Transcript Communications and Weather

Met Data via the
Internet
Tim Thornton
Why use the Internet?
There is plenty of weather data available through the
official marine channels: VHF, Navtex, Shipping
Forecast, Weatherfax, so why use the internet?
November 2007
Smartcom Software Ltd
Why use the Internet?
There is plenty of weather data available through the
official marine channels: VHF, Navtex, Shipping
Forecast, Weatherfax, so why use the internet?
 Convenience – no need to wait for the next broadcast
November 2007
Smartcom Software Ltd
Why use the Internet?
There is plenty of weather data available through the
official marine channels: VHF, Navtex, Shipping
Forecast, Weatherfax, so why use the internet?
 Convenience – no need to wait for the next broadcast
 Content – much better on the internet in terms of
area, parameters, detail etc
November 2007
Smartcom Software Ltd
Why use the Internet?
There is plenty of weather data available through the
official marine channels: VHF, Navtex, Shipping
Forecast, Weatherfax, so why use the internet?
 Convenience – no need to wait for the next broadcast
 Content – much better on the internet in terms of
area, parameters, detail etc
 Comprehension – presentation is often easier to
understand
November 2007
Smartcom Software Ltd
Why use the Internet?
There is plenty of weather data available through the
official marine channels: VHF, Navtex, Shipping
Forecast, Weatherfax, so why use the internet?
 Convenience – no need to wait for the next broadcast
 Content – much better on the internet in terms of
area, parameters, detail etc
 Comprehension – presentation is often easier to
understand
November 2007
Smartcom Software Ltd
How to Connect
A number of different ways to connect to
the internet:
November 2007
Smartcom Software Ltd
How to Connect
A number of different ways to connect to
the internet:
 Broadband at home
 Wi-Fi in the marina
November 2007
Smartcom Software Ltd
How to Connect
A number of different ways to connect to
the internet:
 Broadband at home
 Wi-Fi in the marina
 Mobile phone in coastal waters
 Satellite phone e.g. Iridium or Fleet
offshore
November 2007
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Mobile Coverage
Vodafone Coverage
- Need a good antenna to get this range
- Note lower range of 3G services
Worldwide Coverage (All Networks)
On all 4 GSM frequencies
November 2007
Smartcom Software Ltd
Facilities
Service
Voice
Fax
Text
Data
GMDSS
Cover
WiFi
Via VoIP
Via net
No
2,000,000
No
Marina
GSM
Yes
Yes
Yes
9600
No
10-15 miles
GPRS
Via GSM
Via GSM
Via GSM
~ 30,000
No
10-15 miles
3G
Yes
Yes
Yes
> 380,000
No
10-15 miles
Iridium
Yes
No
Yes
2400
No
Global
Thuraya
Yes
No
No
9600
No
Med, Middle East
GlobalSt
ar
Yes
No
No
9600
No
Offshore
INMARS
AT C
No
Text only
Yes
60
Yes
Global
INMARS
AT MiniM
Yes
Yes
No
2400
No
Offshore
No
56,000
packet, 9,600
dial-up
No
Offshore
INMARS
AT Fleet
33
Yes
November 2007
Yes
Smartcom Software Ltd
Costs (UK£ inc. VAT)
Service
Purchase
Monthly sub
Voice /min
Data per Megabyte
WiFi
< £100
Low
Free
Free
GSM
£200 - £500
0
£0.15 - £1.10
£2.13 - £8.10
GPRS
0
0
N/A
£0.30 - £8.50
Iridium
£1800-£2500
£0 - £25
£0.50-£1.75
£56.80 - £99.50
Thuraya
£1400
£25.00
£0.50 - £1.30
£7.10 - £18.50
GlobalStar
£800 - £1600
£16.60
£0.60 - £2.50
£8.50 - £30.00
INMARSAT C
£1750 - £2700
0
N/A
£5783
Mini-M
£4250
0
£1.60 - £2.80
£91 - £160
INMARSAT Fleet 55
£16000
0
£ 1.50 - £2.30
£10.50 - £14.00 for ISDN, £20 £26 for packet
INMARSAT Fleet 33
TBA
0
£ 1.50 - £2.30
£10.50 - £14.00 for ISDN, £20 £26 for packet
November 2007
Smartcom Software Ltd
How to Get Data
A choice of two different ways to access the
data:
 Web browsing on a PC or mobile phone
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Easy to use
Masses of data
Slow to download
Data not saved for offline access
November 2007
Smartcom Software Ltd
How to Get Data
A choice of two different ways to access the
data:
 Download data to software on your PC
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Needs special software
Data more limited
Faster, cheaper download (especially if direct to
server)
Data available offline
GRIB files often available
November 2007
Smartcom Software Ltd
Sources of Internet Data
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Current weather reports e.g. weather
stations, weather cams
Remote sensing
Forecast maps
Weather Portals – One stop shops
Forecast data e.g. GRIB
Weather routing
Commercial services
November 2007
Smartcom Software Ltd
Weather Reports
Useful for:
 Seeing the current conditions before you
get down to the boat
 Seeing any local effects, e.g. sea
breezes, too small or too short to be
forecast
 Comparing forecasts and actuals
November 2007
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Weather Reports
Weather station reports
 Weather buoys
 Reporting Ships
 Weather cams
Check the time of the weather reports.
