Airborne bacteria were measured when a dust storm passed Beijing in spring 2012 with a focus on cell concentration, viability and TSA- and R2A-cultured strain composition. The concentration varied at an order of 10^7 ...Airborne bacteria were measured when a dust storm passed Beijing in spring 2012 with a focus on cell concentration, viability and TSA- and R2A-cultured strain composition. The concentration varied at an order of 10^7 cells/m3 with dust loading （demonstrated with PM10） and they had a very close correlation （RT2 = 0.91, p 〈 0.01）. At the time of highest PM10 of 652 μg/m3, the bacterial concentration reached 1.4 × 10^8 cells/m3, which was larger than that before and after the dust event by one order. Bacterial viability, the ratio of number concentration of viable cells to total cells, was 32%-64% and smaller in the dust plume than that before the dust arrival. Bacterial strains from the culture ranged between 2.5 × 10^4 and 4.6 × 10^5 CFU/m3 and no correlation with PM10 was determined. Their composition was different before and after the dust arrival according to 16S rRNA gene sequences and strains belong to Actinomycetes and Firmicutes were the majority in the dust samples.展开更多
In this paper, seasonal prediction of spring dust weather frequency （DWF） in Beijing during 1982–2008 has been performed. First, correlation analyses are conducted to identify antecedent climate signals during last...In this paper, seasonal prediction of spring dust weather frequency （DWF） in Beijing during 1982–2008 has been performed. First, correlation analyses are conducted to identify antecedent climate signals during last winter that are statistically significantly related to spring DWF in Beijing. Then, a seasonal prediction model of spring DWF in Beijing is established through multivariate linear regression analysis, in which the systematic error between the result of original prediction model and the observation, averaged over the last 10 years, is corrected. In addition, it is found that climate signals occurring synchronously with spring dust weather, particularly meridional wind at 850 hPa over western Mongolian Plateau, are also linked closely to spring DWF in Beijing. As such, statistical and dynamic prediction approaches should be combined to include these synchronous predictors into the prediction model in the real-time operational prediction, so as to further improve the prediction accuracy of spring DWF in Beijing, even over North China. However, realizing such a prediction idea in practice depends essentially on the ability of climate models in predicting key climate signals associated with spring DWF in Beijing.展开更多
基金the support of the Sumitomo Environmental Foundation(103096) of 2011–2012the Grant-in-Aid for Exploratory Research of JSPS(15K12192)the National Natural Science Foundation of China(No: 31470232)
文摘Airborne bacteria were measured when a dust storm passed Beijing in spring 2012 with a focus on cell concentration, viability and TSA- and R2A-cultured strain composition. The concentration varied at an order of 10^7 cells/m3 with dust loading （demonstrated with PM10） and they had a very close correlation （RT2 = 0.91, p 〈 0.01）. At the time of highest PM10 of 652 μg/m3, the bacterial concentration reached 1.4 × 10^8 cells/m3, which was larger than that before and after the dust event by one order. Bacterial viability, the ratio of number concentration of viable cells to total cells, was 32%-64% and smaller in the dust plume than that before the dust arrival. Bacterial strains from the culture ranged between 2.5 × 10^4 and 4.6 × 10^5 CFU/m3 and no correlation with PM10 was determined. Their composition was different before and after the dust arrival according to 16S rRNA gene sequences and strains belong to Actinomycetes and Firmicutes were the majority in the dust samples.
基金Supported by the Knowledge Innovation Project of the Chinese Academy of Sciences(KZCX2-YW-Q03-3)National Basic Research Program of China(2009CB421406)Special Public Welfare Research Fund of China for Meteorological Profession (GYHY200906018)
文摘In this paper, seasonal prediction of spring dust weather frequency （DWF） in Beijing during 1982–2008 has been performed. First, correlation analyses are conducted to identify antecedent climate signals during last winter that are statistically significantly related to spring DWF in Beijing. Then, a seasonal prediction model of spring DWF in Beijing is established through multivariate linear regression analysis, in which the systematic error between the result of original prediction model and the observation, averaged over the last 10 years, is corrected. In addition, it is found that climate signals occurring synchronously with spring dust weather, particularly meridional wind at 850 hPa over western Mongolian Plateau, are also linked closely to spring DWF in Beijing. As such, statistical and dynamic prediction approaches should be combined to include these synchronous predictors into the prediction model in the real-time operational prediction, so as to further improve the prediction accuracy of spring DWF in Beijing, even over North China. However, realizing such a prediction idea in practice depends essentially on the ability of climate models in predicting key climate signals associated with spring DWF in Beijing.
