmission considered, it is found that the accuracy of d-4DA is superior to that of d-2DA in most of cases, especially for the cloudy sky. The relative errors of d-4DA are generally less than 1% in both the heating rate and flux, while the relative errors of d-2DA can be as high as 6%.

We developed two radiation parameterizations with different resolutions (17-band and 998-band) for perfluorocarbons (PFCs) and sulfur hexafluoride (SF 6 ) using the updated High-resolution Transmission Molecular Absorption (HITRAN) 2004 database and the correlated k-distribution method. We analyzed the impacts of the two radiation schemes on heating rates. Then we studied their instantaneous radiative efficiency, stratospheric adjusted radiative efficiency, global warming potential (GWP), and global temperature potential (GTP), for both clear-and all-sky conditions using a high-resolution radiation scheme. We found that the stratosphere-adjusted radiative efficiencies of C 2 F 6 , CF 4 , and SF 6 for the whole sky were 0.346, 0.098, and 0.680 W m −2 ppbv −1 , respectively. Radiative forcing from the industrial revolution to 2005 was 0.001, 0.007, and 0.004 W m −2 , respectively; and was predicted to rise to 0.008, 0.036, and 0.037 W m −2 , respectively, by 2100, according to emission scenarios provided by the IPCC. The GWPs of C 2 F 6 , CF 4 , and SF 6 are 17035, 7597, and 31298, respectively, for a time horizon of 100 years relative to CO 2 . Their GTPs of pulse and sustained emissions, GTP P and GTP S , are 22468, 10052, and 40935 and 16498, 7355, and 30341, respectively, for a 100-year time horizon.PFCs, SF 6 , radiative forcing, global warming potential (GWP), global temperature potential (GTP), correlated k-distribution Citation:Zhang H, Wu J X, Shen Z P. Radiative forcing and global warming potential of perfluorocarbons and sulfur hexafluoride.