Interannual variations of the air-sea CO2 exchange from 1965 to 2000 in the Pacific Ocean are studied with a Pacific Ocean model. Two numerical experiments are performed, including the control run that is forced by cl...Interannual variations of the air-sea CO2 exchange from 1965 to 2000 in the Pacific Ocean are studied with a Pacific Ocean model. Two numerical experiments are performed, including the control run that is forced by climatological monthly mean physical data and the climate-change run that is forced by interannually varying monthly mean physical data. Climatological monthly winds are used in both runs to calculate the coefficient of air-sea CO2 exchange. The analysis through the differences between the two runs shows that in the tropical Pacific the variation of export production induced by interannual variations of the physical fields is negatively correlated with that of the air-sea CO2 flux, while there is no correlation or a weak positive correlation in the subtropical North and South Pacific. It indicates that the variation of the physical fields can modulate the variation of the air-sea CO2 flux in converse ways in the tropical Pacific by changing the direct transport and biochemical process. Under the interannually varying monthly mean forcing, the simulated EOF 1 of the air-sea CO2 flux is basically consistent with that of sea surface temperature （SST） in the tropical Pacific, but contrary in the two subtropical Pacific Ocean. The correlation coefficient between the regionally integrated air-sea CO2 flux and area-mean SST shows that when the air-sea CO2 flux lags SST by about 5 months, the positive coefficient in the three regions is largest, indicating that in the tropical Pacific or on the longer time scale in the three regions, physical processes control the fiux-SST relationship.展开更多
Compact calli derived from immature spikelet of a foxtail millet variety—Jigu 11cann’t be directly used for protoplast isolation because of its firm physical structure,and must beloosened with subculturing in M<s...Compact calli derived from immature spikelet of a foxtail millet variety—Jigu 11cann’t be directly used for protoplast isolation because of its firm physical structure,and must beloosened with subculturing in M<sub>1</sub>,M<sub>2</sub> and M<sub>3</sub> media successively and altering these media compo-sitions.The loosened calli can be selected from the regulation and used for protoplast isolationsuccessfully.Rate of protoplast division in KM<sub>8</sub>P medium was 12.3—33.5%.Calli derivedthrough protoplast division are loose and cann’t be used directly for plan regeneration because ofits soft physical structure.When they were subcultured in N<sub>6</sub>—1,N<sub>6</sub>—2,N<sub>6</sub>—3 and N<sub>6</sub>—4 media,in which the media compositions were changed,the compact calli were obtained and 129 plantletswere regenerated from them.101 plants,which grew to maturity after transplanting the plantletsinto field,exhibited sterility in some degree.Most of the subsequent lines derived from the regen-erated plants were sterile and only two lines could get normal reproduction.展开更多
Based on the results of water sample measurements of nutrient concentrations at th e Datong Station of the Changjiang River from 1998 to 1999, combined w ith historical data of water quality, seasonal variations of nu...Based on the results of water sample measurements of nutrient concentrations at th e Datong Station of the Changjiang River from 1998 to 1999, combined w ith historical data of water quality, seasonal variations of nutrient concentrations and nutrient transports are discussed.The following results have been obtained: (1) the fluxes of the nitrate nitrogen, ammonium nitrogen and nitrite nitrogen increased by time-series from 1962 to 1990 , even if runoff volume had a little variation; (2) the concentrations and fluxes of the dissolved inorganic nitrogen (DIN) and dissolved in organic phosphorus (DIP) increased notably with time, but those of the dissolved silicon (DSI) decreased pronouncedly; and (3) the concentration s and fluxes changed synchronously with time between the Datong Station a nd the Changjiang Estuary.展开更多
In order to reduce the uncertainty of offline land surface model （LSM） simulations of land evapotranspiration （ET）, we used ensemble simulations based on three meteorological forcing datasets [Princeton, ITPCAS （...In order to reduce the uncertainty of offline land surface model （LSM） simulations of land evapotranspiration （ET）, we used ensemble simulations based on three meteorological forcing datasets [Princeton, ITPCAS （Institute of Tibetan Plateau Research, Chinese Academy of Sciences）, Qian] and four LSMs （BATS, VIC, CLM3.0 and CLM3.5）, to explore the trends and spatiotemporal characteristics of ET, as well as the spatiotemporal pattern of ET in response to climate factors over China's Mainland during 1982-2007. The results showed that various simulations of each member and their arithmetic mean （EnsAVlean） could capture the spatial distribution and seasonal pattern of ET sufficiently well, where they exhibited more significant spatial and seasonal variation in the ET compared with observation-based ET estimates （Obs_MTE）. For the mean annual ET, we found that the BATS forced by Princeton forcing overestimated the annual mean ET compared with Obs_MTE for most of the basins in China, whereas the VIC forced by Princeton forcing showed underestimations. By contrast, the Ens_Mean was closer to Obs_MTE, although the results were underestimated over Southeast China. Furthermore, both the Obs_MTE and Ens_Mean exhibited a significant increasing trend during 1982-98; whereas after 1998, when the last big EI Nifio event occurred, the Ens_Mean tended to decrease significantly between 1999 and 2007, although the change was not significant for Obs_MTE. Changes in air temperature and shortwave radiation played key roles in the long-term variation in ET over the humid area of China, but precipitation mainly controlled the long-term variation in ET in arid and semi-arid areas of China.展开更多
