Exploring the Tropical Atmosphere with Advanced Radio Occultation: Processing, Serving, and Analyzing Radio Occultation Data to Advance Atmospheric Science

利用先进的射电掩星探索热带大气：处理、服务和分析射电掩星数据以推进大气科学

• 批准号: 2054356
• 负责人: Jan-Peter Weiss
• 金额: $ 500万
• 依托单位: University Corporation For Atmospheric Res
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2054356&HistoricalAwards=false
• 关键词: Exploring; Tropical; Atmosphere; Advanced; Radio

The Global Navigation Satellite System (GNSS) is the set of satellite constellations launched worldwide to provide positioning information for all forms of navigation. The system includes the Galileo constellation launched by the European Union, the GLONASS satellites from Russia, Beidou from China, and the US Global Positioning System (GPS). GPS is well known in the US as we rely on it for driving directions and an ever-expanding array of cell phone apps. But the radio waves transmitted for GNSS positioning also have tremendous value for looking at the atmosphere: GNSS radio waves are refracted by the atmosphere to an extent which depends on the temperature and water vapor content of the lower atmosphere and the density of electric charge in the ionosphere. The refraction causes a delay in the phase of the waves when they reach a receiver, and if the reciever is placed on an orbiting satellite the phase delay can be used to measure ionospheric charge and atmospheric temperature and water vapor (although water vapor requires additional information). Because the measurements are made during the rising and setting, or occultation, of a GNSS transmitter satellite relative to a receiver satellite, the technology is referred to as GNSS Radio Occultation (GNSSRO). GNSSRO has proven to be a highly effective observing method as the measurements can be made under all weather conditions, are unaffected by clouds and aerosols, and are absolutely calibrated (SI traceable) through the atomic clocks that support the GNSS transmitters. They also have relatively high vertical resolution, providing a profile of atmospheric properties which can be used to identify sharp features such as the tropopause and fluctuations in temperature caused by atmospheric gravity waves.This award supports work on the development and scientific use of GNSSRSO measurements at the University Corporation for Atmospheric Research (UCAR). UCAR has played a foundational role in GNSSRO technology starting with the GPS/MET proof-of-concept satellite mission in the 1990s, and they led the development of the Constellation Observing System for Meteorology, the Ionosphere, and Climate (COSMIC, also called COSMIC-1 or C1), a constellation of six GNSSRO receiver satellites launched in 2006. They also managed the development of COSMIC-2 (C2, a mission led by the US National Oceanic and Atmospheric Administration), a follow-on constellation of six satellites orbiting over the tropics and subtropics (30 degrees south to 30 north) launched in 2019. The UCAR group, formally known as the UCAR COSMIC Program, has also been collecting and processing GNSSRO data from several other satellite missions, for example SAC-C (from Argentina), GRACE (a NASA mission), Metop-A and -B (EUMETSAT missions), and PAZ (from Spain). Including all satellite misions there are now two decades of continuous GNSSRO observations, a long enough record to be valuable for research on climate trends. Work here emphasizes the low latitudes, motivated by the high density and quality of low-latitude observations available from C2. One question to be addressed is the extent to which RO-based observations can lead to better understanding of hurricanes and other tropical cyclones (TCs), for instance the extent to which accumulation of water vapor in a deep layer near the developing TC promotes storm development. Another is whether the discrepancy between the observed profile of tropical tropospheric warming and the profile simulated in response to greenhouse gas increases is due to inadequacies of climate models or biases in observations. The high resolution and absolute calibration of RO soundings makes them ideal address this question. Other issues to be pursued include better characterization of the tropical waves which drive the stratospheric Quasi-Biennial Oscillation and the use of RO to assess the representation of water vapor in commonly used reanalysis datasets.The project also includes research on the low-latitude ionosphere, taking advantage of the Ion Velocity Meter (IVM) deployed as a secondary payload on the C2 satellites as well as two recently launched NASA missions, the Global-Scale Observations of the Limb and Disk (GOLD) and Ionospheric Connection Explorer (ICON). The suite of C2, ICON, and GOLD observations is used to study equatorial plasma bubbles and the effect of the equatorial dynamo on the ionosphere. Further work seeks to improve the assimilation of GNSSRO observations into ionospheric models.In addition to these research applications the project includes research to advance GNSSRO theory and algorithms so as to maximize the value of RO for atmospheric research. One concern is the effects of random refractivity fluctuations on RO measurements, as such fluctuations are thought to contribute to the negative bias in RO-derived atmospheric moisture commonly found near the surface. A further concern is the detection of super-refraction, in which refraction becomes strong enough to trap GNSS radio waves near the surface and prevent their use for determining temperature and water vapor. Super-refraction must be detected so that data from the ducted portion of the RO profiles is not used. Additional work develops RO methods for the ionosphere, including better methods for detecting localized charge irregularities and ray-tracing techniques which use separate ray paths for the two wavelengths transmitted by GNSS satellites.The work has societal as well as scientific value due to the use of GNSSRO for weather prediction and climate monitoring. GNSSRO is used in most weather forecasting centers and improvements in RO algorithms developed under this award have direct application in weather prediction. The examination of GNSSRO as an observational technique for looking at hurricanes is particularly relevant given the lack of observations that can be used to initialize hurricane forecasts. The ionospheric work is also directly applicable to efforts to predict space weather. In the area of climate monitoring, the project develops datasets from RO observations over multiple satellite missions, processed in a consistent manner so that they can be used to assess long-term trends in temperature and moisture. The award includes support for hosting, archiving, serving, and supporting access to datasets by the research community.The datasets and data services are augmented by several education and outreach efforts seeking to facilitate use of GNSS RO data by the research community. One of these is a postdoctoral research program which supports early-career scientists seeking to work with RO observations. The project also works with the UCAR Significant Opportunities in Atmospheric Research and Science (SOARS) program, through which it provides mentorship to students from underrepresented groups. A two-week summer colloquium is planned for 2022 to bring together experts in GNSSRO and give early career researchers an opportunity to become familiar with GNSSRO and its research applications.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.

