Observed and Predicted Ratios of the Horizontal and Vertical Components of the Solar p-Mode Velocity Eigenfunctions
Observed and Predicted Ratios of the Horizontal and Vertical Components of the Solar p-Mode Velocity Eigenfunctions
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太阳 p 模速度本征函数的水平和垂直分量的观测和预测比率
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
P. Scherrer
中科院分区：
文献类型：
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作者：
E. Rhodes, Jr.;J. Reiter;J. Schou;A. Kosovichev;P. Scherrer
我们提供的证据表明，观测到的太阳中度p模速度特征函数的水平和垂直分量的比值与这些比值的理论预测非常吻合。这一证据来自对观测到的特征函数分量比的估计，这些特征函数分量比是从1996年底和1998年初获得的全球振荡网络组（GONG）项目多普勒图的两个不同的60.75天时间序列计算的低度和中度（l≤200）m平均功率谱的p模振荡峰值拟合得到的。这些拟合是使用峰值拟合方法进行的，在这种方法中，我们用一个模型轮廓来拟合每个观测到的p模多元，该模型轮廓既包括目标模式，也包括它的六个最近的空间副瓣，并且通过拟合的轮廓与时间窗函数的卷积，结合了不完整观测时间序列的影响，时间窗函数是使用两个实际的GONG观测历史计算的。拟合的剖面还通过使用不同的m平均空间泄漏矩阵集，考虑了不同程度的模态空间泄漏对目标光谱的影响。为了研究估计的分量比对计算m平均功率谱的细节和GONG项目所采用的图像掩蔽方案的敏感性，我们总共生成了22组不同的模态拟合。我们发现，预测和推断比率之间的最佳一致性来自使用未加权平均功率谱，该功率谱是使用所谓的n平均分频系数计算的，该系数是通过在广泛的频率范围内交叉相关每l + 1的区域，局部和部门功率谱计算得到的。这种比较产生了总共1906对预测的ct，理论和拟合的ct，拟合特征函数成分比。对这些比值进行线性回归分析，得到以下回归方程：ct，fit =(0.0088±0.0013)+(0.9940±0.0044)ct,theory。相关系数为0.9817。预测比和推断比之间的这种一致性表明，预测比应用于高阶功率谱的拟合，其中由于单个模态峰混合在一起形成宽功率脊，因此无法推断比率。
We present evidence that the observed ratios of the horizontal and vertical components of the solar intermediate-degree p-mode velocity eigenfunctions closely match theoretical predictions of these ratios. This evidence comes from estimates of the observed eigenfunction component ratios that were obtained from the fitting of the p-mode oscillation peaks in low- and intermediate-degree (l ≤ 200) m-averaged power spectra computed from two different 60.75 day time series of Global Oscillation Network Group (GONG) project Dopplergrams obtained in late 1996 and early 1998. These fits were carried out using a peak-fitting method in which we fitted each observed p-mode multiplet with a model profile that included both the target mode and its six nearest spatial sidelobes and which incorporated the effects of the incomplete observational time series through the convolution of the fitted profiles with the temporal window functions, which were computed using the two actual GONG observing histories. The fitted profile also included the effects of the spatial leakage of the modes of differing degrees into the target spectrum through the use of different sets of m-averaged spatial leakage matrices. In order to study the sensitivity of the estimated component ratios to the details of the computation of the m-averaged power spectra and of the image-masking schemes employed by the GONG project, we generated a total of 22 different sets of modal fits. We found that the best agreement between the predicted and inferred ratios came from the use of unweighted averaged power spectra that were computed using so-called n-averaged frequency-splitting coefficients, which had been computed by cross-correlating the 2l + 1 zonal, tesseral, and sectoral power spectra at each l over a wide range of frequencies. This comparison yielded a total of 1906 pairs of predicted ct,theory and fitted ct,fit eigenfunction component ratios. A linear regression analysis of these pairs of ratios resulted in the following regression equation: ct,fit = (0.0088 ± 0.0013) + (0.9940 ± 0.0044)ct,theory. The resulting correlation coefficient was 0.9817. This agreement between the predicted and inferred ratios suggests that the predicted ratios should be used in the fitting of high-degree power spectra where the ratios cannot be inferred because of the blending together of individual modal peaks into broad ridges of power.