In this study, Artemisia biennis was seeded in a greenhouse and raised to an average plant height of 100 cm. Aboveground plant portions were harvested and partitioned into leaves and stems, and dried;while roots were ...In this study, Artemisia biennis was seeded in a greenhouse and raised to an average plant height of 100 cm. Aboveground plant portions were harvested and partitioned into leaves and stems, and dried;while roots were either removed from some soil (soil – roots) or left in soil (soil + roots). Greenhouse studies were conducted to evaluate the allelopathic potential of A. biennis leaves, roots, and stems;and soil – roots, and soil + roots on Solanum melanocerasum plant height and fresh weight plant–1. When 5 g of root and stem biomass were added to soil, S. melanocerasum plant height and fresh weight plant–1 was reduced by 75 and 88%, respectively. In contrast, 5 g of leaf biomass caused an increase in S. melanocerasum plant height and fresh weight plant–1 by 35% and 43%, respectively;whereas, 20 g of leaf biomass depressed both variables by 50% and 65%, also respectively. Plant height was more suppressed when S. melanocerasum grew in soil – roots as opposed to soil + roots, whereas fresh weight plant–1 was similar between soil treatments. S. melanocerasum plant height was reduced by 70 and 55% when grown in soil – roots and soil + roots, respectively. In contrast, S. melanocerasum fresh weight plant–1 was reduced by 76% in both soil treatments. The reduction in S. melanocerasum plant attributes in this study is indicative of the allelopathic potential of A. biennis. Furthermore, A. biennis allelopathy is differenttially expressed among plant parts, primarily in roots. This may explain how A. biennis is capable of dominating a habitat once it becomes established. The presence of extractable compounds with herbicidal activity could increase the potential usefulness of A. biennis.展开更多
Objective: The biennial epidemic pattern of respiratory syncytial virus (RSV) circulation in Croatia has been preserved and could not be related to climatic factors and the predominant RSV subtypes. The possibility th...Objective: The biennial epidemic pattern of respiratory syncytial virus (RSV) circulation in Croatia has been preserved and could not be related to climatic factors and the predominant RSV subtypes. The possibility that the circulation of different RSV genotypes affect the outbreak cycle in children in Croatia (Zagreb region) over a period of 3 consecutive years was explored in the paper. Methods: The study group consisted of inpatients, aged 0-10 years, who were hospi- talized with acute respiratory tract infections caused by RSV, in Zagreb, over the period from 1 January 2006 to 31 De- cember 2008. The virus was identified in the nasopharyngeal secretion using direct immunofluorescence method. The virus subtype and genotype was determined by real-time PCR and sequence analysis, respectively. Results: RSV infec- tions identified in 731 children. RSV subtype A caused 399 infections, and subtype B 332. Two subtype A genotypes (NA1 and GA5) and three subtype B genotypes (BA7, BA9 and BA10) were found. During persistent RSV biennial cycles namely four succeeding outbreaks, the new genotype from the previous smaller outbreak persevered into the up- coming larger outbreak. Conclusion: Our molecular-epidemiology study of RSV subtypes and genotypes during calen- dar months demonstrates that the biennial RSV cycle cannot be fully explained by the dynamic of the predominant cir- culating genotype of RSV. Other unknown factors account for the biennial cycle of RSV epidemics in Croatia.).展开更多
The quasi-biennial oscillation is the primary mode of variability of the equatorial mean zonal wind in the lower stratosphere, which is characterized by downward propagating easterly and westerly wind regimes from 10 ...The quasi-biennial oscillation is the primary mode of variability of the equatorial mean zonal wind in the lower stratosphere, which is characterized by downward propagating easterly and westerly wind regimes from 10 hPa level with a period approximately 28 months. The effects of the stratospheric quasi-biennial oscillation in zonal winds (SQBO) are not only confined to atmospheric dynamics but also seen in the chemical constituent (trace gases) anomalies such as ozone, water vapor, carbon monoxide and methane in the lower stratosphere. In this study, we examined the SQBO and associated ozone quasi-biennial oscillation (OQBO) using the chemistry-climate model CHASER (MIROC-ESM) simulations and ECMWF ERA-Interim ozone reanalysis for the period 2000-2015. We used lower stratospheric zonal wind from the radiosonde observations and total column ozone (TCO) from Aura Satellite (OMI Instruments) over Singapore to compare the SQBO and OQBO phases with model and reanalysis. The SQBO shows large variations