Background:This study was conducted to evaluate the feed nutritional value of brewers’spent grain(BSG)residue resulting from protease aided protein removal.The nutritional value was measured as nutrient content,gas p...Background:This study was conducted to evaluate the feed nutritional value of brewers’spent grain(BSG)residue resulting from protease aided protein removal.The nutritional value was measured as nutrient content,gas production,nutrient digestibility and fermentation characteristics in batch culture.Results:Protein extraction process decreased content of crude protein but concentrated the neutral detergent fibre(NDF)and ferulic acid in BSG residue.The changes in the chemical composition of BSG residue varied with enzyme and enzyme dosage.Digestibility of dry matter(DMD)and NDF of residue differed among proteases.Increasing alcalase dosage linearly decreased DMD,whereas,the DMD linearly increased as everlase or flavourzyme dosage increased.Compared with BSG,the DMD,gas production and fermentation acid concentration of BSG residues were lower,whereas NDF digestibility was higher.Conclusions:The substantially increased NDF content and improved in vitro NDF digestibility due to protease hydrolysis suggest that BSG residue can be potentially exploited as a viable fibre source for ruminant feeding.展开更多
The properties of extracellular cellulase obtained from Bacillus species (FIIRO Strain B223) on supplying cellulose from Brewers Spent Grain (BSG) were studied. Generally, a crude cellulase activity between 11,757 Uni...The properties of extracellular cellulase obtained from Bacillus species (FIIRO Strain B223) on supplying cellulose from Brewers Spent Grain (BSG) were studied. Generally, a crude cellulase activity between 11,757 Units to 13,930 Units was observed for both sources of carbon (BSG and crystalline cellulose). The optimum pH and temperature of 5.0, and 30°C - 40°C for both sources of carbon was observed. Heavy metals such as copper, zinc, and iron inhibited the activities of B223 cellulase while the cellulase activities on alkaline earth metal (manganese) were moderate. The co-factor behaviour of manganese ion was also established. Local production of cellulase in Nigeria using local raw materials such as Brewers Spent Grain reduces enzyme cost;cost of finished products and increases gross domestic products.展开更多
Dairy production plays an integral part in supporting smallholder farmers’ livelihoods. The desire to increase the number of dairy cattle is not feasible due to the reduced output of feed resources occasioned by clim...Dairy production plays an integral part in supporting smallholder farmers’ livelihoods. The desire to increase the number of dairy cattle is not feasible due to the reduced output of feed resources occasioned by climate change. Consequently, the need to increase productivity per cow is inevitable. Conventional protein supplements are costly;hence, the need to explore affordable nutrientdense alternative feed resources. Liquid brewers’ yeast (LBY), a by-product of the brewing industry, is a rich protein supplement in dairy production. This study aimed to assess the dairy farming conditions and utilization levels of LBY as a feed supplement in Githunguri Sub-county, Kiambu. Semi-structured questionnaires were administered to 457 dairy farmers in a cross-sectional survey. The findings revealed that most farmers (94.2%) fed their cattle on established forage/fodder and crop residues with supplementation. Even though 53.1% of the respondents were aware of the use of LBY, only 30.6% utilized it to supplement dairy cows, most of whom (96.0%) used it fresh without preservation. Membership in farmers’ organizations increased awareness of LBY (r = 0.732). Principal component analysis indicated that the benefits of using LBY outweigh the challenges involved with a loading matrix of 0.891 - 0.954 and 0.681 - 0.807, respectively. The low adoption and use levels of LBY as a source of protein supplements were due to low awareness. There is a need for concerted efforts by stakeholders in the industry to increase farmers’ knowledge base on the utilization and effectiveness of LBY in dairy production.展开更多
