Dropsonde
From Wikipedia, the free encyclopedia
A dropsonde is a weather reconnaissance device created by the National Center for Atmospheric Research (NCAR), designed to be dropped from an aircraft at altitude to more accurately measure (and therefore track) tropical storm conditions as the device falls to the ground. The dropsonde contains a GPS receiver, along with pressure, temperature, and humidity (PTH) sensors to capture atmospheric profiles and thermodynamic data. It typically relays these data to a computer in the aircraft by radio transmission. The device's descent is usually slowed by a parachute, allowing for more readings to be taken before it reaches the water beneath.
Dropsondes are commonly used by Hurricane Hunters to obtain data on hurricanes, and these data are then fed into supercomputers for numerical weather prediction, enabling forecasters to track and predict what will happen to the hurricane. 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 (center) of the hurricane, normally at around 10,000 feet (approx. 3,000 meters). The dropsonde sends back coded data, which includes:
- The date and time of the drop. Time is always in UTC.
- Location of the drop, indicated by the latitude, longitude, and Marsden Square.
- 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 dropsonde is descending: 1000, 925, 850, 700, 500, 400, 300, 250 hectopascals (hPa).
- Significant isobaric surfaces: the temperature and dewpoint depression of other levels of atmospheric pressure deemed significant
- Air pressure, temperature, dewpoint depression, wind speed and wind direction of the tropopause.
Also included in the report is information on the aircraft, the mission, the dropsonde itself, and other remarks.