in magnitude and periodicity during the period of study and the amplitude of OQBO also changes in accordance with the westerly (+ve ozone anomaly) and easterly (-ve ozone anomaly) phases of SQBO. During the Westerly phase of Ozone QBO (WQBO) corresponds to average positive total ozone anomaly of ~10 DU and in the Easterly phase of Ozone QBO (EQBO) corresponds to an average negative total ozone anomaly ~−10 DU in the tropical lower stratosphere. Since the SQBO phases were explained by the vertical propagations of Mixed-Ross by Gravity (MRG) waves and Kelvin waves, the correlation of ozone volume mixing ratio with zonal and vertical velocities gives quasi-biennial signals, which indicate the OQBO mechanism more related to dynamical transport than the stratospheric photochemical variations. Since the average amplitude of OQBO phases gives ~+/−10 DU from the observations during easterly and westerly phases SQBO, we need more research focused on the dynamical transport than the photochemical changes to understand the tropical ozone variability due to the ozone quasi-biennial oscillations.展开更多
HALOE data from 1992 to 2003 are used to analyze the interannual variation of the HCl volume mixing ratio and its quasi-biennial oscillation (QBO) in the stratosphere, and the results are compared with the ozone QBO. ...HALOE data from 1992 to 2003 are used to analyze the interannual variation of the HCl volume mixing ratio and its quasi-biennial oscillation (QBO) in the stratosphere, and the results are compared with the ozone QBO. Then, the NCAR two-dimensional interactive chemical, dynamical and radiative model is used to study the effects of the wind QBO on the distribution and variation of HCl in the stratosphere. The results show that the QBO signals in the HCl mixing ratio are mainly at altitudes from 50 hPa to 5 hPa; the larger amplitudes are located between 30 hPa and 10 hPa; a higher HCl mixing ratio usually corresponds to the westerly phase of the wind QBO and a lower HCl mixing ratio usually corresponds to the easterly phase of the wind QBO in a level near 20 hPa and below. In the layer near 10 hPa-5 hPa, the phase of the HCl QBO reverses earlier than the phase of the wind QBO; the QBO signals for HCl in the extratropics are also clear, but with reversed phase compared with those over the Tropics. The HCl QBO signals at 30° N are clearer than those at 30° S; the QBOs for HCl and ozone have a similar phase at the 50 hPa-20 hPa level while they are out of phase near 10 hPa; the simulated structures of the HCl QBO agree well with observations. The mechanism for the formation of the HCl QBO and the reason for differences in the vertical structure of the HCl and ozone QBO are attributed to the transport of HCl and ozone by the wind QBO-induced meridional circulation.展开更多
In order to investigate the spatial patterns of the Tropospheric Biennial Oscillation (TBO) on the global scale, the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) monthly averaged precipitati...In order to investigate the spatial patterns of the Tropospheric Biennial Oscillation (TBO) on the global scale, the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) monthly averaged precipitation and the Climate Diagnostics Center (CDC) monthly outgoing long-wave radiation (OLR) and SST are used in conjunction with TBO bandpass-filtering. The results indicate active biennial variability in the tropical eastern-central Pacific regions. It is evident that observations reflect the biennial component of the ENSO rather than the TBO itself. Since some studies have pointed out that the TBO is a broad-scale phenomenon differing from the ENSO, to investigate the pure TBO the ENSO signal must be excluded. The Scale Interaction Experiment-FRCGC (SINTEX-F) coupled general circulation model (CGCM) developed at Japan Frontier Research Center for Global Change (FRCGC) can capture both the ENSO and the biennial signals. Air-sea interactions in the tropical eastern-central Pacific are decoupled to eliminate the effects of ENSO in a experiment by SINTEX-F and the results show that biennial variability still exists even without ENSO. It seems to mean that the TBO and ENSO are independent from each other. Furthermore, the model results indicate that the two key regions are southwest Sumatra and the tropical western Pacific for the TBO cycle.展开更多
The observed tropospheric biennial oscillation (TBO) in the western North Pacific (WNP) monsoon region has an interdecadal variability with a period of 40–50 yr. That suggests a weaker effect of the TBO on the East A...The observed tropospheric biennial oscillation (TBO) in the western North Pacific (WNP) monsoon region has an interdecadal variability with a period of 40–50 yr. That suggests a weaker effect of the TBO on the East Asia followed by a stronger one. A simple analytic model was designed to investigate the mechanism of the interdecadal variability of the TBO. The results indicated that a local TBO air–sea system not only supports the TBO variability in the WNP monsoon region but also produces an interdecadal variability of the TBO.展开更多
