NINETEENTH CENTURY US WEST COAST SEA LEVEL AND TIDAL PROPERTIES

十九世纪美国西海岸海平面和潮汐特性

• 批准号: 1155610
• 负责人: Stefan Talke
• 金额: $ 9.38万
• 依托单位: Portland State University
• 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: 2012-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1155610&HistoricalAwards=false
• 关键词: NINETEENTH; CENTURY; US; WEST; COAST

Tidal data are the oldest and longest records available from the ocean, but much of the 19th and early 20th century tidal record (along with the weather data collected at tide stations) remains un-digitized and unused. In this project, novel ways of recovering, digitizing, vetting and analyzing 19th century tide data from Astoria, OR (1853-1876) and San Diego, CA (1853-1872) will be pioneered; these are two of the three oldest Pacific Ocean tidal records. The products of this work and related metadata recovery will be used to improve estimates of 19th century mean sea level (MSL) in the north-eastern Pacific, assess the secular change in tidal properties, and estimate long-term changes in storminess, for example, the climate induced, non-tidal variance that occurs due to wind, river flow, and other processes. This project will therefore address important contemporary scientific issues such as the long-term variation and acceleration in MSL, the long-term effects of climate change and local change, and the quality of old data. The data will be improved (by removing errors) and the tabulated data that has already been recovered for Astoria and San Diego will be augmented by obtaining digital copies of selected marigrams (22 m long scrolls that each contain one month of pencil tide tracings) from the US National Archive. Metadata (leveling and datum records, time checks and weather records), will also be recovered and used to correct the raw data and to compare historic mean sea-level with modern measurements. One novel aspect is that recovered tide rolls will be digitized to 6 minute resolution using software, rather than the traditional slow and error prone hand tabulations. Further, innovative analysis techniques will be used to find and correct errors. Using the corrected data sets, MSL variation from San Diego, San Francisco, and Astoria will be assessed and compared. To the extent possible, corrections for barometric pressure, river flow, and isostatic rebound will be applied. The analysis will address whether MSL at San Francisco is representative of the US West Coast, and will, by comparison with the modern record, help constrain long-term trends in MSL variation. Secular shifts in the primary constituents (e.g., M2) and the shallow-water overtides (e.g., M4) will be assessed. Spectral analysis techniques and weather data collected at tide stations will be used to investigate secular changes to the non-tidal variance in the water level signal for San Francisco. Because overtides are produced by bathymetry, river flow, stratification, and other local processes, assessing their change over time can provide insight into locally forced changes to the functioning of estuaries. To the extent possible, the effects of local changes, climate, and river forcing will be separated.Broader Impacts: A better understanding of changes to MSL and storminess helps address important contemporary scientific questions with policy implications. Because the proposal is a proof of concept, the methods to be developed here can in the future be used to recover hundreds of station-years of the 1850-1950 tide data that are currently stored in analog form (usually as marigrams) in archives. The PI is an early career scientist.

潮汐数据是海洋中最古老，最长的记录，但是19世纪和20世纪初的大部分潮汐记录（以及在潮汐站收集的天气数据）仍然没有数字和未使用。 在这个项目中，从阿斯托里亚（Astoria）或（1853-1876）和加利福尼亚州圣地亚哥（1853-1872）恢复，数字化，审查和分析19世纪潮汐数据的新颖方式将开创；这是太平洋最古老的潮汐记录中的两个。 这项工作和相关的元数据恢复的产物将用于改善东北太平洋中19世纪平均海平面（MSL）的估计值，评估潮汐性质的世俗变化，并估计暴风雨度的长期变化，例如，由于风，河流流动以及其他过程，气候诱导的，非潮汐差异。 因此，该项目将解决重要的当代科学问题，例如MSL的长期变化和加速，气候变化和当地变化的长期影响以及旧数据的质量。 数据将得到改进（通过删除错误），并通过从美国国家档案馆中获取选定选定的Marigrams（22 m长的卷轴）的数字副本（每个包含一个月的铅笔潮汐示踪剂）的数字副本来增强已经为Astoria和San Diego恢复的列表数据。 元数据（级别和基准记录，时间检查和天气记录）也将被恢复并用于纠正原始数据，并将历史平均海平面与现代测量结果进行比较。 一个新颖的方面是，恢复的潮汐卷将使用软件数字化至6分钟的分辨率，而不是传统的慢速和错误的手部表格。 此外，创新分析技术将用于查找和纠正错误。 使用校正的数据集，将评估和比较来自圣地亚哥，旧金山和阿斯托里亚的MSL变化。 在可能的情况下，将应用对气压，河流和等静力反弹的校正。 该分析将解决旧金山的MSL是否代表美国西海岸，与现代记录相比，将有助于限制MSL变化的长期趋势。 将评估主要成分（例如M2）和浅水超过（例如M4）的世俗变化。 在潮汐站收集的光谱分析技术和天气数据将用于研究旧金山水位信号中非潮汐差异的世俗变化。 因为超过的河流，河流流，分层和其他局部过程产生，因此评估它们随着时间的变化可以洞悉局部强迫变化的河口功能。 在可能的情况下，将分开当地变化，气候和河流强迫的影响：对MSL的变化和暴风雨的更好理解有助于解决重要的当代科学问题，具有政策的影响。 由于该提案是概念的证明，因此将来可以使用此处开发的方法来恢复目前以模拟形式（通常为Marigrams）存储在档案中的1850 - 1950年潮汐数据中的数百个年度。 PI是早期的职业科学家。