全球导航卫星系统（GNSS）是全球启动的卫星星座，旨在为所有形式的导航提供定位信息。 该系统包括欧盟发起的伽利略星座，来自俄罗斯的格隆斯卫星，来自中国的贝杜和美国全球定位系统（GPS）。 在美国，GPS在美国众所周知，因为我们依靠它来行驶方向和一系列不断扩展的手机应用程序。 但是，用于观察大气的GNSS定位传输的无线电波也具有巨大的价值：GNSS无线电波被大气折射到一定程度上，取决于低大气的温度和水蒸气含量以及电离层中电荷的密度。 当折射到达接收器时，折射会导致它们的阶段延迟，如果将接收器放置在轨道卫星上，则可以使用相延迟来测量电离层电荷和大气温度和水蒸气（尽管水蒸气需要其他信息）。 由于测量是在GNSS发射器卫星相对于接收器卫星的上升，设置或掩盖过程中进行的，因此该技术称为GNSS无线电掩盖（GNSSRO）。 GNSSRO已被证明是一种高效的观察方法，因为在所有天气条件下都可以进行测量，不受云和气溶胶的影响，并且通过支持GNSS发射机的原子钟进行了绝对校准（SI可跟踪）。 它们也具有相对较高的垂直分辨率，提供了大气特性的概况，可用于识别由大气重力波引起的尖锐特征，例如对流层滨和温度的波动。该奖项支持在大气研究（UCAR）大学公司（UCAR）的GNSSSRSO测量的开发和科学使用方面的工作。 UCAR在1990年代从GPS/MET概念验证卫星任务开始，在GNSSRO技术中发挥了基础作用，他们领导了气象学观察系统的发展，电离层，电离层和气候（宇宙）（宇宙，宇宙，也称为Cosmic-1或C1），也称为Cosmic-1或C1），六个Gnsssro Cosien-Satersemit-Satellite-Satelles in 2006 in 2006 in 2006中。 （C2，由美国国家海洋和大气管理局领导的一项任务），这是一个在2019年推出的六颗卫星的随后星座（向热带和亚热带绕30度）发射的六卫星。 NASA任务），Metop -A和-B（Eumetsat任务）和PAZ（来自西班牙）。 包括所有卫星贴剂在内，现在有二十年的连续GNSSRO观察结果，这一记录足够长，足以研究气候趋势。 这里的工作强调了低纬度的，这是由于C2可用的低纬度观测值的高密度和质量。 要解决的一个问题是基于RO的观察可以在多大程度上可以更好地了解飓风和其他热带气旋（TC），例如，在发展中的TC附近的深层层中，水蒸气积聚在多大程度上促进了风暴的发展。 另一个是，观察到的对流层变暖的观察到的曲线与响应温室气体增加的曲线之间的差异是由于气候模型的不足或观察中的偏见所致。 RO响应的高分辨率和绝对校准使它们理想地解决了这个问题。 其他要解决的问题包括更好地表征热带波动，这些波浪驱动了平流层准生物生物振荡，以及使用RO来评估在常用的重新分析数据集中水蒸气表示的表示。该项目还包括对低纬度电离层的研究，利用了近期启动的低位电离层，并将其付诸实践，并在第二个启动时，以及第二个付费量的付费量（IVM）。 NASA任务，肢体和磁盘（黄金）和电离层连接探索器（ICON）的全球规模观察。 C2，图标和金观测的套件用于研究赤道血浆气泡以及赤道发电机对电离层的影响。 进一步的工作旨在将GNSSRO观测的同化为电离层模型。在这些研究应用中，该项目还包括推进GNSSRO理论和算法的研究，以最大程度地提高RO对大气研究的价值。 一个问题是随机折射波动对RO测量的影响，因为这种波动被认为会导致通常在表面附近发现的RO衍生大气水分的负偏差。 另一个问题是检测超差异，其中折射变得足够强，可以捕获表面附近的无线电波，并阻止它们用于确定温度和水蒸气。必须检测到超级折段，以便不使用来自RO轮廓的管道部分的数据。其他工作为电离层开发了RO方法，包括更好地检测局部电荷不规则的方法和射线追踪技术，这些技术使用GNSS卫星传输的两个波长使用单独的射线路径。由于GNSSRO用于天气预测和气候监控，该工作具有社会价值以及科学价值。 GNSSRO用于大多数天气预测中心，根据该奖项开发的RO算法的改进，在天气预测中直接应用。鉴于缺乏可用于初始化飓风预测的观察结果，将GNSSRO作为一种观察飓风的观察技术特别重要。 电离层工作也直接适用于预测太空天气的努力。 在气候监测的领域，该项目从多个卫星任务的RO观察中开发了数据集，这些卫星任务以一致的方式处理，以便它们可以用于评估温度和水分的长期趋势。该奖项包括研究社区对托管，归档，服务和支持访问数据集访问的支持。数据集和数据服务通过几项教育和外展工作增强，以促进研究社区使用GNSS RO数据。 其中之一是一项博士后研究计划，该计划支持寻求进行RO观察的早期职业科学家。 该项目还与UCAR在大气研究和科学计划（SOARS）计划方面的重要机会合作，通过该计划为来自代表性不足群体的学生提供指导。 计划在2022年为期两周的夏季座谈会，以将GNSSRO的专家汇集在一起​​，并使早期的职业研究人员有机会熟悉GNSSRO及其研究应用程序。这项奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子和更广泛影响的评估来通过评估来支持的，这是值得的。

