Solar hard UV is weakening.

Posted: November 21, 2015 by tchannon in Measurement, Solar physics

The EUV spectrum of the Sun: Irradiances during 1998–2014
G. Del Zanna 1 and V. Andretta 2
A&A 584, A29 (2015)
DOI: 10.1051/0004-6361/201526804
(c) ESO 2015
Open access on registration

Examples from paper Fig 6

From abstract

… show that the irradiances in the hot (2–3 MK) lines are significantly
lower for the cycle 24 maximum compared to the previous one.

From Introduction

1. Introduction
The present paper is part of an on-going effort to provide the
best possible solar spectral irradiance in the extreme ultraviolet
(EUV). The solar EUV variability causes dramatic changes in
the temperature and density of the thermosphere
, and it could
also have some indirect effects on the climate. Indeed, some of
the current global circulation models also require EUV irradi-
ances to properly take the solar forcing into account.

The work is about correcting for known satellite instrument degradation.

Post by Tim

  1. goldminor says:

    Thanks for sharing the link.

  2. gymnosperm says:

    EUV alters the earth’s magnetic field causing changes in compass declination that have been well known for centuries (summarizing Lief Svalgaard). EUV measurements from the SOHO spacecraft some 1.5m km out at a particularly serendipitous position between the earth and the sun since 1996 and remarkably equal measurements of the EUV proxy 10.7 microwave flux on earth scale with convincing fidelity to the SQRT of sunspot area. Why would this be? Are we seeing the reciprocal of MC^2? And with no detectable erosion of the signal between the spacecraft afar and the surface despite having created ionospheric winds and tweaking declination (QBO?) Sum Ding Dontadduphere.

  3. ren says:

    • The thermosphere/ionosphere system was indeed cooler, less dense, and lower,
    during the minimum of solar cycle 23/24 than during a “typical” solar minimum.
    • The primary cause of this was lower than “usual” solar EUV irradiance.
    • The Mg II core-to-wing ratio variations are consistent with these observations.
    • Secular change due to increasing CO2 makes a small but significant contribution.
    • Lower geomagnetic activity during 2008-2009 also makes a small but significant
    • Work in progress extends this modeling effort to possible ionospheric changes.

  4. ren says:

    “Their work built on several recent studies. Earlier this year, a team of scientists from the Naval Research Laboratory and George Mason University, measuring changes in satellite drag, estimated that the density of the thermosphere declined between 2007 and 2009 to about 30 per cent less than during the previous solar minimum in 1996. Other studies by scientists at the University of Southern California and CU, using measurements from sub-orbital rocket flights and space-based instruments, have estimated that levels of extreme-ultraviolet radiation-a class of photons with extremely short wavelengths-dropped about 15 per cent during the same period.”

  5. tchannon says:

    These are good comments.

  6. jdmcl says:

    David Evans is saying a similar thing about solar energy at certain wavelengths being the key, not the TSI that the IPCC happily talks about because it doesn’t alter the manmade warming them.


  7. If we could only get accurate readings on EUV. The Layman sunspot site was providing the readings but then the instrumentation got all off and it was curtailed.

    I really liked having access to the EUV light unit of measurement readings when it was on Layman’s Sunspot Site.

  8. ren says:

    Solar Extreme Ultraviolet (EUV) is solar radiation that covers the wavelengths 10 – 120 nm of the electromagnetic spectrum. It is highly energetic and it is absorbed in the upper atmosphere, which not only heats the upper atmosphere but also ionizes it, creating the ionosphere. Solar EUV radiation changes by a factor of ten over the course of a typical solar cycle. This variability produces similar variations in the ionosphere and upper atmosphere. Solar EUV variations are one of the three primary drivers of ionospheric variability.

    Solar Extreme-Ultraviolet (EUV) radiation originates in the corona and chromosphere of the Sun’s atmosphere. The solar EUV spectrum, between 1 and 120 nm, is dominated by spectral lines from hydrogen (H), helium (He), oxygen (O), sodium (Na), magnesium (Mg), silicon (Si), and iron (Fe). The EUV photons reach Earth and are completely absorbed in the upper atmosphere above 80 km. The thermosphere of the earth, 80 to 600 km in altitude, is heated predominantly by solar EUV radiation. The EUV photons also ionize the atmosphere creating electrons, which form the ionosphere. Solar EUV irradiance varies by as much as an order of magnitude on time scales of minutes to hours (solar flares), days to months (solar rotation), and years to decades (solar cycle). The highly varying EUV radiation causes the thermosphere and ionosphere to vary over similar magnitudes and time scales.

