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
Arctic sea ice is a keystone indicator of greenhouse-gas induced global climate change, which is expected to be amplified in the Arctic. Here we directly compare observed variations in arctic sea-ice extent and CO 2 s...Arctic sea ice is a keystone indicator of greenhouse-gas induced global climate change, which is expected to be amplified in the Arctic. Here we directly compare observed variations in arctic sea-ice extent and CO 2 since the beginning of the 20th century, identifying a strengthening linkage, such that in recent decades the rate of sea-ice decrease mirrors the increase in CO 2 , with r ～ -0.95 over the last four decades, thereby indicating that 90% (r 2 ～ 0.90) of the decreasing sea-ice extent is empirically "accounted for" by the increasing CO 2 in the atmosphere. The author presents an empirical relation between annual sea-ice extent and global atmospheric CO 2 concentrations, in which sea-ice reductions are linearly, inversely proportional to the magnitude of increase of CO 2 over the last few decades. This approximates sea-ice changes during the most recent four decades, with a proportionality constant of 0.030 million km 2 per ppmv CO 2 . When applied to future emission scenarios of the Intergovernmental Panel on Climate Change (IPCC), this relationship results in substantially faster ice decreases up to 2050 than predicted by IPCC models. However, departures from this projection may arise from non-linear feedback effects and/or temporary natural variations on interannual timescales, such as the record minimum of sea-ice extent observed in September 2007.展开更多
Production and destruction processes of carbon monoxide (CO) and ozone (O3) are examined in the light of increasing amount of atmospheric carbon dioxide (CO2). It is found that doubling of CO2 will increase the strato...Production and destruction processes of carbon monoxide (CO) and ozone (O3) are examined in the light of increasing amount of atmospheric carbon dioxide (CO2). It is found that doubling of CO2 will increase the stratospheric concentration of CO and will have positive effect on O3 concentration.展开更多
The response of non-uniformity of precipitation extremes over China to doubled CO2has been analyzed using the daily precipitation simulated by a coupled general circulation model,MIROC_Hires.The major conclusions are ...The response of non-uniformity of precipitation extremes over China to doubled CO2has been analyzed using the daily precipitation simulated by a coupled general circulation model,MIROC_Hires.The major conclusions are as follows:under the CO2increasing scenario(SRES A1B),the climatological precipitation extremes are concentrated over the southern China,while they are uniformly distributed over the northern China.For interannual variability,the concentration of precipitation extremes is small over the southern China,but it is opposite over the northern China.The warming effects on the horizontal and vertical scales are different over the northern and southern part of China.Furthermore,the atmospheric stability is also different between the two parts of China.The heterogeneous warming is one of the possible reasons for the changes in non-uniformity of precipitation extremes over China.展开更多
The CO_2-seawater system and the method for calculating the partial pressure of CO2 (pCO2) in seawater are studied. The buffer capability of the ocean to increasing atmospheric CO2 is expressed in terms of the differe...The CO_2-seawater system and the method for calculating the partial pressure of CO2 (pCO2) in seawater are studied. The buffer capability of the ocean to increasing atmospheric CO2 is expressed in terms of the differential buffer factor and buffer index. Dissolutions of aragonite and calcite have a significant inffluence on the differential buffer factor. The trend of change in the buffer factor is obtained by a box model.展开更多
A global mean ocean model including atmospheric heating, heat capacity of the mixed layer ocean, and vertical thermal diffusivity in the lower ocean, proposed by Cess and Goldenberg (1981), is used in this paper to st...A global mean ocean model including atmospheric heating, heat capacity of the mixed layer ocean, and vertical thermal diffusivity in the lower ocean, proposed by Cess and Goldenberg (1981), is used in this paper to study the sensitivity of global warming to the vertical diffusivity. The results suggest that the behaviour of upper ocean temperature is mainly determined by the magnitude of upper layer diffusivity and an ocean with a larger diffusivity leads to a less increase of sea surface temperature and a longer time delay for the global warming induced by increasing CO2 than that with smaller one. The global warming relative to four scenarios of CO2 emission assumed by Intergovernmental Panel of Climate Change (IPCC) is also estimated by using the model with two kinds of thermal diffusivities. The result shows that for various combinations of the CO2 emission scenarios and the diffusivities, the oceanic time delay to the global warming varies from 15 years to 70 years.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supported by the Mohn-Sverdrup Center for Global Ocean StudiesOperational Oceanography at the Nansen Center and the Research Council of Norway+1 种基金is a contribution to the International Polar Year―Climate of the Arcticits Role for Europe (IPY-CARE) project, headed by the author
