Bunching of elementary steps by solution flow is still not yet clarified for protein crystals. Hence, in this study, we observed elementary steps on crystal surfaces of model protein hen egg-white lysozyme (HEWL) un...Bunching of elementary steps by solution flow is still not yet clarified for protein crystals. Hence, in this study, we observed elementary steps on crystal surfaces of model protein hen egg-white lysozyme (HEWL) under forced flow conditions, by our advanced optical microscopy. We found that in the case of a HEWL solution of 99.99% purity, forced flow changed bunched steps into elementary ones (debunching) on tetragonal HEWL crystals. In contrast, in the case of a HEWL solution of 98.5% purity, forced flow significantly induced bunching of elementary steps. These results indicate that in the case of HEWL crystals, the mass transfer of impurities is more significantly enhanced by forced solution flow than that of solute HEWL molecules. We also showed that forced flow induced the incorporation of microcrystals into a mother crystal and the subsequent formation of screw dislocations and spiral growth hillocks.展开更多
In order to understand the sea ice types and its region of origin frozen in Weddell Sea,27 ice cores were taken from Weddell Sea,Antarctica during September and October,2006.Their crystals were analyzed,and their ice ...In order to understand the sea ice types and its region of origin frozen in Weddell Sea,27 ice cores were taken from Weddell Sea,Antarctica during September and October,2006.Their crystals were analyzed,and their ice forming processes were evaluated based on the crystals.Photos of the thin sections from two whole ice cores,and from polygonal granular superimposed ice were taken as well as corresponding stratigraphy descriptions.Vertical profiles of salinity, density and grain size were also obtained.Based on ice core structural texture,the findings include that: 1) although large and smooth ice floes were selected as the investigation sites, the ice sheet at the sampling position may be formed by rafted ice,consolidated ice ridges and second-year ice which were affected by dynamic and thermodynamic processes together subsequently.Ice formed in pure thermal growth comprises minority.The polygonal granular superimposed ice from refrozen wetted dense snow is one type of the ice in Antarctica.2) Of the all 27 ice cores,the granular,mixed granular-columnar and columnar crystals in sea ice occupy 28.7%,14.4% and 55.2%,respectively.3) The pure thermal growth ice is predominant in marginal sea ice zone;the rafted ice and consolidated ice ridges,even second-year ice and polygonal granular superimposed ice from dynamic and thermal effects were found in front of Larsen A Ice Shelf;the thermal growth ice froze in the polynyas of Larsen A,and was transferred outwards.展开更多
A quantitative analysis of the total concentrations of Al and Na in the Antarctic ice sheet during the past 340 kyr was performed by applying the acid digestion method to the Dome Fuji ice core. Atmospheric fluxes of ...A quantitative analysis of the total concentrations of Al and Na in the Antarctic ice sheet during the past 340 kyr was performed by applying the acid digestion method to the Dome Fuji ice core. Atmospheric fluxes of mineral and sea-salt aerosol to Dome Fuji were calculated from the total concentration. The average fluxes of mineral aerosol to Dome Fuji in the periods of glacial maximum, 18.6 ± 10.1 mg·m–2·yr–1, were larger than the value in the interglacial periods, 3.77 ± 2.20 mg·m–2·yr–1. Conversely, the fluxes of sea-salt have no significant difference between the average value of glacial maximum, 130 ± 55 mg·m–2·yr–1, and that of interglacial, 111 ± 54 mg·m–2·yr–1. The results obtained in this study suggest that the variation of mineral aerosol flux in Dome Fuji, together with climate change, was much larger than that of sea-salt aerosol flux. This result may have occurred because the variety in the intensity of the source and transport during the glacial-interglacial cycle is more significant for mineral aerosol than that for sea-salt aerosol.展开更多
