Impacts of the Saharan air layer on the physical properties of the Atlantic tropical cyclone cloud systems: 2003–2019

It is generally known that the tropical cyclone (TC) cloud systems (TCCS) in the North Atlantic region frequently occur during boreal summer, while the Saharan dust outbreaks concurrently. The Sahara air layer (SAL), an elevated layer containing Saharan dry air and mineral dust, makes crucial impact...

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Main Authors: Luo, Hao, Han, Yong
Format: Text
Language:English
Published: 2021
Subjects:
Online Access:https://doi.org/10.5194/acp-2021-462
https://acp.copernicus.org/preprints/acp-2021-462/
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spelling ftcopernicus:oai:publications.copernicus.org:acpd94998 2023-05-15T17:36:55+02:00 Impacts of the Saharan air layer on the physical properties of the Atlantic tropical cyclone cloud systems: 2003–2019 Luo, Hao Han, Yong 2021-06-28 application/pdf https://doi.org/10.5194/acp-2021-462 https://acp.copernicus.org/preprints/acp-2021-462/ eng eng doi:10.5194/acp-2021-462 https://acp.copernicus.org/preprints/acp-2021-462/ eISSN: 1680-7324 Text 2021 ftcopernicus https://doi.org/10.5194/acp-2021-462 2021-07-05T16:22:18Z It is generally known that the tropical cyclone (TC) cloud systems (TCCS) in the North Atlantic region frequently occur during boreal summer, while the Saharan dust outbreaks concurrently. The Sahara air layer (SAL), an elevated layer containing Saharan dry air and mineral dust, makes crucial impacts on the generation and evolution of TCs. However, the effects of SAL on the physical (macro and micro) characteristics of the Atlantic TCCS have not been well constrained, and the interaction mechanisms between them still need further investigation. In this study, our primary interest is to distinguish the various effects of SAL on different intensities of TCs, and further find out the probable causes of the varied feedback. Therefore, we attempt to identify whether and how the effects of the SAL play a positive or negative role on the TCCS, and to draw a qualitative conclusion of how SAL affects the various intensities of the TCs. This paper focuses on the 70 TC samples from July to September in the years of 2003–2019 to investigate the physical effects of SAL on three intensities of TCs, i.e.: the tropical depression (TD), tropical storm (TS), and hurricane (HU). The results show that SAL has a positive impact on the macro properties of HU but significantly suppresses the TD. It appears that the SAL attributes little to the variation of ice cloud effective radius (CER i ) for TS, whereas CER i changes significantly and differentially for TD and HU. When affected by SAL, the probability density function (PDF) curve of CER i generally shifts to the smaller value for TD, but the PDF curve becomes flatten for HU. Our analysis indicates that the various responses of TCCS to SAL are determined by the combined effects of dry air masses, the dust aerosols as ice nuclei, as well as the thermodynamic and moisture conditions. Based on the observation data analysis, a concept scheme description has been concluded to deepen our recognition of the effects of SAL on the TCCS. Text North Atlantic Copernicus Publications: E-Journals
institution Open Polar
collection Copernicus Publications: E-Journals
op_collection_id ftcopernicus
language English
description It is generally known that the tropical cyclone (TC) cloud systems (TCCS) in the North Atlantic region frequently occur during boreal summer, while the Saharan dust outbreaks concurrently. The Sahara air layer (SAL), an elevated layer containing Saharan dry air and mineral dust, makes crucial impacts on the generation and evolution of TCs. However, the effects of SAL on the physical (macro and micro) characteristics of the Atlantic TCCS have not been well constrained, and the interaction mechanisms between them still need further investigation. In this study, our primary interest is to distinguish the various effects of SAL on different intensities of TCs, and further find out the probable causes of the varied feedback. Therefore, we attempt to identify whether and how the effects of the SAL play a positive or negative role on the TCCS, and to draw a qualitative conclusion of how SAL affects the various intensities of the TCs. This paper focuses on the 70 TC samples from July to September in the years of 2003–2019 to investigate the physical effects of SAL on three intensities of TCs, i.e.: the tropical depression (TD), tropical storm (TS), and hurricane (HU). The results show that SAL has a positive impact on the macro properties of HU but significantly suppresses the TD. It appears that the SAL attributes little to the variation of ice cloud effective radius (CER i ) for TS, whereas CER i changes significantly and differentially for TD and HU. When affected by SAL, the probability density function (PDF) curve of CER i generally shifts to the smaller value for TD, but the PDF curve becomes flatten for HU. Our analysis indicates that the various responses of TCCS to SAL are determined by the combined effects of dry air masses, the dust aerosols as ice nuclei, as well as the thermodynamic and moisture conditions. Based on the observation data analysis, a concept scheme description has been concluded to deepen our recognition of the effects of SAL on the TCCS.
format Text
author Luo, Hao
Han, Yong
spellingShingle Luo, Hao
Han, Yong
Impacts of the Saharan air layer on the physical properties of the Atlantic tropical cyclone cloud systems: 2003–2019
author_facet Luo, Hao
Han, Yong
author_sort Luo, Hao
title Impacts of the Saharan air layer on the physical properties of the Atlantic tropical cyclone cloud systems: 2003–2019
title_short Impacts of the Saharan air layer on the physical properties of the Atlantic tropical cyclone cloud systems: 2003–2019
title_full Impacts of the Saharan air layer on the physical properties of the Atlantic tropical cyclone cloud systems: 2003–2019
title_fullStr Impacts of the Saharan air layer on the physical properties of the Atlantic tropical cyclone cloud systems: 2