DCX SERVER INFO AND MANUAL

DCX SERVER INFO AND MANUAL Compiled by Kalevi Mursula, Lauri Holappa, Arto Karinen, Tore Leikanger University of Oulu (UOulu) 28 October 2011

Contents Contents 2 1 Web server of improved local and global Dst indices for history and real-time 3 1.1 Abstract.................................... 3 1.2 The different storm-time indices..................... 3 1.3 The three versions of indices........................ 5 1.3.1 Definite indices........................... 6 1.3.2 Provisional and real-time indices................. 8 1.4 Web service.................................. 10 References 18 2

Chapter 1 Web server of improved local and global Dst indices for history and real-time Prepared by: K. Mursula (UOulu), Arto Karinen (UOulu), Lauri Holappa (UOulu), T. Leikanger (UOulu) 1.1 Abstract In this manual we describe the web-based Dcx server which has been constructed to provide new, global and local indices of magnetic storminess called Dxt and Dcx indices, at hourly resolution and with a good global coverage. We provide historical indices for 1932-2009 that are based on the four Dst stations. We also provide historical indices for an extended network of 17 stations for 2000-2009. Provisional and real-time indices are available since 2010 for 14 stations. 1.2 The different storm-time indices The Dst index is one of the most used geomagnetic indices, and constructed to monitor the strength and temporal development of geomagnetic storms, in particular the ring current. It is traditionally calculated as an hourly averaged disturbance of the horizontal magnetic field observed at the four low-latitude stations of Hermanus (HER), Honolulu (HON), Kakioka (KAK) and San Juan (SJG), which are distributed roughly equally in longitude (see Table 1.1 for station coordinates). Major disturbances in the Dst index are negative, reflecting the westward directed drift of the energetic, positively charged ions produced during the storm, and the ensuing westward directed electric current. However, in addition to the ring cur- 3

Chapter 1: Web server of improved local and global Dst indices 4 rent, other magnetospheric current systems contribute to the Dst index by amounts that vary, e.g., with storm phase. Also, it is known by now that the ring current itself is not isotropic but highly asymmetric in local time (LT), often consisting of a number of limited longitude/lt sections (Lui et al., 1987). (Sometimes one talks about an asymmetric or partial ring current in addition to the isotropically or symmetrically assumed ring current). These effects lead to the fact that the local disturbances at the different Dst stations (in the different longitude/local time sectors) are mostly quite different. The original Dst index is provided by the World Data Center WDC-C1 in Kyoto, Japan. However, they only provide the global Dst index, i.e., the average of the four Dst stations, not the separate, local Dst indices observed at these stations. This is one major gap that the Soteria Deliverable 4.4 aims to fill. As the first step toward this aim, we have reconstructed the global Dst index (Karinen and Mursula, 2005), using the original Dst derivation method (see, e.g., Sugiura, 1964. 1969; Sugiura and Kamei, 1991; WDC-C1, 2011) as closely as possible. We call our version of the reconstructed Dst index the Dxt index, in order to separate the two indices. Over the whole Dst index time interval since 1957, the Dxt index correlates very well with the Dst index (correlation coefficient of 98.7 %). Despite this good correlation, the Dxt index corrects some errors in the original Dst index. (E.g., all annual averages of the Dxt index are negative, in disagreement with the positive annual average of the Dst index in 1965. It is also corrects the Dst index in 1971 when the Dst index depicts an anomalous UT variation). We have also extended the time span of the original Dst index by more than 25 years to start the Dxt index already in 1932, by using CTO, the predecessor of HER station, with all other Dst stations remaining the same. The Dcx server will provide the local Dxt indices for all the four stations and their average, i.e, the global Dxt index, over the whole time interval since 1932. In addition to the Dxt index which, as mentioned above, follows the Dst index recipe, we have also calculated another version of the Dst index, using a different treatment of the quiet daily curve. The Dst index is known to exhibit an excessively large semiannual variation, which is unrelated to magnetic storms (Cliver et al., 2001). This non-storm component in the Dst index arises from the seasonal variation of the quiet-time magnetic field, which is not correctly eliminated from the quiet-day curve when deriving the Dst index (Mursula and Karinen, 2005). The corrected Dst index recipe yields a seasonally corrected index which is called the Dcx index (Mursula and Karinen, 2005). We have shown that the Dcx index is considerably better correlated with other indices of solar and geomagnetic activity than the Dst/Dxt index (Karinen and Mursula, 2006), which further motivates this revision. The Dcx server will also provide the global Dcx index and the correspond-