The South China Sea summer monsoon (SCSSM) behaves with prominent climate variability from the intraseasonal to interdecadal time scales. On the interannual time scale, the biennial variability (so-called tropospheric...The South China Sea summer monsoon (SCSSM) behaves with prominent climate variability from the intraseasonal to interdecadal time scales. On the interannual time scale, the biennial variability (so-called tropospheric biennial oscillation, TBO) is as important as the El Ni o-Southern Oscillation (ENSO) period. Some observed data sets, including reanalysis data, are used to explore the associated air-sea interactive physical processes and how the SCSSM TBO affects the ENSO. The results show that the shearing vorticity induced by the north Indian Ocean sea surface temperature anomalies (SSTAs) and the anomalous Philippine Sea anticyclone both contribute to the TBO in the SCSSM. The results also indicate that the ENSO has a weak effect on the SCSSM TBO, whereas the latter affects the ENSO to some extent.展开更多
A diagnostic analysis is performed of the quasi-biennial oscillations during the ENSO cycle and the results are based to study the interactions between ENSO and the Asian monsoons. It shows that the Asian monsoons hav...A diagnostic analysis is performed of the quasi-biennial oscillations during the ENSO cycle and the results are based to study the interactions between ENSO and the Asian monsoons. It shows that the Asian monsoons have significant influence on the ENSO cycle on the quasi-biennial scale. Materialized through the onset and southward progression of the winter monsoon, the influence appears in the tropical western Pacific to excite severe convection and to further affect the ENSO cycle. The phenomenon is not only reflected in the quasi-biennial mode but the annual variation of the Asian winter monsoon in reality.展开更多
The National Centers for Environmental Prediction (NCEP) reanalysis data, Climate Diagnostics Center Merged Analysis of Precipitation (CMAP) results, and NOAA Extended Reconstructed Sea Surface Temperature (SST), have...The National Centers for Environmental Prediction (NCEP) reanalysis data, Climate Diagnostics Center Merged Analysis of Precipitation (CMAP) results, and NOAA Extended Reconstructed Sea Surface Temperature (SST), have been utilized in this paper to study the quasi-biennial variations in Asia-Pacific monsoon subsystems and associated SST anomalies (SSTA) and wind anomalies. Four monsoon indices are computed from NCEP/ National Center for Atmospheric Research (NCAR) reanalysis to represent the South Asian monsoon (SAM), South China Sea summer monsoon (SCSSM), Western North Pacific monsoon (WNPM) and East Asian monsoon (EAM), respectively. The quasi-biennial periods are very significant in Asia-Pacific monsoons (as discovered by power spectrum analysis), and for SAM and EAM---with moderate effects by El Ni?o-Southern Oscillation (ENSO)---the quasi-biennial periods are the most important factor. For SCSSM and WNPM (once again due to the effects of ENSO), the quasi-biennial periods are of secondary durations. There are obvious interdecadal variations in the quasi-biennial modes of the Asia-Pacific monsoon, so in the negative phase the biennial modes will not be significant or outstanding. The wind anomalies and SSTA associated with the biennial modes are very different in the SAM, WNPM and EAM regions. Since the WNPM and SCSSM are very similar in the biennial modes, they can be combined into one subsystem, called SCS/WNPM.展开更多
There are obvious biennial phenomena of circulation, meteorological and climatic elements in the troposphere, named as Tropospheric (Quasi-) Biennial Oscillation (TBO). Many phenomena of TBO are discovered, such as va...There are obvious biennial phenomena of circulation, meteorological and climatic elements in the troposphere, named as Tropospheric (Quasi-) Biennial Oscillation (TBO). Many phenomena of TBO are discovered, such as variations of TBO in tropospheric temperature, pressure, winds field, monsoon and subtropical high etc. The mechanism of TBO is explored and the results demonstrate that tropical ocean (the Indian Ocean and the Pacific Ocean, mainly) and Stratospheric QBO play important roles in the TBO. In addition, Eurasian snow cover and solar activity of 11yr period can affect TBO very possibly.展开更多
