Based on the daily reanalysis data released by NCEP/NCAR and the daily precipi- tation of 753 Chinese stations from May to August during the period of 1960 to 2012, the statistical characteristics of the cold vortex i...Based on the daily reanalysis data released by NCEP/NCAR and the daily precipi- tation of 753 Chinese stations from May to August during the period of 1960 to 2012, the statistical characteristics of the cold vortex in northeastern China were analyzed. In addition, the strength index, which described the characteristics of the vortex consistently and fre- quently, and the geographical distribution were given by continuous anomalies of circulation. Based on this index, the activity routines of the cold vortex, characteristics of atmospheric circulation, and their effects on precipitation in northeastern China were analyzed. The results show that： the activities of the cold vortex exhibit remarkable features of annual and interde- cadal oscillation, and the vortex high frequency and its characteristics of atmospheric circula- tion are described more accurately by the strength index of the cold vortex, which shows a high correspondence with the vortex precipitation during early summer and midsummer in the northeast. In strong （weak） vortex years, the general circulation in the middle and high lati- tudes of Eurasia is to the advantage （disadvantage） of the formation, development and maintenance of the cold vortex, thus it is easy （difficult） to form the circulation which is bene- ficial to transmit vapor from south to north during the period of July to August. Blocking over the Ural Mountains prevails （does not prevail） in early summer, and blocking over the Sea of Okhotsk prevails （does not prevail） in midsummer. Areas where the subtropical high is too small （large） and moves toward the north too late （early） are better （worse） for the mainte- nance of the cold vortex in northeastern China.展开更多
New estimations of radiative forcing due to CO2 were calculated using updated concentration data of CO2 and a high-resolution radiative transfer model. The stratospheric adjusted radiative forcing （ARF） due to CO2 f...New estimations of radiative forcing due to CO2 were calculated using updated concentration data of CO2 and a high-resolution radiative transfer model. The stratospheric adjusted radiative forcing （ARF） due to CO2 from the year 1750 to the updated year of 2010 was found to have increased to 1.95 W m-2, which was 17% larger than that of the IPCC＇s 4th Assessment Report because of the rapid increase in CO2 concentrations since 2005. A new formula is proposed to accurately describe the relationship between the ARF of CO2 and its concentration. Furthermore, according to the relationship between the ARF and surface temperature change, possible changes in equilibrium surface temperature were estimated under the scenarios that the concentration of CO2 increases to 1.5, 2, 2.5, 3, 3.5 and 4 times that of the concentration in the year 2008. The result was values of ＋2.2℃, ＋3.8℃, ＋5.1℃, ＋6.2℃, ＋7.1℃ and ＋8.0℃ respectively, based on a middle-level climate sensitivity parameter of 0.8 K （W m 3）-1. Non-equilibrium surface temperature changes over the next 500 years were also calculated under two kinds of emission scenarios （pulsed and sustained emissions） as a comparison, according to the Absolute Global Temperature change Potential （AGTP） of CO2. Results showed that CO2 will likely continue to contribute to global warming if no emission controls are imposed, and the effect on the Earth-atmosphere system will be difficult to restore to its original level.展开更多
Two common surface-dust emission schemes using critical wind speed and friction velocity were compared with the regional climate model RegCM3 in East Asia. In the comparison, transport of mineral dust and its distribu...Two common surface-dust emission schemes using critical wind speed and friction velocity were compared with the regional climate model RegCM3 in East Asia. In the comparison, transport of mineral dust and its distribution were simulated from March to April, 2001. Simulation results were also compared with TOMS aerosol index, showing that obvious differences exist in dust emission quantity and its column burden simulated by the dust emission schemes of friction velocity and wind speed criteria. The results obtained by the wind speed criterion are higher than that by friction velocity, bringing forth the problem whether or not the dust emission scheme matches the model. The obvious difference in the two schemes also explains the uncertainty of simulating mineral dust aerosol by modeling.展开更多
基金National Natural Science Foundation of China, No.41375078, No.41405094, No.41175083, No.41275096 Science and technology development plan in Jilin Province of China, No.20150204023 SF