Using probiotics as animal feed additives instead of antibiotics is gaining momentum to avert adverse negative effects on human health. Liquid brewers yeast (LBY) is an industrial by-product containing probiotic micro...Using probiotics as animal feed additives instead of antibiotics is gaining momentum to avert adverse negative effects on human health. Liquid brewers yeast (LBY) is an industrial by-product containing probiotic microorganisms and is also used as a protein supplement for dairy animals. Nevertheless, value chain actors lack of appropriate handling practices compromises the by-products quality and safety. This study aimed to determine the effect of variation in temperature on microbial diversity and probiotic effects during the storage time of LBY sampled from distributors and farmers from Githunguri sub-county of Kenya. The samples were stored at 20C, 25C and 30C, then tested on 0, 5, 10, 15 and 20 days. The studys parameters involved determining the pH levels, lactic acid bacteria (LAB), total coliform count (TCC), mould, and yeast in LBY. The rate (k) of the reaction kinetics model was used to extrapolate the expected probiotic shelf life. The LAB and yeast populations were reduced in a first-order reaction at all storage temperatures. The rate of reduction in the numbers of LAB reduced with an increase in temperature (k = 0.019 and 0.023) at 20C and 30C, respectively. Yeasts highest rate of growth reduction was 25C (k = 0.009) and least at 30C (k = 0.043). The minimum effective concentration for probiotics of 106 CFU/mL needed to observe the beneficial physiological impact on farm animals was achieved between 34.9 and 35.5 days at the tested storage temperatures. The study provides insight into the unexploited low-cost probiotic potential of LBY in dairy production. Conversely, handling practices and environmental microbial contamination along the value chain can compromise product quality and safety. There is a need to advocate its use in dairy for improved productivity and sensitize farmers to appropriate hygienic measures along the LBY value chain.展开更多
Purpose： To extract protein, decrease the cellulose and facilitate the digestion and absorption of brewers＇ spent grain by animal. Topic： Discuss and optimize the hydrolysis conditions of the combined enzymatic hyd...Purpose： To extract protein, decrease the cellulose and facilitate the digestion and absorption of brewers＇ spent grain by animal. Topic： Discuss and optimize the hydrolysis conditions of the combined enzymatic hydrolysis by Novozymes. Method： The fresh brewers＇ spent grain was firstly dried, smashed and sifted. Then as indicators of the protein extraction rate in the enzyme solution and the content of cellulose in the index, the parameters of enzymatic hydrolysis, such as the solid-liquid ratio, reaction temperature, pH, enzyme dosage and reaction time, were investigated in detailed. After hydrolysis, the brewers＇ spent grain was put in the boiling water bath for inactivation for 15 minutes, and centrifuged, the supernatants were volume to 100 mL and the protein content was measured. After the precipitate was dried, the cellulose content was also measured. Achievements： The optimized conditions were with temperature of 50 ℃, pH 6.5, enzyme amount of 30 mg for Novozymes enzyme and 2.5 h for reaction time. Under these conditions, the protein extraction rate in the enzyme reaction reached 41.82%, and the cellulose content reached 13.90%, the degradation rate of cellulose was 18.86%.展开更多
About 39 million tons of Brewer’s spent grain(BSG),the main by-product of beer manufacturing,are produced annually and is used for low value applications.To valorise this rich bioresource,the present work entails bio...About 39 million tons of Brewer’s spent grain(BSG),the main by-product of beer manufacturing,are produced annually and is used for low value applications.To valorise this rich bioresource,the present work entails bioprocessing of BSG with various proteases(Novozymes)at two different concentrations(4%and 9%)to solubilise protein,carbohydrate and polyphenols from the grain and evaluate its effect on gut and brain health.The results show the highest(p<0.05)FRAP(Ferric Reducing Antioxidant Power)based antioxidant activity was obtained for Pro 5(4%:108.10±4.17μmole Trolox Equivalence(TE)/g protein,18.06±0.70μmole TE/g d.w.,which was 3.6 times higher than untreated control extracts.The highest DPPH(1,1-diphenyl-2-picrylhydrazyl)scavenging