Ammonium: 1 – The Proxy War

Ammonium - The Proxy War

An academic debate between the massed ranks of Settled Science and the more solitary Solar Scientists has been festering since the 1990s.

This isn’t a regular, standard issue academic debate.

This is a proxy war between the Anthropomorphic Brigade of Climate Doom and some It’s The Sun Scientists.

Settled Science is playing for extremely high stakes.

The origins of this academic débâcle [for Settled Science] can be traced back to the early 1990s when scientists began to analyse the outliers in the ammonium record from the Greenland Ice Cores.

For example.

Mayewski 1995 - Ammonium

Greenland ice core “signal” characteristics: An expanded view of climate change
P. A. Mayewski, L. D. Meeker, M. C. Morrison, M. S. Twickler, S. I. Whitlow, K. K. Ferland, D. A. Meese, M. R. Legrand, J. P. Steffensen
Journal of Geophysical Research, Vol 98, No D7 : 12,839-12,847, 20 July 1993

The intriguing aspect of these ammonium outliers is that the most tangible events [i.e. the latest] are closely aligned with the 1908 Tunguska Event and the 1859 Carrington Event.

Mayewski 1995 - Ammonium Tunguska

The Tunguska event was a large explosion that occurred near the Stony Tunguska River, in what is now Krasnoyarsk Krai, Russia, on the morning of 30 June 1908 (N.S.).

The explosion over the sparsely populated Eastern Siberian Taiga flattened 2,000 km2 (770 sq mi) of forest and caused no known casualties.

June 30, 1908, 7:14 a.m., central Siberia – Semen Semenov, a local farmer, saw “the sky split in two. Fire appeared high and wide over the forest. . . . From . . . where the fire was, came strong heat. . . . Then the sky shut closed, and a strong thump sounded, and I was thrown a few yards. . . . After that such noise came, as if . . . cannons were firing, the earth shook . . .”

The Tunguska Mystery
Luca Gasperini, Enrico Bonatti and Giuseppe Longo
Scientific American – June 2008

Solar Events

The solar storm of 1859, also known as the Carrington event, was a powerful geomagnetic solar storm in 1859 during solar cycle 10.

A solar coronal mass ejection hit Earth’s magnetosphere and induced one of the largest geomagnetic storms on record.

The associated “white light flare” in the solar photosphere was observed and recorded by English astronomers Richard C. Carrington and Richard Hodgson.

On September 1–2, 1859, one of the largest recorded geomagnetic storms (as recorded by ground-based magnetometers) occurred.

Aurorae were seen around the world, those in the northern hemisphere as far south as the Caribbean; those over the Rocky Mountains in the US were so bright that their glow awoke gold miners, who began preparing breakfast because they thought it was morning.

Telegraph systems all over Europe and North America failed, in some cases giving telegraph operators electric shocks.

Telegraph pylons threw sparks.

Some telegraph operators could continue to send and receive messages despite having disconnected their power supplies.

Unsurprisingly, Settled Science was uncomfortable with the thought that anyone might associate the 1859 Carrington Event [aka Solar Proton Event] with an ammonium outlier because electrifying and Earth Science very rarely appear in the same sentence.

A solar proton event (SPE), or “proton storm”, occurs when particles (mostly protons) emitted by the Sun become accelerated either close to the Sun during a flare or in interplanetary space by CME shocks.

The events can include other nuclei such as helium ions and HZE ions.

These particles cause multiple effects.

They can penetrate the Earth’s magnetic field and cause ionization in the ionosphere.

The effect is similar to auroral events, except that protons rather than electrons are involved.

Energetic protons are a significant radiation hazard to spacecraft and astronauts.

Solar CME and Flare

Therefore, Settled Science diligently produced an alternative narrative in the early 1990s.

Unfortunately, the impact of this alternative narrative was considerably undermined when the title of the paper concluded with the uncertain rhetorical question: “Fingerprint from forest fires?”

Biomass burning is influencing the atmospheric chemistry by emitting large amounts of reactive species such as hydrocarbons, organic acids and nitrogen compounds [Andreae et al., 1988].

Polar ice cores provide a unique record of precipitation whose chemistry reflects the atmospheric composition at the time of deposition.

The analysis of such ice samples therefore allows an estimate to be made of the concentration of atmospheric impurities in the past.

During the first season of the deep drill operation (GRIP) at Summit, Central Greenland (72° 34′ N, 37° 38′ W) continuous ammonium (NH4+) measurements were performed between 100 and 600 m depth covering the time period from 330 to 2500 years B.P.

The NH4+ concentrations show seasonal variations between 1-20 ng.g−1 with some sporadic high values up to 600 ng.g−1 in narrow layers.

The chemical fingerprint points to biomass burning causing the high ammonium peaks.

Large perturbations of ammonium and organic acids content in the summit-Greenland Ice Core. Fingerprint from forest fires?
M Legrand, M De Angelis, T Staffelbach, A Neftel, B Stauffer
Geophysical Research Letters – Volume 19 – Issue 5 Pages 473–475 – 3 March 1992

This mainstream narrative enabled, for example, the ammonium outliers in the GISP 2 ice core to be associated with northern high-latitude biomass burning events.

