Atmospheric Rivers in Africa Observed with GNSS-RO and Reanalysis Data

Atmospheric Rivers (ARs) transport significant amounts of moisture and cause extreme precipitation events, yet their behavior over Africa is not well understood. This study addresses this gap by analyzing the occurrence, seasonal variability, and spatial dynamics of ARs across the continent from 200...

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Main Authors: Linda Martina Maier, Bahareh Rahimi, Ulrich Foelsche
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Remote Sensing
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Online Access:https://www.mdpi.com/2072-4292/17/7/1273
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author Linda Martina Maier
Bahareh Rahimi
Ulrich Foelsche
author_facet Linda Martina Maier
Bahareh Rahimi
Ulrich Foelsche
author_sort Linda Martina Maier
collection DOAJ
description Atmospheric Rivers (ARs) transport significant amounts of moisture and cause extreme precipitation events, yet their behavior over Africa is not well understood. This study addresses this gap by analyzing the occurrence, seasonal variability, and spatial dynamics of ARs across the continent from 2009 to 2019. Utilizing ERA5 reanalysis data, Global Navigation Satellite Systems Radio Occultation (GNSS RO) measurements, and the Image-Processing-based Atmospheric River Tracking (IPART) method, distinct seasonal AR patterns are identified. Southern Africa experiences peak activity during austral summer, while AR occurrence in Northern Africa peaks in boreal winter and spring, aligning with regional rainy seasons. Moisture sources include the Atlantic Ocean, the Arabian Sea, and the Red Sea. A comparison of ERA5 Integrated Water Vapor (IWV) estimates with high-resolution GNSS RO data shows that both datasets effectively capture broad-scale moisture patterns. However, ERA5 consistently delivers higher IWV values compared to GNSS RO, which is likely due to underrepresentation of GNSS RO IWV values, since profiles generally do not reach all the way down to the surface—but also due to an overrepresentation of humidity in the ERA5 reanalyses. Understanding AR dynamics in Africa is essential to improve climate resilience, water management and understanding extreme precipitation events.
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spelling doaj-art-e411a1ecb3f642869970ca11b4c95e932025-08-20T02:09:17ZengMDPI AGRemote Sensing2072-42922025-04-01177127310.3390/rs17071273Atmospheric Rivers in Africa Observed with GNSS-RO and Reanalysis DataLinda Martina Maier0Bahareh Rahimi1Ulrich Foelsche2Institute of Physics, Department of Astrophysics and Geophysics (AGP), University of Graz, 8010 Graz, AustriaInstitute of Physics, Department of Astrophysics and Geophysics (AGP), University of Graz, 8010 Graz, AustriaInstitute of Physics, Department of Astrophysics and Geophysics (AGP), University of Graz, 8010 Graz, AustriaAtmospheric Rivers (ARs) transport significant amounts of moisture and cause extreme precipitation events, yet their behavior over Africa is not well understood. This study addresses this gap by analyzing the occurrence, seasonal variability, and spatial dynamics of ARs across the continent from 2009 to 2019. Utilizing ERA5 reanalysis data, Global Navigation Satellite Systems Radio Occultation (GNSS RO) measurements, and the Image-Processing-based Atmospheric River Tracking (IPART) method, distinct seasonal AR patterns are identified. Southern Africa experiences peak activity during austral summer, while AR occurrence in Northern Africa peaks in boreal winter and spring, aligning with regional rainy seasons. Moisture sources include the Atlantic Ocean, the Arabian Sea, and the Red Sea. A comparison of ERA5 Integrated Water Vapor (IWV) estimates with high-resolution GNSS RO data shows that both datasets effectively capture broad-scale moisture patterns. However, ERA5 consistently delivers higher IWV values compared to GNSS RO, which is likely due to underrepresentation of GNSS RO IWV values, since profiles generally do not reach all the way down to the surface—but also due to an overrepresentation of humidity in the ERA5 reanalyses. Understanding AR dynamics in Africa is essential to improve climate resilience, water management and understanding extreme precipitation events.https://www.mdpi.com/2072-4292/17/7/1273atmospheric rivers (ARs)AfricaERA5 reanalysisGNSS radio occultationIPARTARtracks
spellingShingle Linda Martina Maier
Bahareh Rahimi
Ulrich Foelsche
Atmospheric Rivers in Africa Observed with GNSS-RO and Reanalysis Data
Remote Sensing
atmospheric rivers (ARs)
Africa
ERA5 reanalysis
GNSS radio occultation
IPART
ARtracks
title Atmospheric Rivers in Africa Observed with GNSS-RO and Reanalysis Data
title_full Atmospheric Rivers in Africa Observed with GNSS-RO and Reanalysis Data
title_fullStr Atmospheric Rivers in Africa Observed with GNSS-RO and Reanalysis Data
title_full_unstemmed Atmospheric Rivers in Africa Observed with GNSS-RO and Reanalysis Data
title_short Atmospheric Rivers in Africa Observed with GNSS-RO and Reanalysis Data
title_sort atmospheric rivers in africa observed with gnss ro and reanalysis data
topic atmospheric rivers (ARs)
Africa
ERA5 reanalysis
GNSS radio occultation
IPART
ARtracks
url https://www.mdpi.com/2072-4292/17/7/1273
work_keys_str_mv AT lindamartinamaier atmosphericriversinafricaobservedwithgnssroandreanalysisdata
AT baharehrahimi atmosphericriversinafricaobservedwithgnssroandreanalysisdata
AT ulrichfoelsche atmosphericriversinafricaobservedwithgnssroandreanalysisdata