The public’s attitudes can affect the experience of stuttering of people who stutter.This study investigated the attitudes held by the public about people who stutter in China.A web-based written survey with closed a...The public’s attitudes can affect the experience of stuttering of people who stutter.This study investigated the attitudes held by the public about people who stutter in China.A web-based written survey with closed and open-ended questions was implemented to develop a rich understanding.One hundred and two respondents in 26 provinces and 3 municipalities provided comments on people who stutter in their life aspects such as personality,speech,social life,work,life participation,education,dating and marriage,capability,and communication skills.The predominantly negative attitudes towards the overall domains were identified.Attitudes to people who stutter varied according to the different sources of knowledge.Familiarity with people who stutter might reduce stereotypes.However,knowledge from the media might aggravate stereotypes.Implications and future research orientation were also discussed.展开更多
We consider the following quasiconvex functional I(u)=∫ Gf(x,δu,D mu) d x where u is a vector valued function in W m,p (G),m>1 and p>2. The partial C m,a —regularity is proved fo...We consider the following quasiconvex functional I(u)=∫ Gf(x,δu,D mu) d x where u is a vector valued function in W m,p (G),m>1 and p>2. The partial C m,a —regularity is proved for minimizers of I(u) under weaker conditions.展开更多
In this paper,a nonconforming rectangular plate element,the modified incomplete biquadratic plate element,is considered. The asympotic optimal L~∞-error estimate is obtained for the plate bending problem. This proof ...In this paper,a nonconforming rectangular plate element,the modified incomplete biquadratic plate element,is considered. The asympotic optimal L~∞-error estimate is obtained for the plate bending problem. This proof is based on the method of regularized Green's function and 'the trick of auxiliary element'.展开更多
Since the 1950s, different English translated versions of Cold Mountain poems have come out in succession. These versions, due to different factors, present different characteristics. Thus, by comparing the the differ...Since the 1950s, different English translated versions of Cold Mountain poems have come out in succession. These versions, due to different factors, present different characteristics. Thus, by comparing the the different translated versions of the same original poems, translator's translation skills and the unique characteristics of these versions will be discovered. It is of great significance as they will illustrate the translators' reception of the original as the first group of receptors and these different characteristics will determine the contribution of these version to the reception of Cold Mountain poems abroad.This paper is an attempt to study the translation of one of the most famous Cold Mountain's poems and illustrate their characteristics.展开更多
Based on the reforecasts from ve models of the Subseasonal to Seasonal(S2S)Prediction project,the S2S prediction skill of surface soil moisture(SM)over East Asia during May September is evaluated against ERA-Interim.R...Based on the reforecasts from ve models of the Subseasonal to Seasonal(S2S)Prediction project,the S2S prediction skill of surface soil moisture(SM)over East Asia during May September is evaluated against ERA-Interim.Results show that good prediction skill of SM is generally 510 forecast days prior over southern and northeastern China in the majority of models.Over the Tibetan Plateau and northwestern China,only the ECMWF model has good prediction skill 20 days in advance.Generally,better prediction skill tends to appear over wet regions rather than dry regions.In terms of the seasonal variation of SM prediction skill,some diffierences are noticed among the models,but most of them show good prediction skill during September.Furthermore,the significant positive correlation between the prediction skill of SM and ENSO index indicates modulation by ENSO of the S2S prediction of SM.When there is an El Nino(a La Nina)event,the SM prediction skill over eastern China tends to be high(low).Through evaluation of the S2S prediction skill of SM in these models,it is found that the prediction skill of SM is lower than that of most atmospheric variables in S2S forecasts.Therefore,more attention needs to be given to the S2S forecasting of land processes.展开更多