Surface measurements of aerosol physical properties were made at Anantapur (14.62°N, 77.65°E, 331 m a.s.l), a semiarid rural site in India, during August 2008-July 2009. Measurements included the segregate...Surface measurements of aerosol physical properties were made at Anantapur (14.62°N, 77.65°E, 331 m a.s.l), a semiarid rural site in India, during August 2008-July 2009. Measurements included the segregated sizes of aerosolsas as well as total mass concentration and size distributions of aerosols measured at low relative humidity (RH〈75%) using a Quartz Crystal Microbalance (QCM) in the 25-0.05 um aerodynamic diameter range. The hourly average total surface aerosol mass concentration in a day varied from 15 to 70 ug m-3, with a mean value of 34.02±9.05 ug m-3 for the entire study period. A clear diurnal pattern appeared in coarse, accumulation and nucleation-mode particle concentrations, with two local maxima occurring in early morning and late evening hours. The concentration of coarse-mode particles was high during the summer season, with a maximum concentration of 11.81±0.98 ug m-3 in the month of April, whereas accumulationmode concentration was observed to be high in the winter period contributed 〉68% to the total aerosol mass concentration. Accumulation aerosol mass fraction, Af (= Ma/Mt) was highest during winter (mean value of Af -0.80) and lowest (Af - 0.64) during the monsoon season. The regression analysis shows that both Reff and Rm are dependent on coarse-mode aerosols. The relationship between the simultaneous measurements of daily mean aerosol optical depth at 500 nm (AOD500) and PM2.5 mass concentration ([PM2.5]) shows that surface-level aerosol mass concentration increases with the increase in columnar aerosol optical depth over the observation period.展开更多
The role of N2 fixation in structuring plant communities and influencing ecosystem function will be potentially large. In previous study, we investigated nodule biomass and activity, and calculated the amount of N2 fi...The role of N2 fixation in structuring plant communities and influencing ecosystem function will be potentially large. In previous study, we investigated nodule biomass and activity, and calculated the amount of N2 fixation in a naturally established 18-year-old alder (Alnus hirsute (Turcz.) var. sibirica) stand following disturbance by road construction in Takayama, central Japan. In this study, to estimate the facilitation effects by alder on the spatial distribution of the regenerated tree species, we examined the distribution pattern of the regenerated tree species in this naturally established 18-year-old alder stand. The distribution pattern of alder and the regenerated woody species was analyzed in terms of spatial point processes and the regenerated species tended to distribute near the alder site. In particular, bird-dispersed tree species (endozoochory species) with relatively high shade tolerance showed a significant attraction to alder. These results suggest that alder will be used as roost trees and play the role of mother trees for these regenerated species at the degraded site. It was also suggested that the endozoochory species, which occupy 13 of 26 regenerated species in this stand, might regenerate faster than other species at this alder stand.展开更多
We measured the spatial variability of Cl -, Na +, SO 2- 4, NO - 3 and 7Be concentrations in snow cover along the traverse route from S16 to Dome Fuji station in east Dronning Maud Land, Antarctica. T...We measured the spatial variability of Cl -, Na +, SO 2- 4, NO - 3 and 7Be concentrations in snow cover along the traverse route from S16 to Dome Fuji station in east Dronning Maud Land, Antarctica. The concentrations of Cl - and Na + at the coast exponentially decreased with distance from the coast up to 200 km inland. Between 200 1000 km inland, the concentrations of Na + were nearly constant. On the other hand, the concentrations of Cl - increased with distance beyond 750 km inland. Furthermore, the contribution factors between Cl - and Na + decreased and the Cl -/Na + ratio and the nssCl -/Cl - ratio increased toward the interior of the continent. These results indicate that sea salt aerosols are transported from the coastal region toward the inland region of the Antarctic continent, and that a source of Cl - other than sea salt exists in the inland plateau of Antarctica. The concentrations of SO 2- 4, NO - 3 and 7Be in snow were relatively high in the coastal region and the inland plateau region compared with those in the katabatic wind region.展开更多
A field work was conducted at Moshiri in Japan. The work included intensive snow pit work, taking snow grain photos, recording snow and air temperatures, as well as measuring snow water content. By treating the snow a...A field work was conducted at Moshiri in Japan. The work included intensive snow pit work, taking snow grain photos, recording snow and air temperatures, as well as measuring snow water content. By treating the snow as a viscous fluid, it is found that the snow compactive viscosity decreases as the density increases, which is opposite to the relation for dry snow. Based on the measurements of snow grain size, it is shown that, similar to the watersaturated snow, the frequency distributions of grain size at different times almost have the same shape. This reveals that the waterunsaturated melting snow holds the same graincoarsening behavior as the watersaturated snow does. It is also shown that the waterunsaturated melting snow coarsens much more slowly than the watersaturated snow. The C value, which is the viscosity when the snow density is zero, is related to the mean grain size and found to decrease with increasing grain size. The decreasing rate of C value increases with decreasing graincoarsening rate.展开更多
