Solar Irradiances, Geomagnetic Events, and Total Electron Content Beginning Oct 2003

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Everett Little
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1 Solar Irradiances, Geomagnetic Events, and Total Electron Content Beginning Oct 2003 Bouwer, S.D'., W.K. Tobiska', A. Komjathy'', B. Wilson'', X. Pi'', and A. Mannucci'' ' Space Environment Technologies '' Jet Propulsion Laboratories Solar Irradiance Indices Total Electron Content comparison of 28 Oct 04 (X-ray flare) to 30 Oct 04 (Geomagnetic event) Thermospheric and Ionospheric Effects The SOLAR2000 Irradiance Model and E Mar-04 1

Solar Indices and Active Region Evolution F10.7 significantly differs from E10.7(see page 9) over a solar rotation (and longer time scales) F10.

7 (the integrated 1-105 nm soft X ray and EUV flux in F10.

has a dominant pattern of a rapid rise and gradual decay over 4-5 solar rotations A solar rotational effect in the flux seen at Earth is related to the

2 Solar Indices and Active Region Evolution F10.7 significantly differs from E10.7(see page 9) over a solar rotation (and longer time scales) F10.7 cm flux (2800 MHz radio) represents a mixture of coronal and photospheric variations, and has no thermospheric effect E10.7 (the integrated nm soft X ray and EUV flux in F10.7 units) represents both coronal and chromospheric variations, and better represents the energy input to the thermosphere In general, active region evolution has a dominant pattern of a rapid rise and gradual decay over 4-5 solar rotations A solar rotational effect in the flux seen at Earth is related to the relative opacity of the solar atmosphere to solar irradiances A better index to coronal variations is needed to better represent the X-ray irradiances Images courtesy of the SOHO/EIT Consortium E10.7 and F10.7 F10 E /1/03 9/29/03 10/27/03 11/24/03 12/22/03 1/19/04 2/16/04 Date (27-day) 24-Mar-04 2

3 Solar Indices, 13 Oct to 9 Nov, 2003 E10.7 (see page 9) represents the integrated spectrum from approximately nm, with both chromospheric and coronal components Employs the Penticton F10.7 and NOAA SBUV Mg II data (in Ly-alpha units) A Daily Background X-ray index, Xb = weighted daily hourly minimum of 100*log((X-ray 1-8A flux)*10e+10), shows a different rotational modulation Time series curve of 1-8 A X-rays is due to the X-ray irradiance through an optically thin solar atmosphere as the evolving active region rotates across the disk Xb reduces the short-term logarithmic flares in the time series, creating a daily coronal index on a linear scale Solar Indices, 13 Oct - 9 Nov, /13/03 10/14/03 10/15/03 10/16/03 10/17/03 10/18/03 10/19/03 10/20/03 10/21/03 10/22/03 10/23/03 10/24/03 10/25/03 10/26/03 10/27/03 10/28/03 Date QuickTime and a TIFF (LZW) decompressor are needed to see this picture. Background 1-8A X-ray Penticton F10.7 (+300) Lya (From MgII c/w) Solar2000 E10.7 (+300) 10/29/03 10/30/03 10/31/03 11/1/03 11/2/03 11/3/03 11/4/03 11/5/03 11/6/03 11/7/03 11/8/03 11/9/03 24-Mar-04 3

"Halloween" Events, 13 Oct - 9 Nov 2003 Oct 28 and Nov 4 were primarily X-ray events (low Kp), although Oct 22-23 saw several M-class flares At Earth, major Geomagnetic and particle events

4 "Halloween" Events, 13 Oct - 9 Nov 2003 Oct 28 and Nov 4 were primarily X-ray events (low Kp), although Oct saw several M-class flares At Earth, major Geomagnetic and particle events persisted throughout Oct In general, the variation of X-rays over a solar rotation is what we expect for an optically thin solar atmosphere Images courtesy of the SOHO/EIT Consortium 24-Mar-04 4

5 Thermospheric Heating from Solar EUV Compared to Joule Heating Generally, Solar EUV is responsible for approximately 80% of thermospheric heating; Except during major geomagnetic disturbances, when Joule heating dominates Hemispheric particle power during solarinduced particle events is a 2nd-order effect Power (GW) Daily Average Power Values for Max and Decline of Solar Cycle 23 Joule Power*2 Electron Pcp Power*2 Sum Solar Power Jul 15&16 Aug 12 Mar 31 Nov 6 Nov 24 Oct 29 &30 Nov Climatology of Extreme Upper Atmosphere Heating Events, D.J. Knipp et. al., ASR, in press Year 24-Mar-04 5

