{"id":535,"date":"2008-03-02T17:37:47","date_gmt":"2008-03-02T22:37:47","guid":{"rendered":"http:\/\/www.realclimate.org\/index.php\/archives\/2008\/03\/536-ad-and-all-that\/"},"modified":"2015-02-16T18:23:11","modified_gmt":"2015-02-16T23:23:11","slug":"536-ad-and-all-that","status":"publish","type":"post","link":"https:\/\/www.realclimate.org\/index.php\/archives\/2008\/03\/536-ad-and-all-that\/","title":{"rendered":"536 AD and all that 530 AD y todo eso<\/lang_sp>"},"content":{"rendered":"
\n

\n“during this year a most dread portent took place. For the sun gave forth its light without brightness\u2026 and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear.”\n<\/p><\/blockquote>\n

Eine deutsche \u00dcbersetzung dieses Artikels ist hier<\/a>.<\/lang_de>
\nThis quote from Procopius of Caesarea is matched by other sources<\/a> from around the world pointing to something – often described as a ‘dry fog’ – and accompanied by a cold summer, crop failures and a host of other problems. There’s been a TV special<\/a>, books and much newsprint<\/a> speculating on its cause – volcanoes, comets and other catastrophes have been suggested. But this week there comes a new paper in GRL (Larsen et al, 2008<\/a>) which may provide a definitive answer….
\n
\nTraducido por Angela Carosio<\/small><\/p>\n

\n\u201cen este a\u00f1o hubo un temido presagio. El sol dio su luz sin brillo\u2026y parec\u00eda como un sol de eclipse, pues los rayos de luz no eran claros.\u201d<\/p><\/blockquote>\n

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\n<\/p>\n

<\/a> It’s long been known that tree-rings (such as the one pictured from Arizona) often show an extremely small growth ring for AD 536 (you can count back from the marked AD 550 ring). In fact, if you look at the mean anomaly in a whole range of tree ring constructions, this event stands out along with 1601 and 1815 (known volcanic events) as being exceptional over the last 2000 years. <\/p>\n

<\/p>\n

Average of the high-frequency components of 7 northern European tree ring reconstructions from Larsen et al, 2008. The filtering ensures that uncertainties in long term trends (which are not important in this context) don’t confuse the issue.<\/i><\/p>\n

These data match the written sources quite well. However, tying it to a cause has always been plagued with problems of chronology. An initial attempt to tie this event to a volcanic pulse in the Dye3 ice core in Greenland foundered when the chronology was revised to put it 20 years earlier. However, there has recently been a concerted effort to place all the Greenland ice cores on a common timescale based on annual layer counts (Vintner et al, 2006). Because all the cores are being counted together, ambiguities in one can be corrected by reference to the others. Once the dates have been better established, the sulphate records (which generally show the impact of volcanic aerosols) can be examined to see if they line up. And low and behold, they do:<\/p>\n

<\/center><\/p>\n

The second peak in the picture is dated at 534 AD which is close enough to 536 AD given the one or two year uncertainty in counting. Note that the 534 AD peak is actually smaller than the one a few years earlier. In assessing the importance of an eruption though, it isn’t enough to have just a peak in Greenland. That could simply signify an eruption that was close by. Instead, people look for a matching peak in Antarctica. This signifies that the eruption was likely tropical and the aerosols were carried into both hemispheres by the stratospheric circulation. Here is where previous attempts often faltered. The dating of ice cores in Antarctica is less exact than in Greenland because the accumulation is slower (it doesn’t snow as much). However, the relatively new Dronning Maud Land (DML) core has comparable resolution to the Greenland ones, and this one does have a clear sulphate peak at about 542 +\/- 17 years. That is good enough to be a match to the 536 AD peak in Greenland. The correction you’d need to make to align them exactly would also fix some other apparent offsets for smaller events in the subsequent 100 years. <\/p>\n

So it probably was a volcano, somewhere in the tropics, and it was likely the size of Tambora in 1815. There has been some speculation that it was an earlier eruption of Krakatoa (which went off again in 1883), but that is uncertain, as are the numerous consequences such as the fall of the Rome or the rise of Islam which have been attributed to this event. While not exploring that too deeply, this quote from Michael the Syrian indicates dramatically the potential for climate events like this one to really spoil your day:<\/p>\n

\n“The sun was dark and its darkness lasted for eighteen months; each day it shone for about four hours; and still this light was only a feeble shadow … the fruits did not ripen and the wine tasted like sour grapes.”\n<\/p><\/blockquote>\n

<\/p>\n

Esta cita de Procopius de Cesarea es igual a las de otras fuentes<\/a> alrededor del mundo y se\u00f1ala un fen\u00f3meno clim\u00e1tico, generalmente conocido como niebla seca que viene acompa\u00f1ado por un verano fr\u00edo, el fracaso de las cosechas y otra serie de problemas. En una serie de TV<\/a>, libros y art\u00edculos en la prensa<\/a> se sugirieren, como posibles causas, erupciones volc\u00e1nicas, cometas y otras cat\u00e1strofes. Pero esta semana se public\u00f3 un nuevo art\u00edculo en GRL<\/a> que podr\u00eda ofrecer una respuesta definitiva\u2026<\/p>\n

<\/a>Es bien sabido que los anillos de crecimiento de los \u00e1rboles (como el de la fotograf\u00eda, proveniente de Arizona) generalmente muestran un anillo de crecimiento extremadamente peque\u00f1o para el a\u00f1o AD 536 (\u00e9ste se puede contar hacia atr\u00e1s desde el anillo marcado como AD 550.) En efecto, si observamos las anomal\u00edas de toda una serie de construcciones de anillos de crecimiento, este evento se destaca como excepcional en los \u00faltimos 2000 a\u00f1os, junto con los a\u00f1os 1601 y 1815 (ambos conocidos por erupciones volc\u00e1nicas).<\/p>\n

