摘要
利用巴丹吉林沙漠南缘山地3个采样点的青海云杉树轮样本研制出区域树轮宽度年表。相关分析发现区域树轮宽度年表与5—7月NDVI变化有较好相关性,相关系数为0.670(P<0.001)。利用线性回归模型重建了巴丹吉林沙漠南缘山地1765—2010年5—7月NDVI变化,方差解释量为44.9%。NDVI重建序列揭示在1765—2010年期间巴丹吉林沙漠南缘山地有10个植被生长良好时段和10个植被生长较差时段。同时,NDVI重建序列的低值与河西走廊极端干旱历史事件有着良好的一致性。多窗谱周期分析发现,巴丹吉林沙漠南缘山地5—7月NDVI重建序列具有11.4,8.1,4.9,3.4,2.4 a的准周期变化。交叉小波分析发现太阳黑子活动是区域NDVI变化的重要驱动力之一。基于NDVI与区域干湿变化良好相关,分析了极端低值年份和极端高值年份的矢量风场距平变化发现区域NDVI变化与大范围气候场变化有显著关联,发现当西风增强时,研究区气候偏湿,有利于树木生长,NDVI值偏高,形成较宽的树轮。当研究区被来自北面沙漠地区气流控制时候,研究区气流偏干,不利于树木生长。
A regional tree-ring chronology of Picea crassifolia spanning 1765-2010 was developed from the southern edge of the Badain Jaran Desert, northwestern China. The climate/NDVI response analysis shows the regional tree-ring chronology have a good correlation （r=0.670）with May-July NDVI. Based on the regional tree-ring chronology, we developed a May-July NDVI reconstruction of the southern edge of the Badain Jaran Desert for the period AD 1765-2010. The NDVI/tree-growth model accounts for 44.9% of the observed NDVI variance during the period 1982-2006. Ten high NDVI periods （NDVI values higher than the average of reconstruction） and ten low NDVI periods （NDVI values lower than the average） was found during 1765-2010 respectively, and reflected the strong-weak changes of the Westerlies. There is a reasonable agreement with climatic extremes previously estimated from documentary records in northwest China. The results reveal common climatic extremes over much of Gansu. Many of these events have had profound impacts on the peoples of the Hexi Corridor over the past several centuries. The multitaper method （MTM） spectral analysis indicates the existence of 11.4 years,8.1 years,4.9 years,3.4 years and 2.4 years cycles, which may potentially be the fingerprints of some proposed climate change forcings. Preliminary analysis of links between large-scale climatic variation and the NDVI reconstructions shows that there is a relationship between extremes in NDVI reconstruction and anomalous atmospheric circulation in the region,and revealed that the westerlies have the great effects on the NDVI changes of the study area.
出处
《沙漠与绿洲气象》
2015年第4期1-7,共7页
Desert and Oasis Meteorology
基金
科技部公益性行业(气象))科研专项"沙漠地区历史气候变化序列重建研究"(GYHY201206014)
中国沙漠气象科学研究基金"树轮记录的新疆东部近300年干湿变化及其与周边地区之关联"(Sqj2013015)
中央级基本科研业务费项目"基于树轮密度的秦岭中西部温度的重建和分析"(IDM201105)共同资助