activity was obtained for the same extract(Pro 5 at 4%:0.118±0.006μg AAE/mg d.w.,9%:0.110±0.006μg AAE/mg d.w).Proximate composition showed this extract to contain the highest concentration of proteins at 21.66%±2.71,and color analysis showed the same Pro 5(4%)extract to be the darkest(L*53.73)indicating the possible presence of dark polyphenols.Anticancer screening showed Control and Pro 1 to possess cytotoxic effect against colon cancer cells with IC_(50)of 3.2 and 13.91 mg/mL,respectively.No significant activity was noted against the brain cancer cell line.Thus anti-colon cancer activity of BSG extracts highlights its potential in gut health.The observed bioactivity resulted from a combination of peptides,carbohydrates and polyphenolic compounds in the extract and warrants further characterisation for targeted nutraceutical applications.展开更多
In this study,we utilized gene knockout and overexpression techniques to generate brewer's yeast strains with either a deletion or overexpression of the fatty acyl-CoA oxidase(POX1)gene.The strains studied include...In this study,we utilized gene knockout and overexpression techniques to generate brewer's yeast strains with either a deletion or overexpression of the fatty acyl-CoA oxidase(POX1)gene.The strains studied included the parental strain,the POX1 deletion strain,and the POX1 overexpression strain.These strains were exposed to iso-αacid from hops at a concentration of 300 mg/L,leading to the induction of a viable but nonculturable(VBNC)state.Our results indicated that the silencing of the POX1 gene rendered brewer's yeast cells unable to withstand the high concentration of iso-αacid stress,ultimately leading to cell death.Conversely,the overexpression of POX1 accelerated the transition of yeast cells into the VBNC state compared to the parental strain.Furthermore,we evaluated the levels of reactive oxygen species(ROS),catalase(CAT)activity,superoxide dismutase(SOD)activity,glutathione reductase(GR)activity,and the m RNA expression of genes that regulate these enzymes(the stress-inducible yeast Mpv17(SYM1)gene,CTA1,SOD1,and glutathione reductase(GLR1)gene)in brewer's yeast cells at three distinct stages:normal,short-term stress,and VBNC states.Based on these findings,it can be inferred that the formation of the VBNC state in brewer's yeast is associated with the response to oxidative stress.展开更多
Protein baitsprays were produced from many different sources for the controlling fruit flies in the integrated pest management program around the world.Here,fruit fly baits were formulated based on cost-effective bait...Protein baitsprays were produced from many different sources for the controlling fruit flies in the integrated pest management program around the world.Here,fruit fly baits were formulated based on cost-effective bait mixtures such as local jaggery,brewers spent grain(BSG),apple cider vinegar,wheat bran powder and local red wine with the fresh enzyme from papaya and pineapple.Fruit fly Baits were prepared by mixing the small amount of local detergent as insecticide.Our results indicated that the best efficient fruit fly bait for area wide integrated pest management(AW-IPM)is the BSG-based bait whereas the second efficient bait is local red wine-based bait.The highest fruit fly per trap per day(FTD)value by BSG-based bait traps was discovered.The highest female captured percentage is BSG-based bait with papaya solution.The field analysis of one week and one month old protein-based bait showed that FTD values decreased slightly while only one month old wheat bran-based bait dropped to the base.The BSG-based baits analysis is effective not only female fruit flies but also cockroaches male in Myanmar’s tropical region.Thus our results reveal that the efficient protein-based bait is the fresh BSG-based bait with papaya solution.展开更多
滋养细胞疾病自400BC Hippocrates发现“dropsy of the uterus”和1700年Smellie首次涉及“hydatid and mole”以来,至1895年Marchand阐明其来源与恶性可能,嗣后Fels,Ernhart,Reossler与Zondek等发现患者尿中促性腺激素水平显著增多,用...滋养细胞疾病自400BC Hippocrates发现“dropsy of the uterus”和1700年Smellie首次涉及“hydatid and mole”以来,至1895年Marchand阐明其来源与恶性可能,嗣后Fels,Ernhart,Reossler与Zondek等发现患者尿中促性腺激素水平显著增多,用作诊断,以及近50年来,Hertz, Ross,Lipsett,Delfs, Odell,Vaitukaitus,Hertig, Sheldon, Gore, Brewer,Park,Bagshawe, Acosta-Sison,Goldstein。展开更多