<\/p>\n

Fig. 1: Promedio de los componentes de alta frecuencia en 7 reconstrucciones de anillos de crecimiento de \u00e1rboles del norte de Europa, por Larsen et al, 2008. El filtrado asegura que las incertidumbres en las tendencias a largo plazo (que no son importantes en este contexto) no confundan los resultados.<\/i><\/p>\n

Estos datos coinciden con las fuentes escritas. Sin embargo, la b\u00fasqueda de una causa para AD 536 siempre ha estado plagada de problemas de cronolog\u00eda. El intento de asociar este evento con una erupci\u00f3n volc\u00e1nica en las muestras de coraz\u00f3n hielo Dye3 de Groenlandia se desplom\u00f3 cuando dicha cronolog\u00eda fue revisada y coloc\u00f3 al evento volc\u00e1nico 20 a\u00f1os antes de AD 536. Sin embargo, recientemente ha habido un esfuerzo conjunto para ubicar todas las muestras de corazones de hielo de Groenlandia en una misma escala temporal, basada en el recuento anual de capas (Vintner et al. 2006). Debido a que todos los corazones de hielo est\u00e1n siendo analizados conjuntamente, las ambig\u00fcedades en un coraz\u00f3n pueden ser corregidas cotejando con otros. Una vez que los datos est\u00e9n bien establecidos, los registros de sulfato (SO4) (que generalmente muestran el impacto de gases volc\u00e1nicos), pueden ser examinados para ver si \u00e9stos coinciden. Y as\u00ed lo hicieron:<\/p>\n

<\/center><\/p>\n

El segundo pico de sulfato de la figura corresponde al a\u00f1o AD 534, que es suficientemente cercano a AD 536, dejando uno o dos a\u00f1os de error en el recuento. Se debe notar que el pico alcanzado en AD 534 es menor que el alcanzado unos a\u00f1os antes. Sin embargo, cuando se eval\u00faa la importancia de una erupci\u00f3n, un pico de concentraci\u00f3n de sulfato en Groenlandia no es suficiente, ya que esto podr\u00eda significar que hubo una erupci\u00f3n en un \u00e1rea cercana. En vez, un pico de sulfato coincidente en la Ant\u00e1rtida significa que la erupci\u00f3n ocurri\u00f3 probablemente en alg\u00fan lugar en el tr\u00f3pico y que la circulaci\u00f3n atmosf\u00e9rica transport\u00f3 los gases a ambos hemisferios. Es aqu\u00ed donde intentos previos han fallado. La cronolog\u00eda de las muestras de corazones de hielo ant\u00e1rticos es mucho menos exacta que las de Groenlandia porque la acumulaci\u00f3n en la Ant\u00e1rtida es m\u00e1s lenta (no se nota tanto). Sin embargo, la relativamente nueva muestra de coraz\u00f3n de hielo llamada Dronning Maud Land (DML) tiene una resoluci\u00f3n comparable con las muestras de Groenlandia, y \u00e9sta muestra un claro pico de sulfato alrededor del a\u00f1o 542 +\/- 17 a\u00f1os. Este resultado es suficiente para coincidir con el pico de sulfato de AD 536 en Groenlandia. La correcci\u00f3n necesaria para que estos eventos est\u00e9n perfectamente alineados tambi\u00e9n compensa las aparentes diferencias cronol\u00f3gicas de otros eventos menos importantes en los 100 a\u00f1os subsiguientes.<\/p>\n

Probablemente en el a\u00f1o 536 hubo una erupci\u00f3n volc\u00e1nica en alg\u00fan lugar en el tr\u00f3pico, de la magnitud de Tambora en 1815. Se ha especulado con que fue una erupci\u00f3n del volc\u00e1n Krakatoa (anterior a la de 1883), pero esta especulaci\u00f3n es incierta, as\u00ed como las numerosas consecuencias atribuidas a \u00e9ste evento, como la ca\u00edda del Imperio Romano o el surgimiento del Islam. Sin entrar en mucho detalle al respecto, esta cita de Michael de Syrian indica, dram\u00e1ticamente, el potencial que tiene el clima y eventos volc\u00e1nicos como \u00e9ste para arruinarle el d\u00eda a cualquiera:<\/p>\n

\n\u201cEl sol estaba oscuro y su oscuridad dur\u00f3 18 meses; cada d\u00eda brillaba por cuatro horas, y a\u00fan as\u00ed \u00e9sta luz era una sombra d\u00e9bil\u2026 los frutos no maduraron y el vino ten\u00eda sabor a uva \u00e1cida.\u201d<\/p><\/blockquote>\n

<\/lang_sp><\/p>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

“during this year a most dread portent took place. For the sun gave forth its light without brightness\u2026 and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear.” Eine deutsche \u00dcbersetzung dieses Artikels ist hier. This quote from Procopius of Caesarea is matched by other sources from around […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[17,1,2],"tags":[],"class_list":{"0":"post-535","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-aerosols","7":"category-climate-science","8":"category-paleoclimate","9":"entry"},"aioseo_notices":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts\/535","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/comments?post=535"}],"version-history":[{"count":2,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts\/535\/revisions"}],"predecessor-version":[{"id":18138,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts\/535\/revisions\/18138"}],"wp:attachment":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/media?parent=535"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/categories?post=535"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/tags?post=535"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}