The uncrewed NASA Global Hawk (GH) aircraft took off this morning for a 26-hour mission to study the Saharan Air Layer (dust from Africa) in the far eastern tropical Atlantic. There is currently a tropical wave located in the region that the GH will sample, and data collected from this flight will help researchers and forecasters better understand why some of these waves do or do not develop. One of the primary instruments that is being used on this mission the the NOAA/NCAR (National Center for Atmospheric Research) dropsonde system, called AVAPS (Airborne Vertical Atmospheric Profiling System). Dropsondes are small, cylindrical instruments that fall on parachutes and relay Temperature, Pressure, and Humidity twice a second back to the aircraft and Wind Speed and Direction four times a second. The data is then sent to ground computers where NOAA scientists analyze and quality control the raw data. Graphical and text products for each dropsonde are created by the NOAA scientists and disseminated to modeling centers and other ground stations for researchers and forecasters to view in real time.
Below is a depiction of the NASA aircraft tracker that NASA and NOAA scientists use to track the aircraft. They can overlay a variety of satellite and other imagery to asses the atmospheric conditions that the GH is flying over. In this image, the GH is passing over a cold front northwest of Bermuda where it released two dropsondes near thunderstorms. The plane is heading to the southeast to the relatively dry and dusty tropical air. Also below are Skew-T images from the the first two dropsondes. These images are what meteorologists commonly look at to analyze the vertical structure of temperature (R=red line), humidity (blue line) and winds (barbs with tick marks on the side).
More to follow later in the flight…