AIM: To study the long-term therapeutic effect of 'heartshaped' anastomosis for Hirschsprung's disease.METHODS: From January 1986 to October 1997, we performed one-stage 'heart-shaped' anastomosis ...AIM: To study the long-term therapeutic effect of 'heartshaped' anastomosis for Hirschsprung's disease.METHODS: From January 1986 to October 1997, we performed one-stage 'heart-shaped' anastomosis for 193 patients with Hirschsprung's disease (HD). One hundred and fiftytwo patients were followed up patients (follow-up rate 79%).The operative outcome and postoperative complications were retrospectively analyzed.RESULTS: Early complications included urine retention in 2patients, enteritis in 10, anastomotic stricture in 1, and intestinal obstruction in 2. No infection of abdominal cavity or wound and anastomotic leakage or death occurred in any patients. Late complications were present in 22 cases,including adhesive intestinal obstruction in 2, longer anal in 5, incision hernia in 2, enteritis in 6, occasional stool stains in 7 and 6 related with improper diet. No constipation or incontinence occurred in any patient.CONCLUSION: The early and late postoperative complication rates were 7.8% and 11.4% respectively in our 'heartshaped anastomosis' procedure. 'Heart-shaped'anastomosis procedure for Hirschsprung's disease provides a better therapeutic effect compared to classic procedures.展开更多
Accurately predicting drought a few months in advance is important for drought mitigation and agricultural and water resources management,especially for a river basin like that of the Yellow River in North China.Howev...Accurately predicting drought a few months in advance is important for drought mitigation and agricultural and water resources management,especially for a river basin like that of the Yellow River in North China.However,summer drought predictability over the Yellow River basin is limited because of the low influence from ENSO and the large interannual variations of the East Asian summer monsoon.To explore the drought predictability from an ensemble prediction perspective,29-year seasonal hindcasts of soil moisture drought,taken directly from several North American multimodel ensemble(NMME)models with different ensemble sizes,were compared with those produced by combining bias-corrected NMME model predictions and variable infiltration capacity(VIC)land surface hydrological model simulations.It was found that the NMME/VIC approach reduced the root-mean-square error from the best NMME raw products by 48%for summer soil moisture drought prediction at the lead-1 season,and increased the correlation significantly.Within the NMME/VIC framework,the multimodel ensemble mean further reduced the error from the best single model by 6%.Compared with the NMME raw forecasts,NMME/VIC had a higher probabilistic drought forecasting skill in terms of a higher Brier skill score and better reliability and resolution of the ensemble.However,the performance of the multimodel grand ensemble was not necessarily better than any single model ensemble,suggesting the need to optimize the ensemble for a more skillful probabilistic drought forecast.展开更多
An effective improvement on the empirical orthogonal function(EOF)–based bias correctionmethod for seasonal forecasts is proposed in this paper,by introducing a stepwise regression method into the process of EOF time...An effective improvement on the empirical orthogonal function(EOF)–based bias correctionmethod for seasonal forecasts is proposed in this paper,by introducing a stepwise regression method into the process of EOF time series correction.Using 30-year(1981–2010)hindcast results from IAP AGCM4.1(the latest version of this model),the improved method is validated for the prediction of summer(June–July–August)rainfall anomalies in Southeast China.The results in terms of the pattern correction coefficient(PCC)of rainfall anomalies shows that the 30-year-averaged prediction skill improves from 0.01 to 0.06 with the original correction method,and to 0.29 using the improved method.The applicability in real-time prediction is also investigated,using 2016 summer rainfall prediction as a test case.With a PCC of 0.59,the authors find that the new correction method significantly improves the prediction skill;the PCC using the direct prediction of the model is?0.04,and using the old bias correction method it is 0.37.展开更多