Time series of daily UV radiation measured by the ground-based Brewer spectrophotometer #115 in Hong Kong during 1995-2005 were studied through statistics analysis, with focus on the variability and long term changes ...Time series of daily UV radiation measured by the ground-based Brewer spectrophotometer #115 in Hong Kong during 1995-2005 were studied through statistics analysis, with focus on the variability and long term changes in relation to total ozone, clouds and AOD (Aerosol Optical Depth). The 11-year mean UV daily dose is 2644±262 J/m2, with maxima(3311 J/m2) in 2000 and minima (2415 J/m2) in 2002. The data were compared with that from TOMS (Total Ozone Mapping Spectrometer) Version 8 and show general agreement between the two. However, the Brewer UV measurement is about 10% lower compared to TOMS data. Apart from the common-known strong seasonal cycle, 26 month periodical was resolved by use of wavelet analysis, which was believed to be associated with quasi-biennial oscillation (QBO) of general circulation. In cloudy days, the annual mean UV daily dose decrease 3.5% to 44.5% compared to clear days. It was also found that surface UV irradiance has close relation to air pollution. Under clear sky condition, 1% AOD increase will lead to 0.2% UV decrease. While global UV radiation increase due to the worldwide observed ozone depletion, investigations indicate that this trend is not significant in Hong Kong during the last 11 years. The possible causes can be attributed to the compensative effect from two aspects. One is the increase of UV resulting from the reduction of clouds with rate of 0.56/10 yr. The other is the decrease of UV due to the enhancement of total ozone and AOD with a rate of 4.23 DU/10 yr and 0.33/10 yr, respectively.展开更多
As the strongest subseasonal atmospheric variability during boreal winter, three remarkable sudden stratospheric major warming(SSW) events in the 2000 s are investigated in terms of the Brewer–Dobson circulation(BDC)...As the strongest subseasonal atmospheric variability during boreal winter, three remarkable sudden stratospheric major warming(SSW) events in the 2000 s are investigated in terms of the Brewer–Dobson circulation(BDC) response. Our study shows that the changes of cross-isentropic velocity during the SSWs are not only confined to the polar region, but also extend to the whole Northern Hemisphere: enhanced descent in the polar region, as well as enhanced ascent in the tropics. When the acceleration of the deep branch of the BDC descends to the middle stratosphere, its strength rapidly decreases over a period of one to two weeks. The acceleration of the deep branch of the BDC is driven by the enhanced planetary wave activity in the mid-to-high-latitude stratosphere. Different from the rapid response of the deep branch of the BDC, tropical upwelling in the lower stratosphere accelerates up to 20%–40% compared with the climatology, 20–30 days after the onset of the SSWs,and the acceleration lasts for one to three months. The enhancement of tropical upwelling is associated with the large-scale wave-breaking in the subtropics interacting with the midlatitude and tropical Quasi-Biennial Oscillation–related mean flow.展开更多
基金funded by AAFC Growing forward program(GF2#1542).
文摘Background:This study was conducted to evaluate the feed nutritional value of brewers’spent grain(BSG)residue resulting from protease aided protein removal.The nutritional value was measured as nutrient content,gas production,nutrient digestibility and fermentation characteristics in batch culture.Results:Protein extraction process decreased content of crude protein but concentrated the neutral detergent fibre(NDF)and ferulic acid in BSG residue.The changes in the chemical composition of BSG residue varied with enzyme and enzyme dosage.Digestibility of dry matter(DMD)and NDF of residue differed among proteases.Increasing alcalase dosage linearly decreased DMD,whereas,the DMD linearly increased as everlase or flavourzyme dosage increased.Compared with BSG,the DMD,gas production and fermentation acid concentration of BSG residues were lower,whereas NDF digestibility was higher.Conclusions:The substantially increased NDF content and improved in vitro NDF digestibility due to protease hydrolysis suggest that BSG residue can be potentially exploited as a viable fibre source for ruminant feeding.