Chapter 1: Web server of improved local and global Dst indices 5 ing local Dcx indices for the four Dst stations over the whole time interval since 1932. As explained above, the Dst, Dxt and Dcx indices are based on the magnetic field measurements at the four Dst stations. However, such a small number of stations gives only a coarse longitudinal accuracy, and does not allow for a detailed study of the local time structure of disturbances due to asymmetric current systems like the partial ring current and the tail current. Accordingly, a larger network of stations is needed in order to have a better view of the local storm-time currents. We have increased the number of stations for more recent times, when data from a larger number of stations are available. The definite versions of recent indices that are available now for 2000-2009, are based on 17 stations and are called the Dxt17 and Dcx17 indices. The real-time and provisional versions that are available since 2010 are based on data from 14 stations. The user-friendly web-based server called the Dcx server has been developed within the Soteria Deliverable 4.4 to provide the scientific community with all these indices. The definite, provisional and real-time versions of the global and local Dxt, Dcx, Dxt17, Dcx17, Dxt14 and Dcx14 indices can be downloaded from the Dcx server, and are available at hourly, daily and annual resolution. 1.3 The three versions of indices The measurements of the geomagnetic field, and indices based upon them, can typically be classified into three versions: definite, provisional and real-time, depending on the delay time between measurement and release, or the accuracy of the published data. Definite data are calibrated to the baseline defined by the total magnetic field at the measuring station. Outliers have been removed, and gaps have been filled whenever possible. Definite data are basically the final and the most accurate measurements provided by the station (WDC-C1, 2011; WDC-C3, 2011). However, the definite data are typically not available until two or three years after the measurements. For more recent times, typically since about 6-24 months before present, the data are given as provisional data, while the newest measurements within the last 3 months or so are real-time data. Provisional data have been manually checked by the observatory staff, but the data may not have a correct baseline and may contain outliers or missing values. It is quite possible that a part of provisional data will be replaced by more accurate data before the definite data is released. Real-time data have typically not been checked for noise or for a correct baseline level, and may therefore include significant errors. These are often variometermagnetometer measurements, which only measure the relative variation of the

Chapter 1: Web server of improved local and global Dst indices 6 field and do not include the correct baseline level. In such cases we estimate the base-line by interpolating (or, after 2010 extrapolating) the IGRF model (IGRF, 2010), using the horizontal component of the model as the baseline. In order to calculate the Dxt/Dcx indices we need the horizontal component of the magnetic field vector measured at least at the hourly resolution. In the 1970s, most stations turned typically from the hourly sampling of the geomagnetic field to the one-minute resolution sampling. We will use hourly data for the calculation of the definite and provisional indices, both for historical and modern times. We have decided to download the one-minute real-time data from the stations contributing to the real-time index once every 15 minutes. Accordingly, the real-time Dxt14 and Dcx14 indices are calculated and updated every 15 minutes using the recent magnetic field observations at the 14 geomagnetic low-latitude observatories. This was considered necessary since the different stations provide their data in different ways and different times. The subsequent 15-minute index values within one hour will have more and more stations included in the index calculation until, after the full hour, data from all stations are available. This implies that, practically, we have a warning system which has a 15-minute lead time for large disturbances. This greatly enhances the temporal accuracy of the Dcx server for warning purposes from the originally considered accuracy of one hour to 15 minutes, i.e., by a factor of four. Calculation of the Dxt/Dcx indices also requires the information of the level of the quiet-time magnetic field, i.e., the zero level of the index, which is defined from the internationally selected quietest days of each month (for a list of these days see, e.g., WDC-C1 (2011)). The international quiet days are defined for 1932 onwards, i.e., for the whole Dxt/Dcx time interval, except for the recent years, since they are calculated from the definite values of the magnetic field. For this reason, the quiettime level of the provisional and real-time Dxt/Dcx indices cannot be obtained from the internationally selected days, but will be determined here from the five locally quietest days according to the IHV index (Svalgaard et al., 2004) calculated for each contributing station separately. (For more information on the details of the original and revised Dst index recipes, see Mursula and Karinen (2005); Karinen and Mursula (2005)). 1.3.1 Definite indices Definite Dxt and Dcx indices are calculated from the definite values of the horizontal magnetic field measured at the contributing stations. For the Dcx server, these definite measurements are collected from the WDC database (WDC-C3, 2011). The definite Dxt and Dcx indices for the server must be calculated manually because

