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The creation of the database of images of old analogue magnetograms of Geophysical Observatory "Paratunka", Kamchatka, Russia, 1967-2006
VarSITI / SCOSTEP Project Final Report ­ 2014

1. INTRODUCTION Magnet ic field variat ions show the processes in the Sun-Earth system. The historical pre-digital data are very important for the invest igat ion of old events. These data are contained in analogue magnetograms obtained at the observatories during the last century. In most cases the hourly data were obtained from analog magnetograms according to standard IAGA. However, these photorecords can provide the magnet ic data with high temporal reso lution up to one minute. Regular magnet ic measurements are carried out at Paratunka Geophysical Observatory of the Inst itute of Cosmophysical Research and Radio Wave Propagation of the Far-Eastern Branch of Russian Academy o f Science (IKIR FEB RAS, http://www.ikir.ru/en/About/index.ht ml), Kamchatka, Russia, since 1967. Average mo nthly values, calculated on the basis o f observatory hour data from WDC for Geomagnet ism (Edinburgh), are shown in Fig. 1. The same figure illustrates annual values according to IGRF11 model.
P ET - Parat unk a; daily mean data 1500
H-21000, nT

1000

500 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

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D, arcmin

An archive of analogue magnetograms was created. However, it is inaccessible to the world scientific co mmunit y and inconvenient for digital processing. There is also the possibilit y o f losses due to the presence o f only a single copy. The usual so lut ion of these problems is to obtain the graphic images of magnetograms. The examples of this approach can be found at WDC http://wdc.kugi.kyoto-u.ac.jp/film/index.ht ml http://www.wdcb.ru/stp/data/Images_o f_Magnetog rams/index.ru.ht ml

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Z-45000, nT

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Daily (W DC) IGRF

0 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

Figure 1. Variations of magnetic field at PET observatory (1969-2013, daily values, WDC for Geomagnetism, Edinburgh), obtained from analogue magnetograms (before 1996, IAGA Standards) and INTERMAGNET data (since 2010) and data from IGRF11 model.

2. GOALS The goal of this project is to create the database of the images of analogue magnetograms and complementary information (baseline values and scale coefficients) for Paratunka Geophysical Observatory (IAGA code is PET) for 1967-2006 and to transfer the database to the WDC (Moscow and Kyoto). The database of old analogue magnetogram images will be available to the internat ional scient ific communit y and the digital processing and will so lve the problem o f long-term storage, provide security and data integrit y.


3. DESCRIPTION OF ANALOGUE MAGNETOGRAMS Analogue magnetograms of Paratunka Observatory are daily records of magnet ic fie ld variat ions on photopaper with the width of 28.5 cm and the length of about of 50 cm. The Bobrov's quartz sensors (IZMIRAN) are used as vario meters. Variat ion tracks and a baseline are displayed on the magnetogram for each recorded component. Also, a magnetogram contains: the tit le wit h the date of record beginning and end in UT and the name of the observatory (in Russian); time values on hour marks in UT; the names of tracks with indicat ion of the direct ion of field increase and names o f baselines for every co mponent; temperature in the variat ion house; baseline values, scales and temperature coefficients (periodically).

The primary archive includes the magnetograms of ordinary and storm systems, which are marked as "I" and "II", accordingly. The storm system has smaller sensit ivit y and is used for estimat ion of variat ions during magnet ic storms, when a track is mo ved outside the photopaper or disappears due to high speed of light spot. In addition, the storm system is used as a backup system during the failure of ordinary system (hardware or photopaper defect). On the magnetograms o f ordinary system the variations of magnet ic co mponents D, H, Z are recorded. The storm system also records the variat ions of total field F. The reso lut ion of records of ordinary sys tem is about 2.1-2.5 nT/mm for H, 0.20-0.22 /mm for D and 1.0-3.5 nT/mm for Z.

4. IMAGES OF MAGNETOGRAMS The magnetograms were scanned using an ordinary scanner with A4 format. Three images were obtained fro m every standard magnetogram (beginning, middle, end), with about three-hour overlapping. If a magnetogram was short, only one or two images were obtained. Every image includes a scale with the length of 50 mm. An example of magnetogram images for January 31 ­ February 01, 1987 is presented in Fig.2.

Figure 2. An example of images, which was obtained for a magnetogram of Paratunka Observatory for Jan 31 ­ Feb 01, 1987.


Normally every image is a TIFF format file wit h the resolut ion of 300в300 dpi and of gray co lor (8 bits per pixel), the size of a file is about of 9 Mb. For the magnetograms since 1998 the images o f magnetogram pieces were jo ined into a single daily image and saved as a JPEG file with the reso lution of 200в200 or 300в300 dpi. The names of image files are presented in the format MYYYYMMDD-yyyymmdd_N_SS, where YYYYMMDD and yyyymmdd are the year, month and day of the record beginning and the end of a magnetogram, N is the number of a piece, SS is the code of the system (I ­ ordinary, II ­ storm). Similar names are also used for jointed images. The base of images is structured according to the magnetogram date: directories were sorted by years and months. Also, a special information file was prepared, which include addit ional parameters: baseline values, scale and temperature coeffic ients and dates when these parameters were adopted.

5. RESULTS For the most part, the scanning process was performed fro m April to August, 2014. Jointed images were prepared in advance. Co mplete check of images with re-scanning if necessary and DVD recording were carried out in September, 2014. Total number of images in the database is 41103, the total size of the database is about of 305 Gb. The project was executed by a technician, an engineer, a magnetologist and a project leader. Three external hard disks, a printer, 125 DVD-R disks and so me office supplies were purchased. The base of images of magnetograms for Paratunka Observatory recorded on DVDs was sent to the WDC on Solar-Terrestrial Physics (Moscow, Russia) and to the WDC for Geomagnet ism (Kyoto, Japan). The obtained images are suitable for the fo llowing digit izat ion and for obtaining of magnet ic variat ion with the rate grater than one hour (IAGA Standard). For example, in Fig.3 the minute values of H,D,Z variat ions are presented. These values were obtained for the first image of the magnetogram in Fig. 2 using special routine WFD for digit ization of magnetograms (Waveform digit izer, v.2.1 b4, A.Burtsev, M.Zhizhin, 2003).
P arat unka PET, 31. 01.1987-01.02. 1987 10 8 6
(H, D, Z)-mean (nT, arc m in)

H-21864 nT D+330' Z-45907 nT

This work was supported by SPeCIMEN/VarSITI grant.

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Figure 3. An example of digitization of the magnetogram image presented in Fig. 2: minute values of full H,D,Z components are presented.

Sergey Y. Khomutov, Head of Geophysical Observatory "Paratunka" IKIR FEB RAS, Kamchatka, RUSSIA, email: Kho mutov@ikir.ru, phone: +7-41531-33193