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Urban forest has undergone rapid development in China over the last three decades because of the acceleration of urbanization. Urban forest thus plays an increasingly important role in carbon sequestration at a regional and national scale. As one of the most urbanized cities in China, Shanghai showed an increase of forest coverage from 3% in the 1990s to 13% in 2009. Based on CITY-green model and the second soil survey of Shanghai, the forest biomass carbon (FBC) was estimated to be 0.48 Tg in the urban area and, forest soil organic carbon (SOC) (0-100 cm soil depth) is 2.48 Tg in the urban and suburban areas, respectively. These values are relatively within the median and lower level compared with other Chinese megacities, with the FBC of 0.02 Tg in Harbin to 47.29 Tg in Chongqing and the forest SOC of 1.74 Tg in Nanjing to 418.67 Tg in Chongqing. For the different land-use types in Shanghai, the SOC density ranges from 13.8 (tidal field) to 38.6 t ha (agricultural land). On average, the forest SOC density (31.5 t ha) in Shanghai is lower than that in agricultural lands (38.6 t ha) and higher than that in lawns (26.5 t ha) and gardens (21.3 t ha). In Shanghai, the SOC density in newly established urban parks is generally lower than that in older parks. In the northern and southeastern suburban areas (e.g., Baoshan, Yangpu, and Nanhui districts), greenspace SOC density is higher than that in the central commercial areas (Hongkou, Putuo, Changning, and Zhabei districts) and in newly developed district (Pudong District). Uncertainties still exist in the estimation of urban forest carbon in Shanghai, as well as in other Chinese cities. Thus, future research directions are also discussed in this paper. [ABSTRACT FROM AUTHOR]

This paper studies interdecadal variations of heat waves and sultry weather (HW&SW) in Beijing City by using climatological data gathered from 1940-2000. In general, HW&SW decreased during the 1940s-1970s and increased during the 1970s-1990s. Although variation trends in the number of HW&SW days coincide with air temperature variations, the greatest number of HW&SW days occurred during the 1940s rather than during the much hotter 1990s (which had an average 1.0°C higher air temperature than during the 1940s). The synoptic situations of HW&SW and the correlation analysis between HW&SW occurrences and the Western Pacific Subtropical High (WPSH) index seem to indicate that HW&SW days during the 1990s should exceed those during the 1940s; however, that is not the case. Post-1980s interdecadal variations of the Urban Dry Island (UDI) effect in Beijing City were analyzed in order to explain this inconsistent phenomenon. Our results show that, while the probability of HW&SW occurrences in Beijing City should have been greater due to global warming and increasing summer Urban Heat Island (UHI) intensity, the UDI effect is magnified by rapid urbanization. In addition, the physical comfort index is more sensitive to relative humidity under high temperature conditions. Therefore, the occurrence of HW&SW days during the 1990s is partially offset by the enhanced UDI in Beijing City. [ABSTRACT FROM AUTHOR]

Since current administrative unit-based urban land area statistical data in China lack enough spatial information, the urbanization process research at large scale cannot be effectively supported. Based on the current administrative unit-based urban land area statistical data in China, a new approach to quickly and cheaply derive urban land information from the non-radiance-calibrated Defense Meteorological Satellite Program/ Operational Linescan System (DMSP/OLS) nighttime light imagery is presented in this paper. With the new approach, the urban pattern information in China in 1992, 1996 and 1998 was derived with the urbanization processes in China in the 1990s restored by using the non-radiance-calibrated DMSP/OLS nighttime imagery. The accuracy assessment based on the statistical data showed that the relative error between the derived total urban land area and the statistical data at national scale was less than 2% in 1992, and less than 1% in 1996 and 1998, and the maximum relative error at province scale do not exceed 10% with most of the provinces less than 3%. In addition, the urban patterns derived from the high-resolution Landsat TM imagery were compared with those from the DMSP/OLS data. The results showed that the urban pattern characteristics derived from DMSP/OLS were basically coincident with those from TM imagery with the total accuracy of about 80%. Thus it can be seen that our restored urbanization process in China in the 1990s by using the non-radiance DMSP/OLS night-time imagery can be accepted and can represent the actual urban development in China at that time on the whole. [ABSTRACT FROM AUTHOR]