Assessing the Impacts of the Recent Amazonian Drought

评估近期亚马逊干旱的影响

基本信息

批准号：
NE/D010306/1
负责人：
Oliver Phillips
金额：
$ 3.59万
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2006
资助国家：
英国
起止时间：
2006 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FD010306%2F1
关键词：
Assessing Impacts Recent Amazonian Drought

项目摘要

Over the last few months there has been extreme drought in Amazonia. This may be related to warming of the North Atlantic and Gulf of Mexico, the same feature that helped generate unusually violent hurricanes and contributed to 2005 breaking the record as the most active year for Atlantic tropical cyclones since records began. The Amazon drought may have been a similarly unusual event. In western Amazonia particularly this may have been the most intense drought since weather records began in this region in the mid 20th-century. By October, river stage levels along the middle and lower reaches of the Amazon river had reached the lowest marks for 35 to 60 years, which indicates that most of the vast Amazon basin (about 5 million km2) has seen exceptionally dry conditions for many months. The drought led to a state of emergency in parts of Brazil, where boats could no longer be used to supply towns and villages with essential supplies. Reports from Amazonian towns such as Iquitos (Peru), Leticia (Colombia), and Manaus (Brazil) suggest that temperatures approached, and perhaps exceeded, their all-time temperature records. The drought appears to be ending now. This project will attempt to assess the impacts of this unusual event on the Amazon forest / which harbours more carbon and more species than any other ecosystem on earth. Water is essential for plant growth, so the growth rates of trees may have been severely reduced, and also the rates of tree death may have increased. Changes in rates of tree growth and death impact on the amount of carbon stored. However, at the moment, the severity of these effects is not known. However strong these effects may (or may not) have been, the drought does represent a scientific opportunity that must be seized, because it may provide a window into the future. Human-driven climate change is expected to increase temperatures substantially in this region (by 2 to 5 Celsius within the century), and probably to diminish rainfall. Studying the effects of this drought in detail on the structure of forest canopies, the structure of leaves and branches, and how different species and types of tree respond, can provide the information to make predictions of how Amazonian forests might look in future. This research team is in a unique position to study the effects of this drought. A network of long term monitoring plots has been established over the last five years, building on plots established as long ago as 1970. With our South American colleagues these plots are regularly monitored, and many were remeasured during the last 12 months. In a few, select sites, we have also been looking frequently (as often as every fortnight) at short-term ecological processes such as leaf litter-fall, and measuring the weather that the plots are experiencing. In the proposed research we set out a strategy for measuring the effect that this remarkable drought has had. Not only will we return as soon as possible to make the long-term measurements such as tree growth, death, in as many plots as possible, but we will also make the high-intensity, short-term measurements (such as litterfall) for an additional year following the drought so that we can understand in more detail how Amazon forests recover from the drought. Together with this intensive fieldwork and subsequent laboratory analyses we will also synthesize existing weather data from across the Amazon to understand the precise magnitude, intensity, and distribution of the drought, and also satellite-based measurements of forest canopy properties to understand how the extreme conditions have affected the larger region, and to put our localised fieldwork results in context of the whole region. The overall outcome of the project will be to discover just how serious this event has been for plants in the region, and therefore to allow us to make much better predictions of what might happen in the future.

在过去的几个月中，亚马逊地区一直存在极端干旱。这可能与北大西洋和墨西哥湾的变暖有关，同样的特征帮助引起了异常暴力的飓风，并促成2005年的记录是自记录开始以来大西洋热带气旋的最活跃的一年。亚马逊干旱可能是同样不寻常的事件。在亚马逊西部，特别是自20世纪中期该地区开始天气记录以来，这可能是最激烈的干旱。到10月，亚马逊河中部和下游沿线的河流水平已达到35至60年的最低标记，这表明大多数广阔的亚马逊盆地（约500万公里）已经在许多月的情况下都表现出了异常干燥的条件。干旱导致了巴西部分地区的紧急状态，在那里船只不再可用于为城镇和村庄提供必要的物资。亚马逊镇（例如秘鲁），莱蒂西亚（哥伦比亚）和马纳斯（巴西）等亚马逊城镇的报告表明，温度接近甚至超过了其历史记录。干旱似乎正在结束。该项目将试图评估这一不寻常事件对亚马逊森林 /比地球上任何其他生态系统更多的碳和物种的影响。水对于植物的生长至关重要，因此树木的生长速度可能已大大降低，并且树木死亡的速度也可能增加。树木生长和死亡率对存储碳量的影响。但是，目前尚不清楚这些效果的严重性。无论这些影响都可能（或可能没有），干旱确实代表了必须抓住的科学机会，因为它可能会为未来提供一个窗口。预计以人为驱动的气候变化将大大提高该地区的温度（本世纪内2至5摄氏度），可能会减少降雨量。详细研究这种干旱对森林檐篷的结构，叶子和树枝的结构以及树木反应的不同种类和类型的影响，可以提供信息，以预测亚马逊森林将来的样子。该研究团队处于研究这种干旱影响的独特地位。在过去的五年中，建立了一个长期监测地块的网络，建立在1970年前建立的土地上。随着我们的南美同事，这些地块经常监控，并且在过去的12个月中进行了重新评估。在某些地方，我们还经常在短期生态过程（例如叶子倒下）上（每两周一次）看（每两周一次）看，并测量了地块所经历的天气。在拟议的研究中，我们制定了一项策略，以衡量这种非凡的干旱的影响。我们不仅会尽快返回，以在尽可能多的地块中进行长期测量，例如树木生长，死亡，而且在干旱之后的另一年中，我们还将进行高强度的短期测量（例如乱抛垃圾），以便我们可以更详细地了解亚马逊森林如何从干旱中恢复过来。加上这种密集的现场工作和随后的实验室分析，我们还将综合来自亚马逊各地的现有天气数据，以了解干旱的确切大小，强度和分布，以及基于卫星的森林冠层特性的测量，以了解极端条件如何影响较大的地区，并将我们的本地化现场工作置于整个地区。该项目的总体结果将是发现该事件对该地区的植物有多严重，因此使我们能够更好地预测将来可能发生的事情。