The quality of background error statistics is one of the key components for successful assimilation of observations in a numerical model.The background error covariance(BEC) of ocean waves is generally estimated under...The quality of background error statistics is one of the key components for successful assimilation of observations in a numerical model.The background error covariance(BEC) of ocean waves is generally estimated under an assumption that it is stationary over a period of time and uniform over a domain.However,error statistics are in fact functions of the physical processes governing the meteorological situation and vary with the wave condition.In this paper,we simulated the BEC of the significant wave height(SWH) employing Monte Carlo methods.An interesting result is that the BEC varies consistently with the mean wave direction(MWD).In the model domain,the BEC of the SWH decreases significantly when the MWD changes abruptly.A new BEC model of the SWH based on the correlation between the BEC and MWD was then developed.A case study of regional data assimilation was performed,where the SWH observations of buoy 22001 were used to assess the SWH hindcast.The results show that the new BEC model benefits wave prediction and allows reasonable approximations of anisotropy and inhomogeneous errors.展开更多
This paper focuses on the dilute real symmetric Wigner matrix Mn=1/√n（aij）n×n, whose offdiagonal entries aij （1 ≤ em ≠ j ≤ n） have mean zero and unit variance, Eaij4 =θnα （θ 〉 0） and the fifth momen...This paper focuses on the dilute real symmetric Wigner matrix Mn=1/√n（aij）n×n, whose offdiagonal entries aij （1 ≤ em ≠ j ≤ n） have mean zero and unit variance, Eaij4 =θnα （θ 〉 0） and the fifth moments of aij satisfy a Lindeberg type condition. When the dilute parameter 0 〈 α ≤ 1/3 and the test function satisfies some regular conditions, it proves that the centered linear eigenvalue statistics of Mn obey the central limit theorem.展开更多
基金Supported by the National Natural Science Foundation of China (Nos.40806011,U1133001)the Open Fund of the Key Laboratory of Ocean Circulation and Waves,Chinese Academy of Sciences(No. KLOCAW0806)
文摘The quality of background error statistics is one of the key components for successful assimilation of observations in a numerical model.The background error covariance(BEC) of ocean waves is generally estimated under an assumption that it is stationary over a period of time and uniform over a domain.However,error statistics are in fact functions of the physical processes governing the meteorological situation and vary with the wave condition.In this paper,we simulated the BEC of the significant wave height(SWH) employing Monte Carlo methods.An interesting result is that the BEC varies consistently with the mean wave direction(MWD).In the model domain,the BEC of the SWH decreases significantly when the MWD changes abruptly.A new BEC model of the SWH based on the correlation between the BEC and MWD was then developed.A case study of regional data assimilation was performed,where the SWH observations of buoy 22001 were used to assess the SWH hindcast.The results show that the new BEC model benefits wave prediction and allows reasonable approximations of anisotropy and inhomogeneous errors.
基金supported by National Natural Science Foundation of China (Grant Nos. 11326173,11071213 and 11101362)National Natural Science Foundation of Zhejiang Province in China (Grant No. R6090034)+1 种基金Research Fund for the Doctoral Program of Higher Education (Grant No. 20100101110001)Foundation of He’nan Educational Committee in China (Grant No. 13A110087)
文摘This paper focuses on the dilute real symmetric Wigner matrix Mn=1/√n（aij）n×n, whose offdiagonal entries aij （1 ≤ em ≠ j ≤ n） have mean zero and unit variance, Eaij4 =θnα （θ 〉 0） and the fifth moments of aij satisfy a Lindeberg type condition. When the dilute parameter 0 〈 α ≤ 1/3 and the test function satisfies some regular conditions, it proves that the centered linear eigenvalue statistics of Mn obey the central limit theorem.