Chapter 1: Web server of improved local and global Dst indices 7 the definite values of the magnetic field are updated with a long delay and at different times for each contributing station. Table 1.1 includes all stations that have been used to calculate any version of the indices, including the definite indices. Figure 1.1 shows on the map all stations that have been used for definite indices. Note that in some cases data from two (fairly nearby) stations have been used to provide one series of data for the calculation of the definite index. One of the two stations is considered to be the main station. This station is also used to calculate the provisional and real time indices. The other station is an auxiliary station, which is used, e.g., to fill the data gaps of the main station. There are two such station pairs: BSL (main) and DLR (auxiliary); IZN (main) and AQU (auxiliary). Also CTO can be considered an auxiliary station which continues HER data to earlier years. Geographic Geomagn. IAGA Station Lat. Long. Lat. AAA Alma Ata 43.250 76.920 34.290 AQU L Aquila 42.383 13.317 42.420 BSL Stennis 30.380 272.704 40.090 CNB Canberra 35.315 149.363 42.710 CTO Cape Town 33.950 18.467 33.312 DLR Del Rio 29.490 259.080 38.300 GNA Gnangara 31.780 115.947 41.930 HBK Hartebeesthoek 25.883 27.707 27.130 HER Hermanus 34.425 19.225 33.980 HON Honolulu 21.320 202.000 21.640 IZK Iznik 40.500 29.720 37.561 KAK Kakioka 36.232 140.186 27.370 LZH Lanzhou 36.087 103.845 25.860 MBO Mbour 14.384 343.033 20.160 PPT Pamatai 17.566 210.416 15.013 SJG San Juan 18.110 293.850 28.310 TAM Tamanrassat 22.792 5.530 26.440 TRW Trelew 43.248 294.685 33.050 TUC Tucson 32.170 249.270 39.880 VSS Vassouras 22.400 316.350 13.290 Table 1.1: Geographical coordinates and geomagnetic latitudes (according to IGRF 2010 model IGRF (2010)) of all magnetic stations contributing to any of the Dxt and Dcx indices. In Table 1.2 we give the times when the data from each of the stations have been used to calculate the definite (or provisional/real time) indices. The traditional 4-station indices Dxt and Dcx, consisting of measurements at HER/CTO, HON, KAK, and SJG, have been calculated for 1932-2009. Definite data for almost the whole extended network of 17 stations (except for VSS) have been collected for 2000-2009. Accordingly, the definite Dxt17 and Dcx17 indices have been calculated for 2000-2009. (Year 2009 is based on 16 stations and therefore still preliminary

Chapter 1: Web server of improved local and global Dst indices 8 TUC BSL AQU IZN AAA LZH KAK HON DLR SJG MBO TAM PPT VSS HBK GNA CNB TRW HER, CTO TUC BSL IZN AAA LZH HON SJG MBO TAM PPT HBK GNA CNB HER Figure 1.1: Stations contributing the definite [top] and the provisional and real-time [bottom] Dxt and Dcx indices. Auxiliary stations are marked with blue triangles. for some time). The Dcx server also includes and provides the original Dst index calculated by WDC-C1 (2011) starting on 01.01.1957 and extending presently until 30.04.2009. 1.3.2 Provisional and real-time indices Provisional Dxt and Dcx indices are calculated from the provisional or real-time values of the horizontal H component measured at the contributing stations. We use 14 stations for the provisional indices (see Figure 1.1 and Table 1.2). The time of provisional data (and indices) starts presently at the beginning of 2010. The starting time will naturally change in time as more recent definite values of the measured field will become available from the contributing stations. We use the provisional values of the measured field to calculate the provisional indices as far in time as they are available at each station, and real-time data thereafter. The extent of the provisional data toward the present day (i.e., how recent data are provisional) varies from station to station. Typically, provisional data are