    Because solar EUV radiation is absorbed by the upper atmosphere it is impossible to measure from the ground. Thus, measurements must be made from rockets and satellites. It is difficult to build and maintain sensors that can measure the solar EUV radiation so for many years people relied on proxies for solar EUV such as the Sunspot Number or the F10.7 cm radio flux.

  9. Gail Combs says:

    Yes, the sun’s wavelengths vis and above are the key. The really short wavelengths not only heat the upper atmosphere, they also cause chemical reactions like O2/O3 conversion and reactions with NOx. These in turn change atmospheric dynamics.
    A bit of the data collection I have done on the subject. (Useful for beating alarmist over the head.)

    NASA has finally admitted that the sun is not constant and although the Total Solar Insolation is relatively constant the distribution of the energy among wavelengths is not.

    In recent years, SIM has collected data that suggest the sun’s brightness may vary in entirely unexpected ways. If the SIM’s spectral irradiance measurements are validated and proven accurate over time, then certain parts of Earth’s atmosphere may receive surprisingly large doses of solar radiation even during lulls in solar activity.

    “We have never had a reason until now to believe that parts of the spectrum may vary out of phase with the solar cycle, but now we have started to model that possibility because of the SIM results,” …
    “Between 2004 and 2007, the Solar Irradiance Monitor (blue line) measured a decrease in ultraviolet radiation (less than 400 nanometers) that was a factor of four to six larger than expected.” (wwwDOT)

    NASA has also admitted different wavelengths of sunlight do different things in different parts of the atmosphere.
    Solar Spectral Irradiance Data

    Research and Applications
    Because of selective absorption and scattering processes in the Earth’s atmosphere, different regions of the solar spectrum affect Earth’s climate in distinct ways. Approximately 20-25% of the Total Solar Irradiance (TSI) is absorbed by atmospheric water vapor, clouds, and ozone, by processes that are strongly wavelength dependent. Ultraviolet radiation at wavelengths below 300 nm is completely absorbed by the Earth’s atmosphere and contributes the dominant energy source in the stratosphere and thermosphere, establishing the upper atmosphere’s temperature, structure, composition, and dynamics. Even small variations in the Sun’s radiation at these short wavelengths will lead to corresponding changes in atmospheric chemistry. Radiation at the longer visible and infrared wavelengths penetrates into the lower atmosphere, where the portion not reflected is partitioned between the troposphere and the Earth’s surface, and becomes a dominant term in the global energy balance and an essential determinant of atmospheric stability and convection.

    Sunlight + oxygen (O2) ===> O + O
    (Oxygen is disassociated in to two atoms and wants to glom onto something.)
    O + O2 ====> O3 (ozone)

    The reverse also happens in the atmosphere so the formation and destruction of ozone is dependent on the shifting of the amount of solar radiation at different wavelengths and NASA has shown those amounts DO SHIFT.

    image from: (wwwDOT)



    Ozone is an important atmospheric trace constituent. The depletion of solar radiation between approximately 2000 and 3000 A is the result of strong absorption by ozone in the ultraviolet wave-lengths. The energy absorbed in this process is the prime source of thermal energy in the stratosphere. Because of this, ozone plays an important role in the large-scale motions of the atmosphere….

    ….A strong correlation was found between the meridional gradient of total ozone and the wind velocity in jet stream systems…..

    ….A study of the total ozone distribution over two tropical storms indicated that each disturbance was associated with a distinct ozone minimum….

    A comparison of time-longitude stratospheric radiance values at 60 S with values of the total ozone indicated that low (high) radiance values corresponded very closely with the low (high) ozone variations. The speed at which these ozone ‘waves’ progress eastward is greater in the winter hemisphere. The speed of eastward progression decreases as one approaches the lower latitudes in the winter hemisphere. In the equatorial region and in the Northern Hemisphere summer there is not a strong eastward progression of the ozone ‘waves’ but a westward progression….

    Changes in Ozone and Stratospheric Temperature

    The graph above shows total ozone and stratospheric temperatures over the Arctic since 1979. Changes in ozone amounts are closely linked to temperature, with colder temperatures resulting in more polar stratospheric clouds and lower ozone levels. Atmospheric motions drive the year-to-year temperature changes. The Arctic stratosphere cooled slightly since 1979, but scientists are currently unsure of the cause….


