UPDATE: Sunday 5/6/12 7PM PST – The FAIL occurred, with the predication hype not even close. Read here: Tuvalu flooding FAIL – no supermoon tide of any significance
Guest post by Andi Cockroft
The MSM down under are running with a story about the next close encounter with the moon due in the next day or so, a “super-moon”, and the likely impacts on the low-lying Tuvalu Island Nation.
With a population of just over 10,000, Tuvalu – formerly known as the Ellice Islands – is one of the smallest nations in the world, just ahead of the Vatican!
At its highest, Tuvalu is only 4.6 metres (15 ft) above sea level, and Tuvaluan leaders have been concerned about the effects of rising sea levels for some years. Whether there are measurable changes in the sea level relative to the islands of Tuvalu is a contentious issue. There were problems associated with the pre-1993 sea level records from Funafuti which resulted in improvements in the recording technology to provide more reliable data for analysis. The degree of uncertainty as to estimates of sea level change relative to the islands of Tuvalu is reflected in the conclusions made in 2002 from the available data. The 2011 report of the Pacific Climate Change Science Program published by the Australian Government] concludes: “The sea-level rise near Tuvalu measured by satellite altimeters since 1993 is about 5 mm per year.”
A nearby neighbor are our friends over at Kiribati, who must be completely wetting themselves (but not by high tides) at the thought of all that wonderful UN monies due to head their way. A moon at perigee should be like Manna from Heaven.
But what if nothing significant happens? What then?
At perigee, the moon approaches its closet to earth, and this particular approach is being referred to as a “Super Moon”.
According to website “Stuff”, the interactive arm of Fairfax media:-
A “super-moon” will be a novelty for New Zealanders on Sunday, but for the 12,000 people of Tuvalu it is a foreboding practice for a future where rising seas make their homeland uninhabitable.
On Monday and Tuesday super-moon king tides will leave much of the capital atoll of Funafuti virtually below sea-level.
On Sunday night the Moon will be 14 per cent bigger and 30 per cent brighter than any other full moon this year, the US space agency NASA says.
Known as a “perigee moon”, it occurs when the moon reaches its closest point to Earth.
The full moon will occur at 3.35pm on Sunday, New Zealand time, but will not be visible here until moonrise over New Zealand at 5.23pm.
With a clear sky, it guarantees Sunday night will be a bright one.
NASA says the super moon has a reputation for trouble, causing high tides, making dogs howl and keeping people awake.
The space agency says the best time to look at it is when the moon is near the horizon.
But what is the reality of a Moon at Perigee?
According to those folks over at NOAA, very little – see here.
The moon is the primary source of the gravitational forces which cause the tides. The proximity of the moon in relation to the earth does have an effect on the range of the tides at any given time. In each of its 28-day elliptical orbits, the moon reaches a “perigee,” its closest point of approach to the earth. During these periods, there will be a slight increase in the average range of tides. The increases in the range of the tides is seen by a slightly higher than average high tide, as well as a slightly lower than average low tide. Additionally, twice each month, around the times of the new moon and full moon, when the earth, sun, and moon are nearly in line, there is an increase in the average range of the tides. These are called “spring tides.” Three or four times a year, the occurrence of a new or full moon will coincide with the “perigee” of the moon, which Mr. Wood has termed the “perigean spring tides”.
The difference between the “perigean spring tides” and the normal tidal ranges for all areas of the coast is small. In most cases the difference is only a couple of inches. The largest difference occurs in certain areas of the Alaska coast where the range of the tide was increased by approximately 6 inches. But considering that these areas have an average tidal range of more than 30 feet, the increase is but a small percentage of the whole (less than a 2% increase).
So, will Tuvalu vanish beneath the waves? Well unless it’s less than 2 inches above seal-level, then probably not – so no worries there then.
I really do feel a rather smug FAIL coming on – then again it wouldn’t be the first time I’ve been wrong – hence stopping gambling on the gee-gee’s.