The 7th Biennial Conference of Chinese Ecological Economics Society (CEES) was held from 5th to 7th, Nov.2006 in Qingdao University. The paper summarizes the major viewpoint presented at the conference: eco-economicre...The 7th Biennial Conference of Chinese Ecological Economics Society (CEES) was held from 5th to 7th, Nov.2006 in Qingdao University. The paper summarizes the major viewpoint presented at the conference: eco-economicresearch and construction of a harmonious society in China. The conference put forward that it is an objectivity andinevitability for human being to enter the harmonious society, that eco-economics is one of the theoretical bases for theconstruction of the harmonious society, and that the research of eco-economics in China should reflect new contentsdeveloped in the process of modernization in China and make proper contributions to the construction of the harmonioussociety.展开更多
The National Center for the Atmospheric Research (NCAR) middle atmospheric model is used to study the effects of the quasi-biennial oscillation in the stratosphere (QBO) on the tropopause and uppe troposphere, and the...The National Center for the Atmospheric Research (NCAR) middle atmospheric model is used to study the effects of the quasi-biennial oscillation in the stratosphere (QBO) on the tropopause and uppe troposphere, and the relationship between the QBO and South China Sea Summer Monsoon (SCSSM is explored through NCEP (the National Centers for Environmental Prediction)/NCAR, ECMWF (Euro pean Centre for Medium-Range Weather Forecasts) monthly mean wind data and in situ sounding data The simulations show that the QBO-induced residual circulations propagate downwards, and affect the tropopause and upper troposphere during the periods of mid-late QBO phase and phase transition Meanwhile, diagnostic analyses indicate that anomalous circulation similar to SCSSM circulation is generated to strengthen the SCSSM during the easterly phase and anomalous Hadley-like circulation weakens the SCSSM during the westerly. Though the QBO has effects on the SCSSM by meridiona circulation, it is not a sole mechanism on the SCSSM TBO mode.展开更多
Study of the tropospheric biennial oscillation (TBO) has attracted significant interest since the 1980s.However,the mechanism that drives this process is still unclear.In the present study,ECMWF daily data were applie...Study of the tropospheric biennial oscillation (TBO) has attracted significant interest since the 1980s.However,the mechanism that drives this process is still unclear.In the present study,ECMWF daily data were applied to evaluate variation of the East Asian monsoon and its relationship to the TBO.First,the general East Asian monsoon index (EAMI) was delineated on the basis of a selected area using the 850 hPa u and v components.This new index may describe not only the characteristics of summer monsoons,but also the features of winter monsoons,which is crucial to understand the transition process between summer and winter monsoons.The following analysis of EAMI shows that there is a close relationship between summer and winter monsoons.In general,strong East Asian winter monsoons are followed by strong East Asian summer monsoons,and weak winter monsoons lead to weak summer monsoons.While strong (weak) summer monsoons followed by weak (strong) winter monsoons form a kind of 2-year cycle,which may be the possible mechanism leading to the TBO over the East Asian region.展开更多
On the basis of previous parameterization schemes, considering both the wave breaking and absorbed at critical level, a parameterization with a continuous spectrum of gravity waves is realized by introducing a momentu...On the basis of previous parameterization schemes, considering both the wave breaking and absorbed at critical level, a parameterization with a continuous spectrum of gravity waves is realized by introducing a momentum flux density function for the wave spectrum, and then the parameterization scheme of the gravity waves is improved. Choosing parameter values of the background atmosphere and waves based on the observations, a more realistic equatorial quasi-biennial oscillation (QBO) driven by the incorporated drag from the planetary and gravity waves can be simulated. The numerical results indicate that the forcing magnitude of the planetary and gravity waves varies with the wind field, and in some phases of the QBO, the contribution of the gravity waves is comparable with that of the planetary waves. After the QBO is steadily formed, its amplitude and period and wind configuration are relevant to the effect of vertical diffusion and the momentum flux distribution with spectrum, however, independent of the initial background wind field. Moreover, for any given nonzero initial background wind, a steady QBO can be finally generated due to the incorporated drag from the planetary and gravity waves.展开更多
基金supported by the National Natural Science Foundation of China[grant numbers 41975048,42030605,and 42175069]the Natural Science Foundation of Jiangsu Province[grant number BK20191404]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA17010105].
