This study attempts to investigate the interaction between lower and upper atmosphere, employing daily data of Total Ozone Column (TOC) and atmospheric parameter (cloud cover) over Nigeria from 1998-2012;in order to s...This study attempts to investigate the interaction between lower and upper atmosphere, employing daily data of Total Ozone Column (TOC) and atmospheric parameter (cloud cover) over Nigeria from 1998-2012;in order to study the dynamic effect of ozone on climate and vice versa. This is due to the fact that ozone and climate influence each other and the understanding of the dynamic effect of the interconnectivity is still an open research area. Monthly mean daily TOC and cloud cover data were obtained from the Earth Probe Total Ozone Mass Spectroscopy (EPTOMS) and the International Satellite Cloud Climatology Project (ISCCP)-D2 datasets respectively. Bivariate analysis and Mann Kendall trend tests were used in data analysis. MATLAB and ArcGIS software were employed in analyzing the data. Results reveal that TOC increased spatially from the coastal region to the north eastern region of the country. Seasonally, the highest value of TOC was observed at the peak of rainy season when cloud activity is very high, while the lowest value was recorded in dry season. These variations were attributed to rain producing mechanisms and atmospheric phenomena which influence the transport and distribution of ozone. Furthermore, the statistical analysis reveals significant relationship between TOC and low and middle cloud covers in contrast to high cloud cover. This relationship is consistent with previous studies using other atmospheric variables. This study has given scientific insight which is useful in understanding the coupling of the lower and upper atmosphere.展开更多
The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability...The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability involves the role of atmospheric dynamics, linked in particular to the Saharan Heat Low (SHL). This article addresses this question by comparing the sets of preindustrial control and historical simulation data from climate models carried out in the framework of the CMIP5 project and observations data over the 20<sup>th</sup> century. Through multivariate statistical analyses, it was established that decadal modes of ocean variability and decadal variability of Saharan atmospheric dynamics significantly influence decadal variability of monsoon precipitation. These results also suggest the existence of external anthropogenic forcing, which is superimposed on the decadal natural variability inducing an intensification of the signal in the historical simulations compared to preindustrial control simulations. We have also shown that decadal rainfall variability in the Sahel, once the influence of oceanic modes has been eliminated, appears to be driven mainly by the activity of the Arabian Heat Low (AHL) in the central Sahel, and by the structure of the meridional temperature gradient over the inter-tropical Atlantic in the western Sahel.展开更多
We investigate the continuous variable quantum teleportation in atmosphere channels. The beam-wandering model is employed to analyze the teleportation of the unknown single-mode coherent state. Two methods, one is det...We investigate the continuous variable quantum teleportation in atmosphere channels. The beam-wandering model is employed to analyze the teleportation of the unknown single-mode coherent state. Two methods, one is deterministic by increasing the aperture size of the detecting device and one is probabilistic by entanglement distillation, are proposed to improve the teleportation fidelity in the presence of atmosphere noises.展开更多
Estimation of economic loss is essential for stakeholders to manage flood risk.Most flooding events are closely related to extreme precipitation,which is influenced by large-scale climate factors.Considering the lagge...Estimation of economic loss is essential for stakeholders to manage flood risk.Most flooding events are closely related to extreme precipitation,which is influenced by large-scale climate factors.Considering the lagged influence of climate factors,we developed a flood-risk assessment framework and used Hunan Province in China as an example to illustrate the risk assessment process.The main patterns of precipitation—as a connection between climate factors and flood economic losses—were extracted by the empirical orthogonal function(EOF)analysis.We identified the correlative climate factors through crosscorrelation analysis and established a multiple stepwise linear regression model to forecast future precipitation patterns.Risk assessment was done based on the main precipitation patterns.Because the economic dataset is limited,a Monte Carlo simulation was applied to simulate 1000-year flood loss events under each precipitation regime(rainy,dry,normal years)to obtain aggregate exceedance probability(AEP)and occurrence exceedance probability(OEP)curves.We found that precipitation has a strong influence on economic loss risk,with the highest risk in rainy years.Regional economic development imbalances are the potential reason for the varying economic loss risks in different regions of Hunan Province.As the climate indices with at least several months prediction lead time are strong indicators in predicting precipitation,the framework we developed can estimate economic loss risk several months in advance.展开更多
