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A description of how the merged wind observation product works, how it is produced, and its relevance to various demographics.

Outline

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Background

Differential heating of the Earth’s surface and atmosphere by the Sun provides the fuel for wind generation. Rising air is less dense and produces a low pressure area. Sinking air is denser and produces a high pressure area. The atmosphere seeks to balance itself, so wind is generated by the air moving from an area of high pressure to an area of low pressure, sometimes with considerable force.

Wind patterns can be local or regional which affect a larger area over multiple coastal regions. Local wind patterns can be created by interaction with mountains near the coast and local heating and cooling of the land which produces a sea breeze effect. Larger scale wind patterns are associated with the familiar cold and warm fronts that you see on your local weather station, storm systems and hurricanes.

Wind is a global transportation system for heat, moisture and airborne particles. Since over 70% of the Earth is covered by water, the interaction between the ocean and atmosphere is a complex, but critical part of our climate. Surface ocean circulation, coastal currents, waves and swell are primarily driven by the wind. Meanwhile, ocean circulation plays an important role in the distribution of heat and water vapor in the atmosphere. Monitoring the wind and other variables such as air pressure, air temperature and water vapor gives us valuable information about how the ocean and atmosphere interact to produce changes in our weather and climate.

How to Read a Wind Barb

Reading a wind barb is a little different than reading the color dots on a temperature map. The barbs at the end of the line represent 10 of whatever unit the speed is being displayed in. So if you are looking at winds displayed in knots, 10 knots would be one barb. But if you display the same observation using meters per second, there would only be half of a barb because the speed would be 5.144 m/sec. This isn't so confusing if you think of it like an old fashioned thermometer. If you take your temperature with two thermometers, one reading Fahrenheit (F) and one reading Celsius (C), you will (hopefully) get the same reading, but the mercury might not go as high in the Fahrenheit thermometer as it does in the Celsius one because 98.6 degrees F is only 37 degrees C.

Wind is a little trickier than temperature, however, because you usually need to know both the speed and the direction. The diagram below shows how to the read direction from a wind barb.

Data Gathering and Quality Control

Near, real-time measurements of wind, collected from a variety of platforms, are displayed. Measurement sites include sea buoys, ships, coastal stations, and airports. Satellites provide a wide-area of coverage but only once or twice-a-day.

Each hourly display shows the measurement from all reporting stations taken closest to the top of each hour. Many measurements get displayed within one to two hours from the time the measurement was taken. Observations are available for display up to two weeks after it is posted on this site.

SEA-COOS data contributors are University of Miami (Explorer of the Seas), University of South Florida (COMPS), Skidaway Institute of Oceanography (SABSOON), University of South Carolina (Caro-COOPS), and University of North Carolina (NC-COOS). The federal data sources for surface wind observations whether on land, near-shore or offshore are National Weather Service, National Data Buoy Center, National Ocean Services, United States Geological Survey and Volunteer Observatory Ship Program. Each contributing institution has its own set of data quality control procedures and assurances. However, SEA-COOS does range checks for reasonable values of wind speed and wind direction. For example, only values of direction from 0 to 360 are allowed. If a value falls outside this range, the data are not displayed.

Layer Descriptions
10 m standardized wind
Wind speed tends to increase with height above the surface. To compare winds from one location to another it is useful to standardize the wind to a particular height. The World Meteorological Office uses 10 meters has the height for this standard. Winds measured offshore at heights other than 10 meters can be easily corrected to 10 meters. Whereas winds measured over land are more difficult to correct. Over land the frictional affect is very complex and difficult to predict because of plants, trees, buildings, and geographic features.

Measurements of wind speed and direction are displayed by choosing the “10 m Standardized Wind” Layer from the Map Layers. Just like the Wind Layer, a wind barb is displayed at each measurement location was made and corrected to 10 meters. The correction is applied only to measurements over water.

QuikSCAT winds from satellites
This product layer shows the winds computed by remotely sensing the ocean’s surface via satellite. One of the fundamental problems faced by oceanographers is the sheer size of the oceans. Oceans cover 70 per cent of the Earth's surface. Remote sensing allows measurements to be made of vast areas of ocean at repeated time intervals

QuikSCAT is the name of a NASA satellite which has a SeaWinds scatterometer that measures both the speed and direction of winds near the ocean surface. A scatterometer is a microwave radar sensor used to measure the roughness of the sea surface through the strength of the backscatter signal. The high radio frequency sent to the Earth’s surface from the satellite hits the ocean surface and is scattered back to the satellite’s antenna. A rough ocean produces a stronger signal than a smooth ocean.

The QuikSCAT satellite was launched in June 1999 in a near polar orbit, circling the Earth every 100 minutes and daily taking approximately 400,000 measurements over 90% of the Earth. The primary mission of this satellite is to provide enhanced weather forecasting, storm detection, enhanced information for ship routing, predictive products for critical fisheries related climate phenomena such as El Nino and products related to hurricane development. In addition the program provides climate researchers with long-term measurements of wind changes on the Earth’s surface.

Last 48 hour observations
This product layer shows the location where a wind observation was made within the last 48 hours. This layer is useful to see where observations were made but reported less frequently than once an hour. It is also valuable for monitoring ship measurements.

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