本文基于卫星遥感的观测海表面温度(Sea Surface Temperature,SST)数据和自然资源部第一海洋研究所全球0.1°分辨率海浪-潮流-环流耦合数值预报模式(The surface wave-tide-circulation coupled ocean model developed by First Ins...本文基于卫星遥感的观测海表面温度(Sea Surface Temperature,SST)数据和自然资源部第一海洋研究所全球0.1°分辨率海浪-潮流-环流耦合数值预报模式(The surface wave-tide-circulation coupled ocean model developed by First Institute of Oceanography,MNR,China,FIO-COM)的预报结果,采用线性回归模型和长短期记忆神经网络(Long Short-Term Memory,LSTM)对SST预报结果进行误差校正。利用2016—2021年的数据开展了一系列对比试验,线性回归模型基于局部线性的假设实现对下一时刻误差的预报,LSTM利用2016—2020年共56个月的历史偏差数据训练模型,使用2021年的数据进行检验。结果表明,线性回归模型和LSTM神经网络都可以改善预报结果,LSTM神经网络相对于线性回归模型的效果更好,SST误差降低70%左右;与线性回归模型相比,经LSTM校正后的各点的偏差的概率密度分布集中在0附近。LSTM方法在统计意义上优于线性拟合且结果更稳定,可进一步推广到海洋数值预报多要素偏差校正。展开更多
The SST variability during the summer period in the northeastern tropical Atlantic region (NTA) is characterized by an alternation of warming/cooling which represents 87% of the total variability. The aim of this pape...The SST variability during the summer period in the northeastern tropical Atlantic region (NTA) is characterized by an alternation of warming/cooling which represents 87% of the total variability. The aim of this paper is to study the atmospheric responses as well as the precipitation associated with these oceanic conditions. Based on Reynolds’s SST from 1982 to 2019, a normalized Northern Tropical Atlantic index (NTAI) is computed into the region between 15° - 25°W;12° - 16°N and a composite analysis is then performed. It is shown that the NTAI is significantly correlated with the SST’s first principal component mode (PC1) in this region. Moreover, the composite of SST anomalies and atmospheric parameters exhibits a strong local ocean-atmosphere interaction which highly impacts the large-scale atmospheric circulation in West Africa, particularly in the western Sahel. An in-depth analysis shows that the atmospheric response to the warm (cold) SST is a cyclonic (anticyclonic) circulation in the lower layers near the West Africa Coast. This cyclonic (anticyclonic) circulation strengthens/reduces the moisture transport towards the continent in the low levels. In the middle layers of the atmosphere (500 hPa), the warm (cold) composite is associated with a decrease (increase) in the intensity of the African Easterly Jet (AEJ) whereas, in the upper atmosphere (200 hPa), the strengthening (weakening) of the Tropical Easterly Jet (TEJ) is observed. With regard to the composite precipitation field, a positive/negative SST anomaly is associated with significantly enhanced/reduced rainfall in the western Sahelian region. It is found that this relationship (correlation) increases as we are closer to the coasts.展开更多
本文基于Hadley中心的海表温度资料、全国160站气温资料以及National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)的再分析资料,运用经验正交函数(empirical orthogonal function,EOF)...本文基于Hadley中心的海表温度资料、全国160站气温资料以及National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)的再分析资料,运用经验正交函数(empirical orthogonal function,EOF)分解和相关分析等多种统计方法,研究了1951~2020年秋季(9~11月)北大西洋海温年际异常的主要特征及其对初冬(12月)我国气温异常的影响。结果表明:秋季北大西洋海温异常EOF的第一模态是纽芬兰岛东南部海温为负(正)距平,北大西洋副极地和副热带及其东部海温为正(负)距平的马蹄型海温模态,方差贡献率为20.5%。研究表明,秋季北大西洋马蹄型海温异常与我国大部分地区初冬气温异常有显著的正相关关系,即秋季北大西洋马蹄型海温模态呈正位相时,我国大部分地区初冬气温偏高,反之,我国大部分地区初冬气温偏低。进一步分析表明,秋季北大西洋马蹄型海温异常能够持续到初冬。当秋季北大西洋马蹄型海温呈正(负)位相时,初冬北大西洋副极地和副热带海温异常通过加热(冷却)异常能够引起局地对流层上层的辐散(辐合)运动,并且激发出南、北两支Rossby波列。其中,北支波列由北大西洋副极地向东北方向传播至巴伦支海附近,然后沿西伯利亚向东南方向传播至我国上空;南支波列由北大西洋副热带向东传播至我国上空。在南、北支波列的影响下,我国上空对流层上层出现异常辐合(辐散),与之伴随的异常下沉(上升)运动使得我国上空云量减少(增加),到达地表的短波辐射增加(减少),同时地表向低层大气传输的长波辐射增加(减少),在非绝热加热的作用下,我国大部分地区气温偏高(偏低)。利用NCAR Community Atmosphere Model version 5.3(CAM5.3)模式模拟了北大西洋马蹄型海温异常对初冬大气环流、辐射强迫和气温的影响,模拟结果与观测资料统计分析结果基本一致,进一步表明该海温模态能够激发出遥相关波列,影响东亚大气环流异常,通过非绝热加热的作用影响我国气温异常的年际变化。展开更多
