Xynthia, back to the future

Movie of wind forecast from grib.us (HiRes GRIB model)

As forecasting models improve, forecasters are able to issue more accurate and timely storm warnings and advisories.

Ex.: Weather forecast from wunderground.com,

February 26, 2010 (2 days before the passage)

"A large 1000 mb low pressure system named "Xynthia" is over the eastern Atlantic, and is expected to rapidly intensify Saturday morning into a meteorological 'bomb' that will bring high winds and flooding rains to Portugal, northern Spain, and western France. The models are coming into better agreement now, and have shifted their position for the storm's maximum intensity eastwards. France is now in the bullseye, and the storm is predicted to be at maximum intensity on Sunday morning when it will be positioned over northwestern France. The storm's powerful cold front will sweep ashore south of the low, bringing sustained winds of 50 - 60 mph (80 - 95 km/hr) to the coast of France's Bay of Biscay, with gusts over hurricane force (120 km/hr). The central pressure at that time will range from 966 mb to 972 mb, according to two of our top computer models, the ECMWF and GFS."

How to use Marine GeoGarage : quick overview

Online nautical maps of the world, regularly updated

• Marine GeoGarage is a website that will allow you to look at the NOAA charts. It will open in a new window that you can then maximize to get the best view. Also, if you sign up with the site (free), then you will be able to save waypoints and routes.

• When you open the site, if you first see a satellite view, then zoom into your favorite area by clicking on the map several times and then click on the “Map Content” box in the upper right hand corner of the chart to drop down the menu. Under the “NOAA” box, there is a slider. By moving that slider to the left, the background map will start to show through. The background map you see depends of the little drop down box under “background” at the top of the “Map Content” box. “Hybrid” is a good choice. Click on “Map Content” again to close the box. It is interesting to compare the shoal areas on the chart with the view in the satellite view.

• In the lower left-hand corner of the chart, you will see a lat/lon box giving the lat/lon of the mouse cursor.

• In the upper-left hand corner of the chart you will find the typical navigational tools of a Google Map. You can zoom in and out and move in four directions. You can also zoom with the thumbwheel of your mouse.

• To the right of the navigational tools, there is a tool box. The “hand” lets you move the map around, the “flag” lets you set a waypoint and the “lines and boxes” lets you make a route. Just click on the one you want.

• In the lower right-hand corner, there is a small map. If you grap the shaded box in the middle by clicking and holding your cursor, the can move the box all around the chart quickly.

• Once you play around with the site, it becomes very easy to use.

Press release : Marine GeoGarage, nautical charts web portal

Updated : May 12, 2010

Marine GeoGarage ushers in a new era of nautical mapping services with the launch of its marine charts portal, built on Cloud Computing technology.

http://marine.geogarage.com/routes

The web site is the world's first online nautical map service allowing to display maps coming from different international Hydrographic Services.

Today the catalogue of charts regroups all the public raster charts from NOAA (US), DHN (Brazil), Linz (New Zealand).
Marine GeoGarage's web interface also gives site visitors viewing access to all private charts from UKHO (UK), CHS (Canada), SHN (Argentina) accessible via some monthly 'Chart Premium' subscription (9.9 €/month)
Today more than 3000 electronic charts are available in the GeoGarage servers; additional providers' layers are in preparation.

The big advantage is that all the layers are kept updated regularly so the user is sure to visualize recent documents.

But the web site is not only a seamless chart viewer overlaying charts at different scales on aerial and satellite imagery from Google Maps.
It also allows the user to plot waypoints and to prepare some navigation routes which can be saved in his account after free registering and uploaded to GPS (in gpx format or directly to Garmin GPS via its Communicator web plugin)

Xynthia storm violently hits French Atlantic coast

Sailing boats out of the La Rochelle harbor

Saturday, Xynthia touched Portugal and Spain before crossing the French coast.

In Britanny and much of the Atlantic coast, these winds, coupled with very strong tidal factors, have led to a rise in sea level over a meter.

Links :

• flood impact for Ile de Ré
• Ile de Ré : Spot Image with Google Earth
  

Xynthia formed "when the cold winds of altitude, the famous jet streams very powerful, came into contact with a warm air mass situated in low layer" in the middle of the Atlantic at about 30 ° north latitude. The large temperature difference between the two air masses generated the "deepening" of a huge whirlpool, or depression, which was then evacuated to the northeast.
"These winter storms are relatively common but most of the time they are born farther north off Iceland and the British Isles and do not reach such intensity," says Patrick Galois, Meteo France Engineer.

The violence of Xynthia comes from the fact that it has been formed much farther south than usual and has mobilized a large amount of warm air.

Survey routes design made of parallel transects

http://gridcoverage.appspot.com/

This tool allows to create parallel profiles for a specific survey area just introducing 2 geographical points on the map (generally perpendicular to the general trend of the shore) and an uniformly-spacing distance between a selected number of profiles.

Application : optimization of bathymetric profiles in depth sounding surveys
Possibility to save the result in Olex format, kml for Google Earth display or CVS for spreadsheet and to play with a simulation tool to help to manage the reduction of costs involved in hydrography missions (calculating ETA on waypoints introducing boat speed for each leg)