This study examines the relationship between the subtropical high in the West Pacific and the Okhotsk high in summer, and explains why the subtropical high cannot progress northward when the Okhotsk high is active. Th...This study examines the relationship between the subtropical high in the West Pacific and the Okhotsk high in summer, and explains why the subtropical high cannot progress northward when the Okhotsk high is active. The findings are as follows. (1) A teleconnection pattern, namely, the significant correlation dipole between the index of the Okhotsk high and 500 hPa geopotential height (Z500), over East Asia, tends to occur in summer. (2) The teleconnection is closely related to the wave train propagation from the Okhotsk Sea via Japan to the subtropical regions when the Okhotsk high is developing. (3) The wave train propagation associated with the development of the Okhotsk high can generate a large cyclonic anomaly over the sea east of Japan, even in late summer. The cyclonic anomaly plays an important role in weakening the northern part of the subtropical high. The anomalous southern position of the main body of the subtropical high in the summer of 1998 is partly due to this effect.展开更多
Recently, the light-absorbing organic carbon, i.e., brown carbon(Br C), has received an increasing attention, because they could significantly absorb the solar radiation in the range of short wavelengths rather than t...Recently, the light-absorbing organic carbon, i.e., brown carbon(Br C), has received an increasing attention, because they could significantly absorb the solar radiation in the range of short wavelengths rather than the purely scattering effect. Br C is ubiquitous in the troposphere. It could undergo long range transport within the atmospheric circulation. After the deposition on the surface of snow or ice in the cryospheric region, as the major light absorbing impurities with black carbon and dust, Br C could reduce the snow albedo and accelerate the glacier melting. In this context, this paper summarized the current knowledge of Br C(in aerosols and snow) in the cryospheric regions including the Arctic, Antarctic,and Alpines. Although some works have been conducted in those region, the current dataset on the optical properties of Br C like Absorption?ngstr€om Exponent(AAE) and Mass Absorption Efficiency(MAE) is still limited, which hampers stimulating an accurate evaluation of its climate effects. Especially in the Himalayas and Tibetan Plateau, where very limited information concerning Br C is available. Considering biomass burning as a dominant source of Br C, a large amount of emissions from biomass burning in South Asia could reach the Himalayas and Tibetan Plateau, where the climate effect of Br C merits more investigation in the future.展开更多
In order to understand the relative importance of anthropogenic and biological sources of carbonaceous aerosols in Northeast Asia,we measured total carbon(TC)and water-soluble organic carbon(WSOC)and their stable carb...In order to understand the relative importance of anthropogenic and biological sources of carbonaceous aerosols in Northeast Asia,we measured total carbon(TC)and water-soluble organic carbon(WSOC)and their stable carbon isotope ratios(d^(13)C)in total suspended particulates collected from Sapporo,northern Japan(43.07°N,141.36°E)over a 1-year period(during 2 September 2009and 5 October 2010).Temporal variations of TC showed a gradual decrease from mid-autumn to winter followed by a gradual increase to growing season with a peak in early summer.Both d^(13)C_(TC)and d^(13)C_(WSOC)showed very similar temporal trends with a gradual enrichment of^(13)C from mid-autumn to winter followed by a depletion in the^(13)C to early summer and thereafter it remained stable,except for few cases.Based on the results obtained together with the air mass trajectories,we found that biogenic emissions including biological particles(e.g.,pollen)and secondary organic aerosol formation from biogenic volatile organic compounds are the important sources of carbonaceous aerosols in spring/summer whereas fungal spores from soil and biomass burning and enhanced fossil fuel combustion contribute significantly in autumn/winter and in winter,respectively,in Northeast Asia.展开更多
