Water Vapor Isotopic Measurements on the Chajnantor Plateau, Chile and Implications for Subtropical Humidity Dynamics

智利查南托高原的水蒸气同位素测量及其对副热带湿度动态的影响

• 批准号: 1158582
• 负责人: Joseph Galewsky
• 金额: $ 33.41万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-15 至 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1158582&HistoricalAwards=false
• 关键词: Water; Vapor; Isotopic; Measurements; Chajnantor

This is a project to collect and analyze measurements of water vapor isotope ratios and ozone concentrations at the site of the Atacama Large Millimeter Array (ALMA) observatory on the Chajnantor Plateau in Chile (23S latitude, elevation 5100m). The measurements will be used to study the processes which determine the humidity of subtropical air masses, which are known to be more moist than region of the tropical upper troposphere from which they descend into the subtropics. The site is ideal for making these measurements because it is one of the few places where air from the tropical upper tropopause can descend all the way to the Earth's surface without substantial modification during descent. It is also an extremely convenient site given the research infrastructure already in place for ALMA.The measurements address four questions: 1) What is the co-variability of water vapor and isotopic composition on daily, intraseasonal, seasonal, and interannual time scales? 2) How do upper tropospheric processes set the aridity of the Southern Hemisphere relative humidity minimum? 3) To what extent is subtropical humidity influenced by instrusions of stratospheric air? 4) What processes moisten the subtropical RH minimum to specific humidities above those encountered in the tropical upper troposphere? Ozone measurements are used to address question 3, as high ozone levels can identify intrusions of stratospheric air. The measurements will be complemented by a suite of diagonstic activities to identify water vapor transport pathways that account for the observed isotope ratios, specific humidity, and ozone concentration.The work has broader impacts due to the importance of water vapor in the atmosphere, both through its role in the hydrological cycle and through its radiative effect as a greenhouse gas. The measurements and their analysis will provide increased understanding of the pathways through which water vapor circulates in the atmosphere, and the processes which determine atmospheric relative humidity in dry regions, which may ultimately improve our ability to forecast weather and anticipate climate change. In addition, the project will educate and train a graduate student at a university with a substantial Hispanic and Native American student population.

这是一个项目，旨在收集和分析Atacama大毫米阵列（Alma）天文台的水蒸气同位素比和臭氧浓度的测量值（智利23S纬度，海拔5100m）。 测量结果将用于研究确定亚热带空气质量湿度的过程，该过程已知比热带对流层的区域更潮湿，它们从中下降到亚热带。 该站点是进行这些测量值的理想选择，因为它是热带上对流层顶的空气可以一直降落到地球表面而没有实质性变化的少数地方之一。 鉴于已经建立了ALMA的研究基础设施，这也是一个非常方便的站点。测量值解决了四个问题：1）在每日，季节，季节性，季节性和年龄段的时间尺度上，水蒸气和同位素组成的共同可变性是什么？ 2）对流层上层过程如何设定南半球相对湿度最小的干燥性？ 3）亚热带湿度在多大程度上受平流层空气仪器的影响？ 4）是什么过程使亚热带RH的最小值润湿到在热带对流层中遇到的特定湿度之上？臭氧测量值用于解决问题3，因为高臭氧水平可以鉴定平流层空气的侵入。一系列对角线活动将补充测量值，以鉴定水蒸气传输途径，这些途径构成了观察到的同位素比，特定的湿度和臭氧浓度。由于其在水文周期中的作用以及其辐射性效果，这项工作都会产生更广泛的影响。测量值及其分析将提供对水蒸气在大气中循环的途径以及确定干燥区域大气相对湿度的过程，这最终可能会提高我们预测天气并预测气候变化的能力。 此外，该项目将在一所大学的西班牙裔和美国原住民人数的大学教育和培训一名研究生。