LONGHORIZON.BLUE

References

The papers and monitoring programs behind these pages, with a note on what each supports: the methods behind the map's fields first, then each waterway. As BibTeX: references.bib.

Methods behind the map, its fields and the tides

  1. Booij, N., Ris, R. C. and Holthuijsen, L. H. (1999). A third-generation wave model for coastal regions: 1. Model description and validation. Journal of Geophysical Research: Oceans 104(C4), 7649–7666. doi:10.1029/98JC02622

    SWAN, the wave model the NWS Nearshore Wave Prediction System runs; behind the waves and wind-against-tide layers.

  2. Chen, C., Beardsley, R. and Cowles, G. (2006). An Unstructured Grid, Finite-Volume Coastal Ocean Model (FVCOM) System. Oceanography 19(1), 78–89. doi:10.5670/oceanog.2006.92

    The FVCOM system and its coastal forecast applications, including NECOFS.

  3. Chen, C., Liu, H. and Beardsley, R. C. (2003). An Unstructured Grid, Finite-Volume, Three-Dimensional, Primitive Equations Ocean Model: Application to Coastal Ocean and Estuaries. Journal of Atmospheric and Oceanic Technology 20(1), 159–186. doi:10.1175/1520-0426(2003)020<0159:AUGFVT>2.0.CO;2

    FVCOM, the unstructured-grid model behind the currents layer.

  4. Chin, T. M., Vazquez-Cuervo, J. and Armstrong, E. M. (2017). A multi-scale high-resolution analysis of global sea surface temperature. Remote Sensing of Environment 200, 154–169. doi:10.1016/j.rse.2017.07.029

    The MUR sea surface temperature analysis (the SST layer).

  5. Codiga, D. L. (2011). Unified Tidal Analysis and Prediction Using the UTide Matlab Functions. Technical Report 2011-01, Graduate School of Oceanography, University of Rhode Island; used here through the Python port of UTide. Accessed 2026-10-16

    The harmonic fits behind the tide predictions at the USGS gauges, each to its own year of record, set on NOAA's footing.

  6. Dowell, D. C., Alexander, C. R., James, E. P. et al. (2022). The High-Resolution Rapid Refresh (HRRR): An Hourly Updating Convection-Allowing Forecast Model. Part I: Motivation and System Description. Weather and Forecasting 37(8), 1371–1395. doi:10.1175/WAF-D-21-0151.1

    HRRR, the model behind the wind layer, the next-48-hours plot and its forecast vintages.

  7. Hu, C., Lee, Z. and Franz, B. (2012). Chlorophyll a algorithms for oligotrophic oceans: A novel approach based on three‐band reflectance difference. Journal of Geophysical Research: Oceans 117(C1). doi:10.1029/2011JC007395

    Background: chlorophyll-a retrieval from satellite ocean colour (a band-difference algorithm).

  8. Longuet-Higgins, M. S. and Stewart, R. W. (1961). The changes in amplitude of short gravity waves on steady non-uniform currents. Journal of Fluid Mechanics 10(4), 529–549. doi:10.1017/S0022112061000342

    How an opposing current shortens and heightens waves, and where it stops them: the basis of the wind-against-tide layer.

  9. NASA/JPL (2015). GHRSST Level 4 MUR Global Foundation Sea Surface Temperature Analysis (v4.1). NASA Physical Oceanography Distributed Active Archive Center. doi:10.5067/GHGMR-4FJ04

    The MUR SST dataset (v4.1), served through NOAA CoastWatch.

  10. U.S. Census Bureau (2024). TIGER/Line Shapefiles: Area Hydrography. Accessed 2026-10-16

    The shoreline the Tides view's outline is drawn from, smoothed (public domain).

  11. Wang, M., Son, S. and Harding, L. W. (2009). Retrieval of diffuse attenuation coefficient in the Chesapeake Bay and turbid ocean regions for satellite ocean color applications. Journal of Geophysical Research: Oceans 114(C10). doi:10.1029/2009JC005286

    Background: retrieving the diffuse attenuation coefficient Kd(490) in turbid coastal and estuarine water.

