Introduced in April 2007, a dropsonde is an instrument used to gather information in tropical storms and hurricanes conditions. Primarily used by hurricane hunters, this device contains a GPS receiver, along with pressure, temperature, and humidity sensors to capture atmospheric profiles and thermodynamic data. The data is fed into supercomputers for numerical weather prediction,data.

To obtain the data, an aircraft, either operated by NOAA or the U.S. Air Force, flies into the hurricane. The dropsonde is released when the plane reaches the eye of the hurricane, normally at around 10,000 feet. Its descent is slowed and stabilized by a small square-cone parachute. This allows for multiple readings to be taken before it reaches the ocean surface, taking from three to five minutes.

The information includes:

1. The date and time of the drop.

2. Location of the drop, indicated by the latitude, longitude, and Marsden square.

3. Standard isobaric surfaces: the height, temperature, dewpoint depression, wind speed, and wind direction at the surface, and at where the following air pressures are found as the device is descending: 1000, 925, 850, 700, 500, 400, 300, 250 hectopascals .

4. Air pressure, temperature, dewpoint depression, wind speed and wind direction of the tropopause.

More Info: en.wikipedia.org