  10. Gail Combs says:

    Top-Down Solar Modulation of Climate: evidence for centennial-scale change

    The work presented here is consistent with the interpretation of a recently reported effect [25] of solar variability on the North Atlantic Oscillation (NAO) and European winter temperatures over the interval 1659–2010 in terms of top-down modulation of the blocking phenomenon [52, 53]. In fact, Woollings et al [26] show that the solar response pattern is, despite being similar in form to that of the NAO, significantly different in that it reaches further east. These authors also show that open solar flux has a much stronger control over blocking events in this sector than the previously reported effect of F10.7 [55]. There is seasonality in the solar responses reported here. This is expected as modulation of upwards-propagating planetary waves in wintertime, and the associated stratosphere– troposphere interaction, is most widely believed to be the key mechanism [8, 11]. In addition, the tropospheric signature is a response of the eddy-driven jet streams, and these are at their strongest and most responsive in winter. While the results are presented here as annual means, the regression analysis was actually carried out on monthly mean data and thus takes this seasonality into account. The seasonal evolution of the F10.7 cm flux regression was described in detail by Frame and Gray [53] and this was not significantly affected by using either the open solar flux FS nor the cosmic ray flux, M, instead of F10.7.”

    Then we get into the effect on the poles.

    Quasi-biennial oscillation and solar cycle influences on winter Arctic total ozone


    The total column ozone (TCO) observed from satellites and assimilated in the European Centre for Medium-Range Weather Forecasts since 1979 is used as an atmospheric tracer to study the modulations of the winter Arctic stratosphere by the quasi-biennial oscillation (QBO) and the solar cycle. It is found that both the QBO and solar forcings in low latitudes can perturb the late winter polar vortex, likely via planetary wave divergence, causing an early breakdown of the vortex in the form of sudden stratospheric warming. As a result, TCO within the vortex in late winter can increase by ~60 Dobson unit during either a solar maximum or an easterly phase of the QBO, or both, relative to the least perturbed state when the solar cycle is minimum and the QBO is in the westerly phase. In addition, from the solar maximum to the solar minimum during the QBO easterly phase, the change in TCO is found to be statistically insignificant. Therefore, the “reversal” of the Holton–Tan effect, reported in some previous studies using lower stratospheric temperature, is not evident in the TCO behavior of both observation and assimilation.

    The influence of solar variability and the quasi-biennial oscillation on lower atmospheric temperatures and sea level pressure

    We investigate an apparent inconsistency between two published results concerning the temperature of the winter polar stratosphere and its dependence on the state of the Sun and the phase of the Quasi-Biennial Oscillation (QBO). We find that the differences can be explained by the use of the authors of different pressure levels to define the phase of the QBO.

    We identify QBO and solar cycle signals in sea level pressure (SLP) data using a multiple linear regression approach. First we used a standard QBO time series dating back to 1953. In the SLP observations dating back to that time we find at high latitudes that individually the solar and QBO signals are weak but that a temporal index representing the combined effects of the Sun and the QBO shows a significant signal. This is such that combinations of low solar activity with westerly QBO and high solar activity with easterly QBO are both associated with a strengthening in the polar modes; while the opposite combinations coincide with a weakening. This result is true irrespective of the choice of QBO pressure level. By employing a QBO dataset reconstructed back to 1900, we extended the analysis and also find a robust signal in the surface SAM; though weaker for surface NAM.

    Our results suggest that solar variability, modulated by the phase of QBO, influences zonal mean temperatures at high latitudes in the lower stratosphere and subsequently affect sea level pressure near the poles. Thus a knowledge of the state of the Sun, and the phase of the QBO might be useful in surface climate prediction.

    Climate System Response to Stratospheric Ozone Depletion and Recovery

    Compared to well-mixed greenhouse gases (GHGs), the radiative forcing of climate due to observed stratospheric ozone loss is very small: in spite of this, recent trends in stratospheric ozone have caused profound changes in the Southern Hemisphere (SH) climate system, primarily by altering the tropospheric midlatitude jet, which is commonly described as a change in the Southern Annular Mode. Ozone depletion in the late twentieth century was the primary driver of the observed poleward shift of the jet during summer, which has been linked to changes in tropospheric and surface temperatures, clouds and cloud radiative effects, and precipitation at both middle and low latitudes. It is emphasized, however, that not all aspects of the SH climate response to stratospheric ozone forcing can be understood in terms of changes in the midlatitude jet. The response of the Southern Ocean and sea ice to ozone depletion is currently a matter of debate. ….

