为提升FPGA(Field Programmable Gate Array)高速Serdes通讯稳定性,实时监控其通讯状态,文中设计了一种基于K码控制字符的通讯协议。创建标志用户数据帧起始的动态SOF(Start of Frame)和标志结束的静态EOF(End of Frame)两种K码控制字符...为提升FPGA(Field Programmable Gate Array)高速Serdes通讯稳定性,实时监控其通讯状态,文中设计了一种基于K码控制字符的通讯协议。创建标志用户数据帧起始的动态SOF(Start of Frame)和标志结束的静态EOF(End of Frame)两种K码控制字符,有利于通讯的连续性检测。创建TLINK(Transmit Link)、BLINK(Back Link)的K码控制字符,其中TLINK控制字符在Serdes的发送端进行定期发送,接收端收到TLINK控制字符后,控制本方的Serdes发送端优先输出BLINK控制字符进行应答,以建立通讯双方之间的握手关系,有利于通讯的超时和状态检测。校验独立于SOF、EOF之间的用户数据,进行CRC32(Cyclic Redundancy Check32)计算,有利于通讯的误码检测。实验结果表明,该协议可实现对Serdes链路的丢帧数量、误码数量、超时数量及通讯断开时长进行准确监控,最小时间精度为10μs。展开更多
在全球气候变化背景下,极端高温事件频发,且自21世纪以来其发生频率明显增加,对农业生产及人体健康造成深远影响。为探究地形复杂的伊犁河流域极端高温时空演变规律,本文利用1991—2020年该流域11个气象站逐日气温数据,计算夏季日数(SU...在全球气候变化背景下,极端高温事件频发,且自21世纪以来其发生频率明显增加,对农业生产及人体健康造成深远影响。为探究地形复杂的伊犁河流域极端高温时空演变规律,本文利用1991—2020年该流域11个气象站逐日气温数据,计算夏季日数(SU25)、热夜日数(TR20)、暖昼日数(TX90p)、暖夜日数(TN90p)、日最高气温极高值(TXx)和日最低气温极高值(TNx)6个极端高温指数,并通过线性趋势分析、Mann-Kendall突变检验、经验正交函数分解(Empirical Orthogonal Function decomposition,EOF)以及克里金插值法(Kriging),系统分析伊犁河流域6个极端高温指数的时空变化特征。结果表明:伊犁河流域大部分极端高温指数整体呈快速增长趋势,且在20世纪90年代至21世纪初发生显著突变。其中SU25、TX90p、TXx和TNx的增长速率突出,2015年后各指数处于加速增长阶段。空间分布上,流域大部分极端高温指数呈现明显的“西北高、东南低”格局:西北部为高温指数高值区,昭苏东北部、特克斯、巩留及尼勒克西南部形成稳定低值中心。由EOF分解得到TXx与TNx的空间分布存在两种典型模态,其演变特征与流域极端高温整体变化趋势具有高度一致性。展开更多
This study examines how Algeria’s winter(December-February,DJF)rainfall is affected by the trends and variability of the Mediterranean Sea Surface Temperature(SST)between 1993 and 2023.Empirical Orthogonal Function(E...This study examines how Algeria’s winter(December-February,DJF)rainfall is affected by the trends and variability of the Mediterranean Sea Surface Temperature(SST)between 1993 and 2023.Empirical Orthogonal Function(EOF)analysis and composite diagnostics were used to identify dominant SST modes and their atmospheric linkages using high-resolution datasets(ERSST,CHIRPS,and NCEP/NCAR reanalysis).The second Mediterranean SST mode(EOF2),which is the main cause of rainfall variability in Algeria,accounts for 25.3%of the variance in SST and is distinguished by a zonal dipole(eastern cooling vs.western warming).The associated atmospheric patterns show that whereas cool phases reduce precipitation through anticyclonic conditions and subsidence,warm SST phases increase rainfall through cyclonic circulation,increased vertical motion,and moisture flux convergence.The study concludes that the interannual and annual variation of Mediterranean SST is one of the key regulators of the winter hydroclimate in Algeria,and it has important implications,for the variability of water resources in the region.The importance of interannual SST variability over long-term trends in regulating Algeria’s winter hydroclimate is also highlighted by these findings,which are worth studying in the future.展开更多
Tropospheric ozone pollution has been worsened over most regions of China,adversely affecting human health and ecosystems.The long-term ozone concentration depends largely upon atmospheric circulations.Here,we conduct...Tropospheric ozone pollution has been worsened over most regions of China,adversely affecting human health and ecosystems.The long-term ozone concentration depends largely upon atmospheric circulations.Here,we conducted meteorological adjustment to quantitatively assess the influences of meteorological factors on the ozone evolution in China's seven city clusters during thewarm season(April to October)from 2013 to 2020.Our analysis indicated that northern and eastern regions experienced ozone increases driven by emission changes.Southern regions,particularly the Pearl River Delta(PRD),exhibited ozone rise primarily due to meteorological conditions despite emission changes.In the Sichuan Basin(SCB)and Central Yangtze River Plain(CYP),where ozone levels decreased,meteorological conditions played a significant role