Áfhrif sólar á hitastig Noregshafs siðan árið 1000...

 

 

Nýlega (16. des. s.l.) birtist í tímaritinu Journal of Geophysical Research grein sem nefnist

Response of Norwegian Sea temperature to solar forcing since 1000 A.D.  Sjá hér.

Meðal höfunda er Hafliði Hafliðason prófessor við Háskólann í Bergen.

Vel getur verið að einhverjir hafi áhuga á þessari grein, og þess vegna er vísað á hana hér.

Rannsóknin fór fram á borkjarna sem tekinn var við staðinn P1 á myndinni sem fengin er úr greininni.

 

Í samantekt greinarinnar stendur:

"We report on a 1000 year long oxygen isotope record in sediments of the eastern Norwegian Sea which, we argue, represents the temperature and transport of warm Atlantic waters entering the Nordic Sea basin via the North Atlantic Drift and the large‐scale Meridional Overturning Circulation. The single‐sample resolution of the record is 2.5–10 years and age control is provided by ²¹⁰Pb and ¹³⁷Cs dating, identification of historic tephra, and a ¹⁴C “wiggle‐match” dating method in which the surface reservoir ¹⁴C age in the past is constrained rather than assumed, thereby eliminating a large source of chronological uncertainty. The oxygen isotope results indicate decade‐ to century‐scale temperature variations of 1–2°C in the shallow (∼50 m deep) subsurface which we find to be strongly correlated with various proxies of past solar activity. The correlations are synchronous to within the timescale uncertainties of the ocean and solar proxy records, which vary among the records and in time with a range of about 5–30 years. The observed ocean temperature response is larger than expected based on simple thermodynamic considerations, indicating that there is dynamical response of the high‐latitude ocean to the Sun. Correlations of our results with a gridded temperature reconstruction for Europe are greater in central Europe than in coastal regions, suggesting that the temperature and transport of warm Atlantic waters entering the Nordic Basin and the pattern of temperature variability over Europe are both the proximate responses to a change in the atmospheric circulation, consistent with a forced shift in the primary modes of high‐latitude atmospheric variability".

Í greininni (sjá hér á síðu Svalgaards) stendur meðal annars í kafla 3:

"...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..."

"...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..."

(Sejrup, H.P., Lehman, S.J., Haflidason, H., Noone, D., Muscheler, R., Berstad, I.M. and Andrews, J.T. 2010. Response of Norwegian Sea temperature to solar forcing since 1000 A.D. Journal of Geophysical Research 115: 10.1029/2010JC006264).

 

 

 

Athugasemdir

[Sigurjón Jónsson, 30.3.2011 kl. 17:22]

Þetta er skemmtilegt.

Ertu með kenningu um "Global Warming" út frá þessu.

Eru allir að kalla Úlfur Úlfur og ef svo hvers vegna.