文摘This study attempts to investigate the interaction between lower and upper atmosphere, employing daily data of Total Ozone Column (TOC) and atmospheric parameter (cloud cover) over Nigeria from 1998-2012;in order to study the dynamic effect of ozone on climate and vice versa. This is due to the fact that ozone and climate influence each other and the understanding of the dynamic effect of the interconnectivity is still an open research area. Monthly mean daily TOC and cloud cover data were obtained from the Earth Probe Total Ozone Mass Spectroscopy (EPTOMS) and the International Satellite Cloud Climatology Project (ISCCP)-D2 datasets respectively. Bivariate analysis and Mann Kendall trend tests were used in data analysis. MATLAB and ArcGIS software were employed in analyzing the data. Results reveal that TOC increased spatially from the coastal region to the north eastern region of the country. Seasonally, the highest value of TOC was observed at the peak of rainy season when cloud activity is very high, while the lowest value was recorded in dry season. These variations were attributed to rain producing mechanisms and atmospheric phenomena which influence the transport and distribution of ozone. Furthermore, the statistical analysis reveals significant relationship between TOC and low and middle cloud covers in contrast to high cloud cover. This relationship is consistent with previous studies using other atmospheric variables. This study has given scientific insight which is useful in understanding the coupling of the lower and upper atmosphere.
文摘The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability involves the role of atmospheric dynamics, linked in particular to the Saharan Heat Low (SHL). This article addresses this question by comparing the sets of preindustrial control and historical simulation data from climate models carried out in the framework of the CMIP5 project and observations data over the 20<sup>th</sup> century. Through multivariate statistical analyses, it was established that decadal modes of ocean variability and decadal variability of Saharan atmospheric dynamics significantly influence decadal variability of monsoon precipitation. These results also suggest the existence of external anthropogenic forcing, which is superimposed on the decadal natural variability inducing an intensification of the signal in the historical simulations compared to preindustrial control simulations. We have also shown that decadal rainfall variability in the Sahel, once the influence of oceanic modes has been eliminated, appears to be driven mainly by the activity of the Arabian Heat Low (AHL) in the central Sahel, and by the structure of the meridional temperature gradient over the inter-tropical Atlantic in the western Sahel.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11574400,U1304613,11204197,11204379and 11074244
文摘We investigate the continuous variable quantum teleportation in atmosphere channels. The beam-wandering model is employed to analyze the teleportation of the unknown single-mode coherent state. Two methods, one is deterministic by increasing the aperture size of the detecting device and one is probabilistic by entanglement distillation, are proposed to improve the teleportation fidelity in the presence of atmosphere noises.
基金supported by the National Natural Science Foundation of China(grant No.41671503)。
文摘Estimation of economic loss is essential for stakeholders to manage flood risk.Most flooding events are closely related to extreme precipitation,which is influenced by large-scale climate factors.Considering the lagged influence of climate factors,we developed a flood-risk assessment framework and used Hunan Province in China as an example to illustrate the risk assessment process.The main patterns of precipitation—as a connection between climate factors and flood economic losses—were extracted by the empirical orthogonal function(EOF)analysis.We identified the correlative climate factors through crosscorrelation analysis and established a multiple stepwise linear regression model to forecast future precipitation patterns.Risk assessment was done based on the main precipitation patterns.Because the economic dataset is limited,a Monte Carlo simulation was applied to simulate 1000-year flood loss events under each precipitation regime(rainy,dry,normal years)to obtain aggregate exceedance probability(AEP)and occurrence exceedance probability(OEP)curves.We found that precipitation has a strong influence on economic loss risk,with the highest risk in rainy years.Regional economic development imbalances are the potential reason for the varying economic loss risks in different regions of Hunan Province.As the climate indices with at least several months prediction lead time are strong indicators in predicting precipitation,the framework we developed can estimate economic loss risk several months in advance.