Two ensemble experiments were conducted using a general atmospheric circulation model. These experiments were used to investigate the impacts of initial snow anomalies over the Tibetan Plateau(TP) on China precipitati...Two ensemble experiments were conducted using a general atmospheric circulation model. These experiments were used to investigate the impacts of initial snow anomalies over the Tibetan Plateau(TP) on China precipitation prediction. In one of the experiments, the initial snow conditions over the TP were climatological values; while in the other experiment, the initial snow anomalies were snow depth estimates derived from the passive microwave remote-sensing data. In the current study, the difference between these two experiments was assessed to evaluate the impact of initial snow anomalies over the TP on simulated precipitation. The results indicated that the model simulation for precipitation over eastern China had certain improvements while applying a more realistic initial snow anomaly, especially for spring precipitation over Northeast China and North China and for summer precipitation over North China and Southeast China. The results suggest that seasonal prediction could be enhanced by using more realistic initial snow conditions over TP, and microwave remote-sensing snow data could be used to initialize climate models and improve the simulation of eastern China precipitation during spring and summer. Further analyses showed that higher snow anomalies over TP cooled the surface, resulting in lower near- surface air temperature over the TP in spring and summer. The surface cooling over TP weakened the Asian summer monsoon and brought more precipitation in South China in spring and more precipitation to Southeast China during summer.展开更多
In this study,we evaluate the forecast skill of the subseasonal-to-seasonal(S2S)prediction model of the Beijing Climate Center(BCC)for the boreal summer intraseasonal oscillation(BSISO).We also discuss the key factors...In this study,we evaluate the forecast skill of the subseasonal-to-seasonal(S2S)prediction model of the Beijing Climate Center(BCC)for the boreal summer intraseasonal oscillation(BSISO).We also discuss the key factors that inhibit the BSISO forecast skill in this model.Based on the bivariate anomaly correlation coefficient(ACC)of the BSISO index,defined by the first two EOF modes of outgoing longwave radiation and 850-hPa zonal wind anomalies over the Asian monsoon region,we found that the hindcast skill degraded as the lead time increased.The ACC dropped to below 0.5for lead times of 11 days and longer when the predicted BSISO showed weakened strength and insignificant northward propagation.To identify what causes the weakened forecast skill of BSISO at the forecast lead time of 11 days,we diagnosed the main mechanisms responsible for the BSISO northward propagation.The same analysis was also carried out using the observations and the outputs of the four-day forecast lead that successfully predicted the observed northward-propagating BSISO.We found that the lack of northward propagation at the 11-day forecast lead was due to insufficient increases in low-level cyclonic vorticity,moistening and warm temperature anomalies to the north of the convection,which were induced by the interaction between background mean flows and BSISO-related anomalous fields.The BCC S2S model can predict the background monsoon circulations,such as the low-level southerly and the northerly and easterly vertical shears,but has limited capability in forecasting the distributions of circulation and moisture anomalies.展开更多
The paper is purposed to promote students' writing skills and help them perfect their cognitive structure at the same time by designing some writing tasks. The tasks are based on the contents of the teaching material...The paper is purposed to promote students' writing skills and help them perfect their cognitive structure at the same time by designing some writing tasks. The tasks are based on the contents of the teaching materials, and students can get involved in the activities by thinking critically.展开更多
This paper focuses on variables affecting L1 transfer in L2 acquisition, which, according to the author, are categorized into three groups: learner-related variables, language-based variables and socio-linguistic var...This paper focuses on variables affecting L1 transfer in L2 acquisition, which, according to the author, are categorized into three groups: learner-related variables, language-based variables and socio-linguistic variables, and each of them is clarified in more details.展开更多
This paper discusses a class of second order nonlinear differential euqations. By using the generalized Riccati technique and the averaging technique, some new oscillation criteria are obtained.
