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HOW TO READ SPACE WEATHER GRAPHS


Introduction

This page examines each of the NOAA plots in turn, discussing what each of them portrays. We'll examine them as they appear within the general Space Weather Overview categories described by NOAA:

  1. Geomagnetic Activity Graph
  2. Solar Proton Flux Graph
  3. Solar X-ray Flux Graph

Space Weather Overview Graphs — From December 28-31, 2014

The following space weather overview picture contains three plots; these are the newest versions produced by NOAA in 2014. From the bottom up, these are: 1) Geomagnetic Activity, 2) Solar Proton Flux, and 3) Solar X-ray Flux.

Let's see if we can figure a way to understand the data presented in these three graphs. We'll start with the bottom graph, Geomagnetic Activity, and work our way up.


Status

Clicking on the graph image takes you to NOAA's Space Weather Enthusiasts Dashboard.

1. Geomagnetic Activity Graph — From December 28-31, 2014

The Geomagnetic Activity plot is the easiest to understand. Notice on the left-hand side of the plot we see a series of colored numbers from 1-9, with the number 1 at the bottom and number 9 at the top. The Space Weather Action Center states, "Every three hours throughout the day, magnetic observatories around the world measure the largest magnetic change that their instruments recorded during this time. The result is averaged together with those of the other observatories to produce an index that tells scientists how disturbed the Earth's magnetic field is on a 9-point scale."1

This 9-point scale is called the Kp Index and is represented on the left-hand side of the Geomagnetic Activity plot as the numbers 1-9. According to NOAA, the KP Index is an Estimated Planetary K-index. The colored bars spread across the center of the plot represent the Kp Index over time, in this instance, three days.

The right-hand side of the plot depicts "G" values from G0-G5; that is, G0, G1, G2, G3, G4, and G5. These values indicate severity (intensity) of a geomagnetic storm, with G0 indicating no storm whereas G5 indicates the most severe, or a storm with the greatest intensity; hence, the greater the impact on earth's magnetic field (magnetosphere). The greater the impact on earth's magnetosphere, the greater the environmental influence, as seen in the Space Scales on our Space Weather Scales page.

Numbers 1-4 are green and correspond to the green G0 storm intensity indicator; G0 indicates no geomagnetic storm is in progress. Hence, all is Quiet. Number 5 as yellow corresponds to the G1 storm intensity indicator; G1 indicates that earth's magnetic field is Unsettled. Number 6 as light orange corresponds to the G2 storm intensity indicator; G2 indicates a Mild geomagnetic storm. Number 7 as dark orange corresponds to the G3 storm intensity indicator; G3 indicates a Moderate geomagnetic storm. Number 8 as red corresponds to the G4 storm intensity indicator; G4 indicates a Severe geomagnetic storm, and number 9 as dark red corresponds to the G5 storm intensity indicator; G5 indicates the Most Severe geomagnetic storm possible. A Most Severe geomagnetic storm would create disastrous, if not catastrophic, and longterm results on earth!

2. Solar Proton Flux Graph — From December 28-31, 2014

The middle plot seen in the Space Weather Overview graph picture above depicts Solar Proton Flux variables. Let's explore its meaning.

The Sun is comprised of enormous energies. At times, some of this energy explodes off the Sun, mostly in form of "proton particles." Oftentimes these "proton particles" head in the direction of earth.

To better understand the Solar Proton Flux graph, we need to explore what it is measuring.

  1. The term Solar implies anything to do with the Sun.
  2. The term Proton defines as "a particle with a positive charge that is in the nucleus of an atom."2
  3. The term Flux defines simply as the act of flowing; a continuous moving on or passing by, as of a flowing stream.3
  4. Solar Flux refers to particles exploding off the Sun, reaching earth's magnetosphere, then flowing down magnetospheric magnetic lines into our atmosphere.

NOAA uses terms such as solar flare or coronal mass ejection (CME) to describe these energies [particles] exploding off the Sun. A solar flare emanates from the Sun as an "intense flash of extreme radiation."4

As with the Geomagnetic Activity graph, the Solar Proton Flux graph depicts time as three days across the bottom. The left side of this graph appears as a logarithmic notation, which is quite different from the Geomagnetic Activity graph.

Next, let's determine the difference between a graph using regular numbers to indicate a measure versus one using a log scale.

"A regular graph has numbers spaced at even intervals, while a log scale graph has numbers spaced at uneven intervals."5 This is because regular graphs use typical counting numbers (1, 2, 3, 4, 5, etc.) such as seen in the Geomagnetic Activity graph. On the other hand, a logarithmic graph uses powers of 10 to indicate a growth in measure; for example, a log scale of measure uses 10-100-1000-10,000 and so forth. That is, a log scale graph represents a growth of magnitude as powers of 10, whereas graphs using regular numbers increase in quantity as one number progresses from a lower value to the next higher value.

Okay. The left side of the Solar Proton Flux graph represents measure as particle flux units. "Proton fluxes are integral 5-minute averages for energies >10 MeV, given in particle flux units (pfu)."6 It is probably important to point out that the notation MeV means million electron volts; therefore, >10 MeV equates to greater than 10 Million electron Volts! That represents a bunch of energy folks!

Although it may seem difficult at first, with a little practice, you will be able to assess the Solar Proton Flux graph with ease. Simply keep an eye on the squiggly lines appearing across the center of the graph to see when a solar storm has happened, is happening, or is likely to happen over a three-day period. Then peek at our Space Weather Scales page to determine potential impacts from the storm.

Finally, in the following section, we explore the Solar X-ray Flux graph.

3. Solar X-ray Flux Graph — From December 28-31, 2014

The top plot in the Solar Overview picture seen above is the Solar X-ray Flux graph. The Solar X-ray Flux graph allows us to keep track of solar flares and their corresponding storm intensities.

The left-hand side of the graph depicts a solar flare's "class." Solar flares are classed with letters, "A," "B," "C," "M," and "X." An A-Class Flare is the least intense while an X-Class Flare is the most intense. The right-hand side of the graph depicts storm intensity.

For practical purposes, NOAA keeps track of solar flares in C-Class, M-Class, and X-Class categories. Lower class flares do not adversely affect earth's magnetosphere.

To better understand the Solar X-ray Flux graph, we need to explore what it is measuring.

  1. The term Solar implies anything to do with the Sun.
  2. The term X-ray denotes a "band of electromagnetic radiation with wavelengths between gamma rays and ultraviolet radiation. X-rays are capable of penetrating opaque or solid substances, ionizing gases and body tissues through which they pass or, by extended exposure, destroying tissue."7
  3. The Electromagnetic Spectrum includes the entire range of electromagnetic radiation in order of increasing frequency and decreasing wavelength: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x-rays, and gamma rays.
  4. The term Flux defines simply as the act of flowing; a continuous moving on or passing by, as of a flowing stream.8

Therefore, the Solar X-ray Flux graph depicts a measure of X-rays exploding off the Sun, flowing towards earth, striking earth's magnetosphere, flowing down its magnetic lines into earth's atmosphere. The X-ray band within the electromagnetic spectrum serves to disrupt radio frequency signals. As a point of interest, the more intense the storm caused by X-ray flux, the greater the disturbance to radio signal communication.

Although it may seem difficult at first, with a little practice, you will be able to assess the Solar X-ray Flux graph with ease. Simply keep an eye on the squiggly lines appearing across the center of the graph to see when a solar storm has happened, is happening, or is likely to happen over a three-day period. Then peek at our Space Weather Scales page to determine potential impacts from the storm.

Summary

To summarize, the Space Weather Overview picture seen above presents us with three distinct graphs. Each graph portrays different correlations with energies exploding off the Sun, disturbing earth's magnetosphere, and ultimately, denoting potential impacts on earth.

The Geomagnetic Activity plot presents a measure of the so-called Kp Index. The Kp Index is an indicator of an Estimated Planetary Index. This represents a measure of disturbance to earth's magnetosphere; the greater the disturbance, the greater the impact on earth.

The Solar Proton Flux plot presents a measure of the intensity of particles exploding off the Sun and hitting earth's magnetosphere. The Solar Proton Flux plot is an indicator of the number of particles, measured as particle flux units, hitting earth's magnetosphere. This represents a measure of disturbance to earth's magnetosphere; the greater the disturbance, the greater the impact on earth.

The Solar X-ray Flux plot presents a measure of the intensity of X-rays exploding off the Sun and hitting earth's magnetosphere. The Solar X-ray Flux plot is an indicator of X-ray flux hitting earth's magnetosphere. This represents a measure of disturbance to earth's magnetosphere; the greater the disturbance, the greater the impact on earth.

Now . . . let's take a little tour into the realm of:

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