Beware of local effects, and the location of
the station relative to you
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November 2007
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Met Office
Official Weather Stations
November 2007
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Weather Underground
Personal and Official Weather Stations
November 2007
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Weather Underground
Weather report –
and data tabulated every 5 mins for personal, 1 or 3 hours for official stations
November 2007
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US NDBC – Ships, weather
buoys etc
Search for all weather reports within a given
distance and time period
See all reports with latest data
See the history of data at weather buoys
November 2007
Smartcom Software Ltd
November 2007
Smartcom Software Ltd
SmartMet Weather Reports
November 2007
Smartcom Software Ltd
SmartMet Weather Reports
November 2007
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Remote Sensing
Weather satellite images and derived products
Visible and infra-red images for cloud type and
height, sea surface temperature, ocean
currents available real time
Derived products: wind, wave, current etc very
useful (particularly over sea areas)
Coverage and speed of delivery needs
improving for some products
November 2007
Smartcom Software Ltd
Pseudo Colour Image
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November 2007
Resolution ~1 3km/pixel
Images up to every
15 minutes
White – high cloud;
yellow – low cloud
Can show sea breeze
front on higher res
images
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SmartMet Satellite Images
Satellite image overlaid
with forecast isobars and
wind arrows
November 2007
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Sea Surface Temperature
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November 2007
Needs no clouds!
Land/sea temperatures
can help predict sea and
land breezes
Gulf Stream & other
currents
Fish finding e.g. on
fronts of temperature
changes
Smartcom Software Ltd
Wind Speed and Direction
- QuickScat and Ascat
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November 2007
Satellites each pass
twice daily
Data 1-2 hours old when
processed (or longer
depending on source)
25km resolution over
open water only
Wind direction can be 90
deg out occasionally
Can show local
behaviours not shown
by forecasts
Smartcom Software Ltd
Wind Speed and Direction
- QuickScat and Ascat
November 2007
Smartcom Software Ltd
Digital Atmosphere
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Software for downloading, decoding and viewing current
weather reports
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Also displays GRIB files
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A huge variety of data is available, but some of it is too
technical for the average sailor
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Simple and easy to use
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Not as much data for Europe as for USA, due to different
government policies
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Cost from US$89 for the software, downloads free data
November 2007
Smartcom Software Ltd
Digital Atmosphere
November 2007
Smartcom Software Ltd
Numerical Forecasts
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All forecasts based on numerical models
Manual forecaster input only useful for first 12 days
Synoptic models for global weather forecasts
(e.g. GFS, WW3, ECMWF)
Mesoscale models for higher resolution local
forecasts (e.g. ETA, Theyr, HIRLAM, MM5).
These can better model fronts, sea breezes,
mountain winds etc
November 2007
Smartcom Software Ltd
Forecast Limitations
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The smallest feature in the forecast is about
4x the grid size, so a 0.5° forecast doesn’t know
about most of the Channel
High Res forecasts from Theyr, ProGRIB,
Moving Weather, WindGuru, Kona all use GFS
model as the starting point, with no extra met
data input, so are often no better than the
GFS model (though sometimes they are)
Beware of sites and software that just
interpolate to get a higher resolution, e.g.
Moving Weather, or web sites giving forecasts
for “your location”, e.g. BBC
November 2007
Smartcom Software Ltd
Weather Maps
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Many sites have weather maps for viewing
Typically generated automatically from
numerical models
Sites may use the same data source but just
presented differently
Images can be large, so slow to download
Viewing relatively inflexible
November 2007
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Weather Map Sites
Westwind – www.westwind.ch searchable database of all European
data
Theyr – high resolution forecasts –
www.theyr.net or www.theyr.tv
November 2007
Smartcom Software Ltd
Westwind Example
November 2007
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Met Office
November 2007
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GRIB Files
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Standard file format displayed by many chart plotters
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Download numerical data – faster than images
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Free data: 1 or 0.5 degree, 3 or 6 hour resolution of wind,
pressure etc, all repackaged from standard US sources
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Use tools like Saildocs or download from sites like Raymarine
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Higher resolution data at a charge e.g. Meteo France NaviMail,
ProGrib
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Each file is standalone, so cannot combine downloads
November 2007
Smartcom Software Ltd
Free GRIB File Sources
Raytech – www.raymarine.com (3 day
fcsts)
Navcenter.com –
www.navcenter.com/newdwnld.ccml
Global Marine Net –
www.globalmarinenet.net/grib.htm (5
day fcsts)
Saildocs – www.saildocs.com - e-mail
service
November 2007
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GRIB Files
November 2007
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Moving Weather
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Uses standard GFS data, but interpolates to make it
seem better
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Simple and easy to use
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Good for overview or long passages, but not detailed
enough for coastal sailing
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Cost £25 for the software, and £125/year for the
forecasts
November 2007
Smartcom Software Ltd
UGrib
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Uses standard GFS data for wind, rain and
pressure
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Simple and easy to use
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Uses discrete GRIB files
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Free of charge (at the moment!)
November 2007
Smartcom Software Ltd
SmartMet
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Combines forecasts, satellite imagery, current
weather reports – widest range of data of any
software in its class
Small, fast downloads – smaller than GRIB
Integrated database, no problems of separate
files
GRIB import and export
Subscription £49/year
November 2007
Smartcom Software Ltd
November 2007
Smartcom Software Ltd
November 2007
Smartcom Software Ltd
Chart Plotters with GRIB
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seaPro – GRIB viewer and routing
Maxsea – GRIB downloads, viewer and
optional routing
Raytech – GRIB downloads, viewer and
routing
Nobeltec – GRIB downloads and viewer
November 2007
Smartcom Software Ltd
Weather Routing
Calculating the quickest route to sail
Inputs:
- Your boat’s polars
- Tidal streams / ocean currents
- Forecast winds (GRIB file)
Outputs:
- Optimal route
- Isochrones
Programs: Maxsea, seaPro, Raytech, Deckman
November 2007
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Maxsea Routing
November 2007
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Conclusions
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Huge amounts of data out there
Research the data that meets your needs
before going afloat
Trade-off of cost of data against level of detail,
reliability and comms costs
Always compare the forecast with what you
observe!
November 2007
Smartcom Software Ltd