Long Island Sound

The buoy observations at the heart of the Long Island Sound page come from LISICOS, the Long Island Sound Integrated Coastal Observing System at the University of Connecticut, and from the work of James O'Donnell and his colleagues there.

The observing system

  1. LISICOS, Department of Marine Sciences, University of Connecticut. Long Island Sound Integrated Coastal Observing System. Accessed 2026-10-11

    The buoys behind this page: temperature, salinity, oxygen, turbidity and weather.

The Sound

  1. O’Donnell, J., Wilson, R. E., Lwiza, K. et al. (2013). The Physical Oceanography of Long Island Sound. In Latimer, J. S., Tedesco, M. A., Swanson, R. L. et al. (eds.), Long Island Sound: Prospects for the Urban Sea, pp. 79–158. Springer New York. doi:10.1007/978-1-4614-6126-5_3

    Circulation, stratification and mixing of the Sound: the standard overview.

  2. Shin, Y., Cifuentes‐Lorenzen, A., Howard Strobel, M. M. and O’Donnell, J. (2021). Waves in Western Long Island Sound: A Fetch‐Limited Coastal Basin. Journal of Geophysical Research: Oceans 126(2), e2020JC016468. doi:10.1029/2020JC016468

    Waves in the western Sound are fetch-limited, larger under easterly winds than westerlies.

  3. Latimer, J. S., Tedesco, M. A., Swanson, R. L. et al. (eds.) (2014). Long Island Sound: Prospects for the Urban Sea. Springer Series on Environmental Management. Springer New York. doi:10.1007/978-1-4614-6126-5

    The volume containing both chapters above.

  4. Lewis, R. (2013). The Geology of Long Island Sound. In Latimer, J. S., Tedesco, M. A., Swanson, R. L. et al. (eds.), Long Island Sound: Prospects for the Urban Sea, pp. 47–77. Springer New York. doi:10.1007/978-1-4614-6126-5_2

    Glacial origin of the Sound and the bluffs of Long Island's north shore.

  5. U.S. Geological Survey. Open-File Report 2010-1007: geologic setting of Long Island Sound. Accessed 2026-10-11

    The glacial moraine and the eroding bluffs of Long Island's north shore.

Oxygen and hypoxia

  1. Anderson, T. H. and Taylor, G. T. (2001). Nutrient Pulses, Plankton Blooms, and Seasonal Hypoxia in Western Long Island Sound. Estuaries 24(2), 228. doi:10.2307/1352947

    Nutrient pulses, plankton blooms and seasonal hypoxia in the western Sound.

  2. Torgersen, T., DeAngelo, E. and O’Donnell, J. (1997). Calculations of Horizontal Mixing Rates Using 222 Rn and the Controls on Hypoxia in Western Long Island Sound, 1991. Estuaries 20(2), 328. doi:10.2307/1352348

    Horizontal mixing and the physical controls on western-Sound hypoxia.

  3. U.S. Environmental Protection Agency (2023). Report on the Environment: Hypoxia in the Gulf of America and Long Island Sound. Last updated October 4, 2023. Accessed 2026-10-11

    The national indicator for Long Island Sound hypoxia, with its history since 1987.

  4. Wilson, R. E., Swanson, R. L. and Crowley, H. A. (2008). Perspectives on long‐term variations in hypoxic conditions in western Long Island Sound. Journal of Geophysical Research: Oceans 113(C12). doi:10.1029/2007JC004693

    Long-term variation of hypoxia in the western Sound.

Monitoring programs

  1. Connecticut Department of Energy and Environmental Protection. Long Island Sound Water Quality and Hypoxia Monitoring Program. Accessed 2026-10-11

    Sound-wide ship surveys since 1991: up to 48 stations every two weeks in summer, with nutrients and plankton.

  2. Interstate Environmental Commission. Western Long Island Sound hypoxia surveys. Accessed 2026-10-11

    Weekly summer surveys at 22 western-Sound stations: oxygen, turbidity, Secchi depth, and nutrients and chlorophyll at about half of them.

  3. Long Island Sound Partnership. Hypoxia: area and duration in Long Island Sound. Accessed 2026-10-11

    The EPA National Estuary Program for the Sound: the official hypoxia indicator, nitrogen targets, and how hypoxia forms.