in suppressing the ascent of ozone.Empirical orthogonal functions(EOF)analyses suggested that the spatiotemporal trend ofmeteorologyassociated ozone was strongly correlated with the variation of East Asian Trough(EAT),South Asian High(SAH)and the western Pacific subtropical high(WPSH).The top three EOF patterns explained 33.4%,21.8%,and 16.0%of the total variance inmeteorology-associated ozone.Absolute principal component scores-multiple linear regression(APCS-MLR)analyse quantitatively identified that enhanced EAT and SAH with a northward location of WPSH were favourable to surface ozone formation in central and eastern regions,but unfavourable to ozone formation in edge regions such as SCB.展开更多
This paper demonstrates that the spatial distribution of the ionospheric TEC over the Indian region can be reconstructed with appreciable accuracy using minimal numbers of empirical orthogonal functions as a basis.The...This paper demonstrates that the spatial distribution of the ionospheric TEC over the Indian region can be reconstructed with appreciable accuracy using minimal numbers of empirical orthogonal functions as a basis.These basis functions were derived using the Singular Value Decomposition of a matrix composed of pragmatic vertical Total Electron Content(VTEC)values collected across varied ionospheric conditions and measured over the region of interest.The reconstruction was achieved by linearly combining the appropriately chosen significant bases with corresponding weight factors.The reconstruction accuracy of the algorithm was found to be better than 4 TECU(TECU=1016electrons/m2)for more than 99.9%of the time when tested over the complete year of 2016 with only eight basis vectors.The containment factor,defined here,indicates the goodness of the chosen bases in representing the arbitrary VTEC distributions and is found to remain typically high,aiding in improved algorithm performance.The performance,however,was found to be sensitive to the seasons and geomagnetic conditions.Deteriorated performance was observed when tested for the St.Patrick's Day storm data.The deterioration was attributed to the structural alteration of the ionospheric plasma density and the presence of atypical modes during the storm.The results ascertain the prospect of a faithful representation of the spatial distribution of the ionospheric VTEC using limited parametric variables,which may find utility in navigation,radar,and various other applications.展开更多
文摘在全球气候变化背景下,极端高温事件频发,且自21世纪以来其发生频率明显增加,对农业生产及人体健康造成深远影响。为探究地形复杂的伊犁河流域极端高温时空演变规律,本文利用1991—2020年该流域11个气象站逐日气温数据,计算夏季日数(SU25)、热夜日数(TR20)、暖昼日数(TX90p)、暖夜日数(TN90p)、日最高气温极高值(TXx)和日最低气温极高值(TNx)6个极端高温指数,并通过线性趋势分析、Mann-Kendall突变检验、经验正交函数分解(Empirical Orthogonal Function decomposition,EOF)以及克里金插值法(Kriging),系统分析伊犁河流域6个极端高温指数的时空变化特征。结果表明:伊犁河流域大部分极端高温指数整体呈快速增长趋势,且在20世纪90年代至21世纪初发生显著突变。其中SU25、TX90p、TXx和TNx的增长速率突出,2015年后各指数处于加速增长阶段。空间分布上,流域大部分极端高温指数呈现明显的“西北高、东南低”格局:西北部为高温指数高值区,昭苏东北部、特克斯、巩留及尼勒克西南部形成稳定低值中心。由EOF分解得到TXx与TNx的空间分布存在两种典型模态,其演变特征与流域极端高温整体变化趋势具有高度一致性。
文摘This study examines how Algeria’s winter(December-February,DJF)rainfall is affected by the trends and variability of the Mediterranean Sea Surface Temperature(SST)between 1993 and 2023.Empirical Orthogonal Function(EOF)analysis and composite diagnostics were used to identify dominant SST modes and their atmospheric linkages using high-resolution datasets(ERSST,CHIRPS,and NCEP/NCAR reanalysis).The second Mediterranean SST mode(EOF2),which is the main cause of rainfall variability in Algeria,accounts for 25.3%of the variance in SST and is distinguished by a zonal dipole(eastern cooling vs.western warming).The associated atmospheric patterns show that whereas cool phases reduce precipitation through anticyclonic conditions and subsidence,warm SST phases increase rainfall through cyclonic circulation,increased vertical motion,and moisture flux convergence.The study concludes that the interannual and annual variation of Mediterranean SST is one of the key regulators of the winter hydroclimate in Algeria,and it has important implications,for the variability of water resources in the region.The importance of interannual SST variability over long-term trends in regulating Algeria’s winter hydroclimate is also highlighted by these findings,which are worth studying in the future.