This study has reviewed recent studies about impact of the Rossby wave propagation on the weather of East Asia.Then,we have focused on the northward progression of the subtropical high affected by the propagations and...This study has reviewed recent studies about impact of the Rossby wave propagation on the weather of East Asia.Then,we have focused on the northward progression of the subtropical high affected by the propagations and their interaction.The following results are obtained:(1)The two kinds of meridional Rossby wave propagations often affect the East Asian weather in summer, which propagate in two conflicting directions(northwest-southeastward and southwest-northeast- ward).This is considered as the interaction of the large-scale systems between high and low latitudes with wave propagation,especially to the circulation systems around East Asia.(2)The northward progression of the subtropical high is largely restrained,aecompanied by the southward shift of the convective activity in middle latitudes,under the strong and persistent Rossby wave propagation from high to low latitudes.And the opposite role could be found in the Rossby wave propagation from low to high latitudes.展开更多
A 211 m depth ice core observation was carried out at the top of the Vestfonna Ice Cap in Nordaustlandet, Svalbard, Norway in 1995. Chronology of the ice core was determined by tritium analysis and comparison to the v...A 211 m depth ice core observation was carried out at the top of the Vestfonna Ice Cap in Nordaustlandet, Svalbard, Norway in 1995. Chronology of the ice core was determined by tritium analysis and comparison to the volcanic eruption of Laki; the resulting accumulation rate is 0.34 0.35 m water eq.·yr -1 for the last 400 year. Concentrations of Al, V, Cr, Fe, Cu, Zn, As, Ag, Cd, Pb and U in an ice core have been determined by an inductively coupled plasma mass spectrometry (ICP MS) with a desolvated micro concentric nebulizer, which is a recent development and can achieve high sensitivity with low uptake rate of 60 mL/min. The concentrations of Pb, Cu, and Zn had increased from 1940s declined from 1970s to present. However, the profiles of Pb, Cu, and Zn were different and they seem to be influenced by the difference of sources. Since the ratios between Cu, Pb, and Zn in Svalbard is similar to that in French Alps, the source area of these elements is estimated to be Europe.展开更多
The tolerance to temperature increase was tested for Halobates individuals collected during two cruises in the western tropical Pacific Ocean (MR-06-05-Leg 3, December 21, 2006-January 12, 2007, 0°N-8°N; KH...The tolerance to temperature increase was tested for Halobates individuals collected during two cruises in the western tropical Pacific Ocean (MR-06-05-Leg 3, December 21, 2006-January 12, 2007, 0°N-8°N; KH-06-02-Leg 5, August 18-31, 2006, 12°N-17°N). High temperature coma experiments were conducted on adults and 5th instar larvae. On average, H. sericeus (distributed in the wide latitude zone of 5°N-40°N), H. germanus (distributed in the moderate latitude zone of 0°N-35°N) and H. micans (distributed mainly in the lower latitudes around the equator) were on average paralyzed at 35.6℃(SD: 0.89), 32.9℃ (SD: 2.17) and 31.6℃ (SD: 2.60), respectively (P = 0.035). According to the current dynamics during the cruise, the colony ofH. sericeus at one station (5°N 137°E) may have been transferred from the northern area of 14°N by three currents (North Equatorial Current, Mindanao Current and North Equatorial Counter Current) to the area of 5°N 138°E. Extremely high heat resistance was shown by the adults of H. germanus in the sea area around the equator. Dynamic current and air movements in this area around the equator, that is a "warm seawater pool", could be hypothesized to be related to the high resistance to heat shown in this study.展开更多
