Comparison of Potential Temperature Gradient Estimates from Various Temperature Profile Data Sources

From July through September 2015, concurrent and collocated measurements of temperature profiles from two passive radiometers and a RADAR-RASS (Radio Acoustic Sounding System) were made at a site near the ocean just to the west of Los Angeles International Airport (LAX). In addition, temperature profiles for this same time period from National Oceanic and Atmospheric Administration's (NOAA’s) Rapid Refresh (RAP) hourly-updated assimilation/modeling system were collected. The motivation for this data collection effort was the idea that intercomparisons of data obtained from various temperature profiling sources could be used to characterize the variability of potential temperature gradient (PTG) values. The observed scatter of PTG intercomparisons can be used as a practical way of quantifying the variability in measurements of PTG at 250m. This information is important for understanding the variability of aircraft wake vortex data as well as for providing bounds on the variability of the environmental data used for wake modeling. The authors determined that PTG measurements derived from various sources are mostly consistent and indicate an uncertainty in the measurement of PTG of about one degC/100m. This implies that it may not be possible to measure PTG to much better than a tolerance of that amount. Fast-time model results demonstrated that a one degC/100m variation in PTG can result in uncertainties of 50 m²/sec for vortex circulation and 50m for descent distance.


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Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 25p

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Filing Info

  • Accession Number: 01630121
  • Record Type: Publication
  • Created Date: Mar 27 2017 9:30AM