Chapter 1: Web server of improved local and global Dst indices 9 Data interval used IAGA Definite Prov./real-time AAA 01.01.2000-31.12.2009 01.01.2010 AQU 01.01.2000-31.12.2006 BSL 01.01.2000-31.12.2009 01.01.2010 CNB 01.01.2000-31.12.2009 01.01.2010 CTO 03.08.1932-31.12.1940 DLR 01.01.2005-31.12.2007 GNA 01.01.2000-31.12.2009 01.01.2010 HBK 01.01.2000-31.12.2009 01.01.2010 HER 01.01.1941-31.12.2009 01.01.2010 HON 03.08.1932-31.12.2009 01.01.2010 IZN 01.01.2007-31.12.2009 01.01.2010 KAK 03.08.1932-31.10.2009 LZH 01.01.2000-31.12.2009 01.01.2010 MBO 01.01.2000-31.12.2009 01.01.2010 PPT 01.01.2000-31.12.2009 01.01.2010 SJG 03.08.1932-31.12.2009 01.01.2010 TAM 01.01.2000-31.12.2009 01.01.2010 TRW 01.01.2000-01.01.2009 TUC 01.01.2000-01.01.2009 01.01.2010 VSS 01.01.2000-31.12.2008 4 station 03.08.1932-31.12.2009 17/14 station 01.01.2000-31.12.2009 01.01.2010 Table 1.2: Time intervals of data used for the definite, and provisional/real-time Dxt and Dcx indices. available about three months after the measurement. Thus, provisional indices are typically available until about three months before present. The provisional values of the magnetic field are manually downloaded from WDC-C3 (2011) or from IN- TERMAGNET network (2011). We provide the provisional indices both at hourly and daily resolution. Note also that because the provisional indices are updated and extended as time proceeds, the ending time is changing, but is typically three months before the present day. For this reason the provisional indices may change before they are replaced by definite indices. Note also that the 4-station Dxt and Dcx indices use the GNA station as a substitute for KAK station in the provisional and real-time indices. The real-time indices are the index version that are typically available for the last three months before present. As explained above, the real-time data are being automatically uploaded via FTP every 15 minutes directly from the contributing stations (see Table 1.2 and Figure 1.1). Stations contributing to the real-time indices are the same as those used for the provisional indices. The real-time index time interval continues smoothly after the provisional time period. At each station, the real-time data continues the provisional values of the measured field. However, since the change from provisional to real-time data varies for the different stations, the provisional and real-time indices may be based, at least for some time around

Chapter 1: Web server of improved local and global Dst indices 10 the mean turning time, on both types of data. Therefore, it is natural to combine these two index versions under a common umbrella. The real-time indices may have errors, and may therefore deviate even significantly from the corresponding Dcx index server provisional and definite indices. They can also change during the three-month period for which Dcx index they server are calculated. (Corrected Dst) Front page Index query Movies Stations Data providers Real-time Dcx Figure shows Real-time Dcx index from the last two weeks (up) and for the last 24 hours (bottom). More information: Real-time Dcx info. Dcx and Dxt indices and the Sunspot number Figure 1.2: Front page of the Dcx server. http://dcx.oulu.fi/?link=main[18/10/11 7:14:14 PM] 1.4 Web service The Dcx server is located in the Department of Physics, University of Oulu, at the address http://dcx.oulu.fi/. The front page of the Dcx server web page is shown in Figure 1.2. It depicts the hourly real-time Dcx index for the last two weeks in the upper panel and for the last 18 hours in the second panel, which are updated every 15 minutes. As explained above, the server acts as a warning sys-