项目成果

Comparison of COSMIC and COSMIC-2 Radio Occultation Refractivity and Bending Angle Uncertainties in August 2006 and 2021

2006年8月和2021年COSMIC和COSMIC-2射电掩星折射率和弯曲角不确定度的比较

• DOI: 10.3390/atmos13050790
• 发表时间: 2022
• 期刊: Atmosphere
• 影响因子: 2.9
• 作者: Anthes, Richard;Sjoberg, Jeremiah;Feng, Xuelei;Syndergaard, Stig
• 通讯作者: Syndergaard, Stig

Interannual Variability of Tropospheric Moisture and Temperature and Relationships to ENSO Using COSMIC-1 GNSS-RO Retrievals

使用 COSMIC-1 GNSS-RO 反演对流层湿度和温度的年际变化及其与 ENSO 的关系

• DOI: 10.1175/jcli-d-21-0884.1
• 发表时间: 2022
• 期刊: Journal of Climate
• 影响因子: 4.9
• 作者: Johnston, Benjamin R.;Randel, William J.;Braun, John J.
• 通讯作者: Braun, John J.

Global Maps of Equatorial Plasma Bubbles Depletions Based on FORMOSAT‐7/COSMIC‐2 Ion Velocity Meter Plasma Density Observations

基于 FORMOSAT™7/COSMIC™2 离子速度计等离子体密度观测的赤道等离子体气泡消耗全球图

• DOI: 10.1029/2023sw003438
• 发表时间: 2023
• 期刊: Space Weather
• 影响因子: 3.7
• 作者: Zakharenkova, Irina;Cherniak, Iurii;Braun, John J.;Wu, Qian
• 通讯作者: Wu, Qian

Global Gridded Ionospheric Electron Density Derivation During 2006–2016 by Assimilating COSMIC TEC and Its Validation

• DOI: 10.1029/2022ja030955
• 发表时间: 2022-12
• 期刊: Journal of Geophysical Research: Space Physics
• 作者: Jianhui He;X. Yue;E. Astafyeva;H. Le;Zhipeng Ren;N. Pedatella;Feng Ding;Yong Wei

Equatorial Waves, Diurnal Tides and Small‐Scale Thermal Variability in the Tropical Lower Stratosphere From COSMIC‐2 Radio Occultation

• DOI: 10.1029/2020jd033969
• 发表时间: 2020-10
• 期刊: Journal of Geophysical Research: Atmospheres
• 作者: W. Randel;Fei Wu;A. Podglajen