Atmospheric evolution: from early Earth to exoplanets

类地行星的大气层太棒了。它们是地球上所有废气的混合罐，从微生物到地幔的各种气体，经过光化学和地球化学的处理。大气成分在很大程度上决定了什么生命能在地表生存，并通过设定温室效应的强度和吸收多少阳光来控制行星气候。随着我们进入系外行星时代，大气层是我们了解其他世界的窗口；远程大气表征是探索系外行星并最终发现生命的手段。******我的研究项目是关于行星大气层的演化，研究有人居住的行星（目前只研究地球），比较太阳系中的行星和卫星（金星、火星、土卫六等），以及越来越多的系外行星。提出的研究目标是：提高我们对整个地球历史中气候-地球化学-生物圈耦合演化的理解；在比较行星学框架下发展行星演化理论，将地球与其他类地行星联系起来；并将这一理论应用于确定系外行星是否适合居住的方法。******我们将研究四个主题：(A)地球大气的演化，模拟氮、碳和氧的循环以及大气中N2、O2、CO2、CH4、N2O和NH3的库存，将地球化学和气候变化联系起来。我们将看到大氧化和雪球地球冰川，以及整个地球历史的变化。(B)地球深层过去的气候，使用三维气候模型来了解气候系统，特别是云，以及验证这些模型中使用的辐射代码准确性的项目。(C)其他行星和卫星上的大气演化，研究金星通过失控的温室和土卫六的怪异大气的转变，(D) （Exo）行星的可居住性，发展行星可能孕育生命的理论，以及“可居住区域”如何取决于大气成分和水储量。******提议的工作解决了基本的“蓝天”问题，为地球和类地行星如何进化提供了新的理论。它将直接有助于开发系外行星生命探测和表征的方法，这将是未来几十年快速发展的领域，并利用加拿大的主要资产。它将用于提高对人为气候变化的理解，因为探索地球历史为现代气候变化提供了背景。我的研究项目的一个特别新颖的方面是跨学科的广度：我们解决气候科学、地球化学和大气化学、地质学、天文学和行星科学方面的问题，这是了解我们和其他国家大气演变所必需的。

Terrestrial planet atmospheres are awesome. They are the mixing pot of every waste gas from the planet, gasses from everything from microbes to the mantle, processed by photochemistry and geochemistry. Atmospheric composition largely determines what life can live at the surface and controls planetary climate by setting the strength of the greenhouse effect and how much sunlight is absorbed. As we enter the age of exoplanets, atmospheres are our window to other worlds; remote atmospheric characterization is the means by which exoplanets may be explored and ultimately life may be detected. ******My research program is about the evolution of planetary atmospheres, for inhabited planets (just Earth right now), for comparison planets and moons in the solar system (Venus, Mars, Titan and more) and, increasingly, for exoplanets. The objectives of the proposed research are: to improve our understanding of the coupled climate-geochemical-biosphere evolution of Earth throughout its history; to develop theory of planetary evolution in a comparative planetology framework, linking Earth to the other terrestrial planets; and to apply this theory to developing methodology for discerning whether exoplanets are habitable or inhabited. ******We will research across four themes: (A) Evolution of Earth's atmosphere, modelling cycles of nitrogen, carbon and oxygen and the atmospheric inventories of N2, O2, CO2, CH4, N2O and NH3, linking geochemical and climate changes. We will look at the Great Oxidation and snowball Earth glacials, and change throughout Earth history. (B) Climate of Earth's deep past, using 3-D climate models to understand the climate system and clouds in particular, and a project to verify the accuracy of the radiation codes used in these models. (C) Atmospheric evolution on other planets and moons, studying the transition of Venus through a runaway greenhouse and the weird atmosphere of Titan (D) (Exo)planet habitability, developing theory on which planets could harbour life, and how the "habitable zone" depends on atmospheric composition and water inventory. ******The proposed work addresses fundamental "blue-sky" questions relating, contributing novel theory to how the Earth and terrestrial planets have evolved. It will directly contribute to developing methodology for exoplanet life detection and characterization, which will be a rapidly expanding field over the next few decades and utilize major Canadian assets. It will be applied to improved understanding of anthropogenic climate change, as exploring Earth history provides the context for modern-day changes. A particularly novel aspect of my research program is the interdisciplinary breadth: we tackle problems in climate science, geochemistry and atmospheric chemistry, geology, astronomy and planetary sciences as necessary to understand the evolution of our, and other, atmospheres.