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Text File | 1992-02-19 | 21.8 KB | 395 lines

USERS MANUAL FOR THE KGRAPH SOFTWARE ------------------------------------ Version 1.00 - Copyright 1992 Solar Terrestrial Dispatch INTRODUCTION The daily Solar Geophysical Data Broadcast (SGDB) reports released by the Solar Terrestrial Dispatch contain a large amount of information regarding the state of solar and geophysical activity. In the past, the only software which permitted manipulation of this data was the BCAST software program. However, this software lacks the ability to chart and track the geomagnetic K-index information. The geomagnetic K-index rates geomagnetic activity on a scale between 0 (very quiet) and 9 (very disturbed). The index is based on an open-ended semi-logarithmic algorithm and is measured once every three hours by magnetic observatories around the world. Generally, K-indices greater than 5 indicate major to severe geomagnetic storm conditions. K-indices of 4 or less indicate active to quiet conditions. The geomagnetic K-index is very important to persons such as radio communicators who rely on the geomagnetically-sensitive ionosphere to transmit and receive radio signals. Quiet levels of geomagnetic activity usually result in very good and stable radio communications. Active levels of geomagnetic activity can begin to introduce minor instabilities in radio communications such as rapid fading or flutter and increased directionality. Minor geomagnetic storming (K-indices of 5) and particularly major geomagnetic storming (K-indices of 6) can significantly impair the propagation of radio signals through the ionosphere. Severe geomagnetic storming (K-indices of 7 or more) can produce radio blackout conditions for many middle, high, and polar latitude regions. The level of geomagnetic activity is therefore a very important parameter which must be considered when used in conjunction with radio communications. K-indices are also very important to persons watching for auroral activity. Major to severe storm level excursions of the geomagnetic K-index is often associated with visible levels of auroral activity over the lower latitude regions. People who are interested in attempting to forecast the level of geomagnetic activity into the future will find detailed records of K-indices extremely valuable. Solar phenomena which can influence geomagnetic activity for several solar rotations (ex. such as stable coronal holes) can be identified through records of K-index geomagnetic activity. Knowing when enhanced geomagnetic activity has occurred in the past enables one to determine when it might occur in the future, since the Sun rotates approximately once every 27 days. KGRAPH is a powerful program designed to exploit the detailed K-index information which is stored in your BCAST database file ("datasets.dat"). It will examine and display K-index information in useful graphical detail using the power of your computers VGA graphics system. KGRAPH will produce three-dimensional graphs of geomagnetic activity in a variety of formats. It will graph either the geomagnetic Boulder K-Index (from Boulder, Colorado) or the estimated Planetary K-Index information which is stored in your database file. The three-dimensional graphs are very useful for analyzing episodes of activity relative to neighboring periods of activity. It is also visually impressive and easy to interpret. KGRAPH will also produce detailed high-density VGA-quality graphical plots of Boulder or Planetary K-Index data. These graphical plots of activity let you easily determine the cyclical behavior of geomagnetic activity. As much as eight solar rotations worth of K-index data can be viewed on-screen at one time. This is equivalent to 216 days worth of data, or 1,728 three-hour interval periods. The plots also indicate days in which major flare activity occurred, to help you determine which episodes of activity may have been flare-induced. In addition, the plotting method employed by KGRAPH lets you visually determine, quickly and easily, periods of activity which were associated with major or severe storming. All-in-all, KGRAPH is a powerful visual aid package intended to exploit the large amount of geomagnetic information which has been previously untapped by the BCAST software. It requires the BCAST-maintained database file "datasets.dat" to operate. Registration of the BCAST software program is therefore manditory for anyone who wants to use KGRAPH (see the file "REGISTER.DOC" for more information). For those who have already registered the BCAST software, KGRAPH can immediately be used to examine the large base of K-index information archived in your database file. SELECTING DATES OF DATA TO GRAPH Each of the graphical functions supported by KGRAPH first ask you to type in the date of the last dataset to display on-screen. By default, when you first start up KGRAPH, the date of the last dataset in your database file will be displayed. If this is the date you wish to use, simply press ENTER. If the default date is not what you want to use, type in the appropriate date (using the given format) and press ENTER. Thereafter, the default date becomes the last legal date you typed in. THREE-DIMENSIONAL GRAPHICS FUNCTIONS OF KGRAPH KGRAPH provides eight three-dimensional graphics functions to display K-index data in a variety of ways. These eight functions are described below: 1. KGRAPH can produce a three-dimensional graph of Boulder K-Indices U with dates descending from the bottom of the screen to the top B N of the screen. That is, the date of the data at the "front" of O S the three-dimensional graph would be the most recent date U O graphed. L R D T 2. KGRAPH will generate a three-dimensional graph of Boulder E E K-Indices with dates ascending from the bottom of the screen to R D the top of the screen. In this case, the date of the data at the front of the graph would be the oldest date on-screen. The most K recent date would be at the "back" of the graph, behind the rest. I N 3. KGRAPH will sort the Boulder K-Index data and graph the data in D three-dimensional format in ascending order. Sorting is done by E simply summing the eight three-hour K-index values for each day X S and sorting the summed values. The resulting graph displays the O quietest days at the front of the graph and the most disturbed D R days at the end of the graph. A T T E 4. KGRAPH will sort the Boulder K-indices and graph the data in A D descending order. In this case, the graph shows the quietest days at the end of the graph and the most disturbed days at the front of the graph. U 5. KGRAPH will generate three-dimensional graphs of the estimated P N planetary geomagnetic K-indices in order of descending dates. L S This graph is identical to #1 above, except the K-indices used A O are the estimated planetary data as opposed to the Boulder data. N R E T 6. KGRAPH will generate graphs of planetary K-indices in order of T E ascending dates. This graph functions the same as #2 above, A D except planetary data is used. R Y 7. KGRAPH will sort the estimated planetary (global) geomagnetic S K-indices in ascending order. Graphs of these sorted indices D O are identical to function #3 given above, except planetary A R K-indices are used. T T A E 8. KGRAPH will sort the estimated planetary K-indices in descending D order. These three-dimensional graphs are identical to the graphs produced by function #4, except planetary data is used. The purpose for producing three-dimensional graphs in order of ascending and descending dates is to provide a different view of the data. Since the graphed data is three-dimensional, producing graphs in descending or ascending order may aid in "unblocking" areas which were previously blocked from view. For example, a day which has high K-indices will will produce three-dimensional graph lines which may block out data behind the date with the high K values. By using these functions to view the data in a different order, you may be able to see what is behind the three dimensional "wall" of high K-indices. While viewing these three-dimensional graphs, you can instruct KGRAPH to redraw the data in a "slow mode". To accomplish this, press the "S" key to toggle between the fast and slow modes while viewing graphs of data. While in the slow mode, KGRAPH will redraw the screen one date at a time, pausing in-between dates and waiting for a keypress. Using this feature, you can carefully examine each date of data. To view the next date of data, press any key on your keyboard. KGRAPH will respond by drawing the next series of K-indices, pausing after the next group of eight has been drawn. After all of the indices have been drawn on-screen, you can switch back to the "fast mode" by pressing "S" again. To exit back to the main menu, press any key other than "S". PRODUCING HIGH-DENSITY K-INDEX DATA PLOTS USING KGRAPH The second and third-last options of the main menu engage powerful utilities for viewing large quantities of K-index data on-screen at one time. One option produces a high-density plot of Boulder K-Index data. The other main menu option generates a high-density plot of estimated Planetary (global) geomagnetic K-Index data. Both of these functions produce graphs with identical formats. The only difference is the data which is used. Boulder K-Index data is generally valid for middle latitude regions near Boulder Colorado. The Planetary K-indices represent estimated global levels of geomagnetic activity and may be more reliable characteristics of global activity. The high-density plots use the high-resolution of the VGA graphics system to produce visually pleasing graphs of contiguous activity for as many as eight consecutive solar rotations. As many as 1,728 data points may be plotted on-screen at one time for analysis. The structural format of these high-density graphical plots may be described as follows. Up to eight horizontal segments of the screen are used to graph the data. Each horizontal group of graphed K-indices represents one solar rotation (approximately 27 days). Unfortunately, only 26 days worth of data can be fit on one horizontal screen segment at a time. As a result, each horizontal segment contains 26 days worth of data. The 27th day is not plotted, but will become visible when screen-scrolling of the data occurs after eight