  11. Gail Combs says:


    Climate Change Look up, Look out
    Basic Description

    …The most important part of the Stratosphere is the ozone layer which absorbs harmful incoming radiation from the sun.

    Stratosphere is divided into four zones:

    * Tropics -20°S to 20°N altituted 16 km (50,000 ft), ozone is created in this zone

    * Surf Zone – Middle and high latitudes, the area of air mixing

    * Polar Voretex – beyond 66.5° in each hemisphere

    * Lower Stratosphere – where temperatures stabilize then rise, just above the tropopause

    Surf Zone circulation becomes downward and poleward tending to push ozone in those directions;

    Polar Vortex air is very cold due to its near isolation from the Brewer-Dobson circulation…

    The Brewer-Dobson Circulation transports air molecules and ozone toward the polar regions and downward in the polar zones. Planetary Waves (temperature change and the Coriolis Effect) and large seasonal differences are primary influences of air circulation in the Strtosphere.

    QBO (Quasi-Biennial-Oscillation) is a fluctuation of easterly/westerly equatorial stratospheric winds, generally based on the stratispheric zonal wind at Singapore. The fluctuation occurs irregularly every 22 to 34 months. QBO occurs at higher altitudes (20-35 km) but impacts the atmospheric situation, much like the equatorial El Nino affects earth’s surface weather.

    Polar Night Jet is a jet stream over the polar winter regions which get no sun. This circular Jet Stream isolates polar stratospheric air from the rest of the stratosphere. It is stronger around the South Pole due to colder winters, higher winds, and a more stable environment than the North Pole. This circulation is the primary cause of the Ozone Hole which is enhanced by the polar Night Jet….

    The Antarctic ozone hole: An update

    …The ozone hole also affects the Southern Hemisphere’s surface climate. As the Sun returns to Antarctica [in the spring], ozone should be present, absorbing radiation and thereby warming the polar vortex. There is less heating because of ozone depletion, Antarctic lower-stratospheric temperatures are below their pre-ozone-hole average during spring and summer, and the [cold] polar vortex persists one to two weeks longer. Because the circumpolar flow around Antarctica extends to the surface, the tropospheric jet is strengthened during the southern summer, which increases the surface wind stress and thereby modifies the ocean circulation. Increased greenhouse gas levels lead to surface warming in the Arctic and might be expected to have the same effect in the Antarctic. However, observations and models show that the ozone depletion has caused the interior of Antarctica to cool. The wind and temperature changes driven by ozone depletion also change Southern Hemisphere precipitation patterns…,2LFVV,E4CSKB,9H5SN,1

    06 May 2012 Nature Geoscience | Letter Regional atmospheric circulation shifts induced by a grand solar minimum

    Large changes in solar ultraviolet radiation can indirectly affect climate by inducing atmospheric changes. Specifically, it has been suggested that centennial-scale climate variability during the Holocene epoch was controlled by the Sun. However, the amplitude of solar forcing is small when compared with the climatic effects and, without reliable data sets, it is unclear which feedback mechanisms could have amplified the forcing. Here we analyse annually laminated sediments of Lake Meerfelder Maar, Germany, to derive variations in wind strength and the rate of 10Be accumulation, a proxy for solar activity, from 3,300 to 2,000 years before present. We find a sharp increase in windiness and cosmogenic 10Be deposition 2,759  ±  39 varve years before present and a reduction in both entities 199  ±  9 annual layers later. We infer that the atmospheric circulation reacted abruptly and in phase with the solar minimum. A shift in atmospheric circulation in response to changes in solar activity is broadly consistent with atmospheric circulation patterns in long-term climate model simulations, and in reanalysis data that assimilate observations from recent solar minima into a climate model. We conclude that changes in atmospheric circulation amplified the solar signal and caused abrupt climate change about 2,800 years ago, coincident with a grand solar minimum.

  12. Gail Combs says:

    The Antarctic Circumpolar Current is a wind driven current.

    This is what I have found on the current and the winds that drive it:

    Ozone intensification of the westerly winds connection. (You will need to hold your nose while reading it.)

    In 2009, the ozone hole reached its 10th largest measured size since careful measurements began in 1979….

