Increasing greenhouse gases and likely ozone recovery will be the two most important factors influencing changes in stratospheric temperatures in the 21st century. The radiative effect of increasing greenhouse gases w...Increasing greenhouse gases and likely ozone recovery will be the two most important factors influencing changes in stratospheric temperatures in the 21st century. The radiative effect of increasing greenhouse gases will cause cooling in the stratosphere, while ozone recovery will lead to stratospheric warming. To investigate how stratospheric temperatures change under the two opposite forcings in the 21st century, we use observed ozone and reanalysis data as well as simulation results from four coupled oceanic and atmo- spheric general circulation models （GISS-ER, GFDL-CM20, NCAR-CCSM3, and UKMO-HadCM3） used in the IPCC （Intergovernment Panel for Climate Change） Fourth Assessment Report （AR4）. Observational analysis shows that total column ozone and lower stratospheric temperatures all show increasing in the past 10 years, while middle stratospheric temperatures demonstrate cooling. IPCC AR4 simulations show that greenhouse forcing alone will lead to stratospheric cooling. However, with forcing of both increasing greenhouse gases and ozone recovery, the middle stratosphere will be cooled, while the lower stratosphere will be warmed. Warming magnitudes vary from one model to another. UKMO-HadCM3 generates relatively strong warming for all three greenhouse scenarios, and warming extends to 40 hPa. GFDL-CM20 and NCAR-CCSM3 produce weak warming, and warming mainly exists at lower levels, below about 60 hPa. In addition, we also discuss the effect of temperature changes on ozone recovery.展开更多
A waste heat recovery and denitrification system was developed for improving energy conservation and emissions control especially for control of PM2.5 particles and haze. The system uses enhanced heat and mass transfe...A waste heat recovery and denitrification system was developed for improving energy conservation and emissions control especially for control of PM2.5 particles and haze. The system uses enhanced heat and mass transfer techniques in a packed heat exchange tower with self-rotation and zero-pressure spraying, low temperature NO oxidation by ozone, and neutralization with an alkali solution. Operating data in a test project gave NOx in the exhaust flue gas of less than 30 mg/Nm3 with an ozone addition rate of 8 kg/h and spray water p H of 7.5–8, an average heat recovery of 3 MW, and an average heat supply of 7.2 MW.展开更多
基金Supported by the Natural Sciences Foundation of China (40575031 and 40533016)Ministry of Education of China (106002and 20070001002)National Basic Research Program of China (2007CB411801)
文摘Increasing greenhouse gases and likely ozone recovery will be the two most important factors influencing changes in stratospheric temperatures in the 21st century. The radiative effect of increasing greenhouse gases will cause cooling in the stratosphere, while ozone recovery will lead to stratospheric warming. To investigate how stratospheric temperatures change under the two opposite forcings in the 21st century, we use observed ozone and reanalysis data as well as simulation results from four coupled oceanic and atmo- spheric general circulation models （GISS-ER, GFDL-CM20, NCAR-CCSM3, and UKMO-HadCM3） used in the IPCC （Intergovernment Panel for Climate Change） Fourth Assessment Report （AR4）. Observational analysis shows that total column ozone and lower stratospheric temperatures all show increasing in the past 10 years, while middle stratospheric temperatures demonstrate cooling. IPCC AR4 simulations show that greenhouse forcing alone will lead to stratospheric cooling. However, with forcing of both increasing greenhouse gases and ozone recovery, the middle stratosphere will be cooled, while the lower stratosphere will be warmed. Warming magnitudes vary from one model to another. UKMO-HadCM3 generates relatively strong warming for all three greenhouse scenarios, and warming extends to 40 hPa. GFDL-CM20 and NCAR-CCSM3 produce weak warming, and warming mainly exists at lower levels, below about 60 hPa. In addition, we also discuss the effect of temperature changes on ozone recovery.
基金supported by the National Basic Research Program of China(Grant No.2013CB228301)
文摘A waste heat recovery and denitrification system was developed for improving energy conservation and emissions control especially for control of PM2.5 particles and haze. The system uses enhanced heat and mass transfer techniques in a packed heat exchange tower with self-rotation and zero-pressure spraying, low temperature NO oxidation by ozone, and neutralization with an alkali solution. Operating data in a test project gave NOx in the exhaust flue gas of less than 30 mg/Nm3 with an ozone addition rate of 8 kg/h and spray water p H of 7.5–8, an average heat recovery of 3 MW, and an average heat supply of 7.2 MW.
