The role of land-atmosphere feedbacks in heatwave and drought development

热浪往往与干旱同时发生，并可能对人类健康、资源经济和环境造成严重后果。在加拿大南部，预计热浪将在21世纪变得更加频繁。然而，对热浪和干旱频率和强度的预估仍然存在很大的不确定性。它们的发展依赖于复杂的陆地-大气反馈，而这些反馈在地球系统模式中往往没有得到充分的体现。对土壤-植物-大气连续体的实地观测很少，导致对气候变暖时热浪和干旱频率和强度的预测不确定。综合观测是陆地-大气反馈机制综合诊断和陆地-大气耦合模式评价的迫切需要。改进的热浪和干旱预测为指导加拿大经济的重要组成部分——林业、农业和水电部门的气候缓解和适应工作提供了一个重要工具。这项研究计划的总体目标是提高对热浪和干旱如何发展的理解，以更好地支持气候缓解和适应工作。通过将覆盖加拿大5种主要生态系统类型的土壤-植物-大气连续体的陆地-大气相互作用的跨尺度观测与陆地-大气耦合模拟、卫星遥感和气球探测观测相结合，将实现4个相关的短期目标（2021-2026）。植物生理学和地表热量和水分通量测量将用于分析植被对大气和土壤水分胁迫的反应，并用于参数化陆地-大气模型，大气观测将用于验证模型模拟，遥感和气球探测数据将用于扩大野外站点以外的空间覆盖范围。该研究计划将阐明陆地-大气相互作用如何对热浪和干旱的发展做出贡献，并特别关注加拿大南部。在未来5年内，将培养4名研究生和5名本科生。他们将受益于跨学科的研究方法，并将获得数据管理和分析，编程和沟通技能，为气候科学，天气预报和自然资源管理领域的学术和非学术就业市场做好准备。这项研究计划的一个核心组成部分是在加拿大林业局（加拿大自然资源部）管理的阿卡迪亚研究森林建立一个长期陆地大气观测站。学生将从与NRCan的合作中受益，并通过与NRCan的合作者的密切互动促进向政府机构的知识转移。在本研究项目中开发的知识也将通过期刊出版物和会议报告转移给其他学者。

Heatwaves often co-occur with droughts and can lead to grave consequences for human health, resource economies, and the environment. In southern Canada, heatwaves are expected to become more frequent over the course of the 21st century. However, projections of heatwave and drought frequency and intensity are still subject to large uncertainties. Their development depends on complex land-atmosphere feedbacks, which are often insufficiently represented in Earth system models. Field observations across the soil-plant-atmosphere continuum are scarce, contributing to uncertain projections of heatwave and drought frequency and intensity in a warming climate. Integrated observations are urgently needed for comprehensive diagnosis of land-atmosphere feedback mechanisms and for the evaluation of coupled land-atmosphere models. Improved heatwave and drought projections provide a crucial tool for guiding climate mitigation and adaptation efforts in the forestry, agriculture, and hydro-electricity sectors, which are vital components of the Canadian economy. The overall objective of this research program is to improve the understanding of how heatwaves and droughts develop to better support climate mitigation and adaptation efforts. Four linked short-term objectives (2021-2026) will be achieved by combining cross-scale observations of land-atmosphere interactions across the soil-plant-atmosphere continuum covering 5 major Canadian ecosystem types with coupled land-atmosphere modelling, satellite-based remote sensing, and balloon sounding observations. Plant physiology and surface heat and moisture flux measurements will be used to analyse vegetation responses to atmospheric and soil water stress and to parameterise a land-atmosphere model, atmospheric observations will be used to validate model simulations, and remote sensing and balloon sounding data will be used to expand spatial coverage beyond the field sites. The research program will elucidate how land-atmosphere interactions contribute to heatwave and drought development with a particular focus on southern Canada. Over the next 5 years, 4 graduate and 5 undergraduate students will be trained. They will profit from an interdisciplinary research approach and will acquire data management and analysis, programming, and communication skills preparing them for academic and non-academic job markets in the fields of climate science, weather forecasting, and natural resource management. A core component of this research program is the establishment of a long-term land-atmosphere observatory at the Acadia Research Forest managed by the Canadian Forest Service (Natural Resources Canada [NRCan]). Students will benefit from collaborations with NRCan and knowledge transfer to government agencies will be facilitated through close interactions with collaborators at NRCan. Knowledge developed in this research program will also be transferred to other academics through journal publications and conference presentations.