    The Hole in ozone layer has shielded most of Antarctica from global warming The ozone hole has delayed the impact of greenhouse gas increases on the climate of the continent. Consequently south polar winds (the polar vortex), have intensified and affected Antarctic weather patterns. Westerly winds over the Southern Ocean that surrounds Antarctica have increased by around 15%…

    Measurements of ozone at the same site are given @ (wwwDOT)

    I think this paper has the tail wagging the dog. If they didn’t they would be saying the sun via ozone changes drives ENSO. However it is still the best paper I have come across so far.

    It is a long paper (12 pages) so I have distilled parts of it:

    Eddy response to Southern Ocean climate modes

    1. Introduction

    Eddy processes play an important role in the dynamics and thermodynamics of the Southern Ocean. Strong air‐sea heat and freshwater fluxes in the Southern Ocean, along with strong westerly winds, drive the deep‐reaching eastward flowing Antarctic Circumpolar Current (ACC) as well as a vigorous meridional overturning circulation (MOC). Eddy fluxes, created by baroclinic and barotropic instabilities of this flow, act to maintain the balance of the ACC system. The eddy interfacial form stress helps transfer wind‐driven momentum from the surface to the deep ocean layers where it is balanced by topographic form drag [Munk and Palmén, 1951; Johnson and Bryden, 1989]. In the absence of strong meridional currents in the upper ocean at these latitudes, eddies are also the principal mechanism for transferring heat, salt, and carbon poleward across the zonal ACC and contribute to the mixing of water masses through the diffusion of these tracers [Sallée et al., 2008b]. Recent modeling studies have also shown how eddy fluxes act to maintain the strong meridional gradients of the ACC and contribute to the
    net transport of the MOC [Treguier et al., 2007]

    Most of these eddy budget studies concentrate on mean statistics, but the Southern Ocean eddy field also evolves over time. Recently, Hogg and Blundell [2006], hereafter HB06, used a three‐layer high‐resolution quasi‐geostrophic channel model with realistic topography to simulate the Southern Ocean’s response to wind forcing. Their simple model produced intrinsic interannual variability under constant wind forcing, characterized by a large‐scale increase in potential energy, followed by an increase in eddy kinetic energy (EKE) that peaked 2–3 years later. The model is in a “saturated” state, i.e., the model transport remains relatively stable, and the increased potential energy is transferred to the eddy field. The delay in EKE was caused by a positive feedback in the model; the increased potential energy creates favorable conditions for baroclinic instability, which increases eddy activity and the eddy momentum transfer to deeper layers. There interaction with the bottom topography induces a stronger meridional deep circulation which is intrinsically more unstable, increasing in turn the EKE. This feedback continues until the excess of large‐scale potential energy is consumed.

    A corollary to the intrinsic variability of HB06 is that increases in wind stress have the potential to amplify the natural modes of variability. Such an increase in westerly wind forcing occurs during positive phases of the Southern Annular Mode (SAM). The Southern Annular Mode is the dominant climate mode in the Southern Hemisphere [Thompson and Wallace, 2000]. During its positive phase, there is an intensification of the midlatitude high‐pressure band and the polar lows, leading to a near‐annular meridional pressure difference (Figure 1a), which drives strong westerly wind anomalies, which are also shifted southward. Although there is a trend toward more positive SAM events over the last few decades, SAM also has high‐frequency variations and strong interannual variations. During the 1990s, strong positive
    SAM events occurred in 1993 and in 1998–1999
    (Figure 1c).

    [5] A second mode of climate variability in the Southern Hemisphere is associated with the El Niño Southern Oscillation (ENSO). Although this mode has tropical origins, it generates atmospheric Rossby waves, which propagate its signal to higher latitudes [Karoly, 1989], creating a dipole response in the South Pacific (Figure 1b), which induces local changes in the winds, sea surface temperature, and sea ice extent [Stammerjohn et al., 2008]. Positive ENSO patterns are associated with El Niño events, strongest in 1997/1998, whereas negative ENSO is associated with La Niña events, strongest in 1999/2000 (Figure 1c).

    Meredith and Hogg [2006] (hereafter, MH06) have validated the 2–3 year delay found by the HB06 model by comparing the annual SAM index with basin‐scale annual averages of EKE derived from satellite altimetry in the Atlantic, Indian, and Pacific sectors of the Southern Ocean. They indeed find an increase in observed EKE 2–3 years after the large peak in SAM in 1998/1999. In this paper, we extend their analysis to consider whether this large‐scale EKE response occurs at the same time in all regions or whether there is a local response in relation to the two main climate modes, SAM and ENSO….

