Space weather refers to changes in the space environment near Earth that are driven by solar activity like solar flares and coronal mass ejections. There are three main types of space weather storms: radio blackouts caused by solar flares that arrive in 8 minutes, radiation storms from energetic particles that arrive within 15 minutes to 24 hours, and geomagnetic storms from coronal mass ejections that arrive within 1 to 4 days. Each type of storm has different effects, affecting systems like radio communications, satellites, power grids, and navigation.

1. Space Weather:
What is it?
How Will it Affect You?
An introduction to Space Weather
• What is it?
• Where does it come from?
• What does it do?
Rodney Viereck
NOAA Space Environment Center
Boulder Colorado

2. Space Weather:
What is it?
Space Weather refers
to changes in the space
environment near Earth
Earth
Sun
Sun:
• Energy (386 Billion Billion MegaWatts) released in
the form of…
• Light
• Particles (electrons and protons)
• Magnetic Field
• Activity Cycles
• 27 Days (solar rotation)
• ~100 Days Active Region Development
• 11 years
• 22 years
• 88 years

3. GOES Solar X-Rays
Space weather events
are usually initiated
by a solar flare or a
coronal mass
ejection
During a solar flare,
the x-ray irradiance
can increase by
several orders of
magnitude in just a
few minutes

4. Space Weather refers
to changes in the space
environment near Earth
Sun
Interplanetary Space:
• Solar Wind
•Constant outflow from the sun
•Electrons and protons
• Disturbances from the sun produce
waves and shocks in the solar wind
Interplanetary Space
Space Weather:
What is it?
Earth

5. ACE Solar Wind
• Solar Wind
– Density
• 1 to 100 particles per cm3
– Speed
• 200 to 800 km/sec

6. Space Weather refers
to changes in the space
environment near Earth
Magnetosphere
Magnetosphere:
• Created by Earth’s magnetic field
• Deformed by the Solar Wind
• Particles (electrons and protons) trapped
on magnetic field lines
Sun
Interplanetary Space
Space Weather:
What is it?
Earth

7. GOES Particles and Magnetic Field
• Protons
• Electrons
• Magnetic
Field

8. Space Weather refers
to changes in the space
environment near Earth
Magnetosphere
Sun
Interplanetary Space
Ionosphere
Ionosphere:
• Layer of electrons at the top of the
atmosphere (100 – 300 km up)
• Formed when extreme ultraviolet light
from the sun hits Earth’s Atmosphere
• Strongly affected by changes in the
magnetosphere
• Critical in the reflection and
transmission of radio waves
Space Weather:
What is it?
Earth

9. POES Ionospheric Particles
• Auroral Oval
– Electrons and
Protons collide with
the atmosphere
– The collisions excite
atoms and molecules
to produce the
aurora

10. Other Space Weather Terms
• Solar Flare: An eruption on the sun that emits light (UV and
x-rays) and often particles (electrons and protons).
• CME (Coronal Mass Ejection): A disturbance in the solar wind
caused by an eruption on the sun.
• Solar Wind: The outward flow of electrons, protons, and
magnetic field from the sun.
• Energetic Particles: electrons and protons that have been
accelerated to high speeds.
• Geomagnetic Storm: The disturbance in the near-Earth
particles and magnetic fields that can upset technological
systems and creates aurora.
• Radiation Storm: A large flux of solar energetic protons as
measured near Earth.
• Radio Blackout: An enhancement in the lower ionosphere as a
result of large x-ray flares.

11. Sequence Of Events
• Active Region on the Sun Erupts
1. Solar Flare (x-ray)
2. Shock (energetic particles)
3. Corornal Mass Ejection (particles and fields)
• X-rays reach Earth in 8 minutes (speed of light)
• Energetic Particles reach Earth in 15 min to 24
hours
• Coronal Mass Ejection reaches Earth in 1-4 Days