This study examined the relationship between mature phase of the cold event in 1999 and the East Asian summer atmosphere circulation in 2000.The cold event reaches its mature phase in the autumn and winter of 1999,whi...This study examined the relationship between mature phase of the cold event in 1999 and the East Asian summer atmosphere circulation in 2000.The cold event reaches its mature phase in the autumn and winter of 1999,which is the strongest La Nina episode in recent 11 years.There is a clear anomalous pattern of the atmosphere circulation around East Asia in the summer of 2000, i.e.the negative anomaly centers around the Cherski Mountains and 20°N,170°E at 500 hPa,the main body of the subtropical high keeps in further northern position than usual and the negative anomaly of precipitation located in southern central China.This pattern is thought as the response to the preceding strong cold event in autumn of 1999.It is also identified that the response of the East Asian atmosphere circulation in summer of 2000 to the strong La Nina event in 1999 belongs to the top rank in recent 43 years.On the other hand,the inactive blocking anticyclone around East Asia in summer of 2000 is associated with the positive SST anomaly and the 850 hPa temperature anomaly around the Bering Sea simultaneously.Nevertheless,although the impact on the summer atmosphere circulation around East Asia from La Nina events could not rank with that from E1 Nino,the impact could not be neglected especially in a strong La Nina case.展开更多
基金Chinese Academy of Sciences visiting professorship for senior international scientists(2013T2J0060)
文摘Bunching of elementary steps by solution flow is still not yet clarified for protein crystals. Hence, in this study, we observed elementary steps on crystal surfaces of model protein hen egg-white lysozyme (HEWL) under forced flow conditions, by our advanced optical microscopy. We found that in the case of a HEWL solution of 99.99% purity, forced flow changed bunched steps into elementary ones (debunching) on tetragonal HEWL crystals. In contrast, in the case of a HEWL solution of 98.5% purity, forced flow significantly induced bunching of elementary steps. These results indicate that in the case of HEWL crystals, the mass transfer of impurities is more significantly enhanced by forced solution flow than that of solute HEWL molecules. We also showed that forced flow induced the incorporation of microcrystals into a mother crystal and the subsequent formation of screw dislocations and spiral growth hillocks.
基金supported by National Nature Science Foundation of China(Grant No.40676001)National Key Technology R and D Program(2006BAB18B03)supported by National Nature Science Foundation of China(Grant No.50879008)
文摘In order to understand the sea ice types and its region of origin frozen in Weddell Sea,27 ice cores were taken from Weddell Sea,Antarctica during September and October,2006.Their crystals were analyzed,and their ice forming processes were evaluated based on the crystals.Photos of the thin sections from two whole ice cores,and from polygonal granular superimposed ice were taken as well as corresponding stratigraphy descriptions.Vertical profiles of salinity, density and grain size were also obtained.Based on ice core structural texture,the findings include that: 1) although large and smooth ice floes were selected as the investigation sites, the ice sheet at the sampling position may be formed by rafted ice,consolidated ice ridges and second-year ice which were affected by dynamic and thermodynamic processes together subsequently.Ice formed in pure thermal growth comprises minority.The polygonal granular superimposed ice from refrozen wetted dense snow is one type of the ice in Antarctica.2) Of the all 27 ice cores,the granular,mixed granular-columnar and columnar crystals in sea ice occupy 28.7%,14.4% and 55.2%,respectively.3) The pure thermal growth ice is predominant in marginal sea ice zone;the rafted ice and consolidated ice ridges,even second-year ice and polygonal granular superimposed ice from dynamic and thermal effects were found in front of Larsen A Ice Shelf;the thermal growth ice froze in the polynyas of Larsen A,and was transferred outwards.
文摘A quantitative analysis of the total concentrations of Al and Na in the Antarctic ice sheet during the past 340 kyr was performed by applying the acid digestion method to the Dome Fuji ice core. Atmospheric fluxes of mineral and sea-salt aerosol to Dome Fuji were calculated from the total concentration. The average fluxes of mineral aerosol to Dome Fuji in the periods of glacial maximum, 18.6 ± 10.1 mg·m–2·yr–1, were larger than the value in the interglacial periods, 3.77 ± 2.20 mg·m–2·yr–1. Conversely, the fluxes of sea-salt have no significant difference between the average value of glacial maximum, 130 ± 55 mg·m–2·yr–1, and that of interglacial, 111 ± 54 mg·m–2·yr–1. The results obtained in this study suggest that the variation of mineral aerosol flux in Dome Fuji, together with climate change, was much larger than that of sea-salt aerosol flux. This result may have occurred because the variety in the intensity of the source and transport during the glacial-interglacial cycle is more significant for mineral aerosol than that for sea-salt aerosol.