文摘Based on the daily reanalysis data released by NCEP/NCAR and the daily precipi- tation of 753 Chinese stations from May to August during the period of 1960 to 2012, the statistical characteristics of the cold vortex in northeastern China were analyzed. In addition, the strength index, which described the characteristics of the vortex consistently and fre- quently, and the geographical distribution were given by continuous anomalies of circulation. Based on this index, the activity routines of the cold vortex, characteristics of atmospheric circulation, and their effects on precipitation in northeastern China were analyzed. The results show that： the activities of the cold vortex exhibit remarkable features of annual and interde- cadal oscillation, and the vortex high frequency and its characteristics of atmospheric circula- tion are described more accurately by the strength index of the cold vortex, which shows a high correspondence with the vortex precipitation during early summer and midsummer in the northeast. In strong （weak） vortex years, the general circulation in the middle and high lati- tudes of Eurasia is to the advantage （disadvantage） of the formation, development and maintenance of the cold vortex, thus it is easy （difficult） to form the circulation which is bene- ficial to transmit vapor from south to north during the period of July to August. Blocking over the Ural Mountains prevails （does not prevail） in early summer, and blocking over the Sea of Okhotsk prevails （does not prevail） in midsummer. Areas where the subtropical high is too small （large） and moves toward the north too late （early） are better （worse） for the mainte- nance of the cold vortex in northeastern China.
基金supported by the National Basic Research Program of China (Grant Nos. 2010CB955703 and 2011CB403405)the Public Meteorology Special Foundation of MOST (Grant No. GYHY200906020)
文摘New estimations of radiative forcing due to CO2 were calculated using updated concentration data of CO2 and a high-resolution radiative transfer model. The stratospheric adjusted radiative forcing （ARF） due to CO2 from the year 1750 to the updated year of 2010 was found to have increased to 1.95 W m-2, which was 17% larger than that of the IPCC＇s 4th Assessment Report because of the rapid increase in CO2 concentrations since 2005. A new formula is proposed to accurately describe the relationship between the ARF of CO2 and its concentration. Furthermore, according to the relationship between the ARF and surface temperature change, possible changes in equilibrium surface temperature were estimated under the scenarios that the concentration of CO2 increases to 1.5, 2, 2.5, 3, 3.5 and 4 times that of the concentration in the year 2008. The result was values of ＋2.2℃, ＋3.8℃, ＋5.1℃, ＋6.2℃, ＋7.1℃ and ＋8.0℃ respectively, based on a middle-level climate sensitivity parameter of 0.8 K （W m 3）-1. Non-equilibrium surface temperature changes over the next 500 years were also calculated under two kinds of emission scenarios （pulsed and sustained emissions） as a comparison, according to the Absolute Global Temperature change Potential （AGTP） of CO2. Results showed that CO2 will likely continue to contribute to global warming if no emission controls are imposed, and the effect on the Earth-atmosphere system will be difficult to restore to its original level.
基金This work is sponsored by the National Key Program for Developing Basic Sciences of China （No.2006CB400506） National Natural Science Foundation of China （No. 40675007）+2 种基金 Natural Science Foundation of Yunnan Province of China （2005D0006M） It is also supported by Research for Potential Effect of the 0zonosphere Change in the Regional Climate and Environment （CCSF2007-46）which is supported by Project for Climate Chang of Chinese Meteorological Administration, Project for Innovative Research Team of High Performance Computing in Yunnan University, and Collaboration Project between China Meteorological Administration and Yunnan University.
文摘Two common surface-dust emission schemes using critical wind speed and friction velocity were compared with the regional climate model RegCM3 in East Asia. In the comparison, transport of mineral dust and its distribution were simulated from March to April, 2001. Simulation results were also compared with TOMS aerosol index, showing that obvious differences exist in dust emission quantity and its column burden simulated by the dust emission schemes of friction velocity and wind speed criteria. The results obtained by the wind speed criterion are higher than that by friction velocity, bringing forth the problem whether or not the dust emission scheme matches the model. The obvious difference in the two schemes also explains the uncertainty of simulating mineral dust aerosol by modeling.
