1. Terena Networking Conference, 2011-05-18, Prague examine the performance and delay of 430 tsunami warning stations SEA LEVEL STATION MONITORING FACILITY Bart Vanhoorne, Francisco Hernandez Flanders Marine Institute (VLIZ) Belgium www.ioc-sealevelmonitoring.org

2. Terena Networking Conference, 2011-05-18, Prague Sea level station? tide gauge continuously measure the water level compared to reference level (benchmark) on land / buoy solar power 1 or more sensors sensor types: –float (mechanical) –radar (accoustic) –pressure –… others

3. Terena Networking Conference, 2011-05-18, Prague Tide gauges: what does it look like?

4. Terena Networking Conference, 2011-05-18, Prague Tide gauge purposes Real time: tsunamis Delayed mode: sea level rise (>1800), QC Problems realtime: Storm surge? Tsunami: too late Problems delayed: Vertical land mass movement

5. Terena Networking Conference, 2011-05-18, Prague Tide gauge: tsunami example Japan 2011-03-11

6. Terena Networking Conference, 2011-05-18, Prague Tide gauge management Many networks local/regional/global Own systems/standards Interoperability? US Tide gaue network

7. Terena Networking Conference, 2011-05-18, Prague How is the data retrieved? Transcribe Digitally –go and fetch + physically copy –Wireless: GPRS, satellite, WiFi, etc –Wired: internet, dail-up, leased line, etc Delayed: any will do Real time: 3 methods 1.GTS 2.BGAN 3.Internet: FTP, email, HTTP

8. Terena Networking Conference, 2011-05-18, Prague 1. GTS Global Telecommunications System managed by World Meteorological Organization (WMO) defined as: "The co-ordinated global system of telecommunication facilities and arrangements for the rapid collection, exchange and distribution of observations and processed information within the framework of the World Weather Watch.“ integrated network of point-to-point circuits, and multi- point circuits which interconnect meteorological telecommunication centres

9. Terena Networking Conference, 2011-05-18, Prague GTS Structure Hierarchiecal Main Telecommunication Network (MTN): Melbourne, Moscow and Washington Regional Meteorological Telecommunication Networks (RMTNs) Nationcal Meteorological Centers (NMC) responsible for receiving data and relaying it selectively on GTS circuits IOC Sealevel Station website

10. Terena Networking Conference, 2011-05-18, Prague (dis)advantages GTS ~ black box (user) interconnected via land and satellite network: failover, routing,... limited access (only meteo centers) both data upload/download no congestions independent

11. Terena Networking Conference, 2011-05-18, Prague 2. BGAN Broadband Global Area Network Satellite: Inmarsat Small dish: size of laptop World coverage Public internet IP address Cheap Currently Testing phase HTTP POST

12. Terena Networking Conference, 2011-05-18, Prague 3. Internet FTP server: local at VLIZ or remote: formats! Email: limited HTTP –Webservice (i.e. NOAA: OpenDAP) –SOAP (i.e. German tide network) –Scrape HTML

13. Terena Networking Conference, 2011-05-18, Prague Website + Edit metadata + Webservice JSON/XML

14. Terena Networking Conference, 2011-05-18, Prague From tide gauge to website (GTS) Tide gauge GTS Satellite GTS routed to Belgian METEO Office (KMI) FTP upload at VLIZ (1x/min) Batch PHP script (1x/min) ~250 stations database website Satellite

15. Terena Networking Conference, 2011-05-18, Prague GTS gauges performance Transmit interval GTS = 1x/5min - 1x/15min: time slots Median delay = 11min Ratio expected/arrived ~100% -> almost no message loss

16. Terena Networking Conference, 2011-05-18, Prague From tide gauge to website (Internet) Internet line / ISP / dailup / Wifi /... FTP upload (local) FTP upload at VLIZ Webservice HTML page Batch PHP script (1x/5min) ~200 stations database website Tide gauge

17. Terena Networking Conference, 2011-05-18, Prague Internet performance Lots of communication errors HTTP/FTP/timeout/ … Median delay 11-12min Ratio: bad

18. Terena Networking Conference, 2011-05-18, Prague From tide gauge to website (BGAN) Webservice script triggered database website Satellite Tide gauge + BGAN dish

19. Terena Networking Conference, 2011-05-18, Prague BGAN Performance No batch script delay = 0-1 min terminals only send 1x/5min Transmission cost = expensive Ratio ~100

20. Terena Networking Conference, 2011-05-18, Prague Conclusion GTS + reliable - transmission <1x/5min = difficult - not everyone has access Internet - not reliable - few already do 1x/15sec + easy to use, easy accessible BGAN + Reliable + Fast: triggered, no batch -Expensive

21. Terena Networking Conference, 2011-05-18, Prague Questions? Thanks. www.ioc-sealevelmonitoring.org