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Oceans/
Specialized fields/
Sea level and storm surgeSea level, measured to the millimetre and tied to the land.
Coastal flooding comes from surge on top of the tide, on top of a rising sea. Radar tide gauges measure the water every minute, GNSS on the gauge measures whether the land itself is sinking, and weather sensors explain the surge. The same station serves storm warnings today and the sea-level record for decades.
Plan a deploymentHow it worksStation Builder- Industry
- Oceans
- Measurements
- 4
- Sources cited
- 4
Oceans · Sea level and storm surge
Surge on tide on a rising sea
Coastal flooding happens when a storm surge rides on a high tide, on top of a sea that is slowly rising, along coasts where the land may be sinking. Warning centres need the water level every minute; planners need decades of record they can trust.
What is measured
Water, land and weather
A radar gauge over open water measures sea level every minute, with a pressure gauge below the lowest tide as backup. A GNSS receiver on the structure measures whether the land is moving, and weather sensors measure the pressure and wind that drive the surge.
- Instruments
- Radar tide gauge · Pressure gauge · GNSS · Weather sensors
The base node
Surge, computed at the gauge
The node predicts the tide, computes the surge as observed minus predicted and raises alerts at thresholds. When a sudden change suggests a tsunami, it switches to rapid sampling, and it keeps the datum record so every value stays tied to the benchmarks.
Radio and links
Through the storm
Harbour gauges send one-minute data over cellular to warning centres. A satellite path keeps data flowing when storms take down terrestrial networks, and batteries carry the station through the power cuts that come with the surge it measures. When one path fails, the other carries the data.
- Links
- Public cellular · Satellite
How it works
From a deepening low to a flood warning
A deep low tracks toward the coast at spring tide. Gauges show the surge building hours ahead of high water. The warning centre issues a coastal flood warning, harbour gates close, and the peak water level is recorded against the benchmarks for the next design review.
From order to operation · Order
Scope the coast and its duties
The scope reads the coast’s flood history, warning duties, existing gauges and their datums, and global network commitments. Nexus Observatory Inc. returns the gauge plan, datum design, warning integration and a price per station and per year. The scope is agreed before any site work begins.
Plan a deploymentFrom order to operation · Survey
Survey piers and benchmarks
Crews survey candidate piers and walls for open water at all tides, structural stability, benchmarks nearby, sky view for GNSS, power and backhaul. Findings are recorded with drawings and photographs. Findings shape the kit for each site before anything is built.
From order to operation · Permits
Harbour and coastal consent
Harbour authorities approve installation on their structures, coastal consents are obtained, and radio and radar use are registered. Benchmarks are agreed with the national mapping agency. Every approval is kept with the station record. No crew goes to site before its approvals are in place.
From order to operation · Build
Build and calibrate
Radar and pressure gauges are calibrated, GNSS receivers tested, nodes configured with tide constituents where known and enrolled with their identities. The station runs together for days before shipping. Nothing ships until the whole kit has passed its tests together.
Open the Station BuilderFrom order to operation · Install
Install and level
Crews mount the radar over open water, fix the pressure gauge below the lowest tide, install GNSS and weather sensors, power and backhaul, and level the gauge zero to the benchmarks. Every height is recorded. Crews follow the site safety plan throughout the work.
From order to operation · Commission
Commission against tide staff
Each node proves its identity. Radar readings are compared with tide staff readings over full tidal cycles, pressure and radar are compared, GNSS fixes its position and alerts are tested with the warning centre. Acceptance is recorded with the owner before handover.
From order to operation · Operate
Warn and record
Warning centres see sea level and surge every minute and receive alerts when thresholds are crossed. Scientists receive the long record with land motion removed, and every datum change is kept. Every alert and action is kept on the record.
From order to operation · Maintain
Level every year
Gauges are relevelled to benchmarks each year and after any change, sensors are checked against tide staffs, GNSS series are reviewed for land motion, and software updates roll out in rings. Every change is kept with the station record. Maintenance history stays with each site for its whole life.
Book field servicesData products
For warnings, planners and science
Warning centres and harbour masters receive real-time sea level and surge; climate scientists and planners receive long records with land motion; tsunami warning centres receive rapid data; mapping agencies receive datum records, each tied to gauge, benchmark and time. Every product can be traced back to its readings.
See the data productsEvidence
Tied to the land
Gauges follow the international manual on sea level measurement and the global sea level network’s standards, land motion is measured by GNSS at the gauge, and sea level is reported as an essential climate variable. Every value keeps its datum and levelling record.
