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Abstract: Shenzhen is one of the special economic zones in China. It has been growing rapidly from rural land to an industrial city since the mid-1980s. With the process of urbanization, flooding has become a threat to the security of the city area. In this study, Buji River basin in Shenzhen Region was selected to investigate the effect of urbanization on surface runoff and peak discharge. Land use data were obtained from LANDSAT images in 1980, 1988, 1994, and 2000, and surface runoff in the same period was simulated by SCS model. Results showed that urbanization played an important factor intensifying the flood process. Increase of urbanized land and decrease of farmland might be the main reasons for increasing runoff. At 10%, 50% and 90% rainfall probability (the rainfall probability of 10% means 10-year return period of moist year, 2-year return period of normal year and 10-year return period of dry year), the increase of runoff coefficient was 12.6%, 20.7% and 33.5% respectively under relatively dry soil moisture condition, however, and the value was 2.5%, 4.3% and 6.9% respectively under relatively wet soil moisture condition. Urbanization led to obvious increase in the maximum flood discharge and decrease in runoff confluence time. At 1%, 2% and 5% rainfall probability, the increase of the maximum flood discharge was 20.2%, 23.0% and 28.9% respectively, under relatively dry soil moisture condition. The corresponding value was 1.3%, 1.6% and 2.6% respectively under relatively wet soil moisture condition. Due to urbanization in the past 20 years, runoff coefficient increased 13.4% and the maximum flood discharge increased 12.9% on average. [Copyright &y& Elsevier]

Using the Surface waterproofing to solve moisture expansion which leads to the acceleration of surface weathering of sandstone relics is a hot topic. This study focuses on surface coating protection because of the special status of cultural relics. The fluorinated ZnO/SiO 2 nano-coating was applied on the sandstone matrix in this work. The loading of the fluorinated ZnO/SiO 2 in the nano-coating, the penetration depth of the nano-coating in the sandstone matrix, and the waterproofing effect of the sandstone surface were investigated within the limitation of the color difference systematically. The freeze-thaw cycles, light exposure, water absorption, and aging tests were carried out to evaluate the environmental durability of the nano-coating in a simulated humid environment of southwestern of China. All the tests meet the criteria for the heritage protection color difference. When the loading of fluorinated ZnO/SiO 2 nano-coating is 0.4%, the water contact angle (WCA) and oil contact angle (OCA) are significantly improved, which are larger than 160° and 140°, respectively. The WCA and OCA have little changed after freeze-thaw cycle for three weeks, and the WCA only decreases only 7% after 300 h UV aging treatment. This significantly enhanced stability is due to the good penetration depth of the fluorinated ZnO/SiO 2 nano-coating on the sandstone matrix. Moreover, the excellent air permeability is achieved as well to ensure substrate breathing. This work would provide a new idea for the long-term protection of sandstone heritage in practical environment. [ABSTRACT FROM AUTHOR]

Analyzing the approaches that climatic factors affect the spatial variation of annual gross primary productivity (GPP yr ) would improve our understanding on its spatial pattern. Based on network eddy covariance measurements and published data in literature, we separated GPP yr into radiation use efficiency (RUE) and annual absorbed photosynthesis active radiation (APAR yr ), where APAR yr can be regarded as the product of the fraction of absorbed annual photosynthesis active radiation (FPAR yr ) and annual PAR (PAR yr ). Given that PAR yr affects the spatial variation of GPP yr directly through itself, we investigated factors affecting the spatial variations of RUE and FPAR yr , to reveal how climatic factors affect the spatial variation of GPP yr . Results suggest that the spatial variation of RUE was directly affected by annual mean air temperature (MAT) and annual mean CO 2 mass concentration ( ρ cyr ). The increasing MAT and ρ cyr directly enhanced RUE. The increasing annual precipitation (MAP) directly prompted FPAR yr . Therefore, MAT and ρ cyr affected the spatial variation of GPP yr through altering RUE while the effect of MAP was achieved through altering FPAR yr . Our study could also provide an alternative way for regional GPP yr assessment. [ABSTRACT FROM AUTHOR]

Accurate quantifying the magnitudes and distributions of carbon budgets is helpful for strategies in mitigating global climate change. Based on spatial patterns of carbon fluxes (gross ecosystem productivity (GEP), ecosystem respiration (ER) and net ecosystem productivity (NEP)) and their drivers, we constructed geographical statistical assessment schemes and quantified the magnitudes of carbon fluxes in China. The optimal assessment scheme was then validated with observed eddy covariance data to analyze the spatial distributions of carbon fluxes. Using climate-based geographical statistical assessment schemes, our estimates of GEP, ER and NEP in China during 2000s were 7.51±0.51, 5.82±0.16 and 1.91±0.15PgCyr−1, corresponding to 4.29%–6.80%, 5.65%–6.06% and 9.10%–12.73% of global annual carbon fluxes, respectively. The spatial distributions of GEP, ER and NEP, generated from the optimal scheme, were similar, following a southeast–northwest decreasing gradient. The maximum values for GEP, ER and NEP were 1790, 1300 and 490gCm−2 yr−1, respectively, which occurred in Central subtropics and Southern subtropics. Climate-based geographical statistical assessment schemes provided an independent dataset for the regional carbon budget assessment, which can be deemed as the potential carbon fluxes. Meanwhile, most areas in China were potential carbon sink especially Eastern China and the largest potential carbon sink appeared in Central subtropics and Southern subtropics. [ABSTRACT FROM AUTHOR]