  4. New York City Department of Environmental Protection. New York Harbor Water Quality Report (Harbor Survey). Accessed 2026-10-11

    Since 1909: fecal coliform bacteria, oxygen, chlorophyll and clarity in the harbor, including the East River and the western Sound's city waters.

  5. Save the Sound. How's the water: water quality monitoring programs. Accessed 2026-10-11

    Weekly bacteria (Enterococcus) monitoring at about 65 western-Sound sites, and the Unified Water Study of oxygen, chlorophyll and turbidity in the Sound's bays and harbors.

How the plots are drawn

  1. Tufte, E. R. (2001). The Visual Display of Quantitative Information. Second edition. Graphics Press.

    Data drawn in line work, without ornament; every mark carrying information. The plots throughout the site.

  2. Tufte, E. R. (1990). Envisioning Information. Graphics Press.

    Small multiples and layering: the Sound's departure rows, the four model grids side by side.

  3. Tufte, E. R. (1997). Visual Explanations: Images and Quantities, Evidence and Narrative. Graphics Press.

    Showing cause and effect over time: how the forecast came in, the tide against the wind.

  4. Tufte, E. R. (2006). Beautiful Evidence. Graphics Press.

    Sparklines: the status table's lines and the outlook's 48-hour rows.

  5. Crameri, F., Shephard, G. E. and Heron, P. J. (2020). The misuse of colour in science communication. Nature Communications 11, 5444. doi:10.1038/s41467-020-19160-7

    Ordered, perceptually even colour maps that stay readable with colour-vision deficiency, and no red-green ramps: the currents scales and the checks behind them.

  6. Kovesi, P. (2015). Good Colour Maps: How to Design Them. arXiv:1509.03700. doi:10.48550/arXiv.1509.03700

    Lightness that changes evenly along a colour map keeps fine structure in a field visible: the lightness profile of the currents scales.

  7. Machado, G. M., Oliveira, M. M. and Fernandes, L. A. F. (2009). A Physiologically-based Model for Simulation of Color Vision Deficiency. IEEE Transactions on Visualization and Computer Graphics 15(6), 1291–1298. doi:10.1109/TVCG.2009.113

    The colour-vision simulation used to check that the currents scales, and the hazard crosshatch over them, stay readable with protanopia and deuteranopia.

  8. NOAA Center for Operational Oceanographic Products and Services. Tidal Current Predictions. Accessed 2026-10-19

    The 2026 predictions for Long Island Sound and Block Island Sound set the currents scale's anchors: the regional median daily maximum (0.494 m/s) and Little Gull Island's median daily maximum (2.418 m/s) and annual maximum (3.097 m/s).

  9. NOAA National Ocean Service. Tidal Current Charts: Long Island Sound and Block Island Sound. Accessed 2026-10-19

    How official current displays show speed: arrows labelled in knots rather than a shaded field.

  10. NOAA Office of Coast Survey and National Geospatial-Intelligence Agency (2019). U.S. Chart No. 1: Symbols, Abbreviations and Terms used on Paper and Electronic Navigational Charts. Accessed 2026-10-19

    The chart symbol for tide rips, eddies and overfalls that the wind-against-tide hatching follows, and the chart colours for land, drying ground and shoal water that the currents scale avoids.

  11. OpenCPN. S-52 presentation library colour tables (chartsymbols.xml). Accessed 2026-10-19

    The day colours electronic charts give land, drying ground and depth shades. The light currents scale keeps clear of them, so moving water never reads as land or shoal.

  12. Thyng, K. M., Greene, C. A., Hetland, R. D. et al. (2016). True Colors of Oceanography: Guidelines for Effective and Accurate Colormap Selection. Oceanography 29(3), 9–13. doi:10.5670/oceanog.2016.66

    The cmocean colour maps the map layers follow: ordered ramps, the strongest value the most visible, one colour map per quantity. The light currents scale follows its tempo map (pale aqua to deep blue-green).

Next waterway

If you work on, study or monitor a coastal water and would like to help bring its observations and academic literature here, write to hello@longhorizon.blue.