Terms
longhorizon.blue gathers public observations of coastal waters and presents them with their age, their source and their recent history. These terms cover the data, our figures and text, the files behind the pages, and how we use AI. Last updated October 12, 2026.
The data
The observations come from public agencies and university observing systems, listed below. They are free to use under each provider's terms; please credit the provider. All data are provisional, may contain errors, and may be revised. They are provided as is, without warranty of any kind, and are not intended for navigation, safety-of-life or legal decisions. Long Horizon Observatory is not liable for decisions made using this site.
- LISICOS, Department of Marine Sciences, University of Connecticut: buoy observations
- NOAA CO-OPS: shore stations, water levels and tide predictions
- U.S. Geological Survey: river flow, river turbidity and watershed boundaries
- NOAA NESDIS CoastWatch: chlorophyll-a and water clarity (VIIRS)
- NASA JPL (MUR, via PO.DAAC and CoastWatch): sea surface temperature
- NECOFS, UMass Dartmouth (SMAST): modelled surface currents
- OpenFreeMap and OpenStreetMap contributors: basemap
Plots and text
The plots, maps and writing on this site are by Long Horizon Observatory and are licensed under Creative Commons Attribution-NonCommercial 4.0. You are welcome to share them, including on social media, and to adapt them, with credit to Long Horizon Observatory and a link to the page. Commercial use needs our permission.
Data files
The processed data files behind these pages serve this site and are not yet a public API. Automated or bulk collection of them, or redistribution of the processed data, needs our permission. Requests for research, education and other uses are welcome. For the original observations, use the providers above directly.
Code
The software that builds this site is open source under the MIT license: github.com/lhzn-io/lhzn-blue.
Use of AI
No AI model produces or changes the numbers on this site. Every value in the plots, readouts and maps comes from the instruments, models and satellite products credited above, through fixed code that averages, quality-checks and converts them as each plot's About explains. No AI system runs on these pages or in the data pipeline, and nothing you type or collect here is sent to one.
We use AI tools to build the site. The code is written with Claude Code (Anthropic) under the direction of a person who reviews every change before it is published; each change, and the tools that helped with it, are recorded in the public history. The page text and method notes are drafted with the same tools, then edited and approved by a person who is responsible for them. References come from the publishers' records (DOIs), not from AI-generated citations. Checks on the data, such as comparing a buoy against an independent record of the same instrument, are run as code, and their results are stated in the method notes.
"Ask your AI" (under Collect) prepares an image and a prompt for an assistant you already use; you copy them and paste them in yourself. The site sends nothing to us or to any AI service. The answer comes from your assistant, not from Long Horizon Observatory, and it can be wrong even with the data in front of it: the prompt asks it to quote only the values provided, and the plots are the reference to check it against.
Mistakes on the site are ours to correct, whatever tools were involved: write to hello@longhorizon.blue or use "Send us a suggestion" under Collect.
Contact
Questions, permissions and corrections: hello@longhorizon.blue.