基金supported by the National Natural Science Foundation of China(No.42377095)the Open Research Fund Program of Plateau Atmosphere and Environment Key Laboratory of Sichuan Province(No.PAEKL-2024-K01)Xianyang Key Research and Development Program(No.L2022ZDYFSF040).
文摘Tropospheric ozone pollution has been worsened over most regions of China,adversely affecting human health and ecosystems.The long-term ozone concentration depends largely upon atmospheric circulations.Here,we conducted meteorological adjustment to quantitatively assess the influences of meteorological factors on the ozone evolution in China's seven city clusters during thewarm season(April to October)from 2013 to 2020.Our analysis indicated that northern and eastern regions experienced ozone increases driven by emission changes.Southern regions,particularly the Pearl River Delta(PRD),exhibited ozone rise primarily due to meteorological conditions despite emission changes.In the Sichuan Basin(SCB)and Central Yangtze River Plain(CYP),where ozone levels decreased,meteorological conditions played a significant role in suppressing the ascent of ozone.Empirical orthogonal functions(EOF)analyses suggested that the spatiotemporal trend ofmeteorologyassociated ozone was strongly correlated with the variation of East Asian Trough(EAT),South Asian High(SAH)and the western Pacific subtropical high(WPSH).The top three EOF patterns explained 33.4%,21.8%,and 16.0%of the total variance inmeteorology-associated ozone.Absolute principal component scores-multiple linear regression(APCS-MLR)analyse quantitatively identified that enhanced EAT and SAH with a northward location of WPSH were favourable to surface ozone formation in central and eastern regions,but unfavourable to ozone formation in edge regions such as SCB.
文摘This paper demonstrates that the spatial distribution of the ionospheric TEC over the Indian region can be reconstructed with appreciable accuracy using minimal numbers of empirical orthogonal functions as a basis.These basis functions were derived using the Singular Value Decomposition of a matrix composed of pragmatic vertical Total Electron Content(VTEC)values collected across varied ionospheric conditions and measured over the region of interest.The reconstruction was achieved by linearly combining the appropriately chosen significant bases with corresponding weight factors.The reconstruction accuracy of the algorithm was found to be better than 4 TECU(TECU=1016electrons/m2)for more than 99.9%of the time when tested over the complete year of 2016 with only eight basis vectors.The containment factor,defined here,indicates the goodness of the chosen bases in representing the arbitrary VTEC distributions and is found to remain typically high,aiding in improved algorithm performance.The performance,however,was found to be sensitive to the seasons and geomagnetic conditions.Deteriorated performance was observed when tested for the St.Patrick's Day storm data.The deterioration was attributed to the structural alteration of the ionospheric plasma density and the presence of atypical modes during the storm.The results ascertain the prospect of a faithful representation of the spatial distribution of the ionospheric VTEC using limited parametric variables,which may find utility in navigation,radar,and various other applications.
