Continued Operation of COSMIC GPS Radio Occultation Constellation in Support of Research Applications in Atmospheric Sciences

持续运行 COSMIC GPS 无线电掩星星座以支持大气科学研究应用

• 批准号: 1522830
• 负责人: William Schreiner
• 金额: $ 350万
• 依托单位: University Corporation For Atmospheric Res
• 依托单位国家: 美国
• 项目类别: Cooperative Agreement
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1522830&HistoricalAwards=false
• 关键词: Continued; Operation; COSMIC; GPS; Radio

Launched in 2006, the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) is a constellation of six polar-orbiting satellites in Low Earth Orbit. The primary payload of each satellite is a Global Positioning System (GPS) receiver (developed at the NASA Jet Propulsion Laboratory) which receives positioning signals from the GPS transmitter satellites as they rise and set relative to the COSMIC satellite. The GPS signals are refracted by the atmosphere as they travel from the transmitter to the receiver, 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 transmitted signal which can be inverted to retrieve profiles of electron density (in the ionosphere), dry atmospheric temperature, and water vapor (although water vapor requires additional information). Because the profiles are retrieved from the rising and setting, or occultation, of the GPS transmitters, the technology is referred to as GPS Radio Occultation (GPSRO), or more generally as GNSSRO, where GNSS is the Global Navigation Satellite System. 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 clock system that supports the GPS transmitters.Funds under this award support COSMIC-related work in four categories: 1) processing, serving, and archiving COSMIC data for use by the research community; 2) conducting research to improve GNSSRO inversion science and techniques; 3) conducting research in support of scientific applications of GNSSRO data; and 4) education and outreach activities to promote the use of GNSSRO data and its application to atmospheric research. Item 1 is the bread-and-butter activity of this award and its predecessors, and support is also provided here for improving the quality of the profiles and generating additional data products such as monthly mean climatologies for both lower- and upper-atmospheric variables. In addition to the COSMIC satellites, a small number of GNSSRO "missions of opportunity" are also supported. These are research satellites to which a GNSS receiver has been added as a secondary payload (GRACE-B for example). Activities under item 2 continue the PIs' leadership role in the development of new GNSS processing techniques, for example by developing methods to correct errors caused by diffraction in sporadic E layers in the ionosphere. Research under item 3 develops new assimilation techniques such as the use of 2D ray-tracing methods to account for horizontal refractivity gradients. Another task is to develop long-term climate-quality datasets in which profiles from different satellites are optimally combined to account for differences in their error characteristics. GNSSRO data are well-suited for generating long-term multi-mission datasets given their SI traceability. Work under item 4 addresses a gap between the availability of GPSRO data and its adoption by the research community. Activities include hosting academic visitors, conducting meetings and workshops, and holding summer colloquia and tutorials.The work has intellectual merit due to the great value of the COSMIC observations for weather, climate and ionospheric research. The work has scientific broader impacts through the PIs' education and outreach efforts to promote the adoption and use of the data by scientists from several research communities. In addition, the PIs provide the COSMIC data to operational weather forecasting centers worldwide, and the data has been shown to be quite useful for improving the skill of weather forecasts.This award supercedes AGS-1033112, the previous cooperative agreement under which NSF provided funds to COSMIC. While NSF is no longer providing funds via the earlier CA, that award will remain active as it contains funds from other agencies to support the development of the follow-on COSMIC-2 mission. This award does not provide funds for COSMIC-2.

气象、电离层和气候星座观测系统 (COSMIC) 于 2006 年启动，是由六颗近地轨道极地轨道卫星组成的星座。每颗卫星的主要有效载荷是一个全球定位系统 (GPS) 接收器（由 NASA 喷气推进实验室开发），当 GPS 发射器卫星相对 COSMIC 卫星升起和落下时，该接收器接收来自 GPS 发射器卫星的定位信号。 GPS 信号从发射器传输到接收器时会被大气折射，折射程度取决于低层大气的温度和水蒸气含量以及电离层中的电荷密度。折射会导致传输信号的相位延迟，可以将其反转以检索电子密度（电离层中）、干燥大气温度和水蒸气的分布（尽管水蒸气需要附加信息）。由于剖面图是从 GPS 发射机的升起和落下或掩星中检索的，因此该技术被称为 GPS 无线电掩星 (GPSRO)，或者更一般地称为 GNSSRO，其中 GNSS 是全球导航卫星系统。 GNSSRO 已被证明是一种非常有效的观测方法，因为可以在所有天气条件下进行测量，不受云和气溶胶的影响，并且通过支持 GPS 发射器的时钟系统进行绝对校准（SI 可追溯）。该奖项下的资金支持四类 COSMIC 相关工作：1）处理、服务和归档 COSMIC 数据以供研究界使用； 2) 开展研究以改进 GNSSRO 反演科学和技术； 3) 开展支持 GNSSRO 数据科学应用的研究； 4) 教育和推广活动，以促进 GNSSRO 数据的使用及其在大气研究中的应用。 第 1 项是该奖项及其前身的基础活动，这里还提供支持，以提高剖面的质量并生成额外的数据产品，例如低层和高层大气变量的月平均气候。除了 COSMIC 卫星外，还支持少量 GNSSRO“机会任务”。 这些是研究卫星，其中添加了 GNSS 接收器作为辅助有效载荷（例如 GRACE-B）。 第 2 项下的活动继续发挥 PI 在开发新 GNSS 处理技术方面的领导作用，例如开发纠正电离层零星 E 层衍射引起的误差的方法。第 3 项下的研究开发了新的同化技术，例如使用 2D 射线追踪方法来解释水平折射率梯度。 另一项任务是开发长期气候质量数据集，其中来自不同卫星的剖面被最佳组合，以解释其误差特征的差异。鉴于其 SI 可追溯性，GNSSRO 数据非常适合生成长期多任务数据集。 第 4 项下的工作解决了 GPSRO 数据的可用性与研究界采用它之间的差距。 活动包括接待学术访客、举办会议和研讨会以及举办夏季座谈会和教程。由于 COSMIC 观测对天气、气候和电离层研究的巨大价值，这项工作具有智力价值。 这项工作通过 PI 的教育和推广工作来促进多个研究团体的科学家对数据的采用和使用，从而在科学上产生更广泛的影响。 此外，PI 还向全球运行的天气预报中心提供 COSMIC 数据，这些数据已被证明对于提高天气预报技能非常有用。该奖项取代了之前 NSF 提供资金的合作协议 AGS-1033112到宇宙。 虽然 NSF 不再通过早期的 CA 提供资金，但该奖项将继续有效，因为它包含来自其他机构的资金，以支持后续 COSMIC-2 任务的发展。 该奖项不为 COSMIC-2 提供资金。