solar rotations of data have been accumulated. Each horizontal segment of data is divided into 26 days and each of these days are labelled. The month of the first date encountered on each horizontal segment is displayed adjacent to the horizontal graph segment. Each horizontal graph segment is composed of a series of vertical lines which depict the K-indices being graphed. A sample ASCII representation of one day (eight vertical lines) of K-index data follows below: _o__o__o_ F _o__|__|__|_ E _o__|__|__|_*#* B _o__|__|__|__|_*#* /-<-- Next day of data starts _o__|__|__|__|_*#**#* / on this boundary o__|__|__|__|__|_*#**#*_\/_____________________ | 1 4 | 1 5 | Each vertical line (with a "dot" on top) represents one K-index value. K-Indices are defined as follows: _o__o__o__o_*#* _o__|__|__|_*#**#* _o__|__|__|_*#**#**#* _o__|__|__|__|_*#**#**#* _o__|__|__|__|_*#**#**#**#* o__|__|__|__|__|_*#**#**#**#* /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ || || || || || || || || || || || || || || || || || || || || 0 1 2 3 4 5 6 7 8 9 K - I N D I C E S This method of graphing K-indices has several notable advantages over straight linear graphing. First, the graph line is effectively compressed in vertical extent, allowing a larger number of horizontal segments to be fit on-screen at one time. Second, determination of the value of each K-index point is easily accomplished by counting the horizontal divisions. And finally, visual determination of major to severe storm periods is easily accomplished simply by examining which graph lines are "filled in" (see K-indices 6 through 9 in the graph above). KGRAPH significantly enhances the visibility of major storm periods by "filling in" these intervals with the color red. This easily distinguishes major storm periods from active or quiet periods when viewing the data on-screen. In addition, KGRAPH color-codes the dates of the data as follows: DATE COLOR: RED = One or more Major Flares occurred on this date. YELLOW = A Sudden Magnetic Impulse (SI) occurred on this date. MAGENTA = Both a Sudden Magnetic Impulse AND a Major Flare(s) occurred on this date. WHITE = No Major Flares or Sudden Magnetic Impulses occurred. This scheme for identifying days where major flares occurred is useful when attempting to determine which periods of geomagnetic activity may have been influenced by major flaring. This is particularly valuable when searching for recurrent geomagnetic patterns caused by stable coronal holes. By ignoring the periods of activity which may have been enhanced by major flaring, you can better identify the recurrent patterns attributed to coronal holes. When looking for flare-induced enhancements in geomagnetic activity, keep in mind that increases in geomagnetic activity typically do not occur until after approximately 24 to 48 hours (up to possibly 72 hours) from the onset of the major flare. It usually takes this long for the plasma cloud to traverse the distance from the Sun to the Earth. Also, not all major flares produce enhancements in geomagnetic activity. In fact, only a relatively small percentage are geoeffective. However, knowing which dates are associated with major flares helps to eliminate uncertainties when analyzing the recurrent patterns of geomagnetic activity. The identification of days when sudden magnetic impulses occur is very useful during the analysis of the high-density data plots. Since sudden magnetic impulses are produced by the arrival of interplanetary shockwaves (such as those which are spawned by major flares), it is possible to determine which episodes of activity were produced by the arrival of interplanetary shocks. Coronal holes are not usually associated with sudden magnetic impulses. The enhancements in geomagnetic activity produced by well placed solar coronal holes are most often gradual in nature. USING THE HIGH-DENSITY DATA PLOTS TO DETERMINE RECURRENCE AND OTHER PHENOMENA To use the high-density data plots properly, you must keep in mind that each horizontal row of data represents one solar rotation. Since eight rows may be stacked on top of one another, searching for recurrent patterns is as simple as scanning vertically down the rows of data. Periods of recurrent enhancements in geomagnetic activity will be discerned as consistent increases in K-indices over periods of between 2 or more solar rotations (which is displayed on-screen as two or more horizontal rows spaced vertically above and below each other). Since many coronal holes are constantly evolving and changing in structure, shape, and spatial extent, some deviations from the above may be observed. For example, if a coronal hole which enhances geomagnetic activity during one solar rotation expands in size or becomes elongated in an east-west direction, enhancements in geomagnetic activity may be observed a few days earlier or later than would be expected if the coronal hole remained in the same position and retained the same spatial characteristics. The amplitude of the recurrent enhancement may also differ quite considerably from one solar rotation to the next. As we continue to decline from the solar maximum toward the solar minimum, coronal hole stability and