12. Three Types of Space Weather
Storms
1.Radio Blackouts
– Solar Flares send out x-
rays
– Arrive at Earth in 8
minutes
– Modify the ionosphere
– Disrupt HF radio
communication
– Impacts:
• Airline communication
• HF radio operators
• DoD Communications
• Satellite Communications
2.Radiation Storms
– Solar Flares and Coronal
Mass Ejections (CMEs)
send out Energetic
Particles
– Arrive at Earth in 15
minutes to 24 hours
– Modify the high latitude
ionosphere
– Disrupt HF radio
communication
– Impacts:
• Airline communication
• HF radio operators
• DoD Communications
– Ionizing radiation
penetrates into the
atmosphere
– Impacts:
• Astronauts (radiation)
• Satellite failures
3.Geomagnetic Storms
– Coronal Mass Ejections
(CMEs) send out Magnetic
Clouds
– Arrive at Earth in 1-4
days
– Accelerate particles within
the magnetosphere and
into the ionosphere
– Impacts:
• HF radio communication
• Radio Navigation (GPS)
• Electric Power Grids
• Increased Satellite Drag
• Aurora

13. The Sun
The Energy Source
The sun in X-rays
From GOES 12
•The Sun
• Rotates every 27 days
• Has an 11-year cycle of
activity
•Flares produce large
amounts of x-rays and
extreme ultraviolet light
but not much visible
light
An Erupting Prominence
A Solar Flare
Image from NASA TRACE Satellite
Image from NASA SOHO Satellite

14. Solar Photons (Light)
• Visible light (small slow changes)
– Most of the energy output
– Impacts climate
• UV light (medium slow changes)
– Affects ozone production and loss
• EUV light (large changes)
– Affects radio communication
– Affects navigation
– Affects satellite orbits
• X-ray light (Can change by a
factor of 1000 in five minutes)
– Affects radio communication
Solar spectrum
Solar variability
Atmospheric penetration
X-Ray Flare
Variability
(minutes)
Lean

15. Product for Radio Operators
Effect of Solar X-rays on D-Region and HF Propagation.
• D-Region Absorption Product based on GOES X-RayFlux (SEC Product)
– The map shows regionsaffected by the increased D-region ionization resulting
from enhanced x-ray flux during magnitude X-1 Flare
TJFR

16. CMEs (Coronal Mass Ejections)
in Interplanetary Space
• While Solar flares send out light
(mostly x-rays)
• CMEs produce…
– Energetic particles
– Magnetic structures
Propagate away from the sun
but their paths are modified
by the background solar wind
and the sun’s magnetic field.
Image from NASA SOHO Satellite
Image from NASA SOHO Satellite

17. Magnetosphere
What happens when a CME hits Earth?
1. Solar wind is deflected around Earth
2. Deflected solar wind drags Earth’s magnetic field with it
3. Magnetic field lines “reconnect” and accelerate particles
4. Accelerated particles follow field lines to Earth
Aurora is produced when particles hit Earth’s atmosphere
1. Solar wind
is deflected
around Earth
2. Deflected solar wind
drags Earth’s magnetic field
with it
3. Magnetic field lines
“reconnect” and
accelerate particles
4. Accelerated particles
follow field lines to Earth
Aurora
Outer
Radiation
Belt
Inner
Belt

18. Energetic Particle Effects
Spacecraft Systems
• Systems affected
– Spacecraft electronics
• Surface Charging and Discharge
• Single Event Upsets
• Deep Dielectric Charging
– Spacecraft imaging and attitude systems
Polar Satellite Image Degradation
SOHO Satellite Image
Degradation
Spacecraft Surface Charging (NASA animation)

19. Energetic Particles Effects
Radiation Hazard
Health Hazards from
Energetic Particles
• Humans in space
– Space Shuttle,
International Space
Station, missions to
Mars
• Crew/Passengers in high-
flying jets
– Concorde carries
radiation detectors
– Passengers and crew
may receive radiation
doses equivalent to many
chest X rays.

20. Ionosphere
• The particles collide with
the atmosphere and
produce the Aurora and
currents in the
ionosphere
• As geomagnetic activity
increases, the aurora
gets brighter, more
active, and moves away
from the polar regions.
– Electric Power is affected
– Navigation Systems are
affected
– Radio Communications are
affected
Image from NASA IMAGE Satellite

21. Geomagnetic Storm Effects
March 1989
Hydro Quebec Loses Electric Power for 9 Hours
Transformer Damage
Electric Power
Transformer

22. Aurora
• The particles spiral
down the magnetic
filed lines and collide
with the atmosphere
to produce the
aurora.
• Colors indicate the
atoms or molecules
that are excited by
the incoming particles

23. Geomagnetic Storm Effects
Aurora
• Intensity and location of the aurora depend on strength of storm
• Best time to view is around midnight
• No guarantee that aurora will occur
G5
G3
G1
Photo by Jan Curtis, http://www.geo.mtu.edu/weather/aurora

