SWP Space Weather Indices, Instruments & Observation Systems 1 — Questions and Answers
Question 1: The Kp index is derived from:
- A single polar magnetometer station
- K-indices from 13 sub-auroral magnetometer stations worldwide, averaged using a specific weighting scheme (Correct answer)
- Solar wind data from the DSCOVR satellite
- Riometer measurements of ionospheric absorption
Correct answer: K-indices from 13 sub-auroral magnetometer stations worldwide, averaged using a specific weighting scheme
The global Kp index is a 3-hourly quasi-logarithmic index computed from K-indices measured at 13 specific magnetometer stations at sub-auroral latitudes, providing a global measure of geomagnetic activity.
Question 2: The GOES X-ray Sensor (XRS) monitors solar X-rays in which two channels used to classify flares?
- 0.1–0.8 nm (long) and 0.05–0.4 nm (short) (Correct answer)
- 1–8 nm and 10–50 nm
- 0.1–10 nm and 10–100 nm
- 0.01–0.05 nm and 0.1–0.5 nm
Correct answer: 0.1–0.8 nm (long) and 0.05–0.4 nm (short)
GOES XRS measures the 0.1–0.8 nm (long channel) and 0.05–0.4 nm (short channel) bands; the long channel peak flux defines the flare classification (A, B, C, M, X).
Question 3: The Dst (Disturbance storm time) index measures:
- Total energy of solar wind dynamic pressure
- The ring current intensity via depression of the horizontal geomagnetic field at low-latitude stations (Correct answer)
- Auroral zone electrojet strength
- Equatorial ionospheric plasma drift velocity
Correct answer: The ring current intensity via depression of the horizontal geomagnetic field at low-latitude stations
Dst averages the horizontal component (H) deviation at four near-equatorial magnetometer stations; the ring current's magnetic field partially cancels Earth's field, depressing H proportionally to ring current energy.
Question 4: The AE (Auroral Electrojet) index is primarily used to characterize:
- Ring current intensity during the main phase of geomagnetic storms
- Substorm-associated auroral zone electrojet activity using AU and AL envelopes (Correct answer)
- The peak solar wind speed during CME arrival
- Total electron content changes in the polar cap
Correct answer: Substorm-associated auroral zone electrojet activity using AU and AL envelopes
AE is derived from AU (upper envelope, eastward electrojet) and AL (lower envelope, westward electrojet) measured at high-latitude auroral zone magnetometers, quantifying substorm intensity.
Question 5: The F10.7 cm solar flux index is used in space weather because it:
- Directly measures CME probability
- Is a reliable proxy for solar EUV output and solar activity, measurable from the ground regardless of weather (Correct answer)
- Indicates the strength of the interplanetary magnetic field
- Tracks sunspot area in the southern solar hemisphere only
Correct answer: Is a reliable proxy for solar EUV output and solar activity, measurable from the ground regardless of weather
The 10.7 cm radio emission from the Sun correlates well with EUV flux that drives ionospheric and thermospheric variability, and uniquely can be measured continuously from the ground through clouds.
Question 6: SOHO's LASCO coronagraph is primarily used in space weather operations to:
- Measure solar wind speed at L1
- Detect and characterize coronal mass ejections from solar disk imagery (Correct answer)
- Observe solar flare X-ray emissions
- Monitor the interplanetary magnetic field polarity
Correct answer: Detect and characterize coronal mass ejections from solar disk imagery
LASCO uses an occulting disk to image the corona beyond the solar limb, revealing CME morphology, angular width, and projected speed essential for early CME detection and trajectory estimation.
SWP Space Weather Indices, Instruments & Observation Systems 1
The Kp index is derived from: