In this paper, we present a novel shadow removal system for single natural images as well as color aerial images using an illumination recovering optimization method. We first adaptively decompose the input image into overlapped patches according to the shadow distribution. Then, by building the correspondence between the shadow patch and the lit patch based on texture similarity, we construct an optimized illumination recovering operator, which effectively removes the shadows and recovers the texture detail under the shadow patches. Based on coherent optimization processing among the neighboring patches, we finally produce high-quality shadow-free results with consistent illumination. Our shadow removal system is simple and effective, and can process shadow images with rich texture types and nonuniform shadows. The illumination of shadow-free results is consistent with that of surrounding environment. We further present several shadow editing applications to illustrate the versatility of the proposed method.

Variation in snow cover over the Tibetan Plateau (TP) is a key component of climate change and variability, and critical for many hydrological and biological processes. This review first summarizes recent observed changes of snow cover over the TP, including the relationship between the TP snow cover and that over Eurasia as a whole; recent climatology and spatial patterns; inter-annual variability and trends; as well as projected changes in snow cover. Second, we discuss the physical causes and factors contributing to variations in snow cover over the TP, including precipitation, temperature, and synoptic forcing such as the Arctic Oscillation and the westerly jet, and large scale ocean-atmosphere oscillations such as the El Niño-Southern Oscillation (ESNO), the Indian Ocean dipole, and the southern annular mode. Third, linkage between snow cover over the TP and subsequent weather and climate systems are discussed, including the East and South Asian Summer Monsoons, and their subsequent precipitation regimes. Finally, new perspectives and unresolved issues are outlined, including changes in extreme events and related disasters (e.g., avalanches), the use of novel datasets, the possible elevation dependency in snow cover change, expected snow cover changes under 1.5°C and 2°C global warming, the physical mechanisms modulating climate extremes in the region, and the linkage between snow cover variation and atmospheric pollution. Despite a large body of work over the TP, we argue that there is a need for more comparative studies using multiple snow datasets, and snow cover information over the western TP and during summer would benefit from more attention in the future.

Climate warming on the Tibetan Plateau (TP) potentially influences many climate parameters other than temperature including wind speed, cloudiness and precipitation. Temporal trends of surface wind speed at 71 stations above 2000 m above sea level in the TP are examined during 1980-2005. To uncover causes of observed trends in wind speed, relationships with surface temperature, a TP index and sunshine duration are also analysed. The TP index is calculated as the accumulated 500 hPa geopotential height above 5000 m over the region of 30°N-40°N, 75°E-105°E from NCEP/NCAR reanalysis. The annual mean wind speed patterns during 1980-2005 are similar to those in different seasons, with higher wind speeds in the northern and western parts of the TP. Highest mean wind speeds occur in spring and lowest in autumn. During 1980-2005, annual and seasonal mean wind speeds show statistically decreasing trends at most stations. The mean trend magnitude for annual mean wind speed is -0.24ms-1decade-1, with the maximum decline in spring (-0.29ms-1decade-1) and minimum in autumn (-0.19ms-1decade-1). Both annually and in different seasons, wind speed is significantly negatively correlated with mean temperature, minimum temperature, maximum temperature, and the TP index, but significantly positively correlated with sunshine duration. Wind speed trends fail to show a simple elevation dependency but speeds are positively correlated with meridional surface temperature/pressure gradients. Warming in the TP may weaken the latitudinal gradients of both regional temperature and surface pressure, thus altering the regional atmospheric circulation and accounting in part for the observed decline of wind speed. © 2013 Royal Meteorological Society

Size-controllable Pt nanoparticles ranging from 1.3 to 2.3 nm were successfully loaded onto ZSM-5 (Pt-x/ZSM-5, where x is the mean diameter of the Pt nanoparticles). Catalytic tests in complete oxidation of toluene as a model for VOC removal show that Pt-1.9/ZSM-5 has the highest activity, due to a balance of Pt dispersion and Pt(0) proportion.

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