文摘Surface measurements of aerosol physical properties were made at Anantapur (14.62°N, 77.65°E, 331 m a.s.l), a semiarid rural site in India, during August 2008-July 2009. Measurements included the segregated sizes of aerosolsas as well as total mass concentration and size distributions of aerosols measured at low relative humidity (RH〈75%) using a Quartz Crystal Microbalance (QCM) in the 25-0.05 um aerodynamic diameter range. The hourly average total surface aerosol mass concentration in a day varied from 15 to 70 ug m-3, with a mean value of 34.02±9.05 ug m-3 for the entire study period. A clear diurnal pattern appeared in coarse, accumulation and nucleation-mode particle concentrations, with two local maxima occurring in early morning and late evening hours. The concentration of coarse-mode particles was high during the summer season, with a maximum concentration of 11.81±0.98 ug m-3 in the month of April, whereas accumulationmode concentration was observed to be high in the winter period contributed 〉68% to the total aerosol mass concentration. Accumulation aerosol mass fraction, Af (= Ma/Mt) was highest during winter (mean value of Af -0.80) and lowest (Af - 0.64) during the monsoon season. The regression analysis shows that both Reff and Rm are dependent on coarse-mode aerosols. The relationship between the simultaneous measurements of daily mean aerosol optical depth at 500 nm (AOD500) and PM2.5 mass concentration ([PM2.5]) shows that surface-level aerosol mass concentration increases with the increase in columnar aerosol optical depth over the observation period.
文摘The role of N2 fixation in structuring plant communities and influencing ecosystem function will be potentially large. In previous study, we investigated nodule biomass and activity, and calculated the amount of N2 fixation in a naturally established 18-year-old alder (Alnus hirsute (Turcz.) var. sibirica) stand following disturbance by road construction in Takayama, central Japan. In this study, to estimate the facilitation effects by alder on the spatial distribution of the regenerated tree species, we examined the distribution pattern of the regenerated tree species in this naturally established 18-year-old alder stand. The distribution pattern of alder and the regenerated woody species was analyzed in terms of spatial point processes and the regenerated species tended to distribute near the alder site. In particular, bird-dispersed tree species (endozoochory species) with relatively high shade tolerance showed a significant attraction to alder. These results suggest that alder will be used as roost trees and play the role of mother trees for these regenerated species at the degraded site. It was also suggested that the endozoochory species, which occupy 13 of 26 regenerated species in this stand, might regenerate faster than other species at this alder stand.
文摘We measured the spatial variability of Cl -, Na +, SO 2- 4, NO - 3 and 7Be concentrations in snow cover along the traverse route from S16 to Dome Fuji station in east Dronning Maud Land, Antarctica. The concentrations of Cl - and Na + at the coast exponentially decreased with distance from the coast up to 200 km inland. Between 200 1000 km inland, the concentrations of Na + were nearly constant. On the other hand, the concentrations of Cl - increased with distance beyond 750 km inland. Furthermore, the contribution factors between Cl - and Na + decreased and the Cl -/Na + ratio and the nssCl -/Cl - ratio increased toward the interior of the continent. These results indicate that sea salt aerosols are transported from the coastal region toward the inland region of the Antarctic continent, and that a source of Cl - other than sea salt exists in the inland plateau of Antarctica. The concentrations of SO 2- 4, NO - 3 and 7Be in snow were relatively high in the coastal region and the inland plateau region compared with those in the katabatic wind region.
基金This work was supported by the Ministry of Education,Science,Sports and Culture of Japanthe Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of China.
文摘A field work was conducted at Moshiri in Japan. The work included intensive snow pit work, taking snow grain photos, recording snow and air temperatures, as well as measuring snow water content. By treating the snow as a viscous fluid, it is found that the snow compactive viscosity decreases as the density increases, which is opposite to the relation for dry snow. Based on the measurements of snow grain size, it is shown that, similar to the watersaturated snow, the frequency distributions of grain size at different times almost have the same shape. This reveals that the waterunsaturated melting snow holds the same graincoarsening behavior as the watersaturated snow does. It is also shown that the waterunsaturated melting snow coarsens much more slowly than the watersaturated snow. The C value, which is the viscosity when the snow density is zero, is related to the mean grain size and found to decrease with increasing grain size. The decreasing rate of C value increases with decreasing graincoarsening rate.
