北京大学城市与环境学院朴世龙教授研究小组最近在PNAS 上报道了他们在气候变化对北美植被生长影响研究方面取得的新进展。
植被生长对气候变化的响应是全球变化研究的重要内容之一。遥感数据表明，尽管上世纪80年代和90年代，北半球植被生产力呈显著增加趋势，但在本世纪初，这一增加趋势停止甚至减少。科学家们普遍认为，这一现象与全球气候变暖所导致的干旱有关。北京大学城市与环境学院全球气候变化研究小组，利用长期的遥感数据和气候观测数据，借助遥感、GIS等新技术的支持，综合研究北美陆地植被生长的时空格局及其机制。研究小组发现，北美西北大部分地区自上世纪90年代以来植被生产力下降的现象不能由干旱胁迫解释，而是与该地区春季温度下降密切相关。
论文的通讯作者朴世龙教授主要从事陆地生态系统对全球气候变化的响应及其反馈作用的研究，是联合国政府间气候变化专门委员会（IPCC）第五次评估报告第一工作组全球碳循环章节的主要作者（Lead Author）之一。论文的第一作者王旭辉是朴世龙教授的硕士一年级学生。
本研究得到国家自然科学基金资助。（生物谷Bioon.com）
生物谷推荐原文出处：
PNAS doi: 10.1073/pnas.1014425108
Spring temperature change and its implication in the change of vegetation growth in North America from 1982 to 2006
Xuhui Wanga, Shilong Piaoa,1, Philippe Ciaisb, Junsheng Lic,1, Pierre Friedlingsteinb,d, Charlie Kovene, and Anping Chenf
Abstract
Understanding how vegetation growth responds to climate change is a critical requirement for projecting future ecosystem dynamics. Parts of North America (NA) have experienced a spring cooling trend over the last three decades, but little is known about the response of vegetation growth to this change. Using observed climate data and satellite-derived Normalized Difference Vegetation Index (NDVI) data from 1982 to 2006, we investigated changes in spring (April–May) temperature trends and their impact on vegetation growth in NA. A piecewise linear regression approach shows that the trend in spring temperature is not continuous through the 25-year period. In the northwestern region of NA, spring temperature increased until the late 1980s or early 1990s, and stalled or decreased afterwards. In response, a spring vegetation greening trend, which was evident in this region during the 1980s, stalled or reversed recently. Conversely, an opposite phenomenon occurred in the northeastern region of NA due to different spring temperature trends. Additionally, the trends of summer vegetation growth vary between the periods before and after the turning point (TP) of spring temperature trends. This change cannot be fully explained by summer drought stress change alone and is partly explained by changes in the trends of spring temperature as well as those of summer temperature. As reported in previous studies, summer vegetation browning trends have occurred in the northwestern region of NA since the early 1990s, which is consistent with the spring and summer cooling trends in this region during this period.