Chapter 1: Web server of improved local and global Dst indices 11 tem which has, effectively, a 15-minute lead time for large disturbances, enhances the temporal accuracy for warning purposes from the originally considered hourly accuracy. Below the plot of the recent Dcx index is another plot showing the monthly values of the definite 4-station Dxt and Dcx indices, and the sunspot numbers in 1932-2009. Upper left corner of the front page includes the following links: Index query to the data retrieval pages; Movies to pages presenting movies of the Dcx index for some selected storms; Stations to a page showing the contributing stations on map and in table; Data providers to a page with acknowledgement and information on institutions and observatories providing real-time magnetic data. Also, the logos of the Soteria project (Soteria, 2011), the European Union and its Seventh Framework Programme, as well as the University of Oulu are shown on the front page. The caption under the Dcx index plot includes a link Real-time Dcx info to a page (see Figure 1.3) where additional information on the real-time Dcx index during the last two weeks can be obtained, in particular statistics on the relative contribution of each station to the Dcx index and the fraction of valid data in each station. This information is also updated every 15 minutes. In Index query page shown in Fig. 1.4 the user can select from the three versions of indices: definite, provisional and real-time Dxt/Dcx indices. This page includes a short description of these three versions of indices, and links to the specific query pages of each index version. This page also describes the Rules of the road of using the indices provided by the Dcx server. Note also that the Dcx server does not distribute the original values of the horizontal component measured at any of the contributing stations. Figure 1.5 shows the specific query page for the definite indices. The Dxt/Dcx indices based on the four Dst index stations can be found by selecting the index type 4-station. Selecting the type 17-station gives the indices calculated using all the 17 stations. Individual indices for each station are available when selecting the type Individual. Definite indices are available at hourly, daily and yearly resolution. Dcx server also provides the original Dst index from WDC-C1 (2011). The user must select the time interval, the type of index needed and its resolution. The server prepares an ASCII data file for the user to download and plots the time series of the required data. The ASCII data can be downloaded by right clicking the mouse on the top of the name of the prepared ASCII file including a link. Pressing Download annual files button leads to a web page shown in Figure 1.6 where the user can get all the hourly Dxt and Dcx indices in ready-made yearly files of 4-station and 17-station indices. Figure 1.7 shows the specific query page for the provisional indices. This page

Chapter 1: Web server of improved local and global Dst indices 12 Real-time Dcx Index in the last two weeks Table updated on 18-Oct-2011 08:38:23 UT Station Contr. to Dcx % Valid data % AAA 6.95 93.47 BSL 7.41 99.70 CNB 6.70 90.21 GNA 6.73 90.50 HBK 6.46 86.94 HER 7.37 99.11 HON 7.41 99.70 IZN 6.90 92.88 LZH 7.39 99.41 MBO 7.12 95.85 PPT 7.41 99.70 SJG 7.41 99.70 TAM 7.32 98.52 TUC 7.41 99.70 For each station contributing Dcx in the last two weeks: First column: Contribution to Dcx, Second column: Presence of valid data. Figure 1.3: Page showing (left) the relative contribution of each station to the real-time Dcx index seen on front page, and (right) the relative fraction of valid data from each station. works in a similar way as the corresponding page for the definite indices, except that the number of stations is smaller (14), there are no ready-made annual files available, and the provisional indices are only available at hourly and daily resolution. The time period of provisional indices starts at the end time of the definite indices. Figure 1.8 shows the specific query page for the real-time indices. This page works in a similar way as the corresponding page for the provisional indices. The time period of real-time indices starts at the end time of the provisional indices. The front page includes a link to Movies page displaying a collection of movies presenting magnetic disturbances at different local times for selected time intervals, in particular some pre-selected SOTERIA WP4 events that include major magnetic storms. Figure 1.9 shows one such movie for the storm on 14-17 December, 2006. The movie consists of four panels, all synchronized to the same time. The two upper plots show the time evolution of the 1-minute local and global Dcx indices. An estimate of the asymmetric local time distribution is depicted in the third plot. The bottom plot presents the asymmetric local time distribution in 2 dimension.

