The hurricane array are SVP-BW free drifting buoys deployed every year by
AOML and NAVOCEANO, in the tropical Atlantic, prior to the hurricane season
to help in the prediction and forecast of hurricanes.
These buoys meet the accuracy requirements for the World Meteorological
Organization's (WMO) program, and in addition to measuring sea surface
temperature (SST) they also measure barometric pressure (B), wind speed
and direction (W).
The 2001 hurricane array was composed of ten drifting buoys provided by AOML, deployed by the Navy, from a US Navy aircraft in April, August and September 2001 (buoy id.s 6786-6790, 6690, 6686-6687, 6688-6689) and nine drifting buoys provided by the Navy, deployed in August 2001 (id.s 7647-7648,7772-7776, and 7896-7897). Buoy 7775 died on deployment. Funding for first ten buoys was provided by the NOAA Office of Global Programs. The second nine buoys were contributed by the Naval Meteorology and Oceanography Command (NMOC). NMOC performed both deployments.
The 2002 hurricane array is composed of twelve operational SVP-BW drifters manufactured by Metocean Data Systems, Ltd. Buoys were deployed by US Naval Aircraft in May and August 2002. (Argos ID's 26977-26979 and 27028-27034, 34835-34836). Buoy 27034 died ten days after deployment, the other eleven buoys remain on the GTS. Funding for the twelve operational buoys were contributed by the naval Meteorology and Oceanography Command (NMOC).
Plans exists for the deployment of eleven " DIGITAL MINIMET " SVP-BW drifters manufactured by Pacific Gyre in support of the CBLAST "HURRICANE STUDY". The deployment timing will be coordinated with the CBLAST Hurricane Study Activities. Deployment would be carried out by the 53rd Air National Guard pending air certification. Funding for the eleven DIGITAL MINIMET buoys was provided by the NOAA Office of Global Programs.
The purpose of the annual deployment of the hurricane array is to provide forecasters with surface meteorological data in the region of hurricane development. Normally, weather data over the oceans is observed and sent by merchant ships, but obviously these ships will divert from their normal tracks to avoid areas of rough weather so there is a dearth of data where and when it is needed most. Thus, the buoy data (and data collected by satellites and special research aircraft) are very important. They are input into the computer weather models from which forecasts are made. Additionally, local forecasters use the buoy data to make better regional assessments of the impact of a storm. Fanally, the data helps researchers improve the models, resulting in better forecasts in future hurricane seasons.
Each buoy is a 14 inch sphere which floats partially submerged. A "holey sock" drogue centered at 15 meters depth reduces the effect of the wind pushing the buoy through the water. Sensors measure SST and BP. A wind vane mounted atop the sphere and an internal compass are used to measure the direction from which the wind blows. Two acoustical devices, one listening at 2 KHz and one at 8 KHz, are used to estimate wind speed. Data are acquired continuously and then an average for each sensor is calculated at the top of the hour. When a satellite passes overhead (roughly every six hours), the past four hourly sets of averaged data are transmitted. The satellite also measures the location of the buoy.