geoeffectiveness will increase which will make identification and prediction of recurrent periods easier using the high-density plot functions of KGRAPH. Recurrent phenomena is not limited to enhancements of geomagnetic activity. Indeed, recurrent quiet intervals are also frequently observed. In fact, these quiet intervals are often easier to discern than recurrent enhancements of activity due to coronal holes. The same method of identifying recurrent enhancements of activity applies to the identification of recurrent quiet periods. Simply scan the high-density graphs of K-index data vertically between the horizontal rows of data. Consistent and consecutive periods of low K-indices are typically associated with recurrent quiet intervals. These are often the best periods for radio communicators, since low levels of geomagnetic activity can support very stable and reliable ionospheric communications. Since active solar regions responsible for major flares also rotate with periods of approximately 26-28 days, it is possible to determine potential future influences of energetic active solar regions on the geomagnetic field. This is less reliable than determining recurrence for coronal holes since active regions are much more dynamic and change more rapidly than coronal holes. Although most solar regions fail to survive two solar rotations, and still fewer remain energetic enough to affect terrestrial geomagnetic activity over two rotations, the odd ones do and may be capable of producing recurrent enhancements in geomagnetic activity if they remain energetic for that length of time. Finally, these high-density graphs may also be used to help determine periods of enhanced auroral activity. Since auroral activity is tied closely to levels of geomagnetic activity, it is often possible to determine the potential visibility of future auroral activity simply by determining recurrent patterns of geomagnetic activity. K-indices of six or more are typically required before auroral activity becomes visible over widespread areas. K-indices of 7 or more may produce visible auroral activity over the lower latitude regions. To be most accurate in making predictions, it is important to remember the influence of lunar phase on visible levels of auroral activity. However, since the moon also has a period similar to the solar rotation period of 27 days, the phase of the moon should be approximately the same between vertical rows of the high density graphs. This serves to improve the usefulness of this data, even beyond what has already been discussed. FINAL NOTE REGARDING THE FORMAT OF THE HIGH-DENSITY GRAPHS When displaying the graphs of geomagnetic activity over many solar rotations, you will notice that the flow of dates from the left to the right is contiguous (provided you do not have any missing datasets in your database). You may also notice that the dates between the end of one horizontal graph segment and the beginning of the next horizontal graph segment are NOT contiguous. In short, you may notice that one day is skipped between the end of one graph line and the beginning of the next. This peculiarity is required in order to ensure that each horizontal graph of data is properly aligned to coincide with the solar rotation period of 27 days. One day is skipped because only 26 consecutive days may be graphed horizontally (approximately one day short of a full solar rotation). If no date skipping were performed to maintain alignment, each horizontal graph line would be skewed approximately one day to the right, which would seriously compromise the ability to determine recurrent periods simply by scanning vertically down the rows. Instead, one would have to scan diagnally down the rows in order to account for the skewed nature of the graphs. For this reason, one date is skipped between the end of one horizontal graph segment and the beginning of the next. The dates which are skipped will eventually scroll into view after your database contains at least eight solar rotations of data (or 216 days of data). Until this time, the skipped dates will not scroll into view. After you have accumulated 216 days worth of data in your database, KGRAPH will begin scrolling through your database, displaying eight full solar rotations of data each time the high-density graphing functions are selected. At the present time (mid February), eight solar rotations of SGDB reports have not been accumulated. The service of providing the daily SGDB reports containing the K-index information began on September 4, 1991. The accumulation of eight full solar rotations of data will not occur until after early April 1992. Until then, the daily SGDB reports will continue to be made available on either a monthly basis or a daily basis from the STD BBS (phone number: 403 756-3008), or from the assigned anonymous FTP sites (ex. xi.uleth.ca, solar.stanford.edu, nic.funet.fi, etc). To exit the high-density K-index graphs of geomagnetic activity, simply press any key. EXITING KGRAPH AND RETURNING TO DOS To return to DOS at the main menu of KGRAPH, either select the "Exit Program" function of KGRAPH, press the associated menu letter ('K'), or press the ESCape key.