Dcx index server Chapter Dcx index 1: Web server server of improved local and global Dst indices 13 (Corrected Dst) Front page Index query Movies Stations Data providers Index Query The indices provided by the Dcx server are free for non-commercial, non-profit use according to the Rules of the road given below. The server includes indices at three levels of sophistication: Definite indices Definite indices have been calculated from the definite values of the hourly horizontal magnetic field measured at selected stations (presently up to 17 stations). Definite indices are available at hourly, daily and yearly resolution. Definite indices lag typically by 1-2 years. Provisional indices Provisional indices have been calculated from the provisional values of the hourly horizontal magnetic field measured at the contributing stations (presently up to 14 stations). Provisional indices continue the time interval of definite indices without gap or overlap. Provisional indices are available at hourly and daily resolution. Provisional indices are updated continuously and extend typically until about three months before present. Real-time indices Real-time indices use the real-time data from the same stations as the provisional indices (presently up to 14 stations). Real-time indices continue the time interval of provisional indices without gap or overlap. Real-time indices may have errors and may change in time due to updates of the measured field values. Real-time indices are available at hourly and daily resolution. This server has been developed at the University of Oulu, Finland, within the EU FP7 Collaboration/Space project "Soteria" Work Package 4 by Arto Karinen, Tore Leikanger, Lauri Holappa and Kalevi Mursula in 2008-2011. Please send any comments, corrections, and questions about the Dcx server to Kalevi.Mursula@oulu.fi Rules of the Road The magnetic indices provided through the Dcx server are made freely available for scientific and educational use only, not for commercial or other profit use. Publications using the provided indices should include a statement acknowledging the source, e.g., as follows: Dcx index server Dcx index server (Corrected Dst) The results presented in this paper use Dxt or Dcx indices provided by the Dcx server of the University of Oulu, Finland, at http://dcx.oulu.fi. Figure 1.4: Index query page. Front page Index query Movies Stations Data providers Query for Definite Index YYYY MM DD HH Initial date: Final date: Resolution: Data availability: Index: Dcx17 First available data: 03.08.1932 (00:00) Last available data: 31.12.2009 (23:00) Index: Dcx Dxt Dst Type: (Only for Dcx/Dxt.) 17-Station 4-Station Individual: Right click to Download: Dcxh3208030009123123.txt Plot of the index http://dcx.oulu.fi/?link=query18.10.2011 20:22:10 Maintained by T. Leikanger and A. Karinen Figure 1.5: Index query page for definite indices. The page includes a link to a page giving more details of the movie.

