North Atlantic Oscillation synchronizes tree reproduction across Europe

Posted: December 21, 2017 by oldbrew in Analysis, climate, Cycles, Dataset, Natural Variation, Ocean dynamics, research

The researchers back the idea that ‘a strong NAO synchronizes climate across large parts of Europe’, reports ScienceDaily. ‘Large scale changes in pressure’ are involved.

Research has found a strong correlation between the North Atlantic Oscillation and synchronized tree reproduction across Europe, supporting the idea that this phenomenon plays a greater role in large scale masting, the process whereby forest trees produce large numbers of seeds in the same year.

The North Atlantic Oscillation (NAO) refers to the large scale changes in pressure that occur naturally in the North Atlantic region. It has been shown to have a strong effect on atmospheric circulation and European climate.

It is known that tree reproduction tends to be strongly synchronised within local populations, so that if one tree is producing a very heavy seed or fruit crop, it is very likely that a neighbouring tree will also be heavily fruiting.

However, in a study, published in Nature Communications researchers analysed tree masting observational data taken over a 190-year period for two key tree species in Europe, European beech and Norway spruce, and compared this to data on the Northern Atlantic Oscillation.

They found that in 1976, 1995 and 2011, both of these species across all of Europe simultaneously produced heavy seed crops.

The researchers found that for the last sixty years continent-wide masting in beech and spruce coincided with high-frequency summer- and spring-NAO and low-frequency winter-NAO. It also reveals a weaker relationship between NAO and masting for the first part of the twentieth century.

Dr Andrew Hacket-Pain, Lecturer in Biogeography and Ecology at the University’s Department of Geography and Planning, said: “Our work shows that the remarkable synchronisation of behaviour across such vast distances is linked to the North Atlantic Oscillation.

“We think this is because a strong NAO synchronises climate across large parts of Europe, especially during key phases of the tree reproduction cycle. This helps to synchronise seed crops across such large areas, but future work will be required to firmly establish this mechanism.

“The synchronisation of seed production is important, as it has knock-on effects on forest ecosystems. For example, heavy seed crops increase food availability for woodland-based birds and small animals, and consequently tend to increase the size of such animal populations in the short-term. Additionally, it has implications for human health, as the increase in animal hosts has a positive effect on tick numbers.”

The paper `Inter-annual and decadal changes in teleconnections drive continental-scale synchronization of tree reproduction’ is published in Nature Communications.

Source: North Atlantic Oscillation synchronizes tree reproduction across Europe | ScienceDaily
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Tim Osborn: North Atlantic Oscillation index data

  1. oldbrew says:

    North Atlantic Oscillation (NAO), an irregular fluctuation of atmospheric pressure over the North Atlantic Ocean that has a strong effect on winter weather in Europe, Greenland, northeastern North America, North Africa, and northern Asia. The NAO can occur on a yearly basis, or the fluctuations can take place decades apart. It is an “oscillation” because the changes in atmospheric pressure are essentially a back-and-forth switching between two prevailing patterns, or modes: a “positive mode,” in which a strong subtropical high is located over the Azores islands in the central North Atlantic while a strong low-pressure system is centred over Iceland, and a “negative mode,” in which weaker high- and low-pressure systems are found over the same locations.
    [Encyclopædia Britannica, Inc.]
    – – –
    Graphic below: The typical path of the polar-front jet stream during negative and positive modes of the North Atlantic Oscillation. -[EB]

    Note the jet stream differences.

    The NAO And Shifting Climate

  2. Bitter&twisted says:

    So nowt to do with CO2?
    How was this heresy published?

  3. erl happ says:

    The North Atlantic Oscillation fluctuates in unison with the Arctic Oscillation that is in turn highly correlated with the incidence of geomagnetic activity from the sun that is in turn linked with the incidence of cosmic rays.

    The Annular Modes phenomenon that involves the exchange of atmospheric mass between high and mid latitudes and across the hemispheres is the same phenomenon. These phenomena are the essence of natural climate change due to the fact that the Earth is not a closed system, free of influence from the sun, and the rest of the cosmos.

    But if you want to push the anthropogenic argument that climate change is due to the works of man this will be of no interest to you.

  4. p.g.sharrow says:

    So Erl, do you think that high and low pressure areas in the atmosphere are caused by Geomagnetic fluctuations induced by the interface of the Solar and Earth fields?
    Or the standard model of surface heating and cooling?
    For nearly 60 years this has vexed me as it appears to me that there is a Geomagnetic component here that is fixed to subsurface features…pg.

  5. Saighdear says:

    Huh! Hmmm! I don’t want to jump in on this one with the #me2 – Thought these Botanical processes were linked to day length and Temperatures: “IF” you go along on this one, then it would bring some credence to planting for harvesting with the phases of the Moon, etc. Haven’t we come a long way!
    Funny how YESTERDAY, I felt so great , first thing in the day – New Moon and felt like Spring already – Mild and bright. Indeed we still have Roses blooming. Now if trees are trees….. where do you draw the line on Species of trees with this behaviour? Ah well, folks – Enjoy ruminating over Christmas on this one – just watch out for #meTHANE events 🙂

  6. oldbrew says:

    erl says: ‘the incidence of geomagnetic activity from the sun that is in turn linked with the incidence of cosmic rays’

    Yes, but people like Piers Corbyn argue this is because cosmic ray incidence is just a proxy for solar wind strength, i.e. a stronger solar wind blows off more CRs.