Ammonium: Trend(s) and Sporadic Events
Background levels of ammonium decline exponentially to the present (after model 2), suggesting a decrease from warm to cooler portions of the record of biogenic influences to the region.

Since NH3 concentrations tend to be highest near continents [Logan, 1983], the decrease suggests that source area extent over the continents and/or the processes driving ammonium production or transport declined.

Since modern levels of ammonium do not return to those characteristic of warmer periods, the influence of some form of anthropogenic forcing may be suspected (e.g., removal of ammonium by reaction with increased levels of anthropogenically derived nss sulphate and nitrate [Langford and Fehsenfeld, 1992]).

Ammonium outliers in ice core records from central Greenland have been interpreted as northern high-latitude biomass burning events [Legrand et al., 1992; Taylor et al., 1993].

Greenland ice core “signal” characteristics: An expanded view of climate change
P. A. Mayewski, L. D. Meeker, M. C. Morrison, M. S. Twickler, S. I. Whitlow, K. K. Ferland, D. A. Meese, M. R. Legrand, J. P. Steffensen
Journal of Geophysical Research, Vol 98, No D7 : 12,839-12,847, 20 July 1993

However, even at this early stage, it was noted that these outlier ammonium events were absent from the GISP 2 ice core between [about] 1650 and 1750 i.e. during the Maunder Minimum.

These events are present throughout the entire record except from ~ 1650 to 1750, during which time biomass extent or burn potential would have been reduced in response to lower (LIA) temperatures and consequent reduction in biomass.

Greenland ice core “signal” characteristics: An expanded view of climate change
P. A. Mayewski, L. D. Meeker, M. C. Morrison, M. S. Twickler, S. I. Whitlow, K. K. Ferland, D. A. Meese, M. R. Legrand, J. P. Steffensen
Journal of Geophysical Research, Vol 98, No D7 : 12,839-12,847, 20 July 1993

The Maunder Minimum, also known as the “prolonged sunspot minimum”, is the name used for the period starting in about 1645 and continuing to about 1715 when sunspots became exceedingly rare, as noted by solar observers of the time.

Sunspot Observations

The 1990s also saw the development of an alternate hypothesis that impulsive nitrate depositions in polar ice are associated with extremely large Solar Proton Events.

Atmospheric ionization events break N2 chemical bonds, enabling nitrogen oxides [NO(y)] formation, normally at low atmospheric abundance [e.g. Thomas et al., 2005].

There has been controversy whether NO(y) deposition in ice cores, primarily as nitrate (NO3), can be used as a proxy for very large solar proton events (SPEs).

Based on the impulsive nitrate events identified in polar ice by Dreschhoff and Zeller [1990, 1994, 1998] McCracken et al. [2001a] established a calibration between impulsive nitrate deposition in the 415-year GISP2-H ice core obtained from the top of the ice sheet divide at Summit, Greenland, in 1991 by Dreschhoff and Zeller [1994, 1998] and extremely large SPEs between 1956 and 1989.

These authors identified 70 impulsive nitrate events in the GISP2-H core and concluded that they could be used as proxies to identify past extremely large SPEs.

One of the largest impulsive nitrate events was dated as late 1859 and associated with the well-documented but poorly quantified September 1859 Carrington event [Clauer and Siscoe, 2006].

Low time resolution analysis of polar ice cores cannot detect impulsive nitrate events
D.F. Smart, M.A. Shea, A. L. Melott, and C. M. Laird
Journal of Geophysical Research: Space Physics 119, 9430-9440 (2014)

This festering academic debate tends to focus upon the headline Carrington Event and in 2012 the heavy artillery was eventually rolled out to finally demonstrate the Carrington event is not observed in most ice core nitrate records.

The Carrington Event of 1859 is considered to be among the largest space weather events of the last 150 years.

We show that only one out of 14 well-resolved ice core records from Greenland and Antarctica has a nitrate spike dated to 1859.

No sharp spikes are observed in the Antarctic cores studied here.

In Greenland numerous spikes are observed in the 40 years surrounding 1859, but where other chemistry was measured, all large spikes have the unequivocal signal, including co-located spikes in ammonium, formate, black carbon and vanillic acid, of biomass burning plumes.

We conclude that an event as large as the Carrington Event did not leave an observable, widespread imprint in nitrate in polar ice.

Nitrate spikes cannot be used to derive the statistics of SEPs.

The Carrington Event Not Observed In Most Ice Core Nitrate Records
E W Wolff, M Bigler, M A J Curran, J E Dibb, M M Frey, M Legrand, J R McConnell
Geophysical Research Letters – Volume 39 – Issue 8 – April 2012

However, it appears the heavy artillery has shot itself in the foot… to be continued.

Gallery | This entry was posted in Astrophysics, Atmospheric Science, Cosmic Rays, Earth, Geomagnetism, Glaciology, Greenland. Bookmark the permalink.

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