Chapter 1: Web server of improved local and global Dst indices 14 http://dcx.oulu.fi/dldatadefinite.php Definite indices Dcx Index 4-Station Dcx Yearly text files (use right mouse button to download): Dcx1932.txt Dcx1933.txt Dcx1934.txt Dcx1935.txt Dcx1936.txt Dcx1937.txt Dcx1938.txt Dcx1939.txt Dcx1940.txt Dcx1941. txt Dcx1942.txt Dcx1943.txt Dcx1944.txt Dcx1945.txt Dcx1946.txt Dcx1947.txt Dcx1948.txt Dcx1949.txt Dcx1950.txt Dcx1951.txt Dcx1952.txt Dcx1953.txt Dcx1954.txt Dcx1955.txt Dcx1956.txt Dcx1957.txt Dcx1958.txt Dcx1959.txt Dcx1960. txt Dcx1961.txt Dcx1962.txt Dcx1963.txt Dcx1964.txt Dcx1965.txt Dcx1966.txt Dcx1967.txt Dcx1968.txt Dcx1969.txt Dcx1970.txt Dcx1971.txt Dcx1972.txt Dcx1973.txt Dcx1974.txt Dcx1975.txt Dcx1976.txt Dcx1977.txt Dcx1978.txt Dcx1979. txt Dcx1980.txt Dcx1981.txt Dcx1982.txt Dcx1983.txt Dcx1984.txt Dcx1985.txt Dcx1986.txt Dcx1987.txt Dcx1988.txt Dcx1989.txt Dcx1990.txt Dcx1991.txt Dcx1992.txt Dcx1993.txt Dcx1994.txt Dcx1995.txt Dcx1996.txt Dcx1997.txt Dcx1998. txt Dcx1999.txt Dcx2000.txt Dcx2001.txt Dcx2002.txt Dcx2003.txt Dcx2004.txt Dcx2005.txt Dcx2006.txt Dcx2007.txt Dcx2008.txt Dcx2009.txt Hourly averages in mat format: Dcx.mat Daily and yearly averages in txt format: Dcx_daily.txt Dcx_yearly.txt 17-Station Dcx Yearly text files: Dcx2000.txt Dcx2001.txt Dcx2002.txt Dcx2003.txt Dcx2004.txt Dcx2005.txt Dcx2006.txt Dcx2007.txt Dcx2008.txt Dcx2009. txt Hourly averages in mat format: Dcx17.mat Daily and yearly averages in txt format: Dcx17_daily.txt Dcx17_yearly.txt Dxt Index 4-Station Dxt Yearly text files: Dxt1932.txt Dxt1933.txt Dxt1934.txt Dxt1935.txt Dxt1936.txt Dxt1937.txt Dxt1938.txt Dxt1939.txt Dxt1940.txt Dxt1941.txt Dxt1942.txt Dxt1943.txt Dxt1944.txt Dxt1945.txt Dxt1946.txt Dxt1947.txt Dxt1948.txt Dxt1949.txt Dxt1950.txt Dxt1951.txt Dxt1952.txt Dxt1953.txt Dxt1954.txt Dxt1955.txt Dxt1956.txt Dxt1957.txt Dxt1958.txt Dxt1959.txt Dxt1960.txt Dxt1961.txt Dxt1962.txt Dxt1963.txt Dxt1964.txt Dxt1965.txt Dxt1966.txt Dxt1967.txt Dxt1968.txt Dxt1969.txt Dxt1970.txt Dxt1971.txt Dxt1972.txt Dxt1973.txt Dxt1974.txt Dxt1975.txt Dxt1976.txt Dxt1977.txt Dxt1978.txt Dxt1979.txt Dxt1980.txt Dxt1981.txt Dxt1982.txt Dxt1983.txt Dxt1984.txt Dxt1985.txt Dxt1986.txt Dxt1987.txt Dxt1988.txt Dxt1989.txt Dxt1990.txt Dxt1991.txt Dxt1992.txt Dxt1993.txt Dxt1994.txt Dxt1995.txt Dxt1996.txt Dxt1997.txt Dxt1998.txt Dxt1999.txt Dxt2000.txt Dxt2001.txt Dxt2002.txt Dxt2003.txt Dxt2004.txt Dxt2005.txt Dxt2006.txt Dxt2007.txt Dxt2008.txt Dxt2009.txt Hourly averages in mat format: Dxt.mat Daily and yearly averages in txt format: Dxt_daily.txt Dxt_yearly.txt 17-Station Dxt Yearly text files: Dxt2000.txt Dxt2001.txt Dxt2002.txt Dxt2003.txt Dxt2004.txt Dxt2005.txt Dxt2006.txt Dxt2007.txt Dxt2008.txt Dxt2009.txt Hourly averages in mat format: Dxt17.mat http://dcx.oulu.fi/dldatadefinite.php (1 of 2)18.10.2011 13:48:05 Figure 1.6: Page providing ready-made annual files of Dxt and Dcx indices. The front page includes a link to Data providers page with a list of institutions and observatories providing data for the provisional and real-time indices. Clicking the name of the institution leads to the official web page of the respective data provider. Currently, these data providers are the following: Geomagnetic observatory Alma-Ata, Institute of the Ionosphere, Almaty, Republic of Kazakhstan: Alma-Ata (AAA) The USGS Geomagnetism Program, U.S: Stennis (BSL), Honolulu (HON), San Juan (SJG) and Tucson (TUC)