文摘Arctic sea ice is a keystone indicator of greenhouse-gas induced global climate change, which is expected to be amplified in the Arctic. Here we directly compare observed variations in arctic sea-ice extent and CO 2 since the beginning of the 20th century, identifying a strengthening linkage, such that in recent decades the rate of sea-ice decrease mirrors the increase in CO 2 , with r ～ -0.95 over the last four decades, thereby indicating that 90% (r 2 ～ 0.90) of the decreasing sea-ice extent is empirically "accounted for" by the increasing CO 2 in the atmosphere. The author presents an empirical relation between annual sea-ice extent and global atmospheric CO 2 concentrations, in which sea-ice reductions are linearly, inversely proportional to the magnitude of increase of CO 2 over the last few decades. This approximates sea-ice changes during the most recent four decades, with a proportionality constant of 0.030 million km 2 per ppmv CO 2 . When applied to future emission scenarios of the Intergovernmental Panel on Climate Change (IPCC), this relationship results in substantially faster ice decreases up to 2050 than predicted by IPCC models. However, departures from this projection may arise from non-linear feedback effects and/or temporary natural variations on interannual timescales, such as the record minimum of sea-ice extent observed in September 2007.
文摘Production and destruction processes of carbon monoxide (CO) and ozone (O3) are examined in the light of increasing amount of atmospheric carbon dioxide (CO2). It is found that doubling of CO2 will increase the stratospheric concentration of CO and will have positive effect on O3 concentration.
基金National Basic Research Program of China(973 Program,2012CB955901)National Natural Science Foundation of China(51190090)+3 种基金National Natural Science Foundation of China(41105044,41205038)Open Project Program of State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment(SKLLQG1308)Key Laboratory of Meteorological Disaster of Ministry of Education,Nanjing University of Information Science and Technology(KLME1201)Fundamental Research Funds for the Central Universitites(2012B00114)
文摘The response of non-uniformity of precipitation extremes over China to doubled CO2has been analyzed using the daily precipitation simulated by a coupled general circulation model,MIROC_Hires.The major conclusions are as follows:under the CO2increasing scenario(SRES A1B),the climatological precipitation extremes are concentrated over the southern China,while they are uniformly distributed over the northern China.For interannual variability,the concentration of precipitation extremes is small over the southern China,but it is opposite over the northern China.The warming effects on the horizontal and vertical scales are different over the northern and southern part of China.Furthermore,the atmospheric stability is also different between the two parts of China.The heterogeneous warming is one of the possible reasons for the changes in non-uniformity of precipitation extremes over China.
文摘The CO_2-seawater system and the method for calculating the partial pressure of CO2 (pCO2) in seawater are studied. The buffer capability of the ocean to increasing atmospheric CO2 is expressed in terms of the differential buffer factor and buffer index. Dissolutions of aragonite and calcite have a significant inffluence on the differential buffer factor. The trend of change in the buffer factor is obtained by a box model.
文摘A global mean ocean model including atmospheric heating, heat capacity of the mixed layer ocean, and vertical thermal diffusivity in the lower ocean, proposed by Cess and Goldenberg (1981), is used in this paper to study the sensitivity of global warming to the vertical diffusivity. The results suggest that the behaviour of upper ocean temperature is mainly determined by the magnitude of upper layer diffusivity and an ocean with a larger diffusivity leads to a less increase of sea surface temperature and a longer time delay for the global warming induced by increasing CO2 than that with smaller one. The global warming relative to four scenarios of CO2 emission assumed by Intergovernmental Panel of Climate Change (IPCC) is also estimated by using the model with two kinds of thermal diffusivities. The result shows that for various combinations of the CO2 emission scenarios and the diffusivities, the oceanic time delay to the global warming varies from 15 years to 70 years.
