Scientists are using airplanes, sensors, radar, computer modeling programs and NASA satellites to better understand hurricanes. Some of the NASA satellites include Aqua, the Tropical Rainfall Measuring Mission (TRMM), and the recently-launched Cloudsat/CALIPSO satellite. Edward Zipser of the University of Utah, Salt City, is the chief mission scientist. Following is an on-location report from Dr. Zipser during the NAMMA Hurricane field mission.
Image right: Flying Around a Tropical Disturbance: This is an image from Google Earth that shows the flight path (red line) of NASA's DC-8 aircraft around a tropical disturbance (in red and blue) near the Cape Verde Islands, off the African coast. This was the flight path for August 23, 2006. Credit: NASA
Mission Scientist Report: August 23rd, 2006 - 3rd Science Flight
On August 23, 2006, scientists on the NAMMA mission took an eight hour flight into a tropical disturbance. Edward Zipser noted "surprisingly strong winds at 700 millibars (approximately 10,000 feet high), considering how the system seemed to be struggling to survive in the midst of the Sahara Air Layer."
Spotting Dry Air in a Storm
The Saharan Air Layer (SAL) is a mass of very dry, dusty air which forms over the Sahara Desert during the late spring, summer, and early fall and usually moves out over the tropical Atlantic Ocean. The SAL usually extends between 5,000-20,000 feet in the atmosphere and is associated with large amounts of mineral dust, dry air and strong winds (~25-55 mph).
Zipser said, "We saw evidence of dry air, typically from 750-550 millibars (10,000 to 19,000 feet), on almost all quadrants, but of course we won’t know right away how much of this air actually entered the inner core of the storm."
Communicating Between the Ground and Air
During the previous two flights into the tropical system, the scientists used a communications system called "X-Chat" system. The main advantage was that mission scientist, Jeff Halverson, who was on the ground, watched movie loops of the tropical system and he was able to pass information to the DC-8 aircraft, while the flight scientist could rapidly relay information back.
The scientists on the DC-8 aircraft noted that the storm structure they were flying over featured was not symmetrical (not identical on both sides of a central line) below about 6-7 kilometers (around 4 miles) altitude. They also noted that the system's strongest winds were on the east and north side.
Image/animation left:Animation of Dropsonde (Sensor): Researchers in high-flying planes drop temperature-taking instruments into tropical cyclones from about 3 miles above it. Described by a researcher as "Pringles cans with parachutes," sensors called 'dropsondes' are dropped into tropical cyclones to obtain temperature, pressure, moisture and wind readings throughout different locations of the storm. Credit: NASA
Another benefit to flying into a storm was that the scientists were able to better determine its exact location. The storm was found to be north of the forecast position. Zipser and his crew dropped about 24 dropsondes into the storm. A dropsonde is a sensor that measures temperature, pressure, moisture and winds throughout different locations of a storm.
Looking at Air Circulations Like a Layer Cake
When the scientists flew into the tropical cyclone, they noticed that there were two different air circulations happening, like layers of a cake. In the top layer, higher than the surface, (above 500-400 millibars or 20,000 feet), the center of the cyclone seemed to be well southeast of the cyclone that was on lower level (at the surface).
When the scientists flew over the “eye” or center of the tropical cyclone at a height of 35,000 feet, they we were continuously in thick cirrus clouds (wispy clouds made of ice crystals). Later, however, they were able to look at data from the PR-2 (an airborne radar) showing a sloping eyewall to 7 kilometers (4.3 miles).
Convection (rising air that condenses higher in the atmosphere to form clouds and storms) decreased during the flight with little or no significant turbulence and no large areas of organized rainfall from stratiform clouds (layered clouds).
Measuring the Winds Above and on the Surface
The dropsondes were not spaced closely enough to give a proper description of the wind circulation close to the center of the storm, so the plane carrying Zipser and his crew descended to 10,000 feet (700 millibars) where they mapped the winds on the north and east sides of the storm. Winds were about 40 to 50 nautical miles per hour (45-55 mph), and there were some winds in excess of 60 knots (70 mph). There were no strong winds on the south side of the storm. The scientists estimated the winds on the surface around 40-45 knots (45-51 mph).
Every flight into a storm gives scientists more information about how tropical cyclones work. The NAMMA mission ends in mid-September, 2006.
Rob Gutro | EurekAlert!
In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy