Presentation on theme: "Solar Max Quick Guide ODOT Surveyors Conference Salem, OR 19 March 2013 Ken Bays, PLS Lead Geodetic Surveyor Oregon Dept. of Transportation."— Presentation transcript:
Solar Max Quick Guide ODOT Surveyors Conference Salem, OR 19 March 2013 Ken Bays, PLS Lead Geodetic Surveyor Oregon Dept. of Transportation
Solar Weather Overview Solar activity cycles & their cause 3 types of ionospheric disturbances –NOAA Space Weather Scales used to quantify –NGS recommendations for GPS surveying during solar activity Where to obtain solar activity forecasts and reports –How to interpret in relation to NGS recommendations Improved ORGN real-time correctors from Spider software –Specifically innovated to help GPS surveying during high solar activity
Solar Activity Solar activity cycles –Approximate 11 year cycles –Observed variations from 9 to 14 years –Hard to predict Solar max this year: 2013 –Original prediction: Max would occur in 2010 or 2011 Strongest cycle since 1958 Lots of coverage in the media –Latest prediction as of January 2013: Max will arrive in autumn of 2013 Smallest cycle since 1906 Very little media coverage Strong solar activity possible any time in any cycle.
Sun Spots Sun spots (emerging strong magnetic fields) are the prime indicators of solar activity contributing to increased ionospheric disturbance
NGS User Guidelines for Single Base Real Time GNSS Positioning
Solar Flares A solar flare is a sudden brightening observed over the Suns surface or solar limb, which is interpreted as a large energy release from twisted magnetic fields near sunspots. The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach earth in a day or two. Can trigger ionospheric disturbances.
NOAA Weather Scales for Ionospheric Disturbances Geomagnetic Storms (G 1- G 5 ratings) Solar Radiation Storms (S 1- S 5 ratings) Radio Blackouts (R 1- R 5 ratings)
Geomagnetic Storms Geomagnetic Storms - disturbances in the geomagnetic field caused by gusts in the solar wind (the outward flux of solar particles and magnetic fields from the sun) that blows by Earth. May affect satellite orientation, orbital information, broadcast ephemeris, communication. May cause inability to initialize for the GNSS user and radio problems. NGS Recommendation: Do not try to perform RT during level G3 – G5 storm events. –NGS User Guidelines for Single Base Real Time GNSS Positioning
Solar Radiation Storms Elevated levels of radiation that occur when the numbers of energetic particles increase. Strong to extreme storms may impact satellite operations, orientation and communication. Degraded, intermittent or loss of radio communication in the northern regions are possible. May impact the noise level at the receiver degrading precision. NGS Recommendation: Do not try to perform RT during level S4 – S5 storm events. –NGS User Guidelines for Single Base Real Time GNSS Positioning
Radio Blackouts Disturbances of the ionosphere caused by X-ray emissions from the Sun. Strong to extreme storms may affect satellite signal reception. May cause intermittent, degraded, or loss of radio communication. May increase noise at the receiver causing degraded precision. NGS Recommendations: Do not try to perform RT during level R3 – R5 storm events. Be aware of possible radio problems even at level R2 storm events. –NGS User Guidelines for Single Base Real Time GNSS Positioning
The largest solar event of the period was a M1 event observed at 15/0658Z from Region 1692 (N09W03). There are currently 7 numbered sunspot regions on the disk.
Solar activity is likely to be low with a slight chance for an M-class flare on days one, two, and three (16 Mar, 17 Mar, 18 Mar).
Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 517 km/s at 15/0500Z. Total IMF reached 14 nT at 15/0719Z. The maximum southward component of Bz reached -10 nT at 15/0619Z.
Protons greater than 10 Mev have a slight chance of crossing threshold on days one and two (16 Mar, 17 Mar).