    7. Conclusions
    [35] A circumpolar analysis of altimetric data has been used to investigate the evolving EKE field in the Southern Ocean. When large‐scale averaging is performed along the circumpolar belt, we indeed find a peak in EKE from 2000 to 2002, 2–3 years after the peak in the SAM index, as reported by MH06. However, this EKE signal is dominated by specific regions with high EKE near major bathymetric features. A regional analysis of these high EKE zones reveals a more complex structure, with no clear peak in the southern Indian Ocean, but a strong EKE signal in the Pacific, occurring progressively later toward the east. Despite the fact that SAM is an annular mode, and its forcing is in phase around the circumpolar band, we find the oceanic EKE response varies from one region to another.

    [36] We suggest that the stronger EKE response in the Pacific sector is due to the presence of two climate modes, SAM and ENSO. When strong positive SAM events coincide with La Niña (negative ENSO) events, as happened in 1999, anomalous meridional wind forcing is enhanced in the South Pacific Ocean, inducing the observed increase in EKE 2–3 years later. However, when positive SAM events coincide with El Niño events, as in 1993, the climate modes are in opposition in the South Pacific, which could explain the weak EKE response during the mid 1990s….

  13. Gail Combs says:

    So what we have for the solar driven climate is:

    Change in Solar ==> change in ozone ==> change in Quasi-Biennial Ocillation (QBO) ==> Change in ozone at the poles ==> change in wind strength/patterns in the Antarctic ==> Change in the West Wind Drift (the wind driven Antarctic Circumpolar Current) ==>restriction at Drake Passage causes variable amounts of Antarctic cold water to run up the side of the coast of South America as the Humboldt Current ===> ENSO

    Cold water also runs up the side of the coast of South Africa into the Atlantic and the amount would be controlled by the same wind pattern/strength. (The ENSO tele-connection to the Atlantic anyone?)

    If you look at this Sea Surface Temperature map it has a good image of the tongue of cold water from the Antarctic Circumpolar Current just before Drake Passage, headed up the west coast of South America to Galapagos where El Nino forms. You can also see the tongue of cold water headed up the east coast of South America (Cape Horn Current) as well as the west coast of Africa.

    “…The Cape Horn Current is a cold water current that flows west-to-east around Cape Horn. This current is caused by the intensification of the West Wind Drift as it rounds the cape….” — WIKI

    Retired EPA scientist, F.H. Haynie said on January 18, 2014

    If I were asked to pick a single point on earth that most likely has the greatest effect on global weather and climate, it would be 0 and 90W (Galapagos). This is where El-nino winds, the deep sea Cromwell current, the Panama current, and the Humboldt current meet. These flows are not constant and each has different cycles and those cycles are not constant. Cycles on cycles create extremes in weather and climate. These extremes have an effect globally. I suspect these cycles are also controlling our observed atmospheric concentration of CO2. CO2 is very likely a lagging indicator and not a cause of climate change.


    Effect of Drake Passage on the global thermohaline circulation

    -The Ekman divergence around Antarctica raises a large amount of deep water to the ocean’ surface. The regional Ekman transport moves the up-welled deep water northward out of the circumpolar zone. The divergence and northward surface drift combine, in effect, to remove deep water from the interior of the ocean. This wind-driven removal process is facilitated by a unique dynamic constraint operating in the latitude band containing Drake Passage. Through a simple model sensitivity experiment WC show that the upwelling and removal of deep water in the circumpolar belt may be quantitatively related to the formation of new deep water in the northern North Atlantic. These results show that stronger winds in the south can induct more deep water formation in the north and more deep outflow through the South Atlantic. The fact that winds in the southern hemisphere might influence the formation of deep water in the North Atlantic brings into question long-standing notions about the forces that drive the ocean’ thermohaline s circulation.

    Drake Passage and palaeoclimate

    ABSTRACT: The effect of Drake Passage on the Earth’s climate is examined using an idealised coupled model. It is found that the opening of Drake Passage cools the high latitudes of the southern hemisphere by about 3°C and warms the high latitudes of the northern hemisphere by nearly the same amount. This study also attempts to determine whether the width and depth of the Drake Passage channel is likely to be an important factor in the thermal response. A deeper channel is shown to produce more southern cooling but the magnitude of the effect is not large. Channel geometry is relatively unimportant in the model because of a haline response that develops when the channel is first opened up.

    South America and Australia separated from Antarctica between 20 and 40 million years ago, isolating Antarctica and the South Pole behind a continuous band of ocean water. The palaeoceanographic record shows that this separation led to the accumulation of glacial ice on Antarctica and an abrupt cooling of the ocean’s deep water (Kennett, 1977). Both effects persist to this day. The palaeoceanographic record gives every indication that the isolation of Antarctica was a major step in climate evolution.

    Today, the band of open water around Antarctica is most restricted between the tip of South America and the Palmer Peninsula, a feature known as Drake Passage. In one of the earliest scientific papers written about the output of an ocean general circulation model, Gill and Bryan (1971) showed how a gap such as Drake Passage alters the ocean’s meridional circulation and heat transport. With Drake Passage closed, the ocean transports heat southward by moving warm water poleward near the surface. Cooling at the Antarctic margin leads to deep-water formation and the northward flow of cold water at depth. With Drake Passage open, warm upper ocean water from the north is unable to flow into or across the channel because there is no net east–west pressure gradient to balance the effect of the Earth’s rotation. The ocean’s ability to transport heat southward is thereby diminished. Cox (1989), England (1992) and Mikolajewicz et al. (1993) carried out similar experiment…..

  14. Gail Combs says:

    Research on Drakes Passage today:


    The experiments address a fundamental question of how the circulation of the ocean works. Since the global overturning circulation is apparently sensitive to wind even in regions where the ocean has eastern and western boundaries, it may be influenced by wind outside the Drake Passage latitudes. However, our results indicate that the unique geometry of the Drake Passage latitudes does make the global circulation – and perhaps the climate of the North Atlantic – especially sensitive to wind there.

    Summer upper-layer Antarctic Circumpolar Current structure and transport in Drake Passage based on ship-born ADCP measurements

    It is revealed that the Subantaractic Current mostly consists of two jets. The northern jet is deeper comparing with southern one that generally is narrower and has larger average streamline velocity in the upper 500 m. The Polar current system is also as a rule bimodal. These two jets locate close to each other and often merge. The northern PC jet has a larger velocity amplitude while the southern one strongly varies in vertical direction. It is suggested that the ACC has two regimes – fast and slow switching between that causes predominantly barotropic changes in the upper-layer vertical velocity structure.

    And saving the best for last:
    Sunspots, the QBO, and the Stratosphere in the North Polar Region – 20 Years later Oct. 2005

    We have shown in earlier studies the size of the changes in the lower stratosphere which can be attributed to the 11-year sunspot cycle (SSC). We showed further that in order to detect the solar signal it is necessary to group the data according to the phase of the Quasi-Biennial Oscillation (QBO). Although this is valid throughout the year it was always obvious that the effect of the SSC and the QBO on the stratosphere was largest during the northern winters (January/February).

    Here we extend our first study (Labitzke 1987) by using additional data. Instead of 30 years of data, we now have 65 years. Results for the entire data set fully confirm the early findings and suggest a significant effect of the SSC on the strenght of the stratospheric polar vortex and the mean meridional circulation.

    Effects of solar variability related to the 11-year sunspot cycle are most obvious in the stratosphere, though still not fully understood (Crooks and Gray, 2005; Matthes et al., 2006).
    Labitzke suggested in 1982 that the Sun influences the intensity of the north polar vortex (i.e., the Arctic Oscillation (AO)) in the stratosphere in winter, and that the Quasi-Biennial Oscillation (QBO) is needed to identify the solar signal. Based on these results, Labitzke found in 1987 that a signal of the 11-year Sunspot Cycle (SSC) emerged when the arctic stratospheric temperatures and geopotential heights were grouped into two categories determined by the direction of the equatorial wind in the stratosphere (QBO). This first study was based on 30 years of data (1957-1986), that is barely three solar cycles.

    Several publications criticized the short data record and suggested that the correlations are due to aliasing caused by dividing the data according to the phase of the QBO (e.g., Teitelbaum and Bauer, 1990; Salby and Shea, 1991). But even when 20 more years of data became available, the correlations remained stable, see Table 1 (Labitzke, 2006)….

  15. Gail Combs says:

    So to put it all together.

    NASA has found that although TSI stays relatively constant the ratio of short vs long wavelengths does not. This is important because of ozone formation and destruction. 240 nm = ozone formation and 320 nm = ozone destruction. Therefore a shift in the amount of solar energy at 320 nm vs 240 nm will change the amount of ozone.

    Ozone is linked to many different changes in both the atmosphere and also, via changes of wind strength, in the Antarctic, the oceans and ENSO.