- Drawn against
- IOC Manuals and Guides No. 14 · GLOSS Implementation Plan 2012 · GCOS-244 · WMO-No. 8
What you get
Ocean and coastal observing
Moored buoys, profiling floats, tide and wave gauges, coastal radar and AIS reception with quality-controlled feeds. Delivered as managed service and data licence, for ports, coastal agencies, offshore energy, fisheries. Scale: Coastline to basin. Service levels are written as numbers you can measure on your own dashboard.
Talk to salesNext step
Plan sea level and storm surge with us
Tell us the site, the measurements and the rules it answers to. We reply with a survey proposal, a design and a scope for sea level and storm surge. An engineer replies with a survey proposal and a scope, and the plan grows from one site to the network you need, at your pace.
Plan a deploymentOpen the Station BuilderOpen the Studio
01The place and its hazards
Where it runs, and what can go wrong.
Operating contextSea level is measured to the international manual on sea level measurement, the global sea level observing system sets standards for its core stations, and sea level is an essential climate variable. Gauges must be levelled to benchmarks and their land motion known, or the record mixes ocean change with subsidence.
Hazards
- Storm surges that flood harbours and low coasts
- Tsunamis that need second-by-second data
- Gauges whose land sinks, corrupting the record
- Gauges damaged in the storms they measure
- Datum errors after sensor changes
02What must be measured
What, where, how often, and under which rules.
Each measurement names where it is taken, how often, and the public standard or regulation behind it. Numbers in the sources column open the cited source below.
| Measurement | Where | Cadence | Sources |
|---|---|---|---|
| Sea level | Radar gauge over the water with a pressure gauge as backup | Every minute, faster for tsunami | 12 |
| Vertical land motion | GNSS on the gauge structure | Continuous, daily solutions | 12 |
| Air pressure and wind | Weather sensors at the gauge | Every minute | 31 |
| Datum control | Levelling between the gauge and benchmarks | Each year and after any change | 1 |
03The observation stack
From one base unit to a network.
The same blocks at every scale: instruments and a base node, a site with its radio, a fleet run as one, and a network federated on the open protocol.
- 01
Base unit
A gauge: a radar sensor, a pressure gauge, weather sensors and GNSS on a sensor hub and edge node.
Build a station → - 02
Site
A station: the gauge on a pier or harbour wall, benchmarks, power with backup and two backhaul paths.
Plan a site → - 03
Fleet
A national network of gauges run to one datum and quality plan.
Managed offers → - 04
Network
Agencies share sea level with warning centres and global data centres through open standards.
The open protocol →
- 01Surveillance radar (FMCW)
- 02Water level gauge
- 03Compact weather station
- 04GNSS geodetic station
- 05Sensor and instrument gateway
- 06Edge node (Wedge)
- 07Cellular modem/router
- 08LEO flat-panel terminal
- 09Solar array
- 10Pole
Radio and links
Public cellular
Harbour gauges send one-minute data over cellular to warning centres.
Radio and links
Satellite
A satellite path keeps data flowing when storms take down terrestrial networks.
Edge computeThe node predicts the tide, computes surge as observed minus predicted, raises alerts at thresholds, switches to rapid sampling when a sudden change suggests a tsunami and keeps the datum record.
PowerMains with a long battery backup, or solar on remote coasts; the gauge must keep reporting through the storm that cuts power.
04How it works
From the instrument to the product.
One observation’s path, tier by tier, with the interface on every link and a bill of materials below; then how the one node grows to a site, a fleet and federated networks.
Sea level and storm surge: data path
– of 07
01 Instruments Measurement with sensor identity andcalibration 02 Gateway 03 Node – Wrap in an observation envelope with timequality– Measure quality and uncertainty, attachquality flags– Buffer locally (store-and-forward when thelink drops) 04 Backhaul Commit with transactional outbox andpublish, delivered at least once 05 Site Consumer inbox deduplicates and applieseach record once into governed data 06 Data store Governed product through API, map orexport, correction-aware 07 Products WMO WIS 2.0OGC SensorThings APIRINEX 08 Power and structure Supplies 12 V DC, 24 V DC, 48 V DC to thefield equipment 01 Surveillance radar (FMCW) Ethernet 02 Water level gauge SDI-12 · RS-485 · Ethernet 03 Compact weather station