Preprints
https://doi.org/10.5194/egusphere-2023-1183
https://doi.org/10.5194/egusphere-2023-1183
19 Jun 2023
 | 19 Jun 2023

Measurement uncertainties of scanning microwave radiometers and their influence on temperature profiling

Tobias Böck, Bernhard Pospichal, and Ulrich Löhnert

Abstract. In order to improve observations of the atmospheric boundary layer (ABL), Europe's network of meteorological and hydrological services EUMETNET as well as the European Research Infrastructure ACTRIS are currently working on building networks of microwave radiometers (MWRs). Elevation-scanning MWRs are well suited to obtain temperature profiles of the atmosphere, especially within the ABL. Understanding and assessing measurement uncertainties of scanning MWRs is therefore crucial for accurate temperature profiling. In this paper we discuss measurement uncertainties due to the instrument set-up and originating from external sources, namely (1) horizontal inhomogeneities of the atmosphere, (2) pointing errors or a tilt of the instrument, (3) physical obstacles in line of sight of the instrument, and (4) radio frequency interference (RFI). Horizontal inhomogeneities from observations at the Jülich Observatory of Cloud Evolution (JOYCE) are shown to have a small impact on retrieved temperature profiles (< |0.22 K| in the 25th/75th percentiles below 3000 m). Typical instrument tilts, that could be caused by uncertainties during the instrument set-up, also have a very small impact on temperature profiles and are smaller than 0.1 K below 3000 m for up to 1° of tilt. Physical obstacles at ambient temperatures and in line of sight and filling the complete beam of the MWR at the lowest elevation angle of 5.4° have to be at least 600 m away from the instrument in order to have an impact of less than 0.1 K on obtained temperature profiles. If the obstacle is 5 K warmer than its surroundings then the obstacle should be at least 2700 m away. Finally, we present an approach on how to detect RFI with an MWR with azimuth and elevation scanning capabilities. In this study we detect RFIs in a water vapor channel that does not influence the temperature retrieval, but would be relevant if the MWR were used to detect horizontal humidity inhomogeneities.

Journal article(s) based on this preprint

15 Jan 2024
Measurement uncertainties of scanning microwave radiometers and their influence on temperature profiling
Tobias Böck, Bernhard Pospichal, and Ulrich Löhnert
Atmos. Meas. Tech., 17, 219–233, https://doi.org/10.5194/amt-17-219-2024,https://doi.org/10.5194/amt-17-219-2024, 2024
Short summary

Tobias Böck et al.

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1183', Anonymous Referee #1, 26 Jun 2023
    • AC1: 'Reply on RC1', Tobias Böck, 22 Sep 2023
  • RC2: 'Comment on egusphere-2023-1183', Anonymous Referee #2, 18 Aug 2023
    • AC2: 'Reply on RC2', Tobias Böck, 22 Sep 2023

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1183', Anonymous Referee #1, 26 Jun 2023
    • AC1: 'Reply on RC1', Tobias Böck, 22 Sep 2023
  • RC2: 'Comment on egusphere-2023-1183', Anonymous Referee #2, 18 Aug 2023
    • AC2: 'Reply on RC2', Tobias Böck, 22 Sep 2023

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Tobias Böck on behalf of the Authors (22 Sep 2023)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (06 Oct 2023) by Jian Xu
RR by Anonymous Referee #1 (19 Oct 2023)
RR by Anonymous Referee #2 (24 Oct 2023)
ED: Publish as is (25 Oct 2023) by Jian Xu
AR by Tobias Böck on behalf of the Authors (20 Nov 2023)

Journal article(s) based on this preprint

15 Jan 2024
Measurement uncertainties of scanning microwave radiometers and their influence on temperature profiling
Tobias Böck, Bernhard Pospichal, and Ulrich Löhnert
Atmos. Meas. Tech., 17, 219–233, https://doi.org/10.5194/amt-17-219-2024,https://doi.org/10.5194/amt-17-219-2024, 2024
Short summary

Tobias Böck et al.

Model code and software

Radiative Transfer Model for MATLAB Mario Mech and Ulrich Löhnert https://doi.org/10.5281/zenodo.7990845

Tobias Böck et al.

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Short summary
In this study, measurement uncertainties from microwave radiometers and their impact on temperature profiling are analyzed. These measurement uncertainties include horizontal inhomogeneities of the atmosphere, pointing errors or tilts of the instrument, physical obstacles which are in the line of sight of the radiometer, and radio frequency interferences. Impacts on temperature profiles from these uncertainties is usually small in real life scenarios and when obstacles are far enough away.