基金This study was supported by the National Natural Science Foundation of China under Grant No. 49794030 and the Ministry of Science Technology of China (G1998040908).
文摘This study examines the relationship between the subtropical high in the West Pacific and the Okhotsk high in summer, and explains why the subtropical high cannot progress northward when the Okhotsk high is active. The findings are as follows. (1) A teleconnection pattern, namely, the significant correlation dipole between the index of the Okhotsk high and 500 hPa geopotential height (Z500), over East Asia, tends to occur in summer. (2) The teleconnection is closely related to the wave train propagation from the Okhotsk Sea via Japan to the subtropical regions when the Okhotsk high is developing. (3) The wave train propagation associated with the development of the Okhotsk high can generate a large cyclonic anomaly over the sea east of Japan, even in late summer. The cyclonic anomaly plays an important role in weakening the northern part of the subtropical high. The anomalous southern position of the main body of the subtropical high in the summer of 1998 is partly due to this effect.
基金supported by National Science Foundation of China (41522103, 41501082 and 41225002)Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues (XDA05100105)
文摘Recently, the light-absorbing organic carbon, i.e., brown carbon(Br C), has received an increasing attention, because they could significantly absorb the solar radiation in the range of short wavelengths rather than the purely scattering effect. Br C is ubiquitous in the troposphere. It could undergo long range transport within the atmospheric circulation. After the deposition on the surface of snow or ice in the cryospheric region, as the major light absorbing impurities with black carbon and dust, Br C could reduce the snow albedo and accelerate the glacier melting. In this context, this paper summarized the current knowledge of Br C(in aerosols and snow) in the cryospheric regions including the Arctic, Antarctic,and Alpines. Although some works have been conducted in those region, the current dataset on the optical properties of Br C like Absorption?ngstr€om Exponent(AAE) and Mass Absorption Efficiency(MAE) is still limited, which hampers stimulating an accurate evaluation of its climate effects. Especially in the Himalayas and Tibetan Plateau, where very limited information concerning Br C is available. Considering biomass burning as a dominant source of Br C, a large amount of emissions from biomass burning in South Asia could reach the Himalayas and Tibetan Plateau, where the climate effect of Br C merits more investigation in the future.
基金supported by the Environment Research and Technology Development Fund(B-0903)of the Ministry of the Environment,Japan,the Japan Society for the Promotion of Science(JSPS)Japan through Grant-in-Aid No.24221001985 Project of National Key Universities,Tianjin University,China
文摘In order to understand the relative importance of anthropogenic and biological sources of carbonaceous aerosols in Northeast Asia,we measured total carbon(TC)and water-soluble organic carbon(WSOC)and their stable carbon isotope ratios(d^(13)C)in total suspended particulates collected from Sapporo,northern Japan(43.07°N,141.36°E)over a 1-year period(during 2 September 2009and 5 October 2010).Temporal variations of TC showed a gradual decrease from mid-autumn to winter followed by a gradual increase to growing season with a peak in early summer.Both d^(13)C_(TC)and d^(13)C_(WSOC)showed very similar temporal trends with a gradual enrichment of^(13)C from mid-autumn to winter followed by a depletion in the^(13)C to early summer and thereafter it remained stable,except for few cases.Based on the results obtained together with the air mass trajectories,we found that biogenic emissions including biological particles(e.g.,pollen)and secondary organic aerosol formation from biogenic volatile organic compounds are the important sources of carbonaceous aerosols in spring/summer whereas fungal spores from soil and biomass burning and enhanced fossil fuel combustion contribute significantly in autumn/winter and in winter,respectively,in Northeast Asia.
基金the National Natural Science Foundation of China under Grant No.49794030Ministry of Science and Technology of China(G1998040908).