SDI-12 · RS-485 · Ethernet 04 GNSS geodetic station Ethernet · GNSS antenna · 1PPS/10MHz 05 Sensor and instrument gateway SDI-12 · RS-485 · Analogue I/O ·Ethernet · USB 06 Edge node (Wedge) Ethernet · Fibre · USB · RS-485 ·BMC 07 Cellular modem/router Ethernet · USB · RS-232 08 LEO flat-panel terminal Ethernet Site MQTT 5 with Sparkplug B Governed data store Versioned, correction-aware Real-time sea level and surge Long sea-level records with landmotion Tsunami rapid data Datum records 09 Solar array RS-485 10 Pole Ethernet · MQTT 5 SDI-12 · SDI-12 SDI-12 · SDI-12 Ethernet · ntp-nts Ethernet · MQTT 5 Ethernet Ethernet LTE/NR Satellite IP| Item | Equipment | Data ports | Protocols | Power in |
|---|---|---|---|---|
| 01 | Surveillance radar (FMCW)Short-range FMCW radar for perimeter, traffic, drone and water-surface detection. | Ethernet | MQTT 5, OGC SensorThings API | 12 V DC |
| 02 | Water level gaugeRadar, pressure or float gauge for river, lake, reservoir or tide level. | SDI-12RS-485Ethernet | SDI-12, Modbus, MQTT 5, OGC SensorThings API | 12 V DC |
| 03 | Compact weather stationAll-in-one or compact station for temperature, humidity, pressure, wind and rain at a site. | SDI-12RS-485Ethernet | SDI-12, Modbus, MQTT 5, OGC SensorThings API | 12 V DC |
| 04 | GNSS geodetic stationContinuously operating GNSS station on a stable monument for geodesy, deformation and atmospheric water vapour. | EthernetGNSS antenna1PPS/10 MHz | NTP with NTS | 12 V DC |
| 05 | Sensor and instrument gatewayData logger and gateway that reads instruments on SDI-12, RS-485, analogue and Ethernet ports and publishes observations with calibration and time. | SDI-12RS-485Analogue I/OEthernetUSB | SDI-12, Modbus, MQTT 5, OGC SensorThings API, OGC API Connected Systems, OMA LwM2M | 12 V DC, PoE |
| 06 | Edge node (Wedge)Rugged edge node that boots from signed media, attests itself and establishes a site cell from little or no infrastructure. | EthernetFibreUSBRS-485BMC | MQTT 5, DMTF Redfish, IEEE 1588 PTP, NTP with NTS, OPC UA | 12 V DC, 24 V DC, 48 V DC, AC mains |
| 07 | Cellular modem/routerLTE or NR modem or router that uses a public carrier or private network as backhaul. | EthernetUSBRS-232 | 3GPP E-UTRA air interface, 3GPP NR air interface, OMA LwM2M | 12 V DC, PoE |
| 08 | LEO flat-panel terminalElectronically steered flat-panel user terminal for low-Earth-orbit broadband constellations. | Ethernet | — | PoE, 48 V DC, AC mains |
| 09 | Solar arrayPV modules with charge controller sized to the site’s load and climate. | RS-485 | Modbus | — |
| 10 | PoleUtility, street or dedicated pole with clamp positions. | — | — | — |
How it scales
01 Instruments Arbitrary qualified sensors and instruments whosemeasurements are ingested with calibration, units,geometry, time, custody and uncertainty. ×n 02 Node The minimum useful deployable unit: server, ruggedappliance, radio node, sensor gateway, satelliteterminal, AI, scientific, vehicle or virtual node. Node Node agent 03 Site The minimum independently operable localgovernance and failure domain: one or more nodesplus local network, identity, policy, evidence,storage, products and operator surfaces.SITE
Node Node Node ×n 04 Cluster An optional scale or specialisation domain forscheduling, shared storage, accelerators or datalocality.CLUSTER
×n 05 Fleet Coordinates plans, acknowledgements,convergence evidence, update campaigns andcorrection propagation across nodes and sites.FLEET
Fleet controller ×n 06 Federation An exchange of products, capabilities, events orwork across approved, independently administeredtrust domains, using explicit trust, policy,data-locality, version and correction contracts.TRUST DOMAIN
TRUST DOMAIN
TRUST DOMAIN
×n Verifier Applications Data in the field Telemetry Control Data upstream Control Data upstream Control Exchange Evidence Events Exchange- Data in the field
- MQTT 5 with Sparkplug B; connectors for LoRaWAN, OPC UA and instrument buses.
- Telemetry
- OpenTelemetry OTLP.
- Control
- TLS 1.3 with mutual authentication; protobuf messages over gRPC or HTTP/2.
- Data upstream
- At-least-once publication with repeat-safe keys over the control channel or NATS JetStream; QUIC MAY be used on lossy links.
- Evidence
- DSSE-signed in-toto statements; SLSA provenance; SCITT transparency receipts.
- Events
- Event envelopes mapped to CloudEvents 1.0; channels described in AsyncAPI 3.
- Exchange
- OpenAPI 3.1; the OGC API family; SensorThings; STAC; WIS 2.0.
05From order to operation
Every step, from the first call to a running site.
The same crew and the same record carry the work from scope to maintenance.