6 TIMED GUVI and Solar Indices, 12 Jul - 8 Aug 2002 Thermospheric heating for a period of time similar to the Halloween events was measured by the TIMED GUVI instrument in 2002 A suggestion of coronal components in the GUVI data may be represented by the daily background 1-8 Angstrom X-ray index Xb (1-minute 1-8 A X-ray flux red line in fig) The GUVI local minima near DOY 200 and the slowly declining slope after DOY 210 are not as apparent in the other solar indices as in Xb Flares in GUVI data correspond to GOES X-ray flares Can the 4-40 nm component in thermospheric heating be represented by a 1-8 A X-Ray index? 24-Mar-04 6

Qeuv Heating Rate Thermospheric heating (Qeuv) by solar flux in soft X-ray and EUV wavelengths dominates thermospheric heating other derivative SOLAR2000 products include: derived sunspot number, Rsn

7 Qeuv Heating Rate Thermospheric heating (Qeuv) by solar flux in soft X-ray and EUV wavelengths dominates thermospheric heating other derivative SOLAR2000 products include: derived sunspot number, Rsn (unitless), exospheric temperature at 450 km, Tinf (K) EUV hemispheric power, Peuv (GW) To the extent soft X-ray (in the 1-40 nm range, E1_40) is correlated with the 1-8 Angstrom index Xb, a new coronal proxy may be possible Relative thermospheric Qeuv heating rate near solar maximum, calculated using the SOLAR2000 empirical model (see page 9) 24-Mar-04 7

JPL Total Electron Content TEC collected from over 100 GPS stations by the JPL Ionospheric and Atmospheric Remote Sensing Group The X-Ray flare at 11 UT on Oct 28 is responsible for enhanced TEC

8 JPL Total Electron Content TEC collected from over 100 GPS stations by the JPL Ionospheric and Atmospheric Remote Sensing Group The X-Ray flare at 11 UT on Oct 28 is responsible for enhanced TEC Extensive latitudinal effect Duration of enhanced TEC lasted only several hours In contrast, the geomagnetically induced TEC increase on Oct 30 was much larger, and persisted for several days 24-Mar-04 8

9 SOLAR2000 is an empirical full-disk solar irradiance model for accurately characterizing solar irradiance variability across the spectrum (1-1,000,000 nm at 1nm resolution) It is regularly improved using new satellite and rocket measurements and proxies, steadily improving it s accuracy and applications It is compliant with the developing International Standards Organization (ISO) solar irradiance standard SOLAR2000 captures the essence of historically measured solar irradiances, expanding our knowledge about the quiet and variable Sun, including its historical envelope of variability E10.7 is the integrated SOLAR2000 estimated flux from nm, converted to F10.7 units It more accurately estimates the input to thermospheric and ionospheric processes It can be used to improve other space physics models wherever F10.7 is used SOLAR Mar-04 9

com A SOLAR2000 Professional-Grade (fee-based) software application is available for high-resolution nowcast and forecast operations The

10 SOLAR2000 Products For Research and Engineering Applications A freely-available SOLAR2000 Research-Grade software package is available for studying historical solarterrestrial variations. See A SOLAR2000 Professional-Grade (fee-based) software application is available for high-resolution nowcast and forecast operations The SOLAR2000 solar irradiance specification tool (and associated derivative products) have operational applications in satellite drag, radio communications, TEC, post-event analysis, etc. 24-Mar-04 10

11 SOLAR2000 Forecasts SET employs an automated wavelet-based algorithm for predicting E10.7 (on time scales of hours to years) In extensive tests of the waveletbased algorithm for predictions: The SET forecasts of F10.7 were at least as good as the NOAA/SEC forecaster predictions on 1-3 day time scales The E10.7 forecasts were significantly better on all time scales One-day F10.7/E10.7 forecasts are freely available at the website Longer forecasts are one of the components in fee-based SOLAR2000 products Upgraded SOLAR2000 versions will improve forecasts 24-Mar-04 11

12 Summary The Oct 2003 events demonstrate unique variations in both solar, thermospheric, and ionospheric measurements and indices Permitting the comparison of terrestrial effects due to a solar X-ray flare vs. a geomagnetic storm Solar Irradiance from soft X-rays and EUV (1-40 nm) are the principal driving forces to thermospheric and ionospheric variations Except during major geomagnetic events, when Joule heating dominates SOLAR2000, the E10.7 index, and subsequent derived estimates (e.g., Qeuv, E1_40, Tinf) are effective proxies for estimating solar irradiance, thermospheric, and ionospheric variations SET is currently developing a better index representing coronal X-ray variations (i.e., the background X-ray index Xb and an associated flare index Xf) to improve the SOLAR2000 model and derivative solar-terrestrial proxies 24-Mar-04 12

FORECASTING OF SPACE ENVIRONMENT PARAMETERS FOR SATELLITE AND GROUND SYSTEM OPERATIONS. W. Kent Tobiska a

AIAA 2003-1224 FORECASTING OF SPACE ENVIRONMENT PARAMETERS FOR SATELLITE AND GROUND SYSTEM OPERATIONS W. Kent Tobiska a ABSTRACT The E10.7 solar proxy has been developed to characterize the energy input