文摘This study has reviewed recent studies about impact of the Rossby wave propagation on the weather of East Asia.Then,we have focused on the northward progression of the subtropical high affected by the propagations and their interaction.The following results are obtained:(1)The two kinds of meridional Rossby wave propagations often affect the East Asian weather in summer, which propagate in two conflicting directions(northwest-southeastward and southwest-northeast- ward).This is considered as the interaction of the large-scale systems between high and low latitudes with wave propagation,especially to the circulation systems around East Asia.(2)The northward progression of the subtropical high is largely restrained,aecompanied by the southward shift of the convective activity in middle latitudes,under the strong and persistent Rossby wave propagation from high to low latitudes.And the opposite role could be found in the Rossby wave propagation from low to high latitudes.
文摘A 211 m depth ice core observation was carried out at the top of the Vestfonna Ice Cap in Nordaustlandet, Svalbard, Norway in 1995. Chronology of the ice core was determined by tritium analysis and comparison to the volcanic eruption of Laki; the resulting accumulation rate is 0.34 0.35 m water eq.·yr -1 for the last 400 year. Concentrations of Al, V, Cr, Fe, Cu, Zn, As, Ag, Cd, Pb and U in an ice core have been determined by an inductively coupled plasma mass spectrometry (ICP MS) with a desolvated micro concentric nebulizer, which is a recent development and can achieve high sensitivity with low uptake rate of 60 mL/min. The concentrations of Pb, Cu, and Zn had increased from 1940s declined from 1970s to present. However, the profiles of Pb, Cu, and Zn were different and they seem to be influenced by the difference of sources. Since the ratios between Cu, Pb, and Zn in Svalbard is similar to that in French Alps, the source area of these elements is estimated to be Europe.
文摘The tolerance to temperature increase was tested for Halobates individuals collected during two cruises in the western tropical Pacific Ocean (MR-06-05-Leg 3, December 21, 2006-January 12, 2007, 0°N-8°N; KH-06-02-Leg 5, August 18-31, 2006, 12°N-17°N). High temperature coma experiments were conducted on adults and 5th instar larvae. On average, H. sericeus (distributed in the wide latitude zone of 5°N-40°N), H. germanus (distributed in the moderate latitude zone of 0°N-35°N) and H. micans (distributed mainly in the lower latitudes around the equator) were on average paralyzed at 35.6℃(SD: 0.89), 32.9℃ (SD: 2.17) and 31.6℃ (SD: 2.60), respectively (P = 0.035). According to the current dynamics during the cruise, the colony ofH. sericeus at one station (5°N 137°E) may have been transferred from the northern area of 14°N by three currents (North Equatorial Current, Mindanao Current and North Equatorial Counter Current) to the area of 5°N 138°E. Extremely high heat resistance was shown by the adults of H. germanus in the sea area around the equator. Dynamic current and air movements in this area around the equator, that is a "warm seawater pool", could be hypothesized to be related to the high resistance to heat shown in this study.
基金supported by the program by Minstry of Science and Technology of China(No.2002DIB20067)
文摘This study examined the relationship between mature phase of the cold event in 1999 and the East Asian summer atmosphere circulation in 2000.The cold event reaches its mature phase in the autumn and winter of 1999,which is the strongest La Nina episode in recent 11 years.There is a clear anomalous pattern of the atmosphere circulation around East Asia in the summer of 2000, i.e.the negative anomaly centers around the Cherski Mountains and 20°N,170°E at 500 hPa,the main body of the subtropical high keeps in further northern position than usual and the negative anomaly of precipitation located in southern central China.This pattern is thought as the response to the preceding strong cold event in autumn of 1999.It is also identified that the response of the East Asian atmosphere circulation in summer of 2000 to the strong La Nina event in 1999 belongs to the top rank in recent 43 years.On the other hand,the inactive blocking anticyclone around East Asia in summer of 2000 is associated with the positive SST anomaly and the 850 hPa temperature anomaly around the Bering Sea simultaneously.Nevertheless,although the impact on the summer atmosphere circulation around East Asia from La Nina events could not rank with that from E1 Nino,the impact could not be neglected especially in a strong La Nina case.