Thursday, September 5, 2013

Krakatau


Krakatau (Krakatoa) was a small island in the Sunda Strait between Java and Sumatra in Indonesia.  In April 1883, signs of unusual volcanic activity were observed; then a series of volcanic explosions started about mid-day, with the main eruption (and island destruction) occurring about 10 am local time August 27.

The final explosion was audible nearly 2,000-miles away and it produced an infrasonic pressure pulse that was recorded by barographs around the world.

The northern two-thirds of the island collapsed beneath the sea, generating a series of devastating pyroclastic flows and immense tsunamis that ravaged adjacent coastlines.

So that's in Indonesia, how does that relate to Hawaiʻi?

Rev. Sereno Bishop, a missionary in Hawaiʻi, was the first to provide detailed observations of a phenomenon not previously reported - he noted his observation on September 5, 1883.

"Permit me to call special attention to the very peculiar corona or halo extending from 20° to 30° from the sun, which has been visible every day with us, and all day, of whitish haze with pinkish tint, shading oft' into lilac or purple against the blue. I have seen no notice of this corona observed elsewhere. It is hardly a conspicuous object."  (Sereno Bishop)

"The long continuance and extending diffusion of this haze or dry fog seems to justify expectation that it may become visible around the globe, and give ample opportunity for investigation."  (Sereno Bishop)

"Although not seen in San Francisco until November 23, it was brilliant in Santa Barbara on October 14.  A rapid upper current seems to have borne it in a belt within the tropics in a very few days, leaving a slow diffusion to extend it to the temperate zone. Australia is perhaps an example of this."  (Sereno Bishop)

The whole world was agog with wonder and inquiry as to the cause of the phenomena. There were the usual suggestions of the approaching end of the world and endless speculations, but no theory which would hold water, until from far Hawaii, over the signature of Sereno E. Bishop, appeared an article, illustrated with drawings demonstrating the argument, propounding an explanation which was eventually unanimously accepted by the scientific world as correct.  (Biography of Sereno E. Bishop)

Sereno Bishop was born at Kaʻawaloa on February 7, 1827; he was son of Rev. Artemas and Elizabeth Bishop (part of the 2nd Company of missionaries to Hawaiʻi (1823) and first stationed at Kailua, on the Big Island.)  His mother died at Kailua, the first death in the mission.

Sent back to the continent at age 12 for education (he graduated from Amherst College in 1846 and Auburn Theological Seminary in 1851,) he married Cornelia A Session in 1852 and accepted a position of Seaman's Chaplin in Lāhainā - he returned to Hawaiʻi in 1853.

After 10-years in Lāhainā, he moved to Hāna and later returned to Lāhainā and served from 1865 to 1877 as principal of Lahainaluna.  From there, he moved to Honolulu and became editor of "The Friend," where he lived until his death, March 23, 1909.

But, back to the halo ...

"Gigantic as were these effects, they were surpassed in strangeness and extent, by those conspicuous effects which were left upon the earth’s atmosphere causing remarkable sunset and sunrise glows which have set the world wondering."

It is now known that this halo is caused by diffraction of sunlight around the very small spherical sulphuric acid droplets.

Since this event, it has generally been known as "Bishop's Ring," in honor of its first discoverer.  It is typically observed after large volcanic eruptions.

But the importance of Bishop's observations was not just related to rings around the sun; his observations suggested the existence of the ‘Jet Stream’ (this used to be referred to as the 'Krakatoa Easterlies.')

"It now seems probable that the enormous projections of gaseous and other matter from Krakatoa (Krakatau) have been borne by the upper currents and diffused throughout a belt of half the earth's circumference, and not improbably, as careful observation may yet establish, even entirely around the globe."  (Sereno Bishop)

"This almost incredible statement implies a terrific undulation of the atmosphere, such as could only be produced by a vast and continuous jet of gas projected upwards beyond the limits of the atmosphere, and driving the air in vast waves in every direction. So abnormal and gigantic a force may well have propagated not only its tidal waves as it did across the Pacific, but it may also have transmitted its portentous and lurid vapours to belt the globe with flaming skies."   (Sereno Bishop)

In 1896 his alma mater, Amherst College, conferred upon him the degree of Doctor of Divinity, in recognition of his literary and scientific attainments.

The image shows Bishop's Ring around the sun due to volcanic ash of the Eyjafjallajökull volcano on Iceland in 2010.     In addition, I have added other related images in a folder of like name in the Photos section on my Facebook and Google+ pages.

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