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Polar Maritime

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    Solar and Aurora Activity Chat

    in Space, Science & nature

    Posted · Edited by Polar Maritime

    Almost an X-flare! AR11877 (south of AR11875) has released multiple M flares including an M9.3 flare, which is Earth facing..

     

    Posted ImagePosted Image

     

    http://www.youtube.com/watch?v=St6KOPgxPqA

     

     

    SOLAR FLARE! Earth-facing sunspot AR1877 erupted on Oct. 24th at 00:30 UT (Oct. 23rd at 5:30 pm PDT), producing an M9-class solar flare. A flash of extreme UV radiation from the flare ionized Earth's upper atmosphere and created a brief HF radio blackout on the sunlit side of the planet. Stay tuned for updates about this significant event.http://www.spaceweather.com/

     

     

    • Like 1

    New Research

    in Climate Change

    Posted · Edited by Polar Maritime

    Scientists who braved Somali pirates shed light on Sahara's origins

    Climate research vessel that escaped pirates in the Horn of Africa in 2001 may have just turned the tables on the accepted scientific view of how the Sahara became a desert ;

     

    http://www.theguardian.com/environment/2013/oct/18/scientists-somali-pirates-sahara-origins

     

    What the scientists found was that, far from shifting gradually from wet to dry, the climate in the Horn of Africa changed in perhaps as little as 100 to 200 years, incredibly quickly in geological terms. The reason north Africa warmed up, they believe, was a cyclic change in Earth’s orientation toward the sun (called precession) which caused more sunlight to fall during the Northern Hemisphere's summer. But the precession cycle is slow, taking 23,000 years to complete. So why was the changeover in the Horn of Africa so quick?

    “It shows something really surprising,†says deMenocal. “It’s evidence that climate doesn’t respond gradually to gradual forcing. It would be wonderful in global warming if everything just kept pace with the gradual rise in CO2, then we could plan for this, we would know what is going to happen, there would be some predictability in it."

    But what researchers like Tierney and deMenocal are increasingly finding is that climate doesn’t change in a linear fashion, but suddenly and seemingly unpredictably. That’s because there are positive feedback mechanisms that start to kick in and speed things up. For example, when the Arctic sea ice melts, as it has increasingly in recent years, the area of dark blue heat-absorbing ocean increases, raising temperatures, melting more ice, which in turn raises temperatures still further in an snowballing process.

    Tierney and deMenocal suspect that there were similar positive feedback mechanisms at play in the rapid desertification of the Horn of Africa 5,000 years ago. It could involve what is called the Charney mechanism, which posits that as vegetation begins to thin in an area, it changes the reflectivity of the Earth which heats thing up, dries out more vegetation and leads to the rather abrupt formation of deserts. However, the carbon isotope data collected by the team do not suggest that this was the case. Rather, the authors hypothesize that there was a feedback mechanism involving Indian Ocean sea-surface temperatures, which greatly influence how much rain falls over east Africa.

    Whether that is in fact what happened remains to be proven. It’s just one of the mysteries that need to be investigated further, deMenocal told me. The authors are itching to get back to the Gulf of Aden to drill even deeper core samples that would provide critical information on climate conditions during the period millions of years ago when humans first evolved from our hominid predecessors. This could throw light on the early stages of human evolution, which happened just next door in the East African Rift and the Horn of Africa.

    Tuesday 22nd October General Weather Chat

    in Spring Weather Discussion

    Posted

    Lot's of floods this morning, had to turn round at one point on the way to Bakewell.. The trees have also been stripped a little more with the rain.

     

    A cloudy day with outbreaks of rain some of which were heavy, a high of 14.8c.

     

    Currently; Cloudy with the odd light shower.

    Temp 13.6c

    Wind South 13mph

    Gusting 41mph at 1.58pm

    Rain since midnight 13.2mm

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