edu.ucar.opensky::technotes:352 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T17:14:25.232267 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7668cmq The Relative Accuracy of ALPEX Aircraft Data / an Evaluation of the ALPEX Intercomparison Flight With the NCAR Electra, the NOAA P3, and the DFVLR Falcon 1985-01-01T00:00:00Z publication https://n2t.org/ark:/85065/d7668cmq https://doi.org/10.5065/D6KH0K80 Richner, H. author UCAR/NCAR - Library publisher During the ALPEX progran, three participating large research aircraft - the NCAR Electra, the NOAA P5, and the DFVLR Falcon - joined for an interccmparison flight. Using the data frcm this flight, this report lists the relative accuracies for position, pressure, temperature, humidity, horizontal and vertical winds, radio altitude, and radiation (some of these quantities were measured by two aircraft only). The results are presented in form of basic statistical data such as mean differences, standard deviations, and correlation coefficients, as well as in form of power, coherence and - for some quantities - phase spectra. Notable results are: - Generally, the differences observed are within the accuracies specified for the three aircraft. - The standard deviation of differences in temperature never exceed 0.1 ��C, the differences themselves are of the order of 0.5 ��C. - Humidity data for the Electra exhibits intervals with strong oscillations; the time averaged data shows good agreenent with the measurements frcm the P3 and the Falcon. - The wind measurements of the P3 differ significantly from correlated measurements of the Electra and the Falcon. the well - Longwave radiation data downward for the Falcon appears to be too high. In cases where significant differences were found, an attenpt has been made to determine the basic measurement which is most likely responsible for the suspicious data. The report also discusses the effect of spectral properties of data and lists a procedure lyman-alpha raw data to dewpoint tenperature. NOTE: Based on the algorithm for the other changes were results presented the three aircraft consulted! data resolution on the for converting Electra results of this intercanparison, the wind ccmputation P3 has been modified. As this report went into press, pending. Therefore, before applying any of the in this report to data which was produced by any of after mid 1984, the operating facility should be UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Flight level winds Platform characteristics Static pressure Upper air temperature Sensor characteristics Vertical wind velocity/speed Dew point temperature theme U.S. National Aeronautics and Space Administration Global Change Master Directory GCMD 2021-09-17 revision 11.2 NASA Global Change Master Directory originator Valids List: Science and Services Keywords Copyright Author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation