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Norwegian Sea Temperatures Linked To Solar Variation

April 27, 2015

By Paul Homewood 


h/t Kenneth Richards


Further to my post showing that the Pacific Ocean was warmer back in the Middle Ages, there was another paper, published in 2010, which linked changes in the temperature of the Norwegian Sea to solar variations.






They find that:

Lowest isotope values (highest temperatures) of the last millennium are seen ∼1100–1300 A.D., during the Medieval Climate Anomaly [Bradley et al., 2003], and again after ∼1950 A.D. The largest and most sustained isotopic increases (coolings) are centered at ∼1500 A.D. and ∼1700 A.D., corresponding to the regional Little Ice Age [Jones and Bradley, 1992]. Isotopic increases at these times are ∼0.3 ‰, indicating decreases of nSST of 1–1.5°C. After smoothing, the amplitude of nSST change over the last millennium is 1.5–2°C.


Given the enormous heat content of the ocean, a change of 2C, even just to a depth of 50m, would be expected to have a significant impact on air temperatures at a regional level.

Note as well the reference to “after 1950 AD”.


They continue:

The presence of medieval and 20th century warmth and Little Ice Age cooling in our records suggests a possible connection to known solar variations at these times (i.e., the Spører and Maunder minima and medieval and modern maxima, respectively….

On balance, the observed relationship of nSST and solar proxies suggests a climate response to the Sun within the characteristic inertial timescale of the upper ocean, which is one to several decades…

Despite uncertainty in relating solar proxies to absolute variations of the TSI (or the spectral irradiance) [Lean et al., 2002], it is clear that temperature changes of 1–2°C are large with respect to global or hemisphere-scale surface temperature changes expected in direct response to plausible long-term variations of the TSI in the range of 0.1 to 0.4%. The latter equate to changes in radiative forcing of 0.2 to 0.9 W/m2 (i.e., top-of-atmosphere TSI*(1–0.3)/4), which may be expected to produce a temperature response of 0.1 to 0.5°C (given, for example, a transient climate response of ∼0.5°C per W/m2 [Intergovernmental Panel on Climate Change, 2007]). As simple thermodynamic considerations would lead us to expect smaller temperature changes at the ocean surface than over land, the relatively large near-surface temperature signal we document points to significant regional amplification arising from a dynamical response of the atmosphere-ocean system.


They conclude:

We have presented an oxygen isotopic proxy record of near-surface temperature of Atlantic waters from the area of their primary flow into the eastern Norwegian Sea and find that it is robustly and near-synchronously correlated with various proxies of solar variability spanning the last millennium. The associated decade- to century-scale variation of estimated nSST ranges from 1 to 2°C, significantly larger than expected based on thermodynamic considerations alone. We suggest that this is due to a solar influence on the regional modes of atmospheric variability which, in turn, control the poleward transport and temperature of warm Atlantic surface waters.


To sum up, it is clear that it is the sun, and not CO2, that is the dominant force when it comes to ocean temperatures, and that solar variation links together both the medieval and current warming periods, as well as the Little Ice Age.

  1. April 27, 2015 12:01 pm

    I’ve not actually published this yet, maybe Wednesday. This covers N Norway, N Sweden, N Finland and a bit of Russia. One of the most strongly congruous set of records I’ve seen. Warmest year was 1937.

  2. R2Dtoo permalink
    April 27, 2015 12:05 pm

    Paul: do you know if this paper was used/cited in the last IPCC document(s)?

  3. April 27, 2015 2:50 pm

    I did not see any sun data here, so I looked at SSN again myself.
    I always had some doubts about comparing data from after 1972 with those before 1950, after not trusting the [subjective] measurements which seems [to me] must have improved over time, as observation methods improved. Note my selection of SIDC data from WFT:

    I find that if I offset the amount of SSN by about 10, I get exactly [the average] what I expect in terms of my measurements for the change in the speed of warming, for minima and maxima, with changing points 1927, 1972 and 2016…..

    So, like I surmised before, the sun is now at its brightest point since 1927. This is called the Gleissberg sun/weather cycle. From 2016 we will start the move up the mountain up again. If all the planets arrived in time….

  4. April 27, 2015 3:05 pm

    There have been 120 hurricanes (Cat 1-5) that have impacted North Carolina in the past 162 years (since 1850). More low level (Cat 1-3) hurricanes in the 1850’s-1900 than in later decades. There were only four Cat 4-5 hurricanes in this period and they were in the 1950’s, 1960’s and 1980’s. See NC Climate Office. Does that correlate with the solar warming of the Atlantic Ocean?

  5. April 27, 2015 6:27 pm

    I’m just wondering if the offshore wind parks and the anthropogene activities that are taking part in that region couldn’t influence the sea temperature. From what I’ve read before…. it seems that it does. I’m talking about the effect of stirring given by the wind parks.

  6. April 27, 2015 10:13 pm

    Reblogged this on the WeatherAction News Blog.

  7. April 27, 2015 11:36 pm

    Here are a few more papers that confirm the dominance of solar forcing in the determination of ocean heat content variations.
    It is found that the large SST annual cycle in the eastern equatorial Pacific is, to a large extent, controlled by the annually varying mixed layer depth which, in turn, is mainly determined by the competing effects of solar radiation and wind forcing. With the application of our hybrid vertical mixing scheme the modelsimulated SST annual cycle is much improved in both amplitude and phase as compared to the case of a constant mixed layer depth. Beside the strong effects on vertical mixing, solar radiation is the primary heating term in the surface layer heat budget, and wind forcing influences SST by driving oceanic advective processes that redistribute heat in the upper ocean. For example, the SST seasonal cycle in the western equatorial Pacific basically follows the semiannual variation of solar heating, and the cycle in the central equatorial region is significantly affected by the zonal advective heat flux associated with the seasonally reversing South Equatorial Current.
    Global and hemispheric mean surface temperatures show a significant dependence on solar irradiance at λ [wavelengths] > 250 nm. Also, powerful volcanic eruptions in 1809, 1815, 1831 and 1835 significantly decreased global mean temperature by up to 0.5 K for 2–3 years after the eruption. Reduction of irradiance at λ [wavelengths] > 250 nm leads to a significant (up to 2%) decrease in the ocean heat content (OHC) between 0 and 300 m in depth, whereas the changes in irradiance at λ < 250 nm or in energetic particles have virtually no effect. Also, volcanic aerosol yields a very strong response, reducing the OHC of the upper ocean by up to 1.5%. In the simulation with all forcings, the OHC of the uppermost levels recovers after 8–15 years after volcanic eruption, while the solar signal and the different volcanic eruptions dominate the OHC changes in the deeper ocean and prevent its recovery during the DM. Finally, the simulations suggest that the volcanic eruptions during the DM had a significant impact on the precipitation patterns caused by a widening of the Hadley cell and a shift in the intertropical convergence zone.
    Abstract: The summer extent of the Arctic sea ice cover, widely recognized as an indicator of climate change, has been declining for the past few decades reaching a record minimum in September 2007. The causes of the dramatic loss have implications for the future trajectory of the Arctic sea ice cover. Ice mass balance observations demonstrate that there was an extraordinarily large amount of melting on the bottom of the ice in the Beaufort Sea in the summer of 2007. Calculations indicate that solar heating of the upper ocean was the primary source of heat for this observed enhanced Beaufort Sea bottom melting. An increase in the open water fraction resulted in a 500% positive anomaly in solar heat input to the upper ocean, triggering an ice–albedo feedback and contributing to the accelerating ice retreat.

    Conclusions: There was an extraordinarily large amount of ice bottom melting in the Beaufort Sea region in the summer of 2007. Solar radiation absorbed in the upper ocean provided more than adequate heat for this melting. An increase in the open water fraction resulted in a 500% positive anomaly in solar heat input to the upper ocean, triggering an ice–albedo feedback and contributing to the accelerating ice retreat.

  8. Brian H permalink
    May 18, 2015 5:24 am

    Rename it the “Canary Sea”.


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