Ecological Rates of Change: Monitoring Recent Changes in Biospheric Activity Using Tree Rings and NDVI

生态变化率：利用树木年轮和 NDVI 监测生物圈活动的近期变化

• 批准号: 0211216
• 负责人: Rosanne D'Arrigo
• 金额: $ 24万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0211216&HistoricalAwards=false
• 关键词: Ecological; Rates; Change; Monitoring; Recent

Satellite measures indicate an overall greening of northern forest ecosystems between the early 1980s and the late 1990s. This greening, which indicates higher rates of tree growth, is consistent with rising temperatures, which may be caused by atmospheric increases in greenhouse gases. To validate these findings, this research project will compare satellite-based estimates of increasing growth and greening to tree-ring records from selected sites across the circumpolar zone of northern forests. Satellite data will be summarized using a standard measure of greenness in vegetation: the Normalized-Difference Vegetation Index (NDVI). The following questions will be investigated: 1. How are tree rings related to NDVI? 2. Can tree rings be used to validate intra and interannual variability in NDVI? 3. Can tree rings be used to validate trends in NDVI? 4. Do tree-ring and NDVI indices provide distinct information which, when combined, improve our understanding of biospheric activity? 5. Is there any evidence that increases in the atmospheric concentration of carbon dioxide have directly enhanced the growth of forests north of 40oN? This project will increase understanding of the complex links between global change and ecosystem function and process. Satellite and other observations of the earth system are accumulating rapidly, but the interrelations are exceedingly complex and it is essential that their interpretation include a ground data perspective. The validation of NDVI estimates of forest biomass sinks using ground measurements from tree rings can eventually aid nations concerned with meeting commitments for the Kyoto Protocol. This project will be multidisciplinary in that it will bring together members of the ecosystems/paleoclimate community, involved in ground measurement analysis of vegetation, and the remote sensing community, involved in the processing and interpretation of satellite measurements. It is anticipated that the synergy of this integrated approach will significantly improve understanding of terrestrial biospheric activity for northern latitudes and for the globe.

卫星测量结果表明，1980年代初至1990年代末，北方森林生态系统总体呈绿化趋势。这种绿化表明树木生长速度加快，这与气温上升是一致的，气温上升可能是由大气中温室气体增加造成的。 为了验证这些发现，该研究项目将比较基于卫星的增长和绿化增加的估计与北方森林环极区选定地点的树木年轮记录。 将使用一种衡量植被绿度的标准方法-归一化植被指数对卫星数据进行汇总。本文将研究以下问题：1.树木年轮与NDVI有什么关系？ 2.树木年轮能用来验证NDVI的年内和年际变化吗？ 3.树木年轮能否用来验证归一化差异植被指数的趋势？ 4.树木年轮和归一化差异植被指数是否提供了独特的信息，如果结合起来，就能增进我们对生物圈活动的了解？ 5.是否有任何证据表明大气中二氧化碳浓度的增加直接促进了北纬40度以北森林的生长？该项目将增进对全球变化与生态系统功能和进程之间复杂联系的了解。对地球系统的卫星观测和其他观测正在迅速积累，但相互关系极为复杂，对这些观测的解释必须包括地面数据的观点。利用树木年轮的地面测量数据验证森林生物量汇的归一化差异植被指数估计值，最终可以帮助有关国家履行对京都议定书的承诺。这一项目将是多学科的，因为它将把参与植被地面测量分析的生态系统/古气候界的成员和参与卫星测量结果的处理和解释的遥感界的成员聚集在一起。 预计这一综合办法的协同作用将大大提高对北方纬度和地球仪陆地生物圈活动的了解。