- 01 Order
Scope the coast and its duties
The scope reads the coast’s flood history, warning duties, existing gauges and their datums, and global network commitments. Nexus Observatory Inc. returns the gauge plan, datum design, warning integration and a price per station and per year. The scope is agreed before any site work begins. 2
- 02 Survey
Survey piers and benchmarks
Crews survey candidate piers and walls for open water at all tides, structural stability, benchmarks nearby, sky view for GNSS, power and backhaul. Findings are recorded with drawings and photographs. Findings shape the kit for each site before anything is built. 1
- 03 Permits
Harbour and coastal consent
Harbour authorities approve installation on their structures, coastal consents are obtained, and radio and radar use are registered. Benchmarks are agreed with the national mapping agency. Every approval is kept with the station record. No crew goes to site before its approvals are in place.
- 04 Build
Build and calibrate
Radar and pressure gauges are calibrated, GNSS receivers tested, nodes configured with tide constituents where known and enrolled with their identities. The station runs together for days before shipping. Nothing ships until the whole kit has passed its tests together.
- 05 Install
Install and level
Crews mount the radar over open water, fix the pressure gauge below the lowest tide, install GNSS and weather sensors, power and backhaul, and level the gauge zero to the benchmarks. Every height is recorded. Crews follow the site safety plan throughout the work. 1
- 06 Commission
Commission against tide staff
Each node proves its identity. Radar readings are compared with tide staff readings over full tidal cycles, pressure and radar are compared, GNSS fixes its position and alerts are tested with the warning centre. Acceptance is recorded with the owner before handover. 12
- 07 Operate
Warn and record
Warning centres see sea level and surge every minute and receive alerts when thresholds are crossed. Scientists receive the long record with land motion removed, and every datum change is kept. Every alert and action is kept on the record. 4
- 08 Maintain
Level every year
Gauges are relevelled to benchmarks each year and after any change, sensors are checked against tide staffs, GNSS series are reviewed for land motion, and software updates roll out in rings. Every change is kept with the station record. Maintenance history stays with each site for its whole life. 1
06Data products and integration
What it delivers, to whom, and into which systems.
Data products
- Real-time sea level and surgeWarning centres and harbour masters
- Long sea-level records with land motionClimate scientists and planners
- Tsunami rapid dataTsunami warning centres
- Datum recordsMapping agencies
Integration
- Warning centresAlerts and one-minute data reach coastal flood and tsunami warning systems.
- Global data centresSea level is shared with global sea level centres.
- Harbour operationsWater levels support harbour navigation.
Exchanged through WMO WIS 2.0, OGC SensorThings API, RINEX.
07Questions buyers ask
Before you scope it.
Why GNSS on a tide gauge?
To separate sea-level rise from the land sinking.
Can it warn of tsunamis?
It switches to rapid sampling on sudden changes.
What if the storm cuts power?
Batteries and a satellite path carry it through.
Can old records be joined?
Yes, through levelling to the same benchmarks.
08Resources
The sources behind this page.
Public standards, regulations and guidance, cited where they apply. Each applies only where its jurisdiction or scope does.
- 1IOC Manuals and Guides No. 14: Manual on Sea Level Measurement and Interpretation, Volume VIntergovernmental Oceanographic Commission of UNESCO · 2016
- 2GLOSS Implementation Plan 2012 (IOC Technical Series No. 100)Intergovernmental Oceanographic Commission of UNESCO · 2012
- 3WMO-No. 8: Guide to Instruments and Methods of ObservationWorld Meteorological Organization
- 4GCOS-244: The 2022 GCOS Implementation PlanGlobal Climate Observing System · 2022
09Related
Use cases and solutions.
Use caseStreet flood observatory
Ultrasonic depth sensors on poles report street-level water depth as open data and alerts.The full use case →SolutionOcean and coastal observing
Moored buoys, profiling floats, tide and wave gauges, coastal radar and AIS reception with quality-controlled feeds.Solutions for oceans →SolutionHydrometeorological and flood observing networks
Stream gauges, rain gauges, weather radar and automatic weather stations built to WMO practice, reporting through WIS 2.0 where the agency requires it.Solutions for oceans →SolutionTiming and positioning integrity
PTP grandmasters with GNSS holdover, interference detection and timing monitoring for networks and instruments.Solutions for oceans →10Oceans: specialized fields
Other fields of this industry.
Specialized fieldWaves and coastal buoys
Moored buoys that measure waves, wind and sea temperature off ports and coasts, for safe navigation, coastal design and the warnings that keep people off dangerous seas.The full field →Specialized fieldCoastal and bathing water quality
Sondes and samplers at beaches, estuaries and aquaculture zones that watch temperature, oxygen, turbidity and algal blooms, so authorities protect bathers and shellfish in time.The full field →Specialized fieldUnderwater noise
Hydrophone moorings that measure ship noise, piling and other sound in the sea, for marine protection duties, offshore construction and the animals that depend on hearing.The full field →Bring us the site.
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