文摘The properties of extracellular cellulase obtained from Bacillus species (FIIRO Strain B223) on supplying cellulose from Brewers Spent Grain (BSG) were studied. Generally, a crude cellulase activity between 11,757 Units to 13,930 Units was observed for both sources of carbon (BSG and crystalline cellulose). The optimum pH and temperature of 5.0, and 30°C - 40°C for both sources of carbon was observed. Heavy metals such as copper, zinc, and iron inhibited the activities of B223 cellulase while the cellulase activities on alkaline earth metal (manganese) were moderate. The co-factor behaviour of manganese ion was also established. Local production of cellulase in Nigeria using local raw materials such as Brewers Spent Grain reduces enzyme cost;cost of finished products and increases gross domestic products.
文摘Dairy production plays an integral part in supporting smallholder farmers’ livelihoods. The desire to increase the number of dairy cattle is not feasible due to the reduced output of feed resources occasioned by climate change. Consequently, the need to increase productivity per cow is inevitable. Conventional protein supplements are costly;hence, the need to explore affordable nutrientdense alternative feed resources. Liquid brewers’ yeast (LBY), a by-product of the brewing industry, is a rich protein supplement in dairy production. This study aimed to assess the dairy farming conditions and utilization levels of LBY as a feed supplement in Githunguri Sub-county, Kiambu. Semi-structured questionnaires were administered to 457 dairy farmers in a cross-sectional survey. The findings revealed that most farmers (94.2%) fed their cattle on established forage/fodder and crop residues with supplementation. Even though 53.1% of the respondents were aware of the use of LBY, only 30.6% utilized it to supplement dairy cows, most of whom (96.0%) used it fresh without preservation. Membership in farmers’ organizations increased awareness of LBY (r = 0.732). Principal component analysis indicated that the benefits of using LBY outweigh the challenges involved with a loading matrix of 0.891 - 0.954 and 0.681 - 0.807, respectively. The low adoption and use levels of LBY as a source of protein supplements were due to low awareness. There is a need for concerted efforts by stakeholders in the industry to increase farmers’ knowledge base on the utilization and effectiveness of LBY in dairy production.
文摘Using probiotics as animal feed additives instead of antibiotics is gaining momentum to avert adverse negative effects on human health. Liquid brewers yeast (LBY) is an industrial by-product containing probiotic microorganisms and is also used as a protein supplement for dairy animals. Nevertheless, value chain actors lack of appropriate handling practices compromises the by-products quality and safety. This study aimed to determine the effect of variation in temperature on microbial diversity and probiotic effects during the storage time of LBY sampled from distributors and farmers from Githunguri sub-county of Kenya. The samples were stored at 20C, 25C and 30C, then tested on 0, 5, 10, 15 and 20 days. The studys parameters involved determining the pH levels, lactic acid bacteria (LAB), total coliform count (TCC), mould, and yeast in LBY. The rate (k) of the reaction kinetics model was used to extrapolate the expected probiotic shelf life. The LAB and yeast populations were reduced in a first-order reaction at all storage temperatures. The rate of reduction in the numbers of LAB reduced with an increase in temperature (k = 0.019 and 0.023) at 20C and 30C, respectively. Yeasts highest rate of growth reduction was 25C (k = 0.009) and least at 30C (k = 0.043). The minimum effective concentration for probiotics of 106 CFU/mL needed to observe the beneficial physiological impact on farm animals was achieved between 34.9 and 35.5 days at the tested storage temperatures. The study provides insight into the unexploited low-cost probiotic potential of LBY in dairy production. Conversely, handling practices and environmental microbial contamination along the value chain can compromise product quality and safety. There is a need to advocate its use in dairy for improved productivity and sensitize farmers to appropriate hygienic measures along the LBY value chain.
