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Turbulence forecasting over South Africa using diagnostics from the convective scale ensemble prediction system of the Unified Model : a pilot study

Dissertation (MSc (Meteorology))--University of Pretoria, 2022.

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Other Authors: Dyson, Liesl L.
Format: Thesis
Published: University of Pretoria 2023
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access_status_str Open Access
author2 Dyson, Liesl L.
author_browse Dyson, Liesl L.
author_facet Dyson, Liesl L.
collection Thesis
dc_rights_str_mv © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MSc (Meteorology))--University of Pretoria, 2022.
format Thesis
id oai:repository.up.ac.za:2263/89254
institution University of Pretoria (South Africa)
last_indexed 2026-06-10T12:37:51.329Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2023
publishDateRange 2023
publishDateSort 2023
publisher University of Pretoria
publisherStr University of Pretoria
record_format dspace
source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/89254 Turbulence forecasting over South Africa using diagnostics from the convective scale ensemble prediction system of the Unified Model : a pilot study Dyson, Liesl L. lauren.smith@weathersa.co.za Landman, Stephanie Smith, Lauren Turbulence Ensemble model Case study Cut-off low UCTD Dissertation (MSc (Meteorology))--University of Pretoria, 2022. Clear air turbulence is a hazardous micro-scale feature to the aviation industry, and the forecasting thereof remains a significant challenge. Clear air turbulence indices describe possible turbulent development mechanisms and are utilized as a forecasting tool. The selected indices for this research are the Ellrod Turbulence index and the Turbulence Kinetic Energy index converted into the Eddie Dissipation Rate available from the South African Weather Service Convective Scale Ensemble Prediction System. Through eleven 2018 case study investigations over 39 clear air turbulence events, the indices from the Convective Scale Ensemble Prediction System are evaluated against pilot reports of clear air turbulence. That is to establish which indices are better suited for aviation purposes over South Africa. Eleven case studies were identified for three different weather categories namely cut-off lows, upper air troughs and upper air zonal flow. The investigations established that the ensemble average and ensemble probability forecasts of the two indices are skilful in predicting clear air turbulence events. However, there is evidence of under-forecasting event severity over South Africa. In general, the EDR severity forecasts outperformed the Ellrod severity forecasts. However, Ellrod performed better when forecasting clear air turbulence associated with cut-off lows while the EDR outperformed the Ellrod in the upper air trough and upper air zonal flow weather categories. Ellrod had the most missed forecasts when dealing with the upper air trough weather category. The post-processing of the clear air turbulence maps would contribute to current forecasting methods of clear air turbulence by the conjoint display and interpretation of both indices over South Africa. Geography, Geoinformatics and Meteorology MSc (Meteorology) Unrestricted 2023-02-07T13:08:29Z 2023-02-07T13:08:29Z 2023-04 2022-07 Dissertation Smith, L 2022, Turbulence forecasting over South Africa using diagnostics from the convective scale ensemble prediction system of the Unified Model: a pilot study, MSc dissertation, University of Pretoria, Pretoria viewed yyyymmdd https://repository.up.ac.za/handle/2263/89254 A2023 https://repository.up.ac.za/handle/2263/89254 DOI: https://doi.org/10.25403/UPresearchdata.22005368.v1 10.25403/UPresearchdata.21940079 © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle Turbulence
Ensemble model
Case study
Cut-off low
UCTD
Turbulence forecasting over South Africa using diagnostics from the convective scale ensemble prediction system of the Unified Model : a pilot study
title Turbulence forecasting over South Africa using diagnostics from the convective scale ensemble prediction system of the Unified Model : a pilot study
title_full Turbulence forecasting over South Africa using diagnostics from the convective scale ensemble prediction system of the Unified Model : a pilot study
title_fullStr Turbulence forecasting over South Africa using diagnostics from the convective scale ensemble prediction system of the Unified Model : a pilot study
title_full_unstemmed Turbulence forecasting over South Africa using diagnostics from the convective scale ensemble prediction system of the Unified Model : a pilot study
title_short Turbulence forecasting over South Africa using diagnostics from the convective scale ensemble prediction system of the Unified Model : a pilot study
title_sort turbulence forecasting over south africa using diagnostics from the convective scale ensemble prediction system of the unified model a pilot study
topic Turbulence
Ensemble model
Case study
Cut-off low
UCTD
url https://repository.up.ac.za/handle/2263/89254