In this paper we study a negatively charged exciton (NCE), which is trapped by a two-dimensional (2D) parabolic potential. By using matrix diagonalization techniques, the correlation energies of the low-lying stat...In this paper we study a negatively charged exciton (NCE), which is trapped by a two-dimensional (2D) parabolic potential. By using matrix diagonalization techniques, the correlation energies of the low-lying states with L=0, 1, and 2 are calculated as a function of confinement strength. We find that the size effects of different states are different. This phenomenon can be explained as a hidden symmetry, which is originated purely from symmetry. Based on symmetry, the features of the low-lying states are discussed in the influence of the 2D parabolic potential well. It is found that the confinement may cause accidental degeneracies between levels with different low-excited states. It is shown that the effect of quantum confinement on the binding energy of the heavy hole is stronger than that of a light hole.展开更多
Rwanda is a landlocked country in central-eastern Africa.As a country highly dependent on rain-fed agriculture,Rwanda is vulnerable to rainfall variability.Observational data show that there are two rainy seasons in R...Rwanda is a landlocked country in central-eastern Africa.As a country highly dependent on rain-fed agriculture,Rwanda is vulnerable to rainfall variability.Observational data show that there are two rainy seasons in Rwanda,i.e.,the long rainy season and the short rainy season.This study mainly focuses on the dominant intraseasonal rainfall mode during the long rainy season(February-May),and evaluates the forecast skill for the intraseasonal variability(ISV)over Rwanda and its surrounding regions in a state-of-the-art dynamic model.During the long rainy season,observational results reveal that the dominant intraseasonal rainfall mode in Rwanda exhibits a significant variability on the 10-25-day time scale.One-point-correlation analysis further unveils that the 10-25-day intraseasonal rainfall variability in Rwanda co-varies with that in its adjacent areas,indicating that the overall 10-25-day rainfall variability in Rwanda and its adjacent regions(8°S-3°N,29°-37°E)should be considered collectively when studying the dominant intraseasonal rainfall variability in Rwanda.Composite results show that the development of the 10-25-day rainfall variability is associated with the anomalous westerly wind in Rwanda and its surrounding regions,which may trace back to a pair of westward-propagating equatorial Rossby waves.Based on the observational findings,an ISO_rainfall_index and an ISO_wind_index are proposed for quantitatively evaluating the forecast skill.The ECMWF model has a comparable skill in predicting the wind index and the rainfall index,with both indices showing a skill of 18 days.展开更多
A 30-year hindcast was performed using version 4.1 of the IAP AGCM(IAP AGCM4.1), and its potential predictability of the MJO was then evaluated. The results showed that the potential predictability of the MJO is 13 ...A 30-year hindcast was performed using version 4.1 of the IAP AGCM(IAP AGCM4.1), and its potential predictability of the MJO was then evaluated. The results showed that the potential predictability of the MJO is 13 and 24 days, evaluated using the signal-to-error ratio method based on a single member and the ensemble mean, respectively. However, the MJO prediction skill is only9 and 10 days using the two methods mentioned above. It was further found that the potential predictability and prediction skill depend on the MJO amplitude in the initial conditions. Prediction initiated from conditions with a strong MJO amplitude tends to be more skillful. Together with the results of other measures, the current MJO prediction ability of IAP AGCM4.1 is around 10 days, which is much lower than other climate prediction systems. Furthermore, the smaller difference between the MJO predictability and prediction skill evaluated by a single member and the ensemble mean methods could be ascribed to the relatively smaller size of the ensemble member of the model.Therefore, considerable effort should be made to improve MJO prediction in IAP AGCM4.1 through application of a reasonable model initialization and ensemble forecast strategy.展开更多
In this study, sensitivity experiments were conducted with the Zebiak-Cane ocean-atmosphere coupled model forced by the wind stress anomaly from the U.S. National Centers for Environmental Prediction/National Center f...In this study, sensitivity experiments were conducted with the Zebiak-Cane ocean-atmosphere coupled model forced by the wind stress anomaly from the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data to study the impacts of eastern Pacific warm pool on the formation and development of ENSO events. The effects of climatological mean sea surface temperature of the warm pool on forecast skill during the ENSO events of 1982-1999 are more considerable that those of climatological mean meridional winds and ocean currents. The forecast skill for the 1997/1998 E1 Nifio event is characterized by sensitivity to climatological mean sea surface temperature and anomalies of northerly winds and currents. The forecast skill is found insensitive to climatological mean northerly meridional winds and currents.展开更多
