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INTRODUCTION AND OVERVIEW OF ICE CORE RECORDS AND EXTREME SOLAR PROTON EVENTS Don Smart

INTRODUCTION AND OVERVIEW OF ICE CORE RECORDS AND EXTREME SOLAR PROTON EVENTS Don Smart sssrc@msn.com. PROLOG When Forbush and colleagues (Terr. Mag., 47, 331, 1942) suggested the world-wide

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INTRODUCTION AND OVERVIEW OF ICE CORE RECORDS AND EXTREME SOLAR PROTON EVENTS Don Smart

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  1. INTRODUCTION AND OVERVIEW OF ICE CORE RECORDS AND EXTREME SOLAR PROTON EVENTS Don Smart sssrc@msn.com

  2. PROLOG When Forbush and colleagues (Terr. Mag., 47, 331, 1942) suggested the world-wide cosmic ray increases on February and March, 1942 might be particles from the Sun, Nobel LaureaeteHans Alfvén took exception to this concept. He proceeded to give a series of international lectures employing established physical concepts that describe the infeasibility of this solar particle concept. In his opinion, this was just another unexplained phenomena associated with magnetic storms (Alfven, Nature, 158, 618, 1946). (See Elliott in “Early History of Cosmic Rays Studies”, p375, D. Reidel, 1985)

  3. VERY LARGE HIGH ENERGY SOLAR COSMIC RAY EVENTS DURING THE COSMIC RAY MEASUREMENT ERA

  4. VERY LARGE HIGH ENERGY SOLAR COSMIC RAY EVENTS DURING THE COSMIC RAY MEASUREMENT ERA G GGGGGG B BB Wolff and McConnell cannot resolve any of these events

  5. Nitrate (▄) and conductivity (▼) data from the GISP2-H ice core for 1955-1957. Notice the annual NO(y) cycles (summer high - winter low). (Sample numbers at the top of this figure.) The impulsive NO(y) event identified by McCracken et al. [2001a] is in samples 1133-1136 (a 34-day interval) .

  6. Nitrate (▄) and conductivity (▼) data from the GISP2-H ice core for 1955-1957. GLE# 5 23 Feb 1956, 4554% (NM 15 Min) GLE# 5 23 Feb 1956, 300% (Ion Chamber) Background=72; Max=120; Increase=48 Integral NO(y) deposition = 210 Largest GLE in the cosmic ray measurement era

  7. Nitrate (▄) and conductivity (▼) data from the GISP2-H ice core for 1955-1957. GLE# 5 23 Feb 1956, 9000% (NM Polar Estimate) GLE# 5 23 Feb 1956, 300% (Ion Chamber) Integral NO(y) deposition = 210 Largest GLE in the cosmic ray measurement era

  8. G L E # 5 G L E # 6 Nitrate (▄) and conductivity (▼) data from the GISP2-H ice core for 1955-1957.

  9. NO(y) – Proton fluence– Calibration McCracken et al. tried to “calibrate” the NO(y) events in the GISP2-H core with modern era proton fluence data. At that time, the only proton fluencedata consistently available from 1956 to 2000 were >10 & >30 MeV. The nitrate events in the GISP2-H core were associated with >30 MeV proton fluences> 10^9 /cm^2 and/or very large GLE’s. Small GLE’s do not produce NO(y) events in the GISP2-H core. In the higher time resolution BU core, there are small No(y) events associated with historic 1937-1950 very large PCA events. This suggested that some of the solar cycle 23 events might be detectable in polar snow, but none have been reported. In 2011, Tylka(private communication) suggested that a better calibration would be found at higher energies (~ 100 MeV)

  10. D- region ionosphere PCA events correlate well with >10 MeV Proton flux

  11. NO(y) – Calibration Based on the 1956 very large hard spectrum GLE Tylka and Dietrich (private communication) have calculated the proton fluencefor all GLE’s since 1956 for 18 energies There is an unresolved spectral dependence on NO(y) generation. Using >300 MeV as reference fluence energy, the amount of NO(y) expected in Arctic ice for various events is: (Assuming similar transport mechanisms) 1956 02 1960-11 1972-08 1989-09 2000-07 2005-01 210 52 5 63 12 12 2000-11 1

  12. Anthropogenic pollution Since the development of the Haber-Bosch process in 1895 that generates nitrates for fertilizers and explosives, there has been a continuous increase in the Nitrate background. This background has increased by a factor of ~3 since 1950. As an example, GLE 59 (35% NM increase on 14 July 2000) had a satellite measured >30 MeV proton fluence of 1x10^9 that should be in the impulsive nitrate detectable range. Jack Dibbs in the Summit, Greenland daily snow samples found a small NO(y) associated increase, but in his opinion, it was not preserved in 3 cm pit samples. 2000 average No(y) background is 270 ppb 1956 average No(y) background is 92 ppb

  13. Historic NO(y) event McCracken et al. documented 70 potential impulsive NO(y) increases in the interval 1562 to 1950, all equivalent to or larger than the February 1956 event. These have been essentially ignored, except for a few. Jack Dibb noted a probable biomass event in 1895 Note that there are impulsive NO(y) increases where there are not large increases in conductivity.

