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【GFZ】地磁指数与太阳指数 0 前言 介绍如何下载德国地学中心GFZ提供的地磁行星3小时Kp指数、相关地磁指数和太阳指数。 1 GFZ-FTP 1.1 Kp_ap_Ap_SN_F107 Python爬虫源码如下 import os import socket from ftplib import FTP from ftplib import error_perm ##----------------------------------------------------------------------## # INFO: ftp网站连接 ##----------------------------------------------------------------------## # Outputs: # ftp - ftp根目录 ##----------------------------------------------------------------------## # author: Washy # date: 2024/09/27 ##----------------------------------------------------------------------## def ftp_connect(): # FTP站点 host = 'ftp.gfz-potsdam.de' # 端口号 port = 21 # 文件夹路径 folderpath = '/pub/home/obs/Kp_ap_Ap_SN_F107' ftp = FTP() ftp.encoding = 'utf-8' try: ftp.connect(host, port) ftp.login() ftp.cwd(folderpath) except(socket.error, socket.gaierror): # ftp 连接错误 print("ERROR: cannot connect [{}:{}]".format(host, port)) return None except error_perm: # 用户登录认证错误 print("ERROR: user Authentication failed ") return None return ftp def is_ftp_file(ftp_conn, filename): try: if filename in ftp_conn.nlst(os.path.dirname(filename)): return True else: return False except error_perm: return False # 连接服务器 ftp = ftp_connect() # 需要下载的文件名 filename = "Kp_ap_Ap_SN_F107_2024.txt" # 下载文件 with open(filename, 'wb') as f: ftp.retrbinary('RETR ' + filename, f.write, 1024) # 断开服务器 ftp.close() 下载的数据格式示例如下 # PURPOSE: This file distributes the geomagnetic planetary three-hour index Kp and associated geomagnetic indices as well as relevant solar indices. # LICENSE: CC BY 4.0, except for the sunspot numbers contained in this file, which have the CC BY-NC 4.0 license # SOURCE: Geomagnetic Observatory Niemegk, GFZ German Research Centre for Geosciences # PLEASE CITE: Matzka, J., Stolle, C., Yamazaki, Y., Bronkalla, O. and Morschhauser, A., 2021. The geomagnetic Kp index # and derived indices of geomagnetic activity. Space Weather, https://doi.org/10.1029/2020SW002641 # # Kp, ap and Ap # The three-hourly equivalent planetary amplitude ap is derived from Kp and the daily equivalent planetary amplitude Ap is the daily mean of ap. # Kp is unitless. Ap and ap are unitless and can be multiplied by 2 nT to yield the average geomagnetic disturbance at 50 degree geomagnetic latitude. # Kp, ap and Ap were introduced by Bartels (1949, 1957) and are produced by Geomagnetic Observatory Niemegk, GFZ German Research Centre for Geosciences. # Described in: Matzka et al. (2021), see reference above. # Data publication: Matzka, J., Bronkalla, O., Tornow, K., Elger, K. and Stolle, C., 2021. Geomagnetic Kp index. V. 1.0. GFZ Data Services, # https://doi.org/10.5880/Kp.0001 # Note: the most recent values are nowcast values and will be replaced by definitive values as soon as they become available. # # International Sunspot Number SN # The international sunspot number SN (written with