利用NCEP/NCAR再分析资料、ERSST v5海表温度资料和大气环流模式,分析了2022年夏季热带印度洋-太平洋海温异常对长江中下游地区高温事件的影响机理及相对贡献。研究表明,此次高温异常事件受La Ni a事件和负位相IOD事件的共同影响,长江...利用NCEP/NCAR再分析资料、ERSST v5海表温度资料和大气环流模式,分析了2022年夏季热带印度洋-太平洋海温异常对长江中下游地区高温事件的影响机理及相对贡献。研究表明,此次高温异常事件受La Ni a事件和负位相IOD事件的共同影响,长江中下游地区的温度异常为1.52℃、为近40年来最高,温度正异常的极大值位于河南和湖北两省交界处的西侧。热带印度洋和太平洋海温异常引起了长江中下游约0.39℃的增温,对长江中下游地区此次高温异常的贡献为25.66%。La Ni a事件和负位相IOD事件可通过增强西太平洋副热带高压,进而有利于维持长江中下游地区的异常下沉运动,为高温事件的发生提供了有利条件。展开更多
基金funded by the National Natural Science Foundation of China[grant number 42105063]the Youth Training Project of the Key Laboratory for Meteorological Disaster Monitoring and Early Warning and Risk Management of Characteristic Agriculture in Arid Regions[project number CAMT-202302]a funded project of Hengyang Normal University[project number 2022QD11].
文摘本文基于卫星遥感的观测海表面温度(Sea Surface Temperature,SST)数据和自然资源部第一海洋研究所全球0.1°分辨率海浪-潮流-环流耦合数值预报模式(The surface wave-tide-circulation coupled ocean model developed by First Institute of Oceanography,MNR,China,FIO-COM)的预报结果,采用线性回归模型和长短期记忆神经网络(Long Short-Term Memory,LSTM)对SST预报结果进行误差校正。利用2016—2021年的数据开展了一系列对比试验,线性回归模型基于局部线性的假设实现对下一时刻误差的预报,LSTM利用2016—2020年共56个月的历史偏差数据训练模型,使用2021年的数据进行检验。结果表明,线性回归模型和LSTM神经网络都可以改善预报结果,LSTM神经网络相对于线性回归模型的效果更好,SST误差降低70%左右;与线性回归模型相比,经LSTM校正后的各点的偏差的概率密度分布集中在0附近。LSTM方法在统计意义上优于线性拟合且结果更稳定,可进一步推广到海洋数值预报多要素偏差校正。
文摘The SST variability during the summer period in the northeastern tropical Atlantic region (NTA) is characterized by an alternation of warming/cooling which represents 87% of the total variability. The aim of this paper is to study the atmospheric responses as well as the precipitation associated with these oceanic conditions. Based on Reynolds’s SST from 1982 to 2019, a normalized Northern Tropical Atlantic index (NTAI) is computed into the region between 15° - 25°W;12° - 16°N and a composite analysis is then performed. It is shown that the NTAI is significantly correlated with the SST’s first principal component mode (PC1) in this region. Moreover, the composite of SST anomalies and atmospheric parameters exhibits a strong local ocean-atmosphere interaction which highly impacts the large-scale atmospheric circulation in West Africa, particularly in the western Sahel. An in-depth analysis shows that the atmospheric response to the warm (cold) SST is a cyclonic (anticyclonic) circulation in the lower layers near the West Africa Coast. This cyclonic (anticyclonic) circulation strengthens/reduces the moisture transport towards the continent in the low levels. In the middle layers of the atmosphere (500 hPa), the warm (cold) composite is associated with a decrease (increase) in the intensity of the African Easterly Jet (AEJ) whereas, in the upper atmosphere (200 hPa), the strengthening (weakening) of the Tropical Easterly Jet (TEJ) is observed. With regard to the composite precipitation field, a positive/negative SST anomaly is associated with significantly enhanced/reduced rainfall in the western Sahelian region. It is found that this relationship (correlation) increases as we are closer to the coasts.