基金The Research and Development Special Fund for Public Welfare Industry (meteorology) of the China Meteorological Adminstration under contract No.2008416022the Ocean Public Welfare Scientific Research Project of State Oceanic Administration of China under contract No.200905012-4+1 种基金the National Natural Science Foundation of China under contract Nos 40730106,41075091 and 41105087the National Basic Research Program (973 Program) of China under contract No. 2010CB951802
文摘Interannual variations of the air-sea CO2 exchange from 1965 to 2000 in the Pacific Ocean are studied with a Pacific Ocean model. Two numerical experiments are performed, including the control run that is forced by climatological monthly mean physical data and the climate-change run that is forced by interannually varying monthly mean physical data. Climatological monthly winds are used in both runs to calculate the coefficient of air-sea CO2 exchange. The analysis through the differences between the two runs shows that in the tropical Pacific the variation of export production induced by interannual variations of the physical fields is negatively correlated with that of the air-sea CO2 flux, while there is no correlation or a weak positive correlation in the subtropical North and South Pacific. It indicates that the variation of the physical fields can modulate the variation of the air-sea CO2 flux in converse ways in the tropical Pacific by changing the direct transport and biochemical process. Under the interannually varying monthly mean forcing, the simulated EOF 1 of the air-sea CO2 flux is basically consistent with that of sea surface temperature （SST） in the tropical Pacific, but contrary in the two subtropical Pacific Ocean. The correlation coefficient between the regionally integrated air-sea CO2 flux and area-mean SST shows that when the air-sea CO2 flux lags SST by about 5 months, the positive coefficient in the three regions is largest, indicating that in the tropical Pacific or on the longer time scale in the three regions, physical processes control the fiux-SST relationship.
文摘Compact calli derived from immature spikelet of a foxtail millet variety—Jigu 11cann’t be directly used for protoplast isolation because of its firm physical structure,and must beloosened with subculturing in M<sub>1</sub>,M<sub>2</sub> and M<sub>3</sub> media successively and altering these media compo-sitions.The loosened calli can be selected from the regulation and used for protoplast isolationsuccessfully.Rate of protoplast division in KM<sub>8</sub>P medium was 12.3—33.5%.Calli derivedthrough protoplast division are loose and cann’t be used directly for plan regeneration because ofits soft physical structure.When they were subcultured in N<sub>6</sub>—1,N<sub>6</sub>—2,N<sub>6</sub>—3 and N<sub>6</sub>—4 media,in which the media compositions were changed,the compact calli were obtained and 129 plantletswere regenerated from them.101 plants,which grew to maturity after transplanting the plantletsinto field,exhibited sterility in some degree.Most of the subsequent lines derived from the regen-erated plants were sterile and only two lines could get normal reproduction.
基金National Natural Science Foundation of China,No.39790110
文摘Based on the results of water sample measurements of nutrient concentrations at th e Datong Station of the Changjiang River from 1998 to 1999, combined w ith historical data of water quality, seasonal variations of nutrient concentrations and nutrient transports are discussed.The following results have been obtained: (1) the fluxes of the nitrate nitrogen, ammonium nitrogen and nitrite nitrogen increased by time-series from 1962 to 1990 , even if runoff volume had a little variation; (2) the concentrations and fluxes of the dissolved inorganic nitrogen (DIN) and dissolved in organic phosphorus (DIP) increased notably with time, but those of the dissolved silicon (DSI) decreased pronouncedly; and (3) the concentration s and fluxes changed synchronously with time between the Datong Station a nd the Changjiang Estuary.
基金supported by the National Natural Science Foundation of China(Grant Nos.4140508391437220 and 41305066)+1 种基金the Natural Science Foundation of Hunan Province(Grant No.2015JJ3098)the Fund Project for The Education Department of Hunan Province(Grant No.14C0897)
文摘In order to reduce the uncertainty of offline land surface model （LSM） simulations of land evapotranspiration （ET）, we used ensemble simulations based on three meteorological forcing datasets [Princeton, ITPCAS （Institute of Tibetan Plateau Research, Chinese Academy of Sciences）, Qian] and four LSMs （BATS, VIC, CLM3.0 and CLM3.5）, to explore the trends and spatiotemporal characteristics of ET, as well as the spatiotemporal pattern of ET in response to climate factors over China's Mainland during 1982-2007. The results showed that various simulations of each member and their arithmetic mean （EnsAVlean） could capture the spatial distribution and seasonal pattern of ET sufficiently well, where they exhibited more significant spatial and seasonal variation in the ET compared with observation-based ET estimates （Obs_MTE）. For the mean annual ET, we found that the BATS forced by Princeton forcing overestimated the annual mean ET compared with Obs_MTE for most of the basins in China, whereas the VIC forced by Princeton forcing showed underestimations. By contrast, the Ens_Mean was closer to Obs_MTE, although the results were underestimated over Southeast China. Furthermore, both the Obs_MTE and Ens_Mean exhibited a significant increasing trend during 1982-98; whereas after 1998, when the last big EI Nifio event occurred, the Ens_Mean tended to decrease significantly between 1999 and 2007, although the change was not significant for Obs_MTE. Changes in air temperature and shortwave radiation played key roles in the long-term variation in ET over the humid area of China, but precipitation mainly controlled the long-term variation in ET in arid and semi-arid areas of China.
