Quantifying the Amazon Isoprene Budget: Reconciling top-down versus bottom-up emission estimates

量化亚马逊异戊二烯预算：协调自上而下与自下而上的排放估算

• 批准号: NE/G013810/2
• 负责人: Michael Barkley
• 金额: $ 15.52万
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG013810%2F2
• 关键词: Quantifying; Amazon; Isoprene; Budget; Reconciling

The term climate change is now a household phrase and we are used to hearing about rising greenhouse gas levels and global warming. One of the first events that increased the public's awareness of environmental issues was the discovery of the Antarctic ozone hole in the 1980s. Ozone is a gas that comprises only a tiny fraction of all the gases that make up the atmosphere but it is very important in climate. At high altitudes (about 15 to 30 km), there is lots of ozone which is good thing for the planet, as it shields the Sun's harmful UV radiation. However, ozone is a toxic substance and if it builds up within the troposphere (the lowermost part of the atmosphere) and at the surface then this is not good. Tropospheric ozone is bad for us because it is (a) a greenhouse gas, and (b) and air pollutant that affects the human respiratory system and agricultural crop yields. Ozone is produced near the surface when substances known as volatile organic compounds (VOCs) are emitted from the surface and subsequently react within the atmosphere. VOCs can be emitted from human activities, but they are predominantly emitted by vegetation that grows on land. Of all the biogenic VOCs emitted into the atmosphere, none is more important than isoprene owing to its ability to quickly react with other compounds (to produce tropospheric ozone) and because it is emitted in large amounts. Isoprene is also important, as it is a source of very small particles called secondary organic aerosol (SOA) that scatter light, which influences how the Earth warms, and which also have adverse health effects. We need to know (a) when, (b) where and (c) how much isoprene is emitted into the atmosphere in order to better understand tropospheric ozone and SOA. Currently we use generic computer models that are based on observations to simulate the amount of isoprene emitted from different types of vegetation, such as trees or grasses. Isoprene emissions from the Amazon Basin, which contains the world's largest rain forest and is thought to be one of the biggest isoprene sources, are poorly quantified since it is very difficult to measure the emissions in this largely inaccessible and remote region. Satellite observations of a gas called formaldehyde (HCHO), contain information on isoprene emissions, and can be used to determine the amount of isoprene emitted from terrestrial vegetation. The overall goal of my proposal is to use satellite observations of HCHO to accurately quantify isoprene emissions from the Amazon Basin. To achieve this goal I will develop a new unique high resolution model for the Amazon, which will be able to simulate isoprene emissions and atmospheric chemistry at finer spatial scales than have been able previously. I will then compare the isoprene emissions from this 'bottom-up' model with the 'top-down' isoprene emissions inferred from the satellite observations of HCHO, to identify regions or time periods where there is significant disagreement between the model and the observations, which highlights where we have poor understanding of the isoprene emissions. I will then develop an improved isoprene emission model by fine tuning the 'bottom-up' emission model to the inferred 'top-down' emissions, taking into account individual scenes (utilizing the high spatial resolution of the nested-grid) and different seasons. By reconciling the differences between the 'bottom-up' model and the 'top-down' emissions we will gain a more accurate estimate of how much isoprene is emitted from the Amazon, and more importantly gain a better understanding of the factors that influence when it is emitted. This research is important because the Amazon Basin is also one of the regions identified as being most susceptible to climate change, and it is crucial we determine the key factors that influence its isoprene emissions in order to improve confidence in our ability to predict future climate.

气候变化一词现在是一个家庭短语，我们习惯于听到温室气水平上升和全球变暖的听力。提高公众对环境问题的意识的第一个事件之一是在1980年代发现了南极臭氧洞。臭氧是一种气体，仅包括构成大气的所有气体的一小部分，但在气候中非常重要。在高海拔地区（约15至30公里），有很多臭氧对地球来说是一件好事，因为它屏蔽了太阳的有害紫外线辐射。但是，臭氧是一种有毒物质，如果它在对流层内（大气的最低部分）堆积，并且在表面不好。对流层臭氧对我们有害，因为它是（a）温室气体，（b）和空气污染物影响人类呼吸系统和农作物的产量。当被称为挥发性有机化合物（VOC）的物质从表面排放并随后在大气中反应时，在表面附近产生臭氧。 VOC可以从人类的活动中散发出来，但主要是由于在陆地上生长的植被所发出的。在发出大气中的所有生物源中，由于它能够快速与其他化合物反应（生产对流层臭氧），因此没有比异戊二烯更重要的，并且因为它大量发射。异戊二烯也很重要，因为它是一个非常小的颗粒的来源，称为二次有机气溶胶（SOA），散射光，从而影​​响地球的温暖方式，并且也具有不良的健康效应。我们需要知道（a）（a）何时（b）何时和（c）为了更好地理解对流层臭氧和SOA的大气发射多少。目前，我们使用基于观察结果的通用计算机模型来模拟从不同类型的植被（例如树木或草）中排出的异戊二烯量。亚马逊盆地的异戊二烯排放量含有世界上最大的雨林，被认为是最大的异戊二烯来源之一，由于很难测量在这一难以接近和偏远地区的排放非常困难。对称为甲醛（HCHO）的气体的卫星观察，包含有关异戊二烯排放的信息，可用于确定从陆生植被中排出的异戊二烯量。我的提议的总体目标是使用HCHO的卫星观测来准确量化亚马逊盆地的异戊二烯排放。为了实现这一目标，我将为亚马逊开发一个新的独特的高分辨率模型，该模型将能够以比以前的能力模拟更精细的空间尺度上的异戊二烯排放和大气化学反应。然后，我将将此“自下而上”模型的异戊二烯排放与从HCHO的卫星观察结果推断出的“自下而上”的异戊二烯排放，以确定模型和观测之间存在重大分歧的区域或时间段，这突显了我们对Isoprene排放的理解很差的地方。然后，我将通过将“自下而上”的发射模型调整为推断的“自上而下”排放的改进的异戊二烯发射模型，并考虑到各个场景（利用嵌套网格的高空间分辨率）和不同的季节。通过核对“自下而上”模型与“自上而下”排放之间的差异，我们将对亚马逊发出的异戊二烯进行更准确的估计，更重要的是，对发射时影响的因素有更好的了解。这项研究很重要，因为亚马逊盆地也是被确定为最容易受到气候变化的区域之一，至关重要的是，我们确定影响其异戊二烯排放的关键因素，以提高对预测未来气候的能力的信心。

项目成果

Environmental Change in Siberia

• DOI: 10.1007/978-90-481-8641-9
• 发表时间: 2010
• 作者: H. Balzter

Overview: oxidant and particle photochemical processes above a south-east Asian tropical rainforest (the OP3 project): introduction, rationale, location characteristics and tools

概述：东南亚热带雨林上空的氧化剂和粒子光化学过程（OP3 项目）：简介、基本原理、位置特征和工具

• DOI: 10.5194/acp-10-169-2010
• 发表时间: 2010
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: Hewitt C

Ozone and organic nitrates over the eastern United States: Sensitivity to isoprene chemistry

• DOI: 10.1002/jgrd.50817
• 发表时间: 2013-10
• 期刊: Journal of Geophysical Research: Atmospheres
• 作者: J. Mao;F. Paulot;D. Jacob;R. Cohen;J. Crounse;P. Wennberg;C. Keller;R. Hudman;M. Barkley

Ethane, ethyne and carbon monoxide concentrations in the upper troposphere and lower stratosphere from ACE and GEOS-Chem: a comparison study

• DOI: 10.5194/acp-11-9927-2011
• 发表时间: 2011-09
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: G. G. Abad-G.;N. Allen;P. Bernath;C. Boone;S. McLeod;G. Manney;G. Toon;C. Carouge;Yuxuan Wang;Shiliang Wu;M. Barkley;P. Palmer;Yaping Xiao;T. Fu

Top-down isoprene emissions over tropical South America inferred from SCIAMACHY and OMI formaldehyde columns

• DOI: 10.1002/jgrd.50552
• 发表时间: 2013-06-27
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
• 影响因子: 4.4
• 作者: Barkley, Michael P.;De Smedt, Isabelle;Mao, Jingqiu
• 通讯作者: Mao, Jingqiu