In this paper, we study the convergence rate of two-dimensional Baakakov operators with Jacobi-weights and the approximation equivalence theorem is obtained, making use of multivariate decompose skills and results of ...In this paper, we study the convergence rate of two-dimensional Baakakov operators with Jacobi-weights and the approximation equivalence theorem is obtained, making use of multivariate decompose skills and results of one-dimensional Baskakov operators.展开更多
As a political leader, US President Trump's personality traits affect his policy orientations and current US foreign policy. The authors analyze Trump's personality in several categories—uninhibited and capri...As a political leader, US President Trump's personality traits affect his policy orientations and current US foreign policy. The authors analyze Trump's personality in several categories—uninhibited and capricious, dynamic and capable, profit-orientated and self-centered,competitive and persistent, positive and extraverted. The traits of breaking traditions, skill at strategic deception and negotiation, action-motivated implementation, intuitive decision-making, pursuit of respect and interest exchange, and vengefulness will shape his policy and behavioral orientations. Initial study shows Trump to be a political leader with positive personality traits and double-sided dimensions. The analysis offers insight toward understanding the new US executive and his policy direction.展开更多
文摘The public’s attitudes can affect the experience of stuttering of people who stutter.This study investigated the attitudes held by the public about people who stutter in China.A web-based written survey with closed and open-ended questions was implemented to develop a rich understanding.One hundred and two respondents in 26 provinces and 3 municipalities provided comments on people who stutter in their life aspects such as personality,speech,social life,work,life participation,education,dating and marriage,capability,and communication skills.The predominantly negative attitudes towards the overall domains were identified.Attitudes to people who stutter varied according to the different sources of knowledge.Familiarity with people who stutter might reduce stereotypes.However,knowledge from the media might aggravate stereotypes.Implications and future research orientation were also discussed.
文摘We consider the following quasiconvex functional I(u)=∫ Gf(x,δu,D mu) d x where u is a vector valued function in W m,p (G),m>1 and p>2. The partial C m,a —regularity is proved for minimizers of I(u) under weaker conditions.
文摘In this paper,a nonconforming rectangular plate element,the modified incomplete biquadratic plate element,is considered. The asympotic optimal L~∞-error estimate is obtained for the plate bending problem. This proof is based on the method of regularized Green's function and 'the trick of auxiliary element'.
文摘Since the 1950s, different English translated versions of Cold Mountain poems have come out in succession. These versions, due to different factors, present different characteristics. Thus, by comparing the the different translated versions of the same original poems, translator's translation skills and the unique characteristics of these versions will be discovered. It is of great significance as they will illustrate the translators' reception of the original as the first group of receptors and these different characteristics will determine the contribution of these version to the reception of Cold Mountain poems abroad.This paper is an attempt to study the translation of one of the most famous Cold Mountain's poems and illustrate their characteristics.
基金supported by the National Key R&D Program of China [grant number 2016YFA0602100]
文摘Based on the reforecasts from ve models of the Subseasonal to Seasonal(S2S)Prediction project,the S2S prediction skill of surface soil moisture(SM)over East Asia during May September is evaluated against ERA-Interim.Results show that good prediction skill of SM is generally 510 forecast days prior over southern and northeastern China in the majority of models.Over the Tibetan Plateau and northwestern China,only the ECMWF model has good prediction skill 20 days in advance.Generally,better prediction skill tends to appear over wet regions rather than dry regions.In terms of the seasonal variation of SM prediction skill,some diffierences are noticed among the models,but most of them show good prediction skill during September.Furthermore,the significant positive correlation between the prediction skill of SM and ENSO index indicates modulation by ENSO of the S2S prediction of SM.When there is an El Nino(a La Nina)event,the SM prediction skill over eastern China tends to be high(low).Through evaluation of the S2S prediction skill of SM in these models,it is found that the prediction skill of SM is lower than that of most atmospheric variables in S2S forecasts.Therefore,more attention needs to be given to the S2S forecasting of land processes.
基金Supported by the National Natural Science Foundation of China, No.39670746
文摘AIM: To study the long-term therapeutic effect of 'heartshaped' anastomosis for Hirschsprung's disease.METHODS: From January 1986 to October 1997, we performed one-stage 'heart-shaped' anastomosis for 193 patients with Hirschsprung's disease (HD). One hundred and fiftytwo patients were followed up patients (follow-up rate 79%).The operative outcome and postoperative complications were retrospectively analyzed.RESULTS: Early complications included urine retention in 2patients, enteritis in 10, anastomotic stricture in 1, and intestinal obstruction in 2. No infection of abdominal cavity or wound and anastomotic leakage or death occurred in any patients. Late complications were present in 22 cases,including adhesive intestinal obstruction in 2, longer anal in 5, incision hernia in 2, enteritis in 6, occasional stool stains in 7 and 6 related with improper diet. No constipation or incontinence occurred in any patient.CONCLUSION: The early and late postoperative complication rates were 7.8% and 11.4% respectively in our 'heartshaped anastomosis' procedure. 'Heart-shaped'anastomosis procedure for Hirschsprung's disease provides a better therapeutic effect compared to classic procedures.
基金supported by the China Special Fund for Meteorological Research in the Public Interest(Major projects)(Grant No.GYHY201506001)the National Natural Science Foundation of China(Grant No.91547103)
文摘Accurately predicting drought a few months in advance is important for drought mitigation and agricultural and water resources management,especially for a river basin like that of the Yellow River in North China.However,summer drought predictability over the Yellow River basin is limited because of the low influence from ENSO and the large interannual variations of the East Asian summer monsoon.To explore the drought predictability from an ensemble prediction perspective,29-year seasonal hindcasts of soil moisture drought,taken directly from several North American multimodel ensemble(NMME)models with different ensemble sizes,were compared with those produced by combining bias-corrected NMME model predictions and variable infiltration capacity(VIC)land surface hydrological model simulations.It was found that the NMME/VIC approach reduced the root-mean-square error from the best NMME raw products by 48%for summer soil moisture drought prediction at the lead-1 season,and increased the correlation significantly.Within the NMME/VIC framework,the multimodel ensemble mean further reduced the error from the best single model by 6%.Compared with the NMME raw forecasts,NMME/VIC had a higher probabilistic drought forecasting skill in terms of a higher Brier skill score and better reliability and resolution of the ensemble.However,the performance of the multimodel grand ensemble was not necessarily better than any single model ensemble,suggesting the need to optimize the ensemble for a more skillful probabilistic drought forecast.
基金jointly supported by the National Key Research and Development Program of China [grant number2016YFC0402702]the Key Project of the Meteorological Public Welfare Research Program [grant number GYHY201406021]the National Natural Science Foundation of China [grant numbers 41575095 and 41661144032]
文摘An effective improvement on the empirical orthogonal function(EOF)–based bias correctionmethod for seasonal forecasts is proposed in this paper,by introducing a stepwise regression method into the process of EOF time series correction.Using 30-year(1981–2010)hindcast results from IAP AGCM4.1(the latest version of this model),the improved method is validated for the prediction of summer(June–July–August)rainfall anomalies in Southeast China.The results in terms of the pattern correction coefficient(PCC)of rainfall anomalies shows that the 30-year-averaged prediction skill improves from 0.01 to 0.06 with the original correction method,and to 0.29 using the improved method.The applicability in real-time prediction is also investigated,using 2016 summer rainfall prediction as a test case.With a PCC of 0.59,the authors find that the new correction method significantly improves the prediction skill;the PCC using the direct prediction of the model is?0.04,and using the old bias correction method it is 0.37.
基金supported by the National Basic Research Program of China (Grant No. 2009CB421407)the Special Fund for Public Welfare (Meteorology) (Grant No. GYHY200906018)+1 种基金"Strategic Priority Research Program-Climate Change: Carbon Budget and Related Issues" of the Chinese Academy of Sciences (Grant No. XDA05110201)the National Key Technologies R&D Program of China (Grant No. 2007BAC29B03)
文摘Two ensemble experiments were conducted using a general atmospheric circulation model. These experiments were used to investigate the impacts of initial snow anomalies over the Tibetan Plateau(TP) on China precipitation prediction. In one of the experiments, the initial snow conditions over the TP were climatological values; while in the other experiment, the initial snow anomalies were snow depth estimates derived from the passive microwave remote-sensing data. In the current study, the difference between these two experiments was assessed to evaluate the impact of initial snow anomalies over the TP on simulated precipitation. The results indicated that the model simulation for precipitation over eastern China had certain improvements while applying a more realistic initial snow anomaly, especially for spring precipitation over Northeast China and North China and for summer precipitation over North China and Southeast China. The results suggest that seasonal prediction could be enhanced by using more realistic initial snow conditions over TP, and microwave remote-sensing snow data could be used to initialize climate models and improve the simulation of eastern China precipitation during spring and summer. Further analyses showed that higher snow anomalies over TP cooled the surface, resulting in lower near- surface air temperature over the TP in spring and summer. The surface cooling over TP weakened the Asian summer monsoon and brought more precipitation in South China in spring and more precipitation to Southeast China during summer.
