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Titolo:
HIGH NORTHERN LATITUDE FOREST-FIRES AND VEGETATION EMISSIONS OVER THELAST MILLENNIUM INFERRED FROM THE CHEMISTRY OF A CENTRAL GREENLAND ICE CORE
Autore:
SAVARINO J; LEGRAND M;
Indirizzi:
CNRS,LAB GLACIOL & GEOPHYS ENVIRONM,DOMAINE UNIV,54 RUE MOLIERE,BP 96F-38402 ST MARTIN DHER FRANCE
Titolo Testata:
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
fascicolo: D7, volume: 103, anno: 1998,
pagine: 8267 - 8279
Fonte:
ISI
Lingua:
ENG
Soggetto:
PAST 2000 YEARS; CLIMATE-CHANGE; NORTHWESTERN MINNESOTA; ATMOSPHERIC METHANE; BOREAL-FOREST; RECORD; SUMMIT; AMMONIUM; HISTORY; CHARCOAL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
64
Recensione:
Indirizzi per estratti:
Citazione:
J. Savarino e M. Legrand, "HIGH NORTHERN LATITUDE FOREST-FIRES AND VEGETATION EMISSIONS OVER THELAST MILLENNIUM INFERRED FROM THE CHEMISTRY OF A CENTRAL GREENLAND ICE CORE", J GEO RES-A, 103(D7), 1998, pp. 8267-8279

Abstract

We have analyzed the soluble portion of impurities trapped in solid precipitation that accumulated at Summit (central Greenland) from 1193 A.D. to the present. Seventy-three ice layers show elevated concentrations of ammonium and formate, caused by high-latitude biomass burning debris reaching Greenland. While a mixture of ammonium and formate close to the molar ratio is generally observed in these ice layers, a large depletion of formate relative to ammonium is found in a few cases. The chemical composition of such layers indicates the presence of a mixture of ammonium, formate, and nitrate with a NH4+/(HCOO.+NO3.) molarratio close to 1. These differences may be related to the fire type (flaming versus smoldering) or to meteorological conditions encounteredby plumes during their transport toward Greenland. The high-resolution ammonium and formate profiles are used to reconstruct the frequency and the intensity of high-latitude biomass burning input having reached central Greenland since 1193 A.D. Three periods of enhanced biomass burning input over central Greenland are identified: 1200-1350 A.D., 1830-1930 A.D., and to a lesser extent 1500-1600 A.D. The 1200-1350 A.D. time period coincides with warm and dry conditions which characterized the Medieval Warm Period. After a period of infrequent biomass burning input during the coldest period of the Little Ice Age (1600-1850 A. D.), the frequency was enhanced at the turn of the last century and then decreased throughout this last century. Aside from high-latitude biomass burning, the background levels of formate show a slight and persistent decreasing trend over the last 800 years probably reflecting the deterioration of the boreal vegetation from North America.

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Documento generato il 04/04/20 alle ore 13:46:58