subscript N) is given as the daily total sunspot number version 2.0 introduced in 2015. # The sunspot data is available under the licence CC BY-NC 4.0 from WDC-SILSO, Royal Observatory of Belgium, Brussels. Described in: # Clette, F., Lefevre, L., 2016. The New Sunspot Number: assembling all corrections. Solar Physics, 291, https://doi.org/10.1007/s11207-016-1014-y # Note: the most recent values are preliminary and replaced by definitive values as soon as they become available. # # F10.7 Solar Radio Flux # Local noon-time observed (F10.7obs) and adjusted (F10.7adj) solar radio flux F10.7 in s.f.u. (10^-22 W m^-2 Hz^-1) is provided by # Dominion Radio Astrophysical Observatory and Natural Resources Canada. # Described in: Tapping, K.F., 2013. The 10.7 cm solar radio flux (F10.7). Space Weather, 11, 394-406, https://doi.org/10.1002/swe.20064 # Note: For ionospheric and atmospheric studies the use of F10.7obs is recommended. # # Short file description (for a detailed file description, see Kp_ap_Ap_SN_F107_format.txt): # 40 header lines, all starting with # # ASCII, blank separated and fixed length, missing data indicated by -1.000 for Kp, -1 for ap and SN, -1.0 for F10.7 # YYYY MM DD is date of UT day, days is days since 1932-01-01 00:00 UT to start of UT day, days_m is days since 1932-01-01 00:00 UT to midday of UT day # BSR is Bartels solar rotation number, dB is day within BSR # Kp1 to Kp8 (Kp for the eight eighth of the UT day), ap1 to ap8 (ap for the eight eighth of the UT day), Ap, SN, F10.7obs, F10.7adj # D indicates if the Kp and SN values are definitive or preliminary. D=0: Kp and SN preliminary; D=1: Kp definitive, SN preliminary; D=2 Kp and SN definitive # # # The format for each line is (i stands for integer, f for float): #iii ii ii iiiii fffff.f iiii ii ff.fff ff.fff ff.fff ff.fff ff.fff ff.fff ff.fff ff.fff iiii iiii iiii iiii iiii iiii iiii iiii iiii iii ffffff.f ffffff.f i # The parameters in each line are: #YYY MM DD days days_m Bsr dB Kp1 Kp2 Kp3 Kp4 Kp5 Kp6 Kp7 Kp8 ap1 ap2 ap3 ap4 ap5 ap6 ap7 ap8 Ap SN F10.7obs F10.7adj D 2024 01 01 33603 33603.5 2596 25 0.667 0.333 0.667 1.333 2.000 3.000 3.333 4.000 3 2 3 5 7 15 18 27 10 54 135.7 131.2 1 2024 01 02 33604 33604.5 2596 26 2.667 2.333 0.667 2.000 2.333 2.667 2.000 0.667 12 9 3 7 9 12 7 3 8 66 142.1 137.4 1 2024 01 03 33605 33605.5 2596 27 2.667 2.667 1.000 1.667 1.667 2.667 3.333 3.000 12 12 4 6 6 12 18 15 11 57 140.2 135.5 1 2024 01 04 33606 33606.5 2597 1 1.333 0.667 1.667 0.667 0.667 1.333 1.000 2.667 5 3 6 3 3 5 4 12 5 98 125.8 121.6 1 2024 01 05 33607 33607.5 2597 2 2.000 1.667 0.333 1.000 1.333 1.667 0.333 0.333 7 6 2 4 5 6 2 2 4 117 152.7 147.6 1 -
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Savitzky-Golay滤波器原理-01 0 前言 最近在看文章时，发现有人使用Savitzky-Golay滤波器对数据进行预处理，提取背景值，尝试之后发现效果显著。因此，简单研究下Savitzky-Golay滤波器的原理。 1 Savitzky-Golay滤波器原理 1.1 简介 Savitzky-Golay滤波器（通常简称为S-G滤波器）最初由Savitzky和Golay于1964年提出，发表于Analytical Chemistry 杂志。之后被广泛地运用于数据流平滑除噪，是一种在时域内基于局域多项式最小二乘法拟合的滤波方法。这种滤波器最大的特点在于在滤除噪声的同时可以确保信号的形状、宽度不变$^{[1]}$。 Savitzy-Golay 卷积平滑算法是移动平滑算法的改进。用 Savitzky-Golay 方法进行平滑滤波，可以提高光谱的平滑性，并降低噪音的干扰。Savitzy-Golay 平滑滤波的效果，随着选取窗宽不同而不同，可以满足不同场合的需求$^{[1]}$。 1.2 推导 思想：使用一定长度窗口的数据对窗口中心的数据进行平滑处理。 设窗口的宽度为$2m + 1$，窗口内的数据值为$y_i$， $i = -m,-m+1,\dots,-1,0,1,\dots,m-1,m$，使用$n$阶多项式对其进行拟合，有 $$ f_i = f(i) = \sum_{k=0}^{n} b_k i^k $$ 那么拟合数据与原始数据的残差平方和为 $$ R = \sum_{i=-m}^{m} (f_i - y_i)^2 = \sum_{i=-m}^{m} \left( \sum_{k=0}^{n} b_k i^k - y_i \right)^2 $$ 使用最小二乘的思想，为了使拟合效果最好，需要使残差的平方和最小，则需要使得所有拟合系数的一阶偏导为零。对于第$l$个系数$b_l$有 $$ \frac{\partial R}{\partial b_l} = 2 \sum_{i=-m}^{m} \left( \sum_{k=0}^{n} b_k i^k - y_i \right)i^l = 0 $$ 整理后可得 $$ \sum_{i=-m}^{m} y_i i^l = \sum_{k=0}^{n} b_k \sum_{i=-m}^{m} i^{k+l} $$ 对于$l \in [0,n]$可以得到$n+1$个方程，联立后可以解得所有系数$b_l$。写成矩阵形式，有 $$ \begin{bmatrix} (-m)^0 & \dots & 0^0 & \dots & m^0 \\ \vdots & & \vdots & & \vdots \\ (-m)^l & \dots & 0^l & \dots & m^l \\ \vdots & & \vdots & & \vdots \\ (-m)^n & \dots & 0^n & \dots & m^n \\ \end{bmatrix} \begin{bmatrix} (-m)^0 & \dots & (-m)^k & \dots & (-m)^n \\ \vdots & & \vdots & & \vdots \\ 0^0 & \dots & 0^k & \dots & m^n \\ \vdots & & \vdots & & \vdots \\ m^0 & \dots & m^k & \dots & m^n \\ \end{bmatrix} \begin{bmatrix} b_0 \\ \vdots \\ b_k \\ \vdots \\ b_n \\ \end{bmatrix} = \begin{bmatrix} (-m)^0 & \dots & 0^0 & \dots & m^0 \\ \vdots & & \vdots & & \vdots \\ (-m)^l & \dots & 0^l & \dots & m^l \\ \vdots & & \vdots & & \vdots \\ (-m)^n & \dots & 0^n & \dots & m^n \\ \end{bmatrix} \begin{bmatrix} y_{-m} \\ \vdots \\ y_0 \\ \vdots \\ y_m \\ \end{bmatrix} $$ 得到所有系数后，将其代回拟合方程，并计算中心点处的拟合值 $$ f_0 = f(0) = b_0 $$ 此时，我们就得到了Savitzky-Golay滤波器平滑后的中心点的数值大小。 1.3 一阶形式 当使用一阶多项式进行拟合时，代入上一节矩阵形式，很容易可以得到 $$ \begin{bmatrix} 1 & \dots & 1 & \dots & 1 \\ -m & \dots & 0 & \dots & m \\ \end{bmatrix} \begin{bmatrix} 1 & -m \\ \vdots & \vdots \\ 1 & 0 \\ \vdots & \vdots \\ 1 & m \\ \end{bmatrix} \begin{bmatrix} b_0 \\ b_1 \\ \end{bmatrix} = \begin{bmatrix} 1 & \dots & 1 & \dots & 1 \\ -m & \dots & 0 & \dots & m \\ \end{bmatrix} \begin{bmatrix} y_{-m} \\ \vdots \\ y_0 \\ \vdots \\ y_m \\ \end{bmatrix} $$ 整理后可得 $$ \left\{ \begin{split} &b_0 = \sum_{i=-m}^m y_i / \sum_{i=-m}^{m} 1 \\ &b_1 = \sum_{i=-m}^m y_i i / \sum_{i=-m}^{m} i^2 \\ \end{split} \right. $$ 从而可以得到中心点处的拟合值为 $$ f_0 = b_0 = \sum_{i=-m}^m y_i / (2m+1) $$ 此即为滑窗平均的表达式。 参考： 【UWB】Savitzky Golay filter SG滤波器原理讲解 Savitzky-Golay滤波器原理阐述
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空间物理数据材料整理 0 前言 简单汇总下空间物理学领域部分数据、材料相关的FTP、网站等。 1 数据汇总 序号 简介 链接 备注 1 地磁与太阳活动指数 NOAA-FTP | GFZ-FTP | WDC 爬虫 2 ACE卫星数据 NOAA-FTP 3 GIM Map GIPP-FTP 4 GOLD数据，地球同步轨道远紫外成像仪 GOLD 5 ESA Swarm卫星数据 Swarm 6 NASA太阳观测图像 NASA 7 SEPC太阳H$\alpha$图像 SEPC 8 测高仪数据 GIRO 2 材料汇总 序号 简介 网址 备注 1 国际电联通信相关文档 ITU-R 参考材料 地磁活动指数与太阳活动指数 GFZ数据下载的一种方式分享
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