基金supported by the National Basic Research Program of China (973 Program) (Grant No.2015CB453200)
文摘In this study,we evaluate the forecast skill of the subseasonal-to-seasonal(S2S)prediction model of the Beijing Climate Center(BCC)for the boreal summer intraseasonal oscillation(BSISO).We also discuss the key factors that inhibit the BSISO forecast skill in this model.Based on the bivariate anomaly correlation coefficient(ACC)of the BSISO index,defined by the first two EOF modes of outgoing longwave radiation and 850-hPa zonal wind anomalies over the Asian monsoon region,we found that the hindcast skill degraded as the lead time increased.The ACC dropped to below 0.5for lead times of 11 days and longer when the predicted BSISO showed weakened strength and insignificant northward propagation.To identify what causes the weakened forecast skill of BSISO at the forecast lead time of 11 days,we diagnosed the main mechanisms responsible for the BSISO northward propagation.The same analysis was also carried out using the observations and the outputs of the four-day forecast lead that successfully predicted the observed northward-propagating BSISO.We found that the lack of northward propagation at the 11-day forecast lead was due to insufficient increases in low-level cyclonic vorticity,moistening and warm temperature anomalies to the north of the convection,which were induced by the interaction between background mean flows and BSISO-related anomalous fields.The BCC S2S model can predict the background monsoon circulations,such as the low-level southerly and the northerly and easterly vertical shears,but has limited capability in forecasting the distributions of circulation and moisture anomalies.
文摘The paper is purposed to promote students' writing skills and help them perfect their cognitive structure at the same time by designing some writing tasks. The tasks are based on the contents of the teaching materials, and students can get involved in the activities by thinking critically.
文摘This paper focuses on variables affecting L1 transfer in L2 acquisition, which, according to the author, are categorized into three groups: learner-related variables, language-based variables and socio-linguistic variables, and each of them is clarified in more details.
文摘This paper discusses a class of second order nonlinear differential euqations. By using the generalized Riccati technique and the averaging technique, some new oscillation criteria are obtained.
基金supported by National Natural Science Foundation of China under Grant No.10775035
文摘In this paper we study a negatively charged exciton (NCE), which is trapped by a two-dimensional (2D) parabolic potential. By using matrix diagonalization techniques, the correlation energies of the low-lying states with L=0, 1, and 2 are calculated as a function of confinement strength. We find that the size effects of different states are different. This phenomenon can be explained as a hidden symmetry, which is originated purely from symmetry. Based on symmetry, the features of the low-lying states are discussed in the influence of the 2D parabolic potential well. It is found that the confinement may cause accidental degeneracies between levels with different low-excited states. It is shown that the effect of quantum confinement on the binding energy of the heavy hole is stronger than that of a light hole.
基金jointly supported by the National Key Research and Development Program of China[grant number 2019YFC1510004]and the LASG Open Project.