24. Geomagnetic Storms
• Disrupt Radio Communications • Impact Electric Power Systems
• Impact Satellites• Disrupt Radio Navigations

25. NASA Animation
Sun to Earth
• An animation of a space weather event as it
starts at the sun and end up at Earth
– Solar Flare
• Light
• Particles
• CME
– Magnetosphere
• Deflects the solar wind
• Responds to the disturbance
• Accelerates particles
– Ionosphere
• Accelerated particles collide with the atmosphere
producing the aurora

26. Space Weather Storms
Timing and Consequences
• At T = 0, A Flare and CME
Erupts on the Sun
• 8 Minutes later: First blast of
EUV and X-Ray light increases
the ionospheric density
– Radio transmissions are lost
• 30 min. to 24 hrs. later:
Energetic Particles Arrive
– Astronauts are at risk
– Satellites are at risk
– High altitude aircraft crew
are at risk
• 1 to 4 Days Later: CME Arrives
and energizes the
magnetosphere and ionosphere
– Electric Power is affected
– Navigation Systems are
affected
– Radio Communications are
affected
Movie from NASA SOHO Satellite

27. What Controls the Size a Space Weather
Storm?
• The Size of Flare or CME
– Big solar events tend to
make big storms
• The Location of the flare
site on the SUN
– If it is directed at Earth, it
is more likely to make a
storm
– If it toward the west side of
the sun, the particles will
arrive sooner
• The Direction of the
Magnetic Field in the CME
– If the interplanetary
magnetic field is southward,
then there will likely be a big
storm
Note, there does not have to be
a solar flare or CME to
create a geomagnetic storm

28. Space Weather Scales
• Three Categories
– Geomagnetic Storms
(CMEs)
– Solar Radiation Storms
(Particle Events)
– Radio Blackouts
(Solar Flares)
Combs
Rabin

29. How Often Do Space Weather Storms Occur?
• Solar Cycle is about 11 Years
Radiation Storms
1-4 per month at max
Geomagnetic Storms
3-5 per month at max
Radio Blackouts
50-100 per month at max
Sunspot Number
11-year cycle
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
EventsPerMonthEventsPerMonth
EventsPerMonth

30. The Solar Cycles of the Past
• Sunspots have been recorded for the last 400 years
• Note that there were no sunspots for nearly 60
years after 1640
• During the same period, it was very cold in Europe.
This is a period called “The Little Ice Age”
• Is there a Connection?
• Recent studies say there may be
Solar Maximum
Solar
Minimum

31. Sun and Climate
• The sun is the primary engine for weather and the climate
• Very large climate changes (Ice ages) are known to be caused by
changes in insolation (amount and distribution of sunlight)
• The sun is likely responsible for some of the climate change… up to
1960s… but not the rapid increase in temperatures since then.
NCAR Climate Model
Ammann: SORCE 2003

32. NOAA POES
NOAA GOES
NASA ACE
NASA SOHO
Primary Space Weather Satellites
for SEC
• ACE
– Solar wind composition,
speed, and direction
– Magnetic field
strength and direction
• SOHO
– Solar EUV Images
– Solar Corona
(CMEs)
• STEREO
– CME Direction and
Shape
– Solar wind composition,
speed, and direction
– Magnetic field
strength and direction
• GOES
– Energetic Particles
– Magnetic Field
– Solar X-ray Flux
– Solar X-Ray Images
• POES
– High Energy
Particles
– Total Energy
Deposition
– Solar UV Flux
NASA STEREO
(Ahead)
NASA STEREO
(Behind)
• Events are observed on and near the sun
• No measurements until the Particles or CMEs
are 99% of the way to Earth
• This provides only 30 minutes lead time for
CMEs and no lead time for other events

33. Summary
Arrival 8 minutes 15 min. to 24 hrs. 1 to 4 days
Time
Radio Blackouts
Bursts of X-ray and
EUV radiation
Radiation Storms
Energetic Particles
(electrons and protons)
Geomagnetic
Storms
When the CME
reaches Earth
Systems Radio Comm. Satellites Power Companies
Affected Airlines Astronauts Radio Comm.
Radio Comm. Navigation (GPS)
Satellite Drag
• Space Weather Storms come in three main categories
• Each category originates from different physical processes
• Each category arrives at a different speed
• Each category affects different users and technologies
Space
Weather
Event