Tο πιο γαλάζιο ποτάμι της γης

Αναρτήθηκε τη Κατηγορία: Νέα, Περιβάλλον.

Ο παγετώνας Πίτερμαν, ο μεγαλύτερος επιπλέων παγετώνας στο βόρειο ημισφαίριο, βρίσκεται στη βορειοδυτική Γροιλανδία και συνδέει το στρώμα πάγου της Γροιλανδίας με τον Αρκτικό ωκεανό. Είναι μια στενή λωρίδα που έχει πλάτος 15 χιλιόμετρα και μήκος 70, της οποίας το πάχος του πάγου κυμαίνεται από περίπου 600 μέτρα στη βάση σε περίπου 30-80 μέτρα  στην άκρη. Σύμφωνα με πρόχειρες εκτιμήσεις, περίπου το 80% της μάζας του παγετώνα είναι λιωμένο νερό. Ρέoντας προς τη θάλασσα το νερό του παγετώνα σχηματίζει αυτό το απίστευτο γαλάζιο ποτάμι που βλέπετε στις φωτογραφίες.

An ice penetrating radar is deployed from a string of kayaks to survey a section of the Petermann glacier in Greenland. Three scientists, working in partnership with Greenpeace fit a radar transmitter, receiver and antennas to a chain of four kayaks, to obtain valuable data on the processes operating over floating ice shelves. This will reveal more of the complex nature of the ice thickness, basal melt-rates and insight into the breakup at the front section of Petermann. The scientists are Jason Box, Richard Bates and Alun Hubbard, the three took turns to paddle the kayaks whilst running the radar, over the carefully selected 25 kilometer course along a meltwater channel which runs down the middle of the glacier's floating ice shelf. Kayaking the occasionally hazardous route they were careful to stop just short of a 'whirlpool' which Dr Bates had previously cast with a CTD, finding it to reach the seawater currents in the fjord, 60m below. The team of scientists are on board the Arctic Sunrise during the 1st leg of Greenpeace's 3 month long Arctic Impacts expedition, to document the effects of climate change on the Arctic environment ahead of the Copenhagen summit which will be held in December 2009 Technical notes. 1. The entire route was seaward of the glacier's grounding line and therefore on the 'floating tongue' of the glacier which floats in seawater in the Petermann fjord. 2. The transmitter is installed inside the green un-manned kayak (pictured with solar panel). The receiver in the forward red kayak paddled by scientists Hubbard and Bates. 3. The two 40m antennas (inside the orange rubber hosing) were floated in the water attached to rope between the kayaks. 4. The ice radar works by sending short, discrete bursts of radio waves in the High Frequency range at very high power (4kV pulses) which 'bounce' off internal and basal reflectors creating return waves. A broadband digital spectrum analyser at the receiver decodes and records this information from the return signal received. 5. The radar (aka radio-echo sounder) is a 'deep-look' type, operating in High Frequency range with a high power output, customised by Hubbard in collaboration with Uppsala University. 6. A simple diagram of the setup is available on request, as source material to make graphics. 7. The science team are concentrating their research on the qualities of submarine melting, holding the view that there has is a huge gap in our understanding of this field, over the traditional area of atmospheric melting. They hope to contribute to much needed research that will inform more accurate predictions of sea level rise.Αποστολή της Greenpeace διαπίστωσε ότι οι παγετώνες έχουν χάσει περίπου 100 τετραγωνικά χιλιόμετρα πάγου. Η ποσότητα αυτή είναι αρκετή, για να τροφοδοτήσει με νερό μια πόλη σαν την Αθήνα για διάστημα 10 περίπου ετών.

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