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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.

在过去的几个月里，亚马逊地区出现了极端干旱。这可能与北大西洋和墨西哥湾的变暖有关，同样的特征导致了异常猛烈的飓风，并导致2005年打破了记录，成为有记录以来大西洋热带气旋最活跃的一年。亚马逊的干旱可能也是一个类似的不寻常事件。特别是在亚马逊西部地区，这可能是自20世纪中期该地区有气象记录以来最严重的干旱。到10月，亚马逊河中下游的水位已经达到了35到60年来的最低水平，这表明亚马逊河流域的大部分地区（约500万平方公里）已经经历了几个月的异常干旱。干旱导致巴西部分地区进入紧急状态，无法再用船只向城镇和村庄运送必需品。来自亚马逊地区城镇，如伊基托斯（秘鲁）、莱蒂西亚（哥伦比亚）和马瑙斯（巴西）的报告表明，气温接近甚至可能超过了它们的历史温度记录。干旱似乎即将结束。这个项目将试图评估这一不寻常事件对亚马逊森林的影响，亚马逊森林比地球上任何其他生态系统都蕴藏着更多的碳和更多的物种。水对植物生长至关重要，因此树木的生长速度可能会严重降低，树木的死亡率也可能会增加。树木生长和死亡速度的变化对碳储量有影响。然而，目前尚不清楚这些影响的严重程度。无论这些影响有多强烈（或不强烈），干旱确实代表了一个必须抓住的科学机遇，因为它可能为未来提供一个窗口。预计人类驱动的气候变化将使该地区的气温大幅升高（本世纪内升高2至5摄氏度），并可能减少降雨。详细研究这次干旱对森林冠层结构、树叶和树枝结构的影响，以及不同物种和树木类型的反应，可以为预测亚马逊森林未来的样子提供信息。这个研究小组在研究干旱的影响方面处于独特的地位。在过去五年中建立了一个长期监测地块网络，以早在1970年建立的地块为基础。我们与南美同事一起定期监测这些地块，并在过去12个月内对其中许多地块进行了重新测量。在一些选定的地点，我们还经常（通常每两周）观察短期生态过程，如落叶，并测量这些地块正在经历的天气。在拟议的研究中，我们制定了一项衡量这场显著干旱所产生的影响的策略。我们不仅会尽快返回，在尽可能多的地块上进行长期测量，如树木生长、死亡等，而且还会在干旱后的额外一年进行高强度的短期测量（如凋落物），这样我们就可以更详细地了解亚马逊森林是如何从干旱中恢复的。除了密集的田野调查和随后的实验室分析，我们还将综合来自整个亚马逊地区的现有天气数据，以了解干旱的精确幅度、强度和分布，以及基于卫星的森林冠层特性测量，以了解极端条件如何影响更大的地区，并将我们局部的田野调查结果放在整个地区的背景下。该项目的总体结果将是发现这一事件对该地区植物的严重程度，从而使我们能够更好地预测未来可能发生的事情。