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

热浪经常与干旱同时发生，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，热浪预计将在21世纪变得更加频繁。然而，对热浪和干旱频率和强度的预测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，而这在地球系统模型中往往没有得到充分的体现。整个土壤-植物-大气连续体的实地观测很少，这导致了对气候变暖时热浪和干旱的频率和强度的不确定预测。对于陆地-大气反馈机制的综合诊断和陆地-大气耦合模式的评价，迫切需要综合观测。改进的热浪和干旱预测为指导林业、农业和水电部门的气候缓解和适应工作提供了重要工具，这些部门是加拿大经济的重要组成部分。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努力。将通过对涵盖加拿大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-大气耦合模型、卫星遥感和气球探空观测相结合，实现四个相互关联的短期目标(2021-2026年)。将使用植物生理学和地表热湿通量测量来分析植被对大气和土壤水分胁迫的反应，并将陆地-大气模型进行参数化，将使用大气观测来验证模型模拟，并将使用遥感和气球探空数据将空间覆盖范围扩大到野外以外。该研究计划将阐明陆地-大气相互作用如何促进热浪和干旱的发展，并特别关注加拿大南部。未来5年，将培养4名研究生和5名本科生。他们将从跨学科研究方法中受益，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(自然资源加拿大[NRCan])管理的阿卡迪亚研究森林建立长期陆地大气观测站。学生将从与NRCan的合作中受益，并将通过与NRCan的合作者的密切互动，促进向政府机构的知识转移。在这项研究计划中开发的知识也将通过期刊出版物和会议报告传递给其他学者。

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.