文摘Rwanda is a landlocked country in central-eastern Africa.As a country highly dependent on rain-fed agriculture,Rwanda is vulnerable to rainfall variability.Observational data show that there are two rainy seasons in Rwanda,i.e.,the long rainy season and the short rainy season.This study mainly focuses on the dominant intraseasonal rainfall mode during the long rainy season(February-May),and evaluates the forecast skill for the intraseasonal variability(ISV)over Rwanda and its surrounding regions in a state-of-the-art dynamic model.During the long rainy season,observational results reveal that the dominant intraseasonal rainfall mode in Rwanda exhibits a significant variability on the 10-25-day time scale.One-point-correlation analysis further unveils that the 10-25-day intraseasonal rainfall variability in Rwanda co-varies with that in its adjacent areas,indicating that the overall 10-25-day rainfall variability in Rwanda and its adjacent regions(8°S-3°N,29°-37°E)should be considered collectively when studying the dominant intraseasonal rainfall variability in Rwanda.Composite results show that the development of the 10-25-day rainfall variability is associated with the anomalous westerly wind in Rwanda and its surrounding regions,which may trace back to a pair of westward-propagating equatorial Rossby waves.Based on the observational findings,an ISO_rainfall_index and an ISO_wind_index are proposed for quantitatively evaluating the forecast skill.The ECMWF model has a comparable skill in predicting the wind index and the rainfall index,with both indices showing a skill of 18 days.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA05110200]the Special Scientific Research Fund of the Meteorological Public Welfare Profession of China[grant number GYHY201406021]the National Natural Science Foundation of China[grant numbers 41575095,41175073,41575062,41520104008]
文摘A 30-year hindcast was performed using version 4.1 of the IAP AGCM(IAP AGCM4.1), and its potential predictability of the MJO was then evaluated. The results showed that the potential predictability of the MJO is 13 and 24 days, evaluated using the signal-to-error ratio method based on a single member and the ensemble mean, respectively. However, the MJO prediction skill is only9 and 10 days using the two methods mentioned above. It was further found that the potential predictability and prediction skill depend on the MJO amplitude in the initial conditions. Prediction initiated from conditions with a strong MJO amplitude tends to be more skillful. Together with the results of other measures, the current MJO prediction ability of IAP AGCM4.1 is around 10 days, which is much lower than other climate prediction systems. Furthermore, the smaller difference between the MJO predictability and prediction skill evaluated by a single member and the ensemble mean methods could be ascribed to the relatively smaller size of the ensemble member of the model.Therefore, considerable effort should be made to improve MJO prediction in IAP AGCM4.1 through application of a reasonable model initialization and ensemble forecast strategy.
基金National Natural Science Foundation of China (40875025, 40875030, 40775033, 40921160381)Shanghai Natural Science Foundation of China (08ZR1422900)Key Promotion Project of New Meteorology Technology of the China Meteorological Administration in 2009 (09A13)
文摘In this study, sensitivity experiments were conducted with the Zebiak-Cane ocean-atmosphere coupled model forced by the wind stress anomaly from the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data to study the impacts of eastern Pacific warm pool on the formation and development of ENSO events. The effects of climatological mean sea surface temperature of the warm pool on forecast skill during the ENSO events of 1982-1999 are more considerable that those of climatological mean meridional winds and ocean currents. The forecast skill for the 1997/1998 E1 Nifio event is characterized by sensitivity to climatological mean sea surface temperature and anomalies of northerly winds and currents. The forecast skill is found insensitive to climatological mean northerly meridional winds and currents.
基金Supported by the Scientific Research Fund of Zhejiang Province Education Depart-ment(200700190) Supported by the Science Technique Planed Item of Taizhou City(063KY08)Supported by Major Scientific Research Fund of Taizhou University(09ZD08)
文摘In this paper, we study the convergence rate of two-dimensional Baakakov operators with Jacobi-weights and the approximation equivalence theorem is obtained, making use of multivariate decompose skills and results of one-dimensional Baskakov operators.
文摘As a political leader, US President Trump's personality traits affect his policy orientations and current US foreign policy. The authors analyze Trump's personality in several categories—uninhibited and capricious, dynamic and capable, profit-orientated and self-centered,competitive and persistent, positive and extraverted. The traits of breaking traditions, skill at strategic deception and negotiation, action-motivated implementation, intuitive decision-making, pursuit of respect and interest exchange, and vengefulness will shape his policy and behavioral orientations. Initial study shows Trump to be a political leader with positive personality traits and double-sided dimensions. The analysis offers insight toward understanding the new US executive and his policy direction.