文摘Purpose： To extract protein, decrease the cellulose and facilitate the digestion and absorption of brewers＇ spent grain by animal. Topic： Discuss and optimize the hydrolysis conditions of the combined enzymatic hydrolysis by Novozymes. Method： The fresh brewers＇ spent grain was firstly dried, smashed and sifted. Then as indicators of the protein extraction rate in the enzyme solution and the content of cellulose in the index, the parameters of enzymatic hydrolysis, such as the solid-liquid ratio, reaction temperature, pH, enzyme dosage and reaction time, were investigated in detailed. After hydrolysis, the brewers＇ spent grain was put in the boiling water bath for inactivation for 15 minutes, and centrifuged, the supernatants were volume to 100 mL and the protein content was measured. After the precipitate was dried, the cellulose content was also measured. Achievements： The optimized conditions were with temperature of 50 ℃, pH 6.5, enzyme amount of 30 mg for Novozymes enzyme and 2.5 h for reaction time. Under these conditions, the protein extraction rate in the enzyme reaction reached 41.82%, and the cellulose content reached 13.90%, the degradation rate of cellulose was 18.86%.
文摘About 39 million tons of Brewer’s spent grain(BSG),the main by-product of beer manufacturing,are produced annually and is used for low value applications.To valorise this rich bioresource,the present work entails bioprocessing of BSG with various proteases(Novozymes)at two different concentrations(4%and 9%)to solubilise protein,carbohydrate and polyphenols from the grain and evaluate its effect on gut and brain health.The results show the highest(p<0.05)FRAP(Ferric Reducing Antioxidant Power)based antioxidant activity was obtained for Pro 5(4%:108.10±4.17μmole Trolox Equivalence(TE)/g protein,18.06±0.70μmole TE/g d.w.,which was 3.6 times higher than untreated control extracts.The highest DPPH(1,1-diphenyl-2-picrylhydrazyl)scavenging activity was obtained for the same extract(Pro 5 at 4%:0.118±0.006μg AAE/mg d.w.,9%:0.110±0.006μg AAE/mg d.w).Proximate composition showed this extract to contain the highest concentration of proteins at 21.66%±2.71,and color analysis showed the same Pro 5(4%)extract to be the darkest(L*53.73)indicating the possible presence of dark polyphenols.Anticancer screening showed Control and Pro 1 to possess cytotoxic effect against colon cancer cells with IC_(50)of 3.2 and 13.91 mg/mL,respectively.No significant activity was noted against the brain cancer cell line.Thus anti-colon cancer activity of BSG extracts highlights its potential in gut health.The observed bioactivity resulted from a combination of peptides,carbohydrates and polyphenolic compounds in the extract and warrants further characterisation for targeted nutraceutical applications.
基金funded by National Natural Science Foundation of China(32272279)the Key R&D project of Shandong Province(2023CXPT007)the Key R&D project of Qingdao Science and Technology Plan(22-3-3-hygg-29-hy)。
文摘In this study,we utilized gene knockout and overexpression techniques to generate brewer's yeast strains with either a deletion or overexpression of the fatty acyl-CoA oxidase(POX1)gene.The strains studied included the parental strain,the POX1 deletion strain,and the POX1 overexpression strain.These strains were exposed to iso-αacid from hops at a concentration of 300 mg/L,leading to the induction of a viable but nonculturable(VBNC)state.Our results indicated that the silencing of the POX1 gene rendered brewer's yeast cells unable to withstand the high concentration of iso-αacid stress,ultimately leading to cell death.Conversely,the overexpression of POX1 accelerated the transition of yeast cells into the VBNC state compared to the parental strain.Furthermore,we evaluated the levels of reactive oxygen species(ROS),catalase(CAT)activity,superoxide dismutase(SOD)activity,glutathione reductase(GR)activity,and the m RNA expression of genes that regulate these enzymes(the stress-inducible yeast Mpv17(SYM1)gene,CTA1,SOD1,and glutathione reductase(GLR1)gene)in brewer's yeast cells at three distinct stages:normal,short-term stress,and VBNC states.Based on these findings,it can be inferred that the formation of the VBNC state in brewer's yeast is associated with the response to oxidative stress.
