Global positioning systems meteorology over Morocco: accuracy assessment and comparison of zenith tropospheric delay from global positioning systems and radiosondes

Hdidou, Fatima Zahra; Mordane, Soumia; Sbii, Siham

doi:10.1002/met.1725

Cited by 4 publications

(3 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among the studies of recent years, which are aimed at improving the accuracy of zenith tropospheric delay, the following works can be distinguished: [Hadas, et al, 2020], which investigates the accuracy of ZTD using different GNSS systems and the ability to improve accuracy by combining data from several systems. The publication [Hdidou, et al, 2018] evaluates ZTD that is determined by radio sounding at two stations. Vertical tropospheric gradients were used to improve the accuracy of ZTD interpolation in [Zus, et al, 2019].…”

Section: Analysis Of Recent Researchmentioning

confidence: 99%

Geodesy, Cartography and Aerial Photography

Zablotskyi¹,

Palianytsia²,

Kladochnyi³

et al. 2021

ISTCGCAP

View full text Add to dashboard Cite

The aim of this work is to evaluate the accuracy of determining the wet component of zenith tropospheric delay (ZTD) from GNSS-measurements and the accuracy of determining the hydrostatic component according to the Saastamoinen model in comparison with the radio sounding data as well. Zenith tropospheric delay is determined mainly by two methods - traditional, using radio sounding or using atmospheric models, such as the Saastamoinen model, and the method of GNSS measurements. Determination of the hydrostatic component of the zenith tropospheric delay was performed by radio sounding data obtained at the aerological station Praha-Libus in 2011-2013 and in 2018. Data were processed for the middle decades of January and July of each year at 0h o’clock of the Universal Time. The wet component was calculated from GNSS observations. By a significant number of radio soundings at the Praha-Libus aerological station, hydrostatic and wet components of zenith tropospheric delay (ZTD) and the same number of ZTD values derived for the corresponding time intervals from GNSS measurements at the GOPE reference station were determined. The values of the wet component of ZTD were determined and compared with the corresponding data obtained from radio soundings. We found that the error of the hydrostatic component in winter does not exceed 10 mm in absolute value, and in summer it is approximately 1.5 times smaller. This is due to differences in the stratification of the troposphere and lower stratosphere in winter and summer. As for the wet component of ZTD, its errors do not exceed: in winter 15 mm, in summer – 35 mm. The resulting differences in summer have a negative sign, indicating a systematic shift, and in winter – both negative and positive. Today, there are many studies aimed at improving the accuracy of determining zenith tropospheric delay by both Ukrainian and foreign authors, but the problem of the accuracy of the hydrostatic component remains open. The study provides recommendations for further research to improve the accuracy of zenith tropospheric delay.

show abstract

Section: Analysis Of Recent Researchmentioning

confidence: 99%

Geodesy, Cartography and Aerial Photography

Zablotskyi¹,

Palianytsia²,

Kladochnyi³

et al. 2021

ISTCGCAP

View full text Add to dashboard Cite

show abstract

“…The temporal frequency of the GNSS observations is about 15 minutes. The accuracy of the Moroccan GNSS ZTD network was evaluated by Hdidou et al (2018). There are 17 GNSS stations within the AROME-Morocco domain (Fig.…”

Section: Gnss Observationsmentioning

confidence: 99%

“…Thereby, the above datasets cannot capture accurately the mesoscale variability of water vapour. In order to take advantage of the potential of GNSS data assimilation for improving NWP forecasts of water vapour, the National Meteorological Service in Morocco ('Direction de la M et eorologie Nationale': DMN) has acquired a GNSS meteorological network for NWP applications (Hdidou et al, 2018). DMN operates the high-resolution convection-resolved AROME-Morocco with a 2.5 km horizontal resolution.…”

Section: Introductionmentioning

confidence: 99%

Impact of the variational assimilation of ground-based GNSS zenith total delay into AROME-Morocco model

Hdidou

Mordane

Moll

et al. 2020

Tellus A: Dynamic Meteorology and Oceanography

Self Cite

View full text Add to dashboard Cite

The impact of assimilating zenith total delay (ZTD) observations from the Moroccan ground-based Global Navigation Satellite System (GNSS) network into the high-resolution operational model AROME-Morocco (2.5 km) is assessed over one month. The objective is to investigate the impact on moisture field and rainy event forecasts in a three-dimensional variational (3D-Var) data assimilation framework with a 3-hour cycling. As a first step, a pre-processing of ZTD observations is performed for quality control and bias correction and it points out that all GNSS stations available in the network can be potentially assimilated. Then, two parallel experiments, with and without assimilation of GNSS ZTD, are performed during February-March 2018, for 48-hour lead times. Compared against other observation systems of humidity (radiosonde and surface network), a small and beneficial improvement is found in the atmospheric moisture short-range forecast, despite the limited number of GNSS stations over Morocco. The impact of assimilating GNSS ZTD data on precipitation forecasts is evaluated both subjectively and objectively. The objective precipitation scores against daily rain gauge observations show that the impact is mixed, positive for larger rainfall accumulations and neutral to negative for smaller rainfall accumulations. A specific evaluation for a case study of a rain event highlights an improvement in terms of intensity and location of precipitating areas when GNSS ZTD observations are assimilated.

show abstract