文摘In this study, Artemisia biennis was seeded in a greenhouse and raised to an average plant height of 100 cm. Aboveground plant portions were harvested and partitioned into leaves and stems, and dried;while roots were either removed from some soil (soil – roots) or left in soil (soil + roots). Greenhouse studies were conducted to evaluate the allelopathic potential of A. biennis leaves, roots, and stems;and soil – roots, and soil + roots on Solanum melanocerasum plant height and fresh weight plant–1. When 5 g of root and stem biomass were added to soil, S. melanocerasum plant height and fresh weight plant–1 was reduced by 75 and 88%, respectively. In contrast, 5 g of leaf biomass caused an increase in S. melanocerasum plant height and fresh weight plant–1 by 35% and 43%, respectively;whereas, 20 g of leaf biomass depressed both variables by 50% and 65%, also respectively. Plant height was more suppressed when S. melanocerasum grew in soil – roots as opposed to soil + roots, whereas fresh weight plant–1 was similar between soil treatments. S. melanocerasum plant height was reduced by 70 and 55% when grown in soil – roots and soil + roots, respectively. In contrast, S. melanocerasum fresh weight plant–1 was reduced by 76% in both soil treatments. The reduction in S. melanocerasum plant attributes in this study is indicative of the allelopathic potential of A. biennis. Furthermore, A. biennis allelopathy is differenttially expressed among plant parts, primarily in roots. This may explain how A. biennis is capable of dominating a habitat once it becomes established. The presence of extractable compounds with herbicidal activity could increase the potential usefulness of A. biennis.
文摘Objective: The biennial epidemic pattern of respiratory syncytial virus (RSV) circulation in Croatia has been preserved and could not be related to climatic factors and the predominant RSV subtypes. The possibility that the circulation of different RSV genotypes affect the outbreak cycle in children in Croatia (Zagreb region) over a period of 3 consecutive years was explored in the paper. Methods: The study group consisted of inpatients, aged 0-10 years, who were hospi- talized with acute respiratory tract infections caused by RSV, in Zagreb, over the period from 1 January 2006 to 31 De- cember 2008. The virus was identified in the nasopharyngeal secretion using direct immunofluorescence method. The virus subtype and genotype was determined by real-time PCR and sequence analysis, respectively. Results: RSV infec- tions identified in 731 children. RSV subtype A caused 399 infections, and subtype B 332. Two subtype A genotypes (NA1 and GA5) and three subtype B genotypes (BA7, BA9 and BA10) were found. During persistent RSV biennial cycles namely four succeeding outbreaks, the new genotype from the previous smaller outbreak persevered into the up- coming larger outbreak. Conclusion: Our molecular-epidemiology study of RSV subtypes and genotypes during calen- dar months demonstrates that the biennial RSV cycle cannot be fully explained by the dynamic of the predominant cir- culating genotype of RSV. Other unknown factors account for the biennial cycle of RSV epidemics in Croatia.).
文摘The quasi-biennial oscillation is the primary mode of variability of the equatorial mean zonal wind in the lower stratosphere, which is characterized by downward propagating easterly and westerly wind regimes from 10 hPa level with a period approximately 28 months. The effects of the stratospheric quasi-biennial oscillation in zonal winds (SQBO) are not only confined to atmospheric dynamics but also seen in the chemical constituent (trace gases) anomalies such as ozone, water vapor, carbon monoxide and methane in the lower stratosphere. In this study, we examined the SQBO and associated ozone quasi-biennial oscillation (OQBO) using the chemistry-climate model CHASER (MIROC-ESM) simulations and ECMWF ERA-Interim ozone reanalysis for the period 2000-2015. We used lower stratospheric zonal wind from the radiosonde observations and total column ozone (TCO) from Aura Satellite (OMI Instruments) over Singapore to compare the SQBO and OQBO phases with model and reanalysis. The SQBO shows large variations in magnitude and periodicity during the period of study and the amplitude of OQBO also changes in accordance with the westerly (+ve ozone anomaly) and easterly (-ve ozone anomaly) phases of SQBO. During the Westerly phase of Ozone QBO (WQBO) corresponds to average positive total ozone anomaly of ~10 DU and in the Easterly phase of Ozone QBO (EQBO) corresponds to an average negative total ozone anomaly ~−10 DU in the tropical lower stratosphere. Since the SQBO phases were explained by the vertical propagations of Mixed-Ross by Gravity (MRG) waves and Kelvin waves, the correlation of ozone volume mixing ratio with zonal and vertical velocities gives quasi-biennial signals, which indicate the OQBO mechanism more related to dynamical transport than the stratospheric photochemical variations. Since the average amplitude of OQBO phases gives ~+/−10 DU from the observations during easterly and westerly phases SQBO, we need more research focused on the dynamical transport than the photochemical changes to understand the tropical ozone variability due to the ozone quasi-biennial oscillations.
基金This work was supported by the National Natural Science Foundation of China(Grant No.40375012)
文摘HALOE data from 1992 to 2003 are used to analyze the interannual variation of the HCl volume mixing ratio and its quasi-biennial oscillation (QBO) in the stratosphere, and the results are compared with the ozone QBO. Then, the NCAR two-dimensional interactive chemical, dynamical and radiative model is used to study the effects of the wind QBO on the distribution and variation of HCl in the stratosphere. The results show that the QBO signals in the HCl mixing ratio are mainly at altitudes from 50 hPa to 5 hPa; the larger amplitudes are located between 30 hPa and 10 hPa; a higher HCl mixing ratio usually corresponds to the westerly phase of the wind QBO and a lower HCl mixing ratio usually corresponds to the easterly phase of the wind QBO in a level near 20 hPa and below. In the layer near 10 hPa-5 hPa, the phase of the HCl QBO reverses earlier than the phase of the wind QBO; the QBO signals for HCl in the extratropics are also clear, but with reversed phase compared with those over the Tropics. The HCl QBO signals at 30° N are clearer than those at 30° S; the QBOs for HCl and ozone have a similar phase at the 50 hPa-20 hPa level while they are out of phase near 10 hPa; the simulated structures of the HCl QBO agree well with observations. The mechanism for the formation of the HCl QBO and the reason for differences in the vertical structure of the HCl and ozone QBO are attributed to the transport of HCl and ozone by the wind QBO-induced meridional circulation.
基金the National Natural Science Foundation of China (GrantNo. 40505019)
文摘In order to investigate the spatial patterns of the Tropospheric Biennial Oscillation (TBO) on the global scale, the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) monthly averaged precipitation and the Climate Diagnostics Center (CDC) monthly outgoing long-wave radiation (OLR) and SST are used in conjunction with TBO bandpass-filtering. The results indicate active biennial variability in the tropical eastern-central Pacific regions. It is evident that observations reflect the biennial component of the ENSO rather than the TBO itself. Since some studies have pointed out that the TBO is a broad-scale phenomenon differing from the ENSO, to investigate the pure TBO the ENSO signal must be excluded. The Scale Interaction Experiment-FRCGC (SINTEX-F) coupled general circulation model (CGCM) developed at Japan Frontier Research Center for Global Change (FRCGC) can capture both the ENSO and the biennial signals. Air-sea interactions in the tropical eastern-central Pacific are decoupled to eliminate the effects of ENSO in a experiment by SINTEX-F and the results show that biennial variability still exists even without ENSO. It seems to mean that the TBO and ENSO are independent from each other. Furthermore, the model results indicate that the two key regions are southwest Sumatra and the tropical western Pacific for the TBO cycle.
基金Project supported by the National Natural Science Foundation of China （Grant No 40505019） and the 0pen Research Fund of Laboratory of China Meteorological Administration （Grant No CMATG2006L03）.
基金supported by the National Natural Science Foundation of China (Grant No 40505019)
文摘The observed tropospheric biennial oscillation (TBO) in the western North Pacific (WNP) monsoon region has an interdecadal variability with a period of 40–50 yr. That suggests a weaker effect of the TBO on the East Asia followed by a stronger one. A simple analytic model was designed to investigate the mechanism of the interdecadal variability of the TBO. The results indicated that a local TBO air–sea system not only supports the TBO variability in the WNP monsoon region but also produces an interdecadal variability of the TBO.
基金The Major State Basic Research Development Program(973Program)of China under contract No.2011CB403403)
文摘The South China Sea summer monsoon (SCSSM) behaves with prominent climate variability from the intraseasonal to interdecadal time scales. On the interannual time scale, the biennial variability (so-called tropospheric biennial oscillation, TBO) is as important as the El Ni o-Southern Oscillation (ENSO) period. Some observed data sets, including reanalysis data, are used to explore the associated air-sea interactive physical processes and how the SCSSM TBO affects the ENSO. The results show that the shearing vorticity induced by the north Indian Ocean sea surface temperature anomalies (SSTAs) and the anomalous Philippine Sea anticyclone both contribute to the TBO in the SCSSM. The results also indicate that the ENSO has a weak effect on the SCSSM TBO, whereas the latter affects the ENSO to some extent.
文摘A diagnostic analysis is performed of the quasi-biennial oscillations during the ENSO cycle and the results are based to study the interactions between ENSO and the Asian monsoons. It shows that the Asian monsoons have significant influence on the ENSO cycle on the quasi-biennial scale. Materialized through the onset and southward progression of the winter monsoon, the influence appears in the tropical western Pacific to excite severe convection and to further affect the ENSO cycle. The phenomenon is not only reflected in the quasi-biennial mode but the annual variation of the Asian winter monsoon in reality.
基金supported by the Special Fund for Meteorological Research in the Public Interest[grant number GYHY201206041]the projects entitled‘Comprehensive Evaluation of Polar Areas in Global and Regional Climate Changes’[grant number CHINARE2015–2019]‘Polar Environment Comprehensive Investigation and Assessment’[grant number CHINARE2015–2019]
基金National Natural Science Foundation of China (40505019)
文摘The National Centers for Environmental Prediction (NCEP) reanalysis data, Climate Diagnostics Center Merged Analysis of Precipitation (CMAP) results, and NOAA Extended Reconstructed Sea Surface Temperature (SST), have been utilized in this paper to study the quasi-biennial variations in Asia-Pacific monsoon subsystems and associated SST anomalies (SSTA) and wind anomalies. Four monsoon indices are computed from NCEP/ National Center for Atmospheric Research (NCAR) reanalysis to represent the South Asian monsoon (SAM), South China Sea summer monsoon (SCSSM), Western North Pacific monsoon (WNPM) and East Asian monsoon (EAM), respectively. The quasi-biennial periods are very significant in Asia-Pacific monsoons (as discovered by power spectrum analysis), and for SAM and EAM---with moderate effects by El Ni?o-Southern Oscillation (ENSO)---the quasi-biennial periods are the most important factor. For SCSSM and WNPM (once again due to the effects of ENSO), the quasi-biennial periods are of secondary durations. There are obvious interdecadal variations in the quasi-biennial modes of the Asia-Pacific monsoon, so in the negative phase the biennial modes will not be significant or outstanding. The wind anomalies and SSTA associated with the biennial modes are very different in the SAM, WNPM and EAM regions. Since the WNPM and SCSSM are very similar in the biennial modes, they can be combined into one subsystem, called SCS/WNPM.
基金funded by the National Natural Science Foundation of China[grant number 41776031]the Guangdong Natural Science Foundation[grant number 2015A030313796]+3 种基金the National Program on Global Change and Air-Sea Interaction[grant number GASI-IPOVAI-04]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA11010104]the program for scientific research start-upfunds of Guangdong Ocean Universitythe Foundation for Returned Scholars of the Ministry of Education of China
基金Scaling Project of the open foundation by Guangzhou Institute of Tropical Marine and Meteorology of China Meteorological Administration-"Preliminary study on interdecadal variability of TBO".
文摘There are obvious biennial phenomena of circulation, meteorological and climatic elements in the troposphere, named as Tropospheric (Quasi-) Biennial Oscillation (TBO). Many phenomena of TBO are discovered, such as variations of TBO in tropospheric temperature, pressure, winds field, monsoon and subtropical high etc. The mechanism of TBO is explored and the results demonstrate that tropical ocean (the Indian Ocean and the Pacific Ocean, mainly) and Stratospheric QBO play important roles in the TBO. In addition, Eurasian snow cover and solar activity of 11yr period can affect TBO very possibly.
文摘The 7th Biennial Conference of Chinese Ecological Economics Society (CEES) was held from 5th to 7th, Nov.2006 in Qingdao University. The paper summarizes the major viewpoint presented at the conference: eco-economicresearch and construction of a harmonious society in China. The conference put forward that it is an objectivity andinevitability for human being to enter the harmonious society, that eco-economics is one of the theoretical bases for theconstruction of the harmonious society, and that the research of eco-economics in China should reflect new contentsdeveloped in the process of modernization in China and make proper contributions to the construction of the harmonioussociety.
基金Supported by the National Natural Science Foundation of China (Grant No. 40505019)
文摘The National Center for the Atmospheric Research (NCAR) middle atmospheric model is used to study the effects of the quasi-biennial oscillation in the stratosphere (QBO) on the tropopause and uppe troposphere, and the relationship between the QBO and South China Sea Summer Monsoon (SCSSM is explored through NCEP (the National Centers for Environmental Prediction)/NCAR, ECMWF (Euro pean Centre for Medium-Range Weather Forecasts) monthly mean wind data and in situ sounding data The simulations show that the QBO-induced residual circulations propagate downwards, and affect the tropopause and upper troposphere during the periods of mid-late QBO phase and phase transition Meanwhile, diagnostic analyses indicate that anomalous circulation similar to SCSSM circulation is generated to strengthen the SCSSM during the easterly phase and anomalous Hadley-like circulation weakens the SCSSM during the westerly. Though the QBO has effects on the SCSSM by meridiona circulation, it is not a sole mechanism on the SCSSM TBO mode.
基金supported by the National Natural Science Foundation of China (U0833602)the National Basic Research Program of China(2007CB411805 and 2010CB950400)
文摘Study of the tropospheric biennial oscillation (TBO) has attracted significant interest since the 1980s.However,the mechanism that drives this process is still unclear.In the present study,ECMWF daily data were applied to evaluate variation of the East Asian monsoon and its relationship to the TBO.First,the general East Asian monsoon index (EAMI) was delineated on the basis of a selected area using the 850 hPa u and v components.This new index may describe not only the characteristics of summer monsoons,but also the features of winter monsoons,which is crucial to understand the transition process between summer and winter monsoons.The following analysis of EAMI shows that there is a close relationship between summer and winter monsoons.In general,strong East Asian winter monsoons are followed by strong East Asian summer monsoons,and weak winter monsoons lead to weak summer monsoons.While strong (weak) summer monsoons followed by weak (strong) winter monsoons form a kind of 2-year cycle,which may be the possible mechanism leading to the TBO over the East Asian region.
基金Supported by National Natural Science Foundation of China (Grant Nos. 40731055 and 40774085)the Innovative Research Team Project, Ministry of Education, the Knowledge Innovation Program of the Chinese Academy of Sciences (IAP07315)+1 种基金the China Meteorological Administration (Grant No. GYHY200706013)the Open Programs of Key Laboratory of Geospace Environment and Geodesy, Ministry of Education
文摘On the basis of previous parameterization schemes, considering both the wave breaking and absorbed at critical level, a parameterization with a continuous spectrum of gravity waves is realized by introducing a momentum flux density function for the wave spectrum, and then the parameterization scheme of the gravity waves is improved. Choosing parameter values of the background atmosphere and waves based on the observations, a more realistic equatorial quasi-biennial oscillation (QBO) driven by the incorporated drag from the planetary and gravity waves can be simulated. The numerical results indicate that the forcing magnitude of the planetary and gravity waves varies with the wind field, and in some phases of the QBO, the contribution of the gravity waves is comparable with that of the planetary waves. After the QBO is steadily formed, its amplitude and period and wind configuration are relevant to the effect of vertical diffusion and the momentum flux distribution with spectrum, however, independent of the initial background wind field. Moreover, for any given nonzero initial background wind, a steady QBO can be finally generated due to the incorporated drag from the planetary and gravity waves.
