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Abstract. A novel fiber-optic distributed temperature sensing instrument, the Fiber-optic Laser Operated Atmospheric Temperature Sensor (FLOATS), was developed for continuous in situ profiling of the atmosphere up to 2 km below constant-altitude scientific balloons. The temperature-sensingsystem uses a suspended fiber-optic cable and temperature-dependent scattering of pulsed laser light in the Raman regime to retrieve continuous3 m vertical-resolution profiles at a minimum sampling period of 20 s.FLOATS was designed for operation aboard drifting super-pressure balloons inthe tropical tropopause layer at altitudes around 18 km as part of theStratéole 2 campaign. A short test flight of the system was conductedfrom Laramie, Wyoming, in January 2021 to check the optical, electrical, andmechanical systems at altitude and to validate a four-reference temperaturecalibration procedure with a fiber-optic deployment length of 1170 m. During the 4 h flight aboard a vented balloon, FLOATS retrieved temperatureprofiles during ascent and while at a float altitude of about 19 km. TheFLOATS retrievals provided differences of less than 1.0 ∘Ccompared to a commercial radiosonde aboard the flight payload during ascent.At float altitude, a comparison of optical length and GPS position at thebottom of the fiber-optic revealed little to no curvature in the fiber-opticcable, suggesting that the position of any distributed temperaturemeasurement can be effectively modeled. Comparisons of the distributed temperature retrievals to the reference temperature sensors show strongagreement with root-mean-square-error values less than 0.4 ∘C. Theinstrument also demonstrated good agreement with nearby meteorologicalobservations and COSMIC-2 satellite profiles. Observations of temperatureand wind perturbations compared to the nearby radiosounding profiles provide evidence of inertial gravity wave activity during the test flight. Spectral analysis of the observed temperature perturbations shows that FLOATS is an effective and pioneering tool for the investigation of small-scale gravity waves in the upper troposphere and lower stratosphere.
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Field Test of Altitude-Controlled Stratospheric Ozonesonding with Vented Balloons during the 2024 Total Solar Eclipse
The concentration of the stratospheric ozone layer is of great interest to the atmospheric science community, since it is critical in blocking the harmful UV radiation from the sun. Typically, regular weather balloons with Electrochemical Cell (ECC) ozonesondes are used to determine the vertical profile of ozone column concentration within a flight time of ~2 hours, with a limited fraction of the data relevant to the ozone layer. Therefore, it would be ideal if ozonesonde flights can be maintained within the ozone layer (~60,000 to 80,000 ft) to maximize the efficiency in data acquisition, especially considering the rising costs of ozonesonding and high-altitude ballooning. We adapted the vented balloon with altitude-control flight capability from the Nationwide Eclipse Ballooning Program (NEBP) for atmospheric ozonesonding and deployed a commercial ECC ozonesonde payload with this approach from Central Texas during the 2024 total solar eclipse in the hope of (1) field testing the performance and application potential of vented balloons in horizontal ozone layer profiling and (2) monitoring the stratospheric ozone layer during the solar eclipse for an extended period of time. The adapted vent valve successfully lowered the balloon from 71,000 ft to 41,000 ft within minutes and demonstrated promising performance in the field. Unfortunately, unexpected radio communication difficulties were experienced from six hours before the totality to two hours after, leaving the second research objective largely unobtainable.
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- Award ID(s):
- 1847019
- PAR ID:
- 10541241
- Publisher / Repository:
- Iowa State University Digital Press
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract On 8 April 2024, a total solar eclipse overpassed Texas in the southern portion of the United States. To monitor the impact of the total solar eclipse, a group of students from Texas A&M University–Corpus Christi developed two weather balloon payloads and six ground-based instrument packages using microcontrollers and low-cost sensors. These instrument packages were deployed to six different sites spanning nearly 600 km along the total eclipse path from the Mexican border to North Texas. During the total eclipse, air temperature decreased, and relative humidity increased consistently at all six stations due to the reduction in sensible heating. The dewpoint temperatures decreased at the near surface at all sites likely due to the reduction in evaporation. Five of the six ground stations observed a slight dampening of the wind speed, and two of the six stations recorded significant counterclockwise wind shifts. No consistent pattern was observed in the surface vertical electric field at the six ground stations. The two balloon payloads captured the damping of the visible and ultraviolet (UV) radiation in the upper troposphere and lower stratosphere throughout the event. Though a slight decrease in both temperature and ozone in the lower stratosphere was observed after the totality, it is difficult to determine the impact from the eclipse on the ozone mixing ratio and dynamics in the lower stratosphere from only a few vertical profiles. For the students who participated, this field campaign has provided invaluable experiences in instrumentation, fieldwork, and data collection.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.31274/ahac.17935