    There are many other connections but that is one.

    (Seems the earth’s magnetic field is weakening and that too changes ozone.)

    Magnetic field changes, NOx and Ozone by James A. Marusek. Nuclear Physicist & Engineer. U.S. Department of the Navy, retired.‎

  16. tchannon says:

    Awful lot of reading there Gail. 🙂
    I hope that is useful as an archive.Vast amount on the Talkshop.

  17. ren says:

    Gail Combs the magnetic field of the solar wind pushes the ozone over the poles, because ozone is diamagnetic.
    Diamagnetic materials create an induced magnetic field in a direction opposite to an externally applied magnetic field, and are repelled by the applied magnetic field. In contrast, the opposite behavior is exhibited by paramagnetic materials. Diamagnetism is a quantum mechanical effect that occurs in all materials; when it is the only contribution to the magnetism the material is called a diamagnet. Unlike a ferromagnet, a diamagnet is not a permanent magnet.
    ” The Earth’s Magnetic Field and the
    Magnetic Properties of Oxygen, Nitrogen
    Oxides, Chlorine Atoms and Some
    Chlorine Combinations and Ozone
    Many of the problems cited above can be overcome by
    taking into account an effect which should be playing an
    important role in the transport of gaseous substances
    throughout the atmosphere. In the analysis of the data
    made until the moment an important physical property of
    gaseous molecules has not been considered. This property
    is linked to the presence in the HOMO of the concerned
    molecule of paired or unpaired electrons. In the
    first case the corresponding molecules would be diamagnetic
    in nature, whereas in the second instance they
    would be paramagnetic. The diamagnetic molecules interact
    with a magnetic field in such a way that they
    would tend to be driven towards regions where the magnetic
    field intensity is lower, unlike the paramagnetic
    ones, which would be shifted towards places where the
    magnetic field intensity is higher. Thus, for the case of
    the Earth’s magnetic field, paramagnetic molecules
    would be driven towards the poles where the magnetic
    field presents maximum intensities, whereas diamagnetic
    molecules would tend to be shifted from polar latitudes
    towards equatorial ones.
    A classification can be made of the gaseous substances
    which participate in the chemical and photochemical
    reactions of destruction of the ozone layer. Thus, paramagnetic
    species are O2, NO, NO2, NO3, NOy, ClO, Cl,
    whereas diamagnetic species are O3 and N2O.
    The interaction between diamagnetic and paramagnetic
    gas molecules with the Earth’s magnetic field can
    contribute to a continuous flow of paramagnetic gases
    towards the poles and of gases composed by diamagnetic
    molecules equatorial- or tropical-wards. Therefore, according
    to the classification made before of the magnetic
    properties of different gaseous molecules present in the
    atmosphere, O2, NO, NO2, NO3, NOy, ClO and Cl tend to
    accumulate near the poles where they react with the O3
    molecules through chemical (in the absence of photons)
    or photochemical reactions, whenever the conditions are
    adequate for it (low temperatures which allow the presence
    of ice needles in suspension able to contribute to the
    third body effect). Such an accumulation is in agreement
    with the measured continuous decrease of the (O3/NOy)
    ratio mentioned before. The destruction mechanism of
    ozone is accompanied by the tendency of the ozone
    molecules to be shifted by the magnetic field towards
    equatorial latitudes, so that both effects can account for
    the rapid degradation of the ozone layer observed during
    the winter.”

  18. Bob Weber says:

    Gail, I know ren isn’t surprised by this, as he pointed out many times over the past several winters on many blogs regarding the real-time solar influence on ozone and the polar vortex:

    “Effects of solar variability related to the 11-year sunspot cycle are most obvious in the stratosphere, though still not fully understood (Crooks and Gray, 2005; Matthes et al., 2006).
    Labitzke suggested in 1982 that the Sun influences the intensity of the north polar vortex (i.e., the Arctic Oscillation (AO)) in the stratosphere in winter, and that the Quasi-Biennial Oscillation (QBO) is needed to identify the solar signal. Based on these results, Labitzke found in 1987 that a signal of the 11-year Sunspot Cycle (SSC) emerged when the arctic stratospheric temperatures and geopotential heights were grouped into two categories determined by the direction of the equatorial wind in the stratosphere (QBO). This first study was based on 30 years of data (1957-1986), that is barely three solar cycles. ”

    links to ren’s last citation:

    Great stuff all – thanks for your efforts.