    ‘the GCR flux is observed to be anti-correlated with the solar wind which is consistent with data from neutron monitors’

    From: The Relationship Between GCR and Solar Wind
    – – –
    Solar Wind Changes Atmospheric Pressure over South Korea

    Evidence is growing that interplanetary magnetic fields can have a significant influence on our weather.
    July 13, 2011

  7. oldbrew says:

    Piezoelectric lighter hovering above South Pole may help pinpoint mystery source of cosmic energy
    December 21, 2017

    The ultimate experimental goal is to measure ultra-high energy neutrinos and ultra-high energy cosmic rays that interact in the Antarctic ice, or with the Earth’s atmosphere, creating radio waves.

    Read more at:

  8. oldbrew says:

    21 December 2017

    The Met Office global temperature forecast suggests that 2018 will be another very warm year globally but is unlikely to be a new record due to a moderate La Niña in the Pacific.

    The Met Office forecasts the global average temperature for 2018 to be between 0.88 °C and 1.12 °C, with a central estimate of 1.00 °C, above the pre-industrial average period from 1850–1900. This corresponds to an increase of between 0.28 °C and 0.52 °C, and a central estimate of 0.40 °C above the 1981–2010 long term average of 14.3 °C.

    If El Niño gets warmists excited, what does La Niña do?

  9. erl happ says:

    Re PG Sharrows question: So Erl, do you think that high and low pressure areas in the atmosphere are caused by Geomagnetic fluctuations induced by the interface of the Solar and Earth fields? Or the standard model of surface heating and cooling?

    High pressure cells do tend to occur over cool surfaces but it is not true that low pressure systems are a response to surface warming. The largest and most intense low pressure systems originate at 60-70 degrees of latitude where the surface is very cold. In fact it is warming in the stratosphere that gives rise to these low pressure systems as discovered by the French balloonist De Bort in the 1890’s and Gordon Miller Bourne Dobson who devoted his life to the study of ozone and the stratosphere, concerning himself with the question as to why the strongest winds occur not at the surface but at the region of the tropopause and in the process developing a technique for measuring total column ozone by observing ultraviolet spectra in a spectrometer.

    Further, it is observed that surface pressure has been falling on the margins of Antarctica and rising in the mid latitudes over the last seventy years, in fact for as long as measurements of surface pressure exist.

    Given the relationship between column ozone and surface pressure we (climate science) should address the question as to what is responsible for change in the partial pressure of ozone in the region where these extra- tropical cyclones occur.,Extra Tropical cyclones are also called Polar cyclones or simply mid latitude cyclones.Climate science has yet to come to grips with the question of what drives ozone partial pressure in part because it is dedicated to the notion that the Antarctic ozone hole is due to the impact of industrial societies on the stratosphere.

    There are none so blind as those who will not see.

    The big question is why ozone accumulates in high latitudes in winter and with marked variations on all time scales. There are those who suggest that ozone can be created via a pathway involving ionisation of the atmosphere by cosmic rays.

    The logical pathway for causation goes like this: A quiet solar wind allows more cosmic rays to enter the atmosphere enhancing the production of ozone giving rise to lower pressure in high latitudes, resulting in higher surface pressure elsewhere.

    The distribution of surface pressure is responsible for the ‘planetary winds’ that are in turn responsible for the movement of warm air and moisture from the tropics to cooler mid and high latitudes. The mid and high latitudes will warm as the partial pressure of ozone increases in high latitudes IN WINTER. Winter is observed to be the time when the air warms (climate change). There has been negligible warming in summer. Peak month for warming is February for all locations north of 30° south with the degree of warming increasing with latitude. South of 30° south peak month for warming is July.

    Geomagnetic activity is a proxy for the strength of the solar wind and therefore the incidence of cosmic rays the relationship being inverse.

    I hope this makes sense to you. If not please come back to me with a query.

  10. oldbrew says:

    Erl H: would it also be fair to say that a quiet solar wind makes ‘wavy’ jet stream patterns more likely to occur (in winter), as per the ‘negative mode’ in the graphic above? [@ December 21, 2017 at 4:31 pm]

  11. erl happ says:

    A quiet solar wind means more cosmic ray activity, more ozone, a deepening of the low pressure cells that dominate high latitudes and more frontal activity in the mid latitudes. The contrast between low pressure in high altitudes and high pressure in the mid latitudes is enhanced. The interaction zone between these pressure cells more turbulent.

    But there is a marked difference between the hemispheres in this respect. The lows of the southern hemisphere are like a necklace round the Antarctic continent and this is the lowest surface pressure zone on the planet…..all the year round. In the northern hemisphere polar lows are associated with the oceans (only in winter) and high pressure zones the continental landmasses. There no consistent high pressure cell over the Arctic. This yields two different zones where the oscillation is expressed being the Atlantic and the Pacific respectfully with the East Asian High centred over Siberia and North China a source of out flowing air that is the northern hemisphere version of what the Antarctic does for the southern hemisphere.

    There is a lead lag situation that relates to the Antarctic vis a vis the rest of the globe. Everything happens first and most vigorously in high southern latitudes. The Chinese are the first inhabitants of the northern hemisphere to realise that their weather is dictated in high southern latitudes.

    Why is it so? Its a matter of the distribution of land and sea. The southern hemisphere does not have the land surfaces in high latitudes to disrupt the natural pattern of pressure distribution.

    It’s what happens in high latitudes that drives climate, not the other way round. The notion that atmospheric flows are a response to energy gain in low latitudes is plain wrong.