Trend analysis of the Younger Dryas event record

Abstract

As the latest abrupt cold event, the study on the Younger Dryas event is important to forecast the change of future climate, especially to present global warming. So that what caused the event and how the event worldly spread is crucial to anticipate anything like that. Spatial distribution and relative timing of the Younger Dryas event are central for our understanding of causes and transferring mechanism of it. From the large numbers of the published works on the late Quaternary paleoclimatic research, the evidences of the Younger Dryas event were summarized and the accurate coordinates of these sites were put on the world map with Mapinfo software From more than 200 sites which have the event records, the onset, the termination and duration trend of it are figured and analyzed. The onset time of the event is different from 11.8 cal. ka B.P. to 13.7 cal. ka B.P. The mean value is 12.72 cal. ka B.P. The contour line of 12.8 cal. ka B.P. circle more than half of the earth, from Europe to Qinghai-Tibet Plateau, southwest Pacific, east Antarctica, South Africa, South Atlantic Ocean and South America. The earliest site is 13.7 cal. ka B.P. at MD01-2386 core, West Pacific Warm Pool and at AD91-17, South Adriatic Sea, not at Arctic region. The end time of the event is 7.8-12.53 cal. ka B.P., mean is 11.52 cal. ka B.P. The contour line of 11.5 cal. ka B.P. covers almost north Hemisphere except North Africa and west Pacific, from north to south total tread of the terminative time is younger. The terminative time of the event at continents is earlier than around oceans. The duration of the Younger Dryas event is 0.25-4.46 cal. ka, the mean value is 1.20 cal. ka. The areas more than 1.2 cal. ka is most in low latitude. At the North Africa and the West Pacific Warm Pool the duration is longer than at other places. While at high latitude it is shorter. The results indicate that the origin of the Younger Dryas event is at West Pacific Warm Pool. The trigger is Qinghai-Tibet Plateau. The changing of the atmosphere general circulation is the reason of the beginning and the ending of the event. And the signs of the event are transferred by the air circulation and ocean-air exchanging. Because special factors the local responses of the Younger Dryas event are diversity in different places.