Topics in Space WeatherTopics in Space Weather

Earth Atmosphere & Ionosphere

Topics in Space WeatherTopics in Space Weather

Earth Atmosphere & Ionosphere

• Sun and Earth: Overview• Physical Processes• Effects on Technological Systems

Robert R. Meier

School of Computational SciencesGeorge Mason University

rmeier@gmu.edu

CSI 76930 August 2005

surface

particles and magnetic fields

SUN EARTH

Sun-Earth SystemSun-Earth System:: Energy Coupling Energy Coupling

photons

core

convection zoneradiative zone

surface atmosphere

magnetosphere

sunspotplage

coronal mass ejection

bow shock

plasmasphere

not to scale

solar wind

heliosphereatmosphere

Lecture 11

Solar Radiative Output

Lecture 11

StratosphereStratosphere

TroposphereTroposphere

MesosphereMesosphere

315

wavelengths > 300 nm troposphere & surface

ThermosphereThermosphereIonosphereIonospherewavelengths 100-300 nm

mesosphere/stratosphere

wavelengths < 100 nm thermosphere/ionosphere

Solar Radiation Establishes the Thermal Solar Radiation Establishes the Thermal Structure of the Earth and its AtmosphereStructure of the Earth and its Atmosphere

SUN (255 K) + GHG (33 K) = 288 K Lecture 11

Why does the Atmospheric Temperature vary with Altitude?

Surface Heating

Ozone Heating: O3 + sunlight O + O2

Oxygen Heating: O2 + sunlight O + O

Ionization: O, N2, O2 + sunlight e + …

Lecture 12

Lecture 11

SOLAR CYCLE CHANGES IN EUV RADIATION SOLAR CYCLE CHANGES IN EUV RADIATION IMPACT UPPER ATMOSPHERE IMPACT UPPER ATMOSPHERE TEMPERATURE and DENSITYTEMPERATURE and DENSITY

Solar Cycle Changes Solar Cycle Changes at 700 km:at 700 km:

Neutral Temperature:Neutral Temperature: 2 times2 times

Neutral Density:Neutral Density: 50 times50 times

Electron Density:Electron Density: 10 times10 times

Lecture 12-13

Solar Energy in the Upper Atmosphere

ENERGETIC SUNLIGHT AND PARTICLES

EXCITATION

IONIZATION DISSOCIATION

ION CHEMISTRY NEUTRALCHEMISTRY

COLLISIONALDEACTIVATION

PHOTOELECTRONS

ELECTRON HEATING ION HEATING NEUTRAL HEATING

SPECTRALEMISSIONS

Lecture 11-13

Why Do We Care About Space Weather?

www.nas.edu.ssb/cover.html

Solar Particles and Solar Particles and Plasma Can Affect EarthPlasma Can Affect Earth

spacecraft drag, collisions, loss communications & navigation aurora currents induced in power grids spacecraft detector upsets hazards to humans in space ozone depletion in major events speculated climate impacts

LASCO Detector: 1997-11-06

March 1989:Auroral Oval

Solar, magnetospheric and galactic particles ionize and heat Earth’s atmosphere and ionosphere

Power System Events

Lecture 12

Lecture 14

Solar Variability Can Affect Human Space Flight

• Radiation Protection operations for future human missions (both to the ISS and to Mars) should be provided with observations of CME’s from several vantage points, such as would be provided by SOHO and STEREO.

• Space Station Orbit is Exposed to High Energy Solar Particles

• Space debris can collide with the Space Station

Oct 20, 1989Solar Protons

NOAA-10

Lecture 14

• disrupts communications disrupts communications

• degrades radar accuracydegrades radar accuracy- space-based & surveillance space-based & surveillance radars, HF OTHradars, HF OTH

• disrupts/degrades navigationdisrupts/degrades navigation-VLF Omega, GPSVLF Omega, GPS

• degrades precision targetingdegrades precision targeting

IONOSPHERE ELECTRON DENSITIES IONOSPHERE ELECTRON DENSITIES Communication, Navigation

Lecture 14

Thousands of Objects Orbit the Earth Thousands of Objects Orbit the Earth in the Upper Atmospherein the Upper Atmosphere

The Naval Space Surveillance radar tracks 12,000 + resident space objects larger than 20 cm

• remote sensing• surveillance• weather monitors• communications• navigation• science

Lecture 14

Space Weather Data Sites• National Space Science Data Center

– http://nssdc.gsfc.nasa.gov/space/• OmniWeb

– solar wind and geomagnetic data– http://nssdc.gsfc.nasa.gov/omniweb/

• Space Physics Models– http://nssdc.gsfc.nasa.gov/space/model

• Solar Activity Reports– http://www.dxlc.com/solar/

• Current Space Weather Conditions– www.spaceweather.com

• Space Weather Today– http://www.windows.ucar.edu/spaceweather/