Atmospheric horizontal gradients measured with eight co-located GNSS stations and a microwave radiometer

<p>We used eight co-located global navigation satellite system (GNSS) stations with different antenna mounts to estimate atmospheric signal propagation delays in the zenith direction and linear horizontal gradients. The gradients are compared with the results from a water vapour radiometer (W...

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Main Authors: T. Ning, G. Elgered
Format: Article
Language:English
Published: Copernicus Publications 2025-05-01
Series:Atmospheric Measurement Techniques
Online Access:https://amt.copernicus.org/articles/18/2069/2025/amt-18-2069-2025.pdf
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author T. Ning
G. Elgered
author_facet T. Ning
G. Elgered
author_sort T. Ning
collection DOAJ
description <p>We used eight co-located global navigation satellite system (GNSS) stations with different antenna mounts to estimate atmospheric signal propagation delays in the zenith direction and linear horizontal gradients. The gradients are compared with the results from a water vapour radiometer (WVR). The water drops in the atmosphere have a negative influence on the retrieval accuracy of the WVR. Hence, we see better agreement using WVR data with a liquid water content (LWC) less than 0.05 mm compared to when LWC values of up to 0.7 mm are included. We used two different constraints when estimating the linear gradients from the GNSS data. Using a weak constraint enhances the GNSS estimates to track large gradients of short duration at the cost of increased formal errors. To mitigate random noise in the GNSS gradients, we adopted a fusion approach, averaging estimates from the GNSS stations. This resulted in significant improvements for the agreement with the WVR data, a maximum of 17 % increase in the correlation, and a 14 % reduction in the root mean square (RMS) difference for the east gradients. The corresponding values for the north gradients are both 25 %. Overall, no large differences in terms of quality are observed for the eight GNSS stations. However, one station shows slightly poorer agreement for the north gradients compared to the others. This is attributed to the station's proximity to a radio telescope, which causes data loss of observations at low-elevation angles in the south-south-west direction.</p>
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1867-8548
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spelling doaj-art-2de0a5557eaa41bba5596f8db5f241542025-08-20T02:16:10ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482025-05-01182069208210.5194/amt-18-2069-2025Atmospheric horizontal gradients measured with eight co-located GNSS stations and a microwave radiometerT. Ning0G. Elgered1Lantmäteriet (Swedish Mapping, Cadastral and Land Registration Authority), 80182 Gävle, SwedenDepartment of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 43992 Onsala, Sweden<p>We used eight co-located global navigation satellite system (GNSS) stations with different antenna mounts to estimate atmospheric signal propagation delays in the zenith direction and linear horizontal gradients. The gradients are compared with the results from a water vapour radiometer (WVR). The water drops in the atmosphere have a negative influence on the retrieval accuracy of the WVR. Hence, we see better agreement using WVR data with a liquid water content (LWC) less than 0.05 mm compared to when LWC values of up to 0.7 mm are included. We used two different constraints when estimating the linear gradients from the GNSS data. Using a weak constraint enhances the GNSS estimates to track large gradients of short duration at the cost of increased formal errors. To mitigate random noise in the GNSS gradients, we adopted a fusion approach, averaging estimates from the GNSS stations. This resulted in significant improvements for the agreement with the WVR data, a maximum of 17 % increase in the correlation, and a 14 % reduction in the root mean square (RMS) difference for the east gradients. The corresponding values for the north gradients are both 25 %. Overall, no large differences in terms of quality are observed for the eight GNSS stations. However, one station shows slightly poorer agreement for the north gradients compared to the others. This is attributed to the station's proximity to a radio telescope, which causes data loss of observations at low-elevation angles in the south-south-west direction.</p>https://amt.copernicus.org/articles/18/2069/2025/amt-18-2069-2025.pdf
spellingShingle T. Ning
G. Elgered
Atmospheric horizontal gradients measured with eight co-located GNSS stations and a microwave radiometer
Atmospheric Measurement Techniques
title Atmospheric horizontal gradients measured with eight co-located GNSS stations and a microwave radiometer
title_full Atmospheric horizontal gradients measured with eight co-located GNSS stations and a microwave radiometer
title_fullStr Atmospheric horizontal gradients measured with eight co-located GNSS stations and a microwave radiometer
title_full_unstemmed Atmospheric horizontal gradients measured with eight co-located GNSS stations and a microwave radiometer
title_short Atmospheric horizontal gradients measured with eight co-located GNSS stations and a microwave radiometer
title_sort atmospheric horizontal gradients measured with eight co located gnss stations and a microwave radiometer
url https://amt.copernicus.org/articles/18/2069/2025/amt-18-2069-2025.pdf
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AT gelgered atmospherichorizontalgradientsmeasuredwitheightcolocatedgnssstationsandamicrowaveradiometer