A Neophyte's Notes on Kite Aerial Photography: Miscellaneous

Bay Area Winds

I find when I am out and about that I constantly check for wind sign. I scan, and generally appreciate, the swaying of tree limbs, the water vapor leaving a cooling tower, or a flag's angle of repose. A similar phenomenon strikes when I am connected to the Internet.  Several times a day I will check an amazing source for near real time wind data in the Bay Area. called San Francisco Bay Area Wind Patterns. The site is one of the best examples of what I call an Internet dividend. It provides access to the results from a somewhat esoteric project to a  broad, and appreciative, audience. The Wind Patterns Project uses first principles and several dozen observed weather reports to generate predicted real time wind velocities across the Bay Area. Originally developed to support cleanup efforts for potential oil spills, the results now support the recreational pursuits of windsurfers, sailors, sailplane enthusiasts, and kite fliers. They have recently added a fun, animated streaklines version of the map. Bravo. 

They have kindly given me permission to link to their most current image below:

Image courtesy USGS San Francisco Bay Wind Patterns Page

Another fun and useful site provide the results from radiosonde soundings above Oakland. Upper air data that are collected and transmitted during the flight of a radiosonde include the air pressure, air temperature and humidity measured continuously by the instruments aboard the radiosonde package. The radiosonde observations (RAOB) are directly transmitted by the radio transmitter for various levels in the free atmosphere. At the receiving station, the height of the package is sequentially computed at each reporting level using an equation (hypsometric equation) from the reported pressure, temperature and humidity of each incremental layer. The wind information at various levels is determined The wind speed and wind direction at various levels are determined from the ground-based radio tracking antenna that tracks the instrument package as it is carried by the wind during the ascent of the radiosonde. Radiosonde data are presented in Skew-T plots -- neat stuff.  

It also seems that the Internet can connect you to a weather station within a few blocks of your house (here is my example.) If you are interested in the San Francisco Bay Area, the National Weather Service runs a great GIS (map) based guide to real time weather data from dozens of Bay Area data collection sites (this map scrolls to cover the entire Bay Area).. 

AWS is a major player in this area with over 5,000 weather stations placed in the field. Most are equipped with an external rooftop WeatherNet monitoring system and an InstaCam. The WeatherNet System is a real-time commercial weather monitoring system that measures outdoor and indoor temperatures, rainfall, relative humidity, light intensity, wind speed and direction and barometric pressure.

The big picture sometimes helps and a good place to start is the Intellicast Sailing Forecast page. There is also a San Francisco area specific page available from Intellicast. You also cannot go wrong in consulting the regional WWW site for the National Weather Service.

The National Weather Service has been working on improving their site and is making great progress. Of  interest here is a seven-day forecast summary that includes winds in the first few days.

In the category of  military dividend is a US Navy site that serves animated wind data for California. Or you can zoom out to see the eastern Pacific Ocean and an ingenious derivation of wind speeds from satellite images. Wind estimates are produced by tracking features in the GOES-8/9 water vapor and infrared window channel data (clouds) and are designated as ' water vapor` and 'cloud drift' winds. Automated pattern recognition software is used to detect and track features in three successive images, each 30 minutes apart. The wind vectors thus created, consisting of speed and direction, are assigned a height above the earth's surface based on the infrared energy signatures and guidance from corresponding numerical weather forecast parameters. Additional information is available at a general weather forecast page for the Western US.

John Gilmore of the Oregon County Fair Embassy Camp forwarded another lovely military dividend where one can find the US Navy's forecast for wave height and direction over the entire Pacific Ocean -- really fun to track if you live near the Pacific. John wrote "when I visit local beaches, I check the NOAA buoy data and then I look at this page to figure out what's happening out in the Pacific and when it's likely to arrive on our coast. It's pretty cool to watch the storms develop and fade out."  

Ken Poulton provides a tabular summary of current Bay Area Wind Conditions. Of course, you can generate your own tabular data and plots by finding and querying meteorological databases. One of my favorites is the California Data Exchange Center. (CDEC) run by the California Department of Water Resources. It allows you to slide and dice data from a network of hundreds of secondary weather stations. Here is example data from within 1/2 mile of  my house (Oakland North station).  

I also appreciate this site for providing comprehensive data from Northern California bouy reports

The local USGS site is chock full of fun pages. For instance, you can plot your own time series graphs or look at a map-based readout of tide and wind at five SF Bay weather stations. Finally, the Bay Area is well covered by Live Cams and these are useful for checking fog and cloudcover --come give us a visit.

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Comments to author: crisp@socrates.berkeley.edu . All content, graphics and
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All rights reserved. Revised: 25 June, 2010

URL: http://kap.ced.berkeley.edu/background/wind1.html