NOAA Space Weather Alerts Description and Criteria Good page to start understanding NOAA alerts Many alert service products correspond with the NOAA Space Weather Scales thresholds. NOAA Space Weather Scales 4 types of Space Weather Alert Messages –Watch messages are issued for long-lead-time geomagnetic activity predictions –Warning messages are issued when some condition is expected –Alert messages are issued when an event threshold is crossed –Summary messages are issued after the event ends
NOAA Space Weather Alerts Description and Criteria Space Weather Alerts are issued for these categories: –X-ray Flux Alert and Event SummariesX-ray –Radio Burst Alerts and SummaryRadio –Geomagnetic Sudden Impulse Warning and AlertGeomagnetic Sudden Impulse –Geomagnetic K-index Watches, Warnings, and AlertsGeomagnetic K-index –Electron Flux AlertElectron –Proton 10MeV and 100MeV Flux Warnings, Event Alerts and SummariesProton
Solar Radiation Storms
NOAA Space Weather Data and Products NOAA Space Weather Advisory Outlooks –http://www.swpc.noaa.gov/advisories/outlooks.htmlhttp://www.swpc.noaa.gov/advisories/outlooks.html –Issued every Monday –Summary of solar activity for previous week –Forecast of expected activity for coming week Geomagnetic K-indices –http://www.swpc.noaa.gov/alerts/k-index.htmlhttp://www.swpc.noaa.gov/alerts/k-index.html –A report of geomagnetic activity in blocks of time. –Need a secret decoder chart to convert to NOAA scale. NOAA SWPC Product Subscription –https://pss.swpc.noaa.gov/LoginWebForm.aspx?ReturnUrl=%2fproductsubscriptionservice%2f –Space Weather Outlook (weekly) –Report of Solar Geophysical Activity (daily)
NOAA Space Weather Advisory Outlooks Monday
NOAA Space Weather Advisory Outlooks
Geomagnetic K-indices This chart is updated every 15 minutes.
Relationship between the NOAA G-scale and Kp The Kp scale is a reasonable way to summarize the global level of geomagnetic activity It has not always been easy for those affected by the space environment to understand its significance. The NOAA G-scale was designed to correspond, in a straight forward way, to the significance of effects of geomagnetic storms.
Relationship between the NOAA G-scale and Kp Estimates of the planetary average Kp index is used to determine Geomagnetic Storm (NOAA Space Weather Scale) level: Kp of 0 to 4 is below storm level and labeled G0
Two NOAA Subscription Products Space Weather Outlook –Weekly –Same as NOAA Space Weather Advisory Outlooks at –Understandable in terms of NGS GPS guidelines. Solar Geophysical Activity Report and Forecast –Daily with a three day forecast –Not as useful when using NGS GPS guidelines or predicting how it will affect your GPS surveying or when. Solar flares Electron flux Proton Events –But does have general prediction for geomagnetic activity.
Space Weather Outlook Subscription Same as NOAA Space Weather Outlook web page but sent to your
Solar Geophysical Activity Report and Forecast
Spider 4.3 Improved Network Processing during Solar Max –Automated FTP file downloads by Spider: Precise Emphemeris files DCB (Differential Code Bias) files IONEX (IONsphere Map EXchange) files –These files are used to improve Spider real-time correctors
TEC The charged particles in the ionosphere affect radio waves proportional to the "total electron content" (TEC) along the wave path. TEC is the total number of free electrons along the path between the satellite and GNSS receiver. TEC varies with the changes of solar and geomagnetic conditions during the day, with geographic location and with season.
Spider 4.3 Improved Network Processing: IONEX Files ION osphere Map EX change format Contain info on Total Electron Content (TEC) of the ionosphere Radio propagation depends on electron density in the ionosphere IONEX files exchange geographic grid of 2-D & 3-D TEC maps Generated on a daily basis using data from about 150 GPS sites of the IGS and other institutions. Spider v 4.3 automatically downloads IONEX files daily from FTP sites and uses this predicted ionosphere TEC to improve processing of network RTK correctors.
Solar Weather Review Solar activity cycles & their cause 3 types of ionospheric disturbances –NOAA space weather scales –NGS recommendations for GPS surveying Where to get solar activity forecasts and reports –How to interpret in relation to NGS recommendations Improved ORGN real-time correctors from Spider software –How they help GPS surveying during high solar activity
Solar Flare Classifications X-class flares are big; they are major events that can trigger planet-wide radio blackouts and long-lasting radiation storms. M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth's polar regions. Minor radiation storms sometimes follow an M-class flare. Compared to X- and M-class events, C-class flares are small with few noticeable consequences here on Earth.
Precise Orbits: prior to late 2009
Improved precise orbits: after late 2009
DCB Files Differential Code Bias files The time dependent bias between C1 and P1 code pseudoranges, or, the P1 and P2 code pseudoranges. or What part of : –http://www.navipedia.net/index.php/Combining_pairs_of_signals_and _clock_definitionhttp://www.navipedia.net/index.php/Combining_pairs_of_signals_and _clock_definition dont you understand?