Posts Tagged ‘cycles’

Interesting paper from Xhao & Feng finds strong coherence of De Vries 208 year millennial solar variation with temperature in Antarctica. Also finds incoherence between CO2 and temperature.

xhao-feng

Fig. 2.

(a) Squared wavelet coherence between the SSN and T time series. The thick black contours indicate the 95% confidence level against red noise. Black arrows represent phase angles of the cross wavelet (with in-phase pointing right, anti-phase pointing left, SSN leading T by 90° pointing straight down, and SSN lagging T by 90° pointing straight up). The regions inside COI are removed. (b) The global wavelet coherence (Cg, solid line) and the phase angle strength (Sθ, dashed line) between SSN and T plotted against period. (c) Same as (a) but for the CO2 and T time series. (d) Same as (b) but for the CO2 and Ttime series. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Abstract

The solar impact on the Earth’s climate change is a long topic with intense debates. Based on the reconstructed data of solar sunspot number (SSN), the local temperature in Vostok (T), and the atmospheric CO2 concentration data of Dome Concordia, we investigate the periodicities of solar activity, the atmospheric CO2 and local temperature in the inland Antarctica as well as their correlations during the past 11,000 years before AD 1895. We find that the variations of SSN and T have some common periodicities, such as the 208 year (yr), 521 yr, and ~1000 yr cycles. The correlations between SSN and T are strong for some intermittent periodicities. However, the wavelet analysis demonstrates that the relative phase relations between them usually do not hold stable except for the millennium-cycle component. The millennial variation of SSN leads that ofT by 30–40 years, and the anti-phase relation between them keeps stable nearly over the whole 11,000 years of the past. As a contrast, the correlations between CO2 and T are neither strong nor stable. These results indicate that solar activity might have potential influences on the long-term change of Vostok’s local climate during the past 11,000 years

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I pointed Richard Betts to the Charles D. Keeling (Yes, that Charles D. Keeling) and Timothy Whorf paper on lunar tidal cycles and their connection with rapid climate change ‘The 1,800-year oceanic tidal cycle: A possible cause of rapid climate change.’

Here’s what happened:

betts-keeling

Basically, Betts ran away. He’s a natural climate change denier. His job is to ‘do outreach’ promoting the Carbon Dioxide causes climate change hypothesis, but maintain plausible deniability that anyone ever showed him what a crock of crap it is compared to more likely explanations.

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The moon is linked to long term Atlantic changes.

Posted: November 30, 2009 by tallbloke in climate
Tags: , , ,

For some time I’ve been wondering how the longer term cyclicities of the moon might affect the Earth’s climate.

I just came across this very interesting 2008 paper:

Lunar nodal tide effects on variability of sea level, temperature, and salinity in the Faroe-Shetland Channel and the Barents Sea
Yndestad Harald; Turrell, William R and Ozhigin, Vladimir:
Link to full paper (paywalled)

Abstract:

The Faroe-Shetland Channel and the Kola Section hydrographic time-series cover a time period of more than 100 years and represent two of the longest oceanographic time-series in the world. Relationships between the temperature and salinity of Atlantic water from these two areas are examined in this paper, which also presents for the first time comparisons between them and annual mean sea levels in the region. The investigation was based on a wavelet spectrum analysis used to identify the dominant cycle periods and cycle phases in all time-series. The water-property time-series show mean variability correlated to a sub-harmonic cycle of the nodal tide of about 74 years, with an advective delay between the Faroe-Shetland Channel and the Barents Sea of about 2 years. In addition, correlations better than R=0.7 were found between dominant Atlantic water temperature cycles and the 18.6-year lunar nodal tide, and better than R=0.4 for the 18.6/2=9.3-year lunar nodal phase tide. The correlation between the lunar nodal tides and the ocean temperature variability suggests that deterministic lunar nodal tides are important regional climate indicators that should be included when future regional climate variability is considered. The present analysis suggests that Atlantic water temperature and salinity fluctuations in the Nordic Seas are influenced by forced tidal mixing modulated by harmonics of the nodal tide and influencing the water mass characteristics at some point “down stream” from the Faroe-Shetland Channel. The effects of the modulated oceanic mixing are subsequently distributed as complex coupled lunar nodal sub-harmonic spectra in the thermohaline circulation.

Lunar nodal tides against Atlantic temperature 1900-2005

Lunar nodal tides against Atlantic temperature 1900-2005 Harald Yndestad

Harald has a page on climate here: http://ansatte.hials.no/hy/climate/defaultEng.htm

He says:

In this analysis we may understand the forced gravitation oscillation between the earth, sun and the moon as a forced coupled oscillation system to the earth. The tide and the earth rotation responds as a non-linear coupled oscillation to the forced gravity periods from the moon and the sun. This is a complex oscillation in periods between hours and thousands of years. The forced gravitation introduces a tidal mixing in the Atlantic Ocean. This tidal mixing introduces temperature and salinity fluctuations that influences climate and the eco system.”

It looks to me like the coincidence of these lunar cycles with the planetary cycles in my previous post may go some way to explaining the peak temperatures Earth experienced recently. These longer term cycles cause tidal mixing and overturning in the ocean which will affect the absorption and release of oceanic heat energy. This will be the subject of my next post.