Collaborative Research: Multicentury Drought Reconstructions from Guatemala and the Context for Past and Future Hydroclimatic Change

合作研究：危地马拉的多世纪干旱重建以及过去和未来水文气候变化的背景

• 批准号: 0852648
• 负责人: Matthew Taylor
• 金额: $ 7.05万
• 依托单位: University of Denver
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0852648&HistoricalAwards=false
• 关键词: Collaborative; Research; Multicentury; Drought; Reconstructions

While the signature of anthropogenic climatic change is associated with observed and ongoing increases in temperature, it is concomitant changes in precipitation and the frequency and duration of drought that will have the most direct and immediate consequences for human populations. Changes in regional hydroclimate will exacerbate threats to sustainable water supplies from growing populations, pollution, declining infrastructure, and resource conflicts. One robust prediction of the most recent Intergovernmental Panel on Climate Change (IPCC) climate model ensemble is that precipitation rates will decrease over Guatemala and most parts of Central America in both the summer and winter under future increased greenhouse gas scenarios. Critical to mitigating the consequences of changes in water availability is a long-term perspective on the potential range of variability in precipitation and the integration of this knowledge within water planning and natural resources policy. However, long-term instrumental records of drought are sparse in Guatemala and throughout the Central American tropics. This is particularly true for high elevation regions, which are likely to demonstrate the earliest and more severe local consequences of global climate change. In the absence of long instrumental records, scientists investigating the causes and consequences of climate variability and change depend on proxy records that can be used to reconstruct past ocean-atmosphere conditions. Tree-ring chronologies form the bulk of the available, high-resolution terrestrial proxy records. However, they are almost entirely absent from the tropical Americas south of Mexico. The lack of a high resolution, long-term perspective on drought from this region also limits opportunities to validate climate model predictions. The development of long, annually resolved records of climate from this region is therefore necessary for understanding the local response to broad-scale forcing, detecting and attributing long-term trends related to anthropogenic climate change, and verifying the fidelity of the climate models used as the primary forecasting tool for predicting future change.The investigators will expand the geographic frontier of dendroclimatology into the mountains of Guatemala, identifying species and sites which show sensitivity to precipitation, and developing estimates of drought variability over the last several centuries. They will investigate and utilize a combination of high elevation tropical conifer species in this study. All candidate taxa will be carefully and systematically examined to establish annual ring formation and chronology development. Once dating and chronology development has been completed and verified, the tree-ring time series will be compared against the available local and gridded meteorological data in order to detect physiologically reasonable climate/growth relationships. Models will be developed to estimate past climate anomalies from the absolutely dated ring width series. Reconstructions of past precipitation and drought will be objectively compared against independently developed climate fields as well as estimates of past forcing. The drought reconstructions will also be used to interpret the possible role of climate in important historical events of the last several hundred years. This research will provide a long-term context for drought variability that is critical for efforts to mitigate the consequences for vulnerable human populations from climatic change. Active outreach and participatory education in Maya communities in the regions are integrated in the proposed research.

虽然人为气候变化的特征与观测到的和持续的温度升高有关，但对人类人口产生最直接和直接后果的是伴随而来的降水变化以及干旱的频率和持续时间。区域水文气候的变化将加剧人口增长、污染、基础设施退化和资源冲突对可持续供水的威胁。最近政府间气候变化专门委员会（IPCC）气候模式集合的一个可靠预测是，在未来温室气体增加的情景下，夏季和冬季危地马拉和中美洲大部分地区的降水率将下降。对降水变异性的潜在范围有长远的看法，并将这方面的知识纳入水资源规划和自然资源政策，是减轻可用水变化后果的关键。然而，在危地马拉和整个中美洲热带地区，干旱的长期仪器记录很少。对于高海拔地区来说尤其如此，这些地区可能是全球气候变化最早和更严重的局部后果。在缺乏长期仪器记录的情况下，科学家调查气候变率和变化的原因和后果依赖于可用于重建过去海洋-大气条件的代理记录。树木年轮年表构成了大部分可用的高分辨率陆地代用记录。然而，它们在墨西哥以南的热带美洲几乎完全没有。缺乏对该地区干旱的高分辨率、长期视角也限制了验证气候模式预测的机会。因此，开发该地区长期的、每年确定的气候记录对于了解当地对大尺度强迫的响应，探测和归因与人为气候变化有关的长期趋势，以及验证用作预测未来变化的主要预测工具的气候模式的保真度是必要的。研究人员将把树木气候学的地理前沿扩展到危地马拉的山区，确定对降水敏感的物种和地点，并对过去几个世纪的干旱变化进行估计。他们将在本研究中调查和利用高海拔热带针叶树物种的组合。所有候选分类群将被仔细和系统地检查，以确定年轮形成和年代学发展。一旦定年和年代学发展完成并得到验证，将把树木年轮时间序列与现有的当地和网格化气象数据进行比较，以便探测生理上合理的气候/生长关系。将开发模式，根据绝对定年的环宽序列估计过去的气候异常。对过去降水和干旱的重建将客观地与独立发展的气候场以及对过去强迫的估计进行比较。干旱重建也将被用来解释气候在过去几百年的重要历史事件中可能扮演的角色。这项研究将提供干旱变化的长期背景，这对于减轻气候变化对脆弱人群的影响至关重要。在该地区的玛雅社区积极的外展和参与式教育被整合到拟议的研究中。