  14. Some of the nitrate increases reported from the GISP2-H core are associated with biomass burning. This is indicated by the conductivity increase being larger than the nitrate increase. The biomass burning indicators are recognizable in all cores and could be used to resolve dating uncertainties

  15. We have re-examined the large NO(y) event in McCracken et al. Table 1 and selected events for which there is a significant impulsive NO(y) increase and not a corresponding conductivity increase. Using the 5-sigma selection criteria, the NO(y) increase must be 5 sigma larger than the conductivity increase, there are 42 events, 35 that are equal to or larger than the February 1956 event.

  16. Note that there are two distinct events in 1859. Wolff et al. cannot resolve these distinct events. Wolff et al. concentrated on the Carrington event and, to the best of our knowledge, did not investigate any other of the 70 impulsive NO(y) events in the McCracken table 1. The conductivity associated with this NO(y) enhancement is very large compared with the NO(y) amplitude This section of the Greenland ice is distant from outstanding volcano events and there are dating uncertainties.

  17. Wolff et al. note that they cannot identify a NO(y) event in 1859 Wolff et al., GRL 39, 2012

  18. Note the low resolution of the data displayed; especially the Zoe and D4 cores We maintain that Wolff et al. vastly overstated the resolution of the data they used. It is our opinion that the resolution of the Zoe and D4 data full width-half maximum is ~3 months Wolff et al., GRL 39, 2012

  19. Wolff and McConnell have sent us their muti-species analysis of the D4 and Zoe ice cores from Greenland. The question to be resolved is: “Do either of these cores find evidence for nitrates from the known very large solar cosmic ray events (GLE’s) in the 1940’s detected by ionization chambers?.” Specifically GLE # 1 & 2 in 1942 (1942 02 23) & (1942 03 02) GLE # 3 (1946 07 25) GLE # 4 (1949 11 19)

  20. The BU short core from Summit, Greenland resolves each of these known solar cosmic ray events at very high resolution. The full width - half maximum of these impulsive events is 11 days. Volcano GLE#3 GLE #4 BU 30m GLE 1 &2 BU YEAR (~300 Samples per year)

  21. Note that there are no impulsive NO(y) events (black lines) in February 1942, July 1946, or November 1949 in the ZOE data. Also, note that the full width – half max resolution is ~3 months. The standard glaciology 1 cm water equivalent resolution cannot resolve anything smaller than seasonal nitrate increases

  22. BU-Zoe comparison. Note the impulsive nitrate events in the very high resolution BU plot. Each of these correspond to known solar events! Note that the Zoe plot with 3-month full-width-half-max resolution cannot resolve any of these events. Also note that none of the BU events correspond to biomass burning.

  23. SUMMARY The solar proton event – impulsive nitrate event controversy There is a coincidence between outstanding historic solar events and impulsive events in ice cores High temporal resolution data in several cores find the known events in the cosmic ray measurement era These same events cannot be resolved in the standard sub-annual resolution data used by glaciologists.

  24. Some of the nitrate increases reported from the GISP2-H core are associated with biomass burning. This is indicated by the conductivity increase being larger than the nitrate increase. The biomass burning indicators are recognizable in all cores and could be used to resolve dating uncertainties

  25. Common ordinary solar proton events do not generate enough nitrate to be detectable in polar ice. The 1990-2000 association with large fluence of >10 or > 30 MeV protons is misleading. The best association is with large fluence high energy GLEs.

  26. There are at least 40 impulsive nitrate events in the last 300 years, each as large as the February 1956 high energy solar cosmic ray event that should be detectable in high time resolution polar ice cores. None of these correspond to dated biomass burning events in the Zoe or D4 ice cores.

  27. BU-D4 comparison. Note the impulsive nitrate events in the very high resolution BU plot. Each of these correspond to known solar events! Note that the D4 plot with 3-month full-width-half-max resolution cannot resolve any of these events. Also note that none of the BU events correspond to biomass burning.

  28. Note the impulsive NO(y) events (black lines) in February, March 1942 (GLE 1 & 2), July1946 (GLE 3), and November 1949 (GLE 4) Note impulsive events in 1937, 1939, 1941, corresponding to large PCA

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