SPACE WEATHER

For solar wind dials without any explanatory text, see this page. It also has a few dials that are not shown here. A web page with more explanatory text is also available.

Current Space Weather Status

This "stoplight" shows the most severe of the following three gauges of space weather:

Most Recent K_P Index:: Condition GREEN

This index is based on the most recent USAF/NOAA estimated planetary geomagnetic activity (K_P) 3-hour index. Our index is determined as follows:
Condition Estimated (3-Hour) K_P

Green K_P < 4

Yellow 4 <= K_P < 7

Red K_P >= 7
Solar Wind Observations: Condition GREEN

This index is keyed to the estimated instantaneous asymptotic voltage across the polar cap, the single most important measure of electrical power delivered to the atmosphere from the solar wind. We now use data from the ACE Real-Time Solar Wind package since this spacecraft is tracked more often than WIND. (The old estimate was based on observations from NASA's WIND spacecraft.) The index is determined as follows:
Condition Polar Cap Potential (PCP) Range

Green 0 kV <= PCP < 110 kV

Yellow 110 kV <= PCP < 200 kV

Red PCP >= 200 kV^*

^* The PCP status is changed to red only if the current 10-minute average exceeds 200 kV AND the previous 10-minute average exceeds 150 kV. This is designed to reduce shifts in status due to short-term spikes in the value of the potential.
NOAA/SEC Forecast: Condition GREEN

This index is based on the forecasted geomagnetic event probabilities over the next two days (section VI of the NOAA/SEC Forecast) as follows:
Condition Next Day Probabilites (P₁) Second Day Probabilities (P₂)

Green P₁ <= 35% P₂ <= 35%

Yellow 35% < P₁ < 50% P₂ > 35%

Red P₁ >= 50% Not Applicable

Condition	Estimated (3-Hour) K_P
Green	K_P < 4
Yellow	4 <= K_P < 7
Red	K_P >= 7

Condition	Polar Cap Potential (PCP) Range
Green	0 kV <= PCP < 110 kV
Yellow	110 kV <= PCP < 200 kV
Red	PCP >= 200 kV^*

Condition	Next Day Probabilites (P₁)	Second Day Probabilities (P₂)
Green	P₁ <= 35%	P₂ <= 35%
Yellow	35% < P₁ < 50%	P₂ > 35%
Red	P₁ >= 50%	Not Applicable

Latest Observations from the ACE spacecraft

Last Measurement (at Sun-Earth L1 Point): July 3, 2009 22:11 UT

Sun-Earth L1 Point is approximately 45 minutes upwind of the Earth.

Solar Wind

Interplanetary Magnetic Field

Link to Recent History of Solar Wind Parameters

Magnetospheric Response: Voltage Across the Polar Cap

You can now receive e-mail notification whenever the stoplight sets to red! (Actually, you can be notified whenever any of these conditions change.) Just go to the Rice University Lists and subscribe to the SPACALRT Mailing List. To unsubscribe follow the instructions on the SPACALRT Mailing List page, or send an e-mail to this address.

Stoplight state changes are once again logged. There are three logs, one for each condition index (K_P, Solar Wind, and NOAA/SEC.) The earliest logged transition occurred on September 25, 2003.

More about the solar wind's recent behavior can be found on the Current Solar Wind Conditions page.
Also, here's an index to Space Weather Resources. Other items of interest include NOAA/SEC Current Conditions, the composite current Auroral Images page, Windows on the Universe: Space Weather, and Public Outreach Index, Department of Physics and Astronomy, Rice University.

Patricia H. Reiff

(reiff@rice.edu)

Department of Physics & Astronomy
Rice University

Static information was last revised on 10/31/2003.