A series of 17-yr equilibrium simulations using the NCAR COM3 (T42resolution) were performed to investigate the regional scale impacts of land cover change andincreasing CO_2 over China. Simulations with natural and c...A series of 17-yr equilibrium simulations using the NCAR COM3 (T42resolution) were performed to investigate the regional scale impacts of land cover change andincreasing CO_2 over China. Simulations with natural and current land cover at CO_2 levels of 280,355, 430, and 505 ppmv were conducted. Results show statistically significant changes in majorclimate fields (e.g. temperature and surface wind speed) on a 15-yr average following land coverchange. We also found increases in the maximum temperature and in the diurnal temperature range dueto land cover change. Increases in CO_2 affect both the maximum and minimum temperature so thatchanges in the diurnal range are small. Both land cover change and CO_2 change also impact thefrequency distribution of precipitation with increasing CO_2 tending to lead to more intenseprecipitation and land cover change leading to less intense precipitation―indeed, the impact ofland cover change typically had the opposite effect versus the impacts of CO_2. Our results providesupport for the inclusion of future land cover change scenarios in long-term transitory climatemodelling experiments of the 21st Century. Our results also support the inclusion of land surfacemodels that can represent future land cover changes resulting from an ecological response to naturalclimate variability or increasing CO_2. Overall, we show that land cover change can have asignificant impact on the regional scale climate of China, and that regionally, this impact is of asimilar magnitude to increases in CO_2 of up to about 430 ppmv. This means that that the impact ofland cover change must be accounted for in detection and attribution studies over China.展开更多
On the basis of the thermodynamic calculation of precipitation and considering the effect of strain on the precipitation behavior and chemical composition （Si and Mn）, the kinetics of precipitation from austenite ha...On the basis of the thermodynamic calculation of precipitation and considering the effect of strain on the precipitation behavior and chemical composition （Si and Mn）, the kinetics of precipitation from austenite has been investigated for different temperatures and strains. Nucleation theory and the solubility product of niobium, carbon, and nitrogen in austenite have been used to derive equations for the start time of precipitation as a function of temperature and composition. The value of n in Avrami equation was determined using the available experimental data from the published reports, which indicated that n is a constant independent of temperature and the end time of precipitation is a function of n and the start time of precipitation. The values of the start time and end time of precipitation predicted by the new model are compared with the experimental values and a good agreement was obtained between both.展开更多
文摘A series of 17-yr equilibrium simulations using the NCAR COM3 (T42resolution) were performed to investigate the regional scale impacts of land cover change andincreasing CO_2 over China. Simulations with natural and current land cover at CO_2 levels of 280,355, 430, and 505 ppmv were conducted. Results show statistically significant changes in majorclimate fields (e.g. temperature and surface wind speed) on a 15-yr average following land coverchange. We also found increases in the maximum temperature and in the diurnal temperature range dueto land cover change. Increases in CO_2 affect both the maximum and minimum temperature so thatchanges in the diurnal range are small. Both land cover change and CO_2 change also impact thefrequency distribution of precipitation with increasing CO_2 tending to lead to more intenseprecipitation and land cover change leading to less intense precipitation―indeed, the impact ofland cover change typically had the opposite effect versus the impacts of CO_2. Our results providesupport for the inclusion of future land cover change scenarios in long-term transitory climatemodelling experiments of the 21st Century. Our results also support the inclusion of land surfacemodels that can represent future land cover changes resulting from an ecological response to naturalclimate variability or increasing CO_2. Overall, we show that land cover change can have asignificant impact on the regional scale climate of China, and that regionally, this impact is of asimilar magnitude to increases in CO_2 of up to about 430 ppmv. This means that that the impact ofland cover change must be accounted for in detection and attribution studies over China.
基金This work was supported by the National Natural Science Foundation of China （No. 50334010 and No. 50474086）.
文摘On the basis of the thermodynamic calculation of precipitation and considering the effect of strain on the precipitation behavior and chemical composition （Si and Mn）, the kinetics of precipitation from austenite has been investigated for different temperatures and strains. Nucleation theory and the solubility product of niobium, carbon, and nitrogen in austenite have been used to derive equations for the start time of precipitation as a function of temperature and composition. The value of n in Avrami equation was determined using the available experimental data from the published reports, which indicated that n is a constant independent of temperature and the end time of precipitation is a function of n and the start time of precipitation. The values of the start time and end time of precipitation predicted by the new model are compared with the experimental values and a good agreement was obtained between both.