文摘Protein baitsprays were produced from many different sources for the controlling fruit flies in the integrated pest management program around the world.Here,fruit fly baits were formulated based on cost-effective bait mixtures such as local jaggery,brewers spent grain(BSG),apple cider vinegar,wheat bran powder and local red wine with the fresh enzyme from papaya and pineapple.Fruit fly Baits were prepared by mixing the small amount of local detergent as insecticide.Our results indicated that the best efficient fruit fly bait for area wide integrated pest management(AW-IPM)is the BSG-based bait whereas the second efficient bait is local red wine-based bait.The highest fruit fly per trap per day(FTD)value by BSG-based bait traps was discovered.The highest female captured percentage is BSG-based bait with papaya solution.The field analysis of one week and one month old protein-based bait showed that FTD values decreased slightly while only one month old wheat bran-based bait dropped to the base.The BSG-based baits analysis is effective not only female fruit flies but also cockroaches male in Myanmar’s tropical region.Thus our results reveal that the efficient protein-based bait is the fresh BSG-based bait with papaya solution.
文摘滋养细胞疾病自400BC Hippocrates发现“dropsy of the uterus”和1700年Smellie首次涉及“hydatid and mole”以来,至1895年Marchand阐明其来源与恶性可能,嗣后Fels,Ernhart,Reossler与Zondek等发现患者尿中促性腺激素水平显著增多,用作诊断,以及近50年来,Hertz, Ross,Lipsett,Delfs, Odell,Vaitukaitus,Hertig, Sheldon, Gore, Brewer,Park,Bagshawe, Acosta-Sison,Goldstein。
文摘Time series of daily UV radiation measured by the ground-based Brewer spectrophotometer #115 in Hong Kong during 1995-2005 were studied through statistics analysis, with focus on the variability and long term changes in relation to total ozone, clouds and AOD (Aerosol Optical Depth). The 11-year mean UV daily dose is 2644±262 J/m2, with maxima(3311 J/m2) in 2000 and minima (2415 J/m2) in 2002. The data were compared with that from TOMS (Total Ozone Mapping Spectrometer) Version 8 and show general agreement between the two. However, the Brewer UV measurement is about 10% lower compared to TOMS data. Apart from the common-known strong seasonal cycle, 26 month periodical was resolved by use of wavelet analysis, which was believed to be associated with quasi-biennial oscillation (QBO) of general circulation. In cloudy days, the annual mean UV daily dose decrease 3.5% to 44.5% compared to clear days. It was also found that surface UV irradiance has close relation to air pollution. Under clear sky condition, 1% AOD increase will lead to 0.2% UV decrease. While global UV radiation increase due to the worldwide observed ozone depletion, investigations indicate that this trend is not significant in Hong Kong during the last 11 years. The possible causes can be attributed to the compensative effect from two aspects. One is the increase of UV resulting from the reduction of clouds with rate of 0.56/10 yr. The other is the decrease of UV due to the enhancement of total ozone and AOD with a rate of 4.23 DU/10 yr and 0.33/10 yr, respectively.
文摘As the strongest subseasonal atmospheric variability during boreal winter, three remarkable sudden stratospheric major warming(SSW) events in the 2000 s are investigated in terms of the Brewer–Dobson circulation(BDC) response. Our study shows that the changes of cross-isentropic velocity during the SSWs are not only confined to the polar region, but also extend to the whole Northern Hemisphere: enhanced descent in the polar region, as well as enhanced ascent in the tropics. When the acceleration of the deep branch of the BDC descends to the middle stratosphere, its strength rapidly decreases over a period of one to two weeks. The acceleration of the deep branch of the BDC is driven by the enhanced planetary wave activity in the mid-to-high-latitude stratosphere. Different from the rapid response of the deep branch of the BDC, tropical upwelling in the lower stratosphere accelerates up to 20%–40% compared with the climatology, 20–30 days after the onset of the SSWs,and the acceleration lasts for one to three months. The enhancement of tropical upwelling is associated with the large-scale wave-breaking in the subtropics interacting with the midlatitude and tropical Quasi-Biennial Oscillation–related mean flow.
