全新世安达曼海周边区域火灾历史及其影响因素

Holocene Fire History and Its Influencing Factors in the Surrounding Areas of the Andaman Sea

火事件的发生与气候变化以及植被变化密切相关,系统性地研究全新世火活动的时空演化规律,可以更清晰地理解火活动机制与区域性气候、植物变化的关联,同时有助于预测未来火的演化趋势。为了解安达曼海周边地区火灾活动的演化以及可能的驱动因素,以安达曼海南部的海洋钻孔ADM-C1为研究材料,对其全新世以来的炭屑记录进行深入分析,并综合安达曼海周边地区其余的5个炭屑记录,重建了全新世以来安达曼海周边地区火灾活动的演变过程。研究表明,尽管点火、火灾天气和植被组成在各地不尽相同,导致火灾发生频率在区域和地方范围有所不同,但在广泛的气候变化背景下,全新世安达曼海周边各地的火事件发生频率变化具有广泛同步性。全新世安达曼海周边的火灾活动发生频率受到区域性植被和降水变化影响,并最终受控于印度夏季风强度的变化。与末次冰消期相比,12.0~9.0 ka BP安达曼海周边区域火灾活动的发生频率呈下降趋势,反映了印度夏季风降水逐步增加以及木本植物含量逐渐上升的区域环境;9.0~5.0 ka BP较低的区域火灾活动发生频率同时受到较高的印度夏季风降水量和区域木本植物含量的制约;5.0 ka BP后高频的区域火灾活动更多反映了印度夏季风降水的降低。此外,研究结果还表明全新世安达曼海周边区域火灾活动发生频率与厄尔尼诺—南方涛动强度、印度洋偶极子位相和热带辐合带位置的变化相关。

The occurrence of fire events is closely related to climate change and vegetation changes.A systematic study of the spatial and temporal evolutionary patterns of Holocene fire activities enables a clearer comprehension of the association between fire activity mechanisms and regional climate and vegetation changes,and contributes to the prediction of future fire evolutionary trends simultaneously.In order to comprehend the fire evolution and potential driving factors in the surrounding areas of the Andaman Sea,charcoal analysis was conducted on core ADM-C1 in the southern Andaman Sea to reconstruct its Holocene fire record.Additionally,five other charcoal records were synthesized to reconstruct Holocene fire activities in the surrounding areas of the Andaman Sea in this study.Although the nature of the changes of ignition,fire weather,and vegetation composition varied from place to place,leading to regional and local variations in fire frequency,the changes of fire event frequency around the Andaman Sea were widely synchronized under broader climate change during the Holocene.The frequency of fire activity around the Andaman Sea during the Holocene was influenced by regional variations in vegetation and precipitation,and ultimately by changes in the intensity of the Indian Summer Monsoon.Compared to the last deglaciation,there was a decrease in the frequency of fire activities in the surrounding areas of the Andaman Sea during 12.0~9.0 ka BP period,reflecting a gradual increase in Indian Summer Monsoon precipitation and woody plant abundance within this region.During 9.0~5.0 ka BP period,regional fire activity was constrained by higher Indian summer monsoon precipitation and woody plants.After 5.0 ka BP,an increase in regional fire activity primarily reflected a decrease in Indian Summer Monsoon precipitation.Furthermore,the changes in El Niño-Southern Oscillation(ENSO)intensity,Indian Ocean Dipole(IOD)phase and the location of the Intertropical Convergence Zone(ITCZ)were related to fire activity frequency around Andaman Sea during the Holocene.