文摘本文基于Hadley中心的海表温度资料、全国160站气温资料以及National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)的再分析资料,运用经验正交函数(empirical orthogonal function,EOF)分解和相关分析等多种统计方法,研究了1951~2020年秋季(9~11月)北大西洋海温年际异常的主要特征及其对初冬(12月)我国气温异常的影响。结果表明:秋季北大西洋海温异常EOF的第一模态是纽芬兰岛东南部海温为负(正)距平,北大西洋副极地和副热带及其东部海温为正(负)距平的马蹄型海温模态,方差贡献率为20.5%。研究表明,秋季北大西洋马蹄型海温异常与我国大部分地区初冬气温异常有显著的正相关关系,即秋季北大西洋马蹄型海温模态呈正位相时,我国大部分地区初冬气温偏高,反之,我国大部分地区初冬气温偏低。进一步分析表明,秋季北大西洋马蹄型海温异常能够持续到初冬。当秋季北大西洋马蹄型海温呈正(负)位相时,初冬北大西洋副极地和副热带海温异常通过加热(冷却)异常能够引起局地对流层上层的辐散(辐合)运动,并且激发出南、北两支Rossby波列。其中,北支波列由北大西洋副极地向东北方向传播至巴伦支海附近,然后沿西伯利亚向东南方向传播至我国上空;南支波列由北大西洋副热带向东传播至我国上空。在南、北支波列的影响下,我国上空对流层上层出现异常辐合(辐散),与之伴随的异常下沉(上升)运动使得我国上空云量减少(增加),到达地表的短波辐射增加(减少),同时地表向低层大气传输的长波辐射增加(减少),在非绝热加热的作用下,我国大部分地区气温偏高(偏低)。利用NCAR Community Atmosphere Model version 5.3(CAM5.3)模式模拟了北大西洋马蹄型海温异常对初冬大气环流、辐射强迫和气温的影响,模拟结果与观测资料统计分析结果基本一致,进一步表明该海温模态能够激发出遥相关波列,影响东亚大气环流异常,通过非绝热加热的作用影响我国气温异常的年际变化。
文摘利用NCEP/NCAR再分析资料、ERSST v5海表温度资料和大气环流模式,分析了2022年夏季热带印度洋-太平洋海温异常对长江中下游地区高温事件的影响机理及相对贡献。研究表明,此次高温异常事件受La Ni a事件和负位相IOD事件的共同影响,长江中下游地区的温度异常为1.52℃、为近40年来最高,温度正异常的极大值位于河南和湖北两省交界处的西侧。热带印度洋和太平洋海温异常引起了长江中下游约0.39℃的增温,对长江中下游地区此次高温异常的贡献为25.66%。La Ni a事件和负位相IOD事件可通过增强西太平洋副热带高压,进而有利于维持长江中下游地区的异常下沉运动,为高温事件的发生提供了有利条件。