Dcx index server Chapter Dcx index 1: Webserver of improved local and global Dst indices 15 (Corrected Dst) Front page Index query Movies Stations Data providers Query for Provisional Index YYYY MM DD HH Initial date: Final date: Resolution: Data availability: Index: Dcx14 First available data: 01.01.2010 (00:00) Last available data: 20.07.2011 (08:00) Index: Dcx Dxt Type: 14-Station 4-Station Individual: Right click to Download: Prov.Dcx14h1001010011101823.txt Plot of the index Figure 1.7: Index query for provisional indices. Maintained by T. Leikanger and A. Karinen Geomagnetism Project, Geoscience Australia: Canberra (CNB) and Gnangara (GNA) South African National Space Agency (SANSA), South Africa: Hermanus (HER) and Hartebeesthoek (HBK) Boğaziçi University, Kandilli Observatory and Earthquake Research Institute: Iznik (IZN) Centre de Recherche en Astronomie Astrophysique et Geophysique (CRAAG), Algeria: Tamanrasset (TAM) Institut de Physique du Globe de Paris (IPGP), France: Mbour (MBO), Pamatai (PPT), Tamanrasset (TAM) Lanzhou (LZH), http://dcx.oulu.fi/?link=queryprovisional18.10.2011 13:41:58 Chinese Earthquake Administration (CEA), China: Lanzhou (LZH) Institut de Recherche pour le Développement (IRD), France: Mbour (MBO)

Chapter 1: Web server of improved local and global Dst indices 16 Dcx index server Dcx index server (Corrected Dst) Front page Index query Movies Stations Data providers Query for Real-Time Index YYYY MM DD HH Initial date: Final date: Resolution: Index: Dcx Dxt Data availability: Index: Dcx Real-time First available data: 20.07.2011 (09:00) Last available data: 18.10.2011 (09:00) Right click to Download: RealTime.Dcxh1107170011101823.txt Plot of the index Figure 1.8: Index query for real-time indices. Maintained by T. Leikanger and A. Karinen http://dcx.oulu.fi/?link=queryrealtime18.10.2011 13:44:32

Chapter 1: Web server of improved local and global Dst indices Figure 1.9: Movie presentation of the Dcx index during the storm on 26-30 July, 2004. 17

References Cliver, E. W., Kamide, Y., Ling, A. G., and Yokoyama, N.: Semiannual variation of the geomagnetix Dst index: Evidence for a dominant nonstorm component, J. Geophys. Res., 106, 21 297 21 304, 2001. IGRF: International Geomagnetic Reference Field, the International Association of Geomagnetism and Aeronomy (IAGA), (http://www.iugg.org/iaga/iaga_pages/ pubs_prods), 2010. INTERMAGNET network: INTERMAGNET, the global network of observatories monitoring the Earth s magnetic field, http://www.intermagnet.org, 2011. Karinen, A. and Mursula, K.: A new reconstruction of the dst index for 1932-2002, Ann. Geophysicae, 23, 475 485, 2005. Karinen, A. and Mursula, K.: Correcting the dst index: Consequences for absolute level and correlations, J. Geophys. Res., 111, A08 207, doi:10.1029/2005ja011299, 2006. Lui, A. T. Y., McEntire, R. W., and Krimigis, S. M.: Evolution of the ring current during two geomagnetic storms, J. Geophys. Res., 92, 7459 7470, 1987. Mursula, K. and Karinen, A.: Explaining and correcting the excessive semiannual variation in the dst index, Geophys. Res. Lett., 32, 14 107, doi:10.1029/2005gl023132, 2005. Soteria: Solar-Terrestrial Investigations and Archives, (http://soteria-space.eu), 2011. Sugiura, M.: Hourly values of equatorial Dst for the IGY, Ann. Int. Geophys. Year, 35, 9, 1964. Sugiura, M.: IAGA Resolution 2, in IAGA Bulletin 27, p. 123, Madrid, Spain, 1969. 18

References 19 Sugiura, M. and Kamei, T.: Equatorial Dst index 1957-1986, in IAGA Bulletin 40, edited by A. Berthelier and M. Menvielle, ISGI Publ. Office, Saint-Maur-des- Fossés, France, 1991. Svalgaard, L., Cliver, E. W., and Le Sager, P.: Ihv: a new long-term geomagnetic index, Advances in Space Research, 34, 436 439, doi:10.1016/j.asr.2003.01.029, 2004. WDC-C1: The World Data Center for Geomagnetism (Kyoto), (http://swdcdb.kugi.kyoto-u.ac.jp), Kyoto, Japan, 2011. WDC-C3: The World Data Center for Geomagnetism (Edinburgh), (http://www.wdc.bgs.ac.uk/), Edinburgh, UK, 2011.