Solar Eclipse-Induced Changes in the Ozone Layer Observed with UV/VIS (UltraViolet–VISible Spectroscopy) Radiometer

使用 UV/VIS（紫外可见光谱）辐射计观测日食引起的臭氧层变化

• 批准号: 2328210
• 负责人: Germar Bernhard
• 金额: $ 7.91万
• 依托单位: Biospherical Instruments Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2328210&HistoricalAwards=false
• 关键词: Solar; Eclipse; Induced; Changes; Ozone

Solar eclipses are rare astronomical phenomena, which provide a natural testbed for probing processes occurring in Earth’s atmosphere. It has been reported that the Moon’s shadow as it travels over our planet during an eclipse will lead to fluctuations in the ozone layer, a result which is controversial and demands additional new research. The Earth’s ozone layer protects life on our planet from the Sun’s harmful ultraviolet (UV) radiation. This project strives to resolve this issue by performing measurements of “total ozone” (ozone amounts integrated from the Earth’s surface to the top of the atmosphere) and solar UV radiation during the total solar eclipse of 8 April 2024 with two distinct instruments. Results from the project will improve our understanding about the way radiation from the Sun travels through the atmosphere to Earth’s surface where it interacts with the living world. Apart from providing new insights in this "transfer of radiation", the project will contribute to the desire of mankind to better understand the awe-inspiring phenomenon of a solar eclipse and its implications. Furthermore, the project will advance the academic skills of an international graduate student who will simulate the irradiance during totality and compare it with the measurements. Participation of observers in Mexico and scientists from Germany at no additional costs to the project promote international collaborations.It is well established that solar eclipses generate gravity waves in the upper atmosphere (ionosphere) as the Moon’s shadow travels at supersonic speeds over Earth. However, effects on the stratospheric ozone layer are less well established, with some publications supporting a link, some disputing one, and some presenting ambiguous results because of measurement artifacts. The overarching objective of this project is to resolve these contradictions by measuring short-term (seconds to minutes) variations in the total ozone column (TOC) using “global” (Sun and sky) and direct-Sun observations in the ultraviolet (UV) range during the total solar eclipse of 8 April 2024. Measurements will be performed at Mazatlán, Mexico, under the path of totality. At this location, totality will last 4 minutes and 25 seconds and the likelihood of clear skies is one of the highest along the path of the eclipse. Global observations will be made with a GUVis-3511 radiometer, which uses 19 wavebands between 305 and 1640 nm; TOC is calculated from measurements between 305 and 340 nm. The radiometer is equipped with a shadow band to allow alternating global and diffuse measurements from which the direct spectral irradiance is calculated. A MICROTOPS II sun photometer will also be used for direct-Sun observations. Use of two distinct instruments reduces the risk that observational variations in TOC caused by measurement artifacts are incorrectly attributed to real ozone changes. Data collected as a part of this project will improve the understanding of the coupling between the upper atmosphere and the stratosphere. In addition to TOC observations, measurements of the global spectral irradiance during totality at the Earth’s surface will be compared with results of a 3-D radiative transfer model. This will enhance understanding of photon transport during a solar eclipse where photons entering the atmosphere outside the Moon’s shadow are scattered many times before reaching the observer, which is a numerically challenging problem to solve. A similar comparison during the 2017 eclipse has expanded our knowledge of the effects of surface albedo, topography, aerosols, and the vertical ozone distribution on the photon path. Data recorded during the 2024 eclipse will increase our understanding of this important effect further.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

日食是罕见的天文现象，它为探测地球大气层中发生的过程提供了一个天然的试验台。据报道，月食期间月球在地球上的阴影会导致臭氧层的波动，这是一个有争议的结果，需要更多的新研究。地球的臭氧层保护地球上的生命免受太阳有害的紫外线辐射。该项目致力于解决这一问题，在2024年4月8日日全食期间，使用两种不同的仪器测量“臭氧总量”（从地球表面到大气层顶部的臭氧量）和太阳紫外线辐射。该项目的结果将提高我们对太阳辐射通过大气层到达地球表面与生物世界相互作用的方式的理解。该项目除了为这种“辐射转移”提供新的见解外，还将有助于人类更好地了解日食这一令人敬畏的现象及其影响。此外，该项目将提高一名国际研究生的学术技能，他将模拟全食期间的辐照度并将其与测量结果进行比较。墨西哥的观察员和德国的科学家在不增加项目费用的情况下参与该项目，促进了国际合作。然而，对平流层臭氧层的影响还没有得到很好的确定，一些出版物支持一种联系，一些出版物对一种联系提出质疑，还有一些出版物由于测量人为因素而提出了模棱两可的结果。该项目的总体目标是通过在2024年4月8日日全食期间利用“全球”（太阳和天空）和直射太阳观测紫外线（UV）范围内测量臭氧总柱（TOC）的短期（秒至分钟）变化来解决这些矛盾。测量将在墨西哥的马萨特兰进行，在全食的路径下。在这个位置，全食将持续4分25秒，晴朗天空的可能性是最高的沿着日食的路径。全球观测将使用GUVis-3511辐射计进行，该辐射计使用305至1640纳米之间的19个波段;总有机碳是根据305至340纳米之间的测量值计算的。辐射计配备了阴影带，以允许交替的全球和漫反射测量，直接光谱辐照度的计算。还将使用MICROTOPS II太阳光度计进行太阳直射观测。使用两种不同的仪器降低了测量人为因素造成的TOC观测变化被错误地归因于真实的臭氧变化的风险。作为该项目的一部分而收集的数据将增进对高层大气与平流层之间相互作用的了解。除了TOC观测外，还将把在地球表面全食期间对全球光谱辐照度的测量结果与三维辐射传输模型的结果进行比较。这将增强对日食期间光子传输的理解，在日食期间，进入月球阴影外大气层的光子在到达观察者之前被散射多次，这是一个具有数值挑战性的问题。在2017年日食期间进行的类似比较扩大了我们对地表水、地形、气溶胶、和光子路径上的臭氧垂直分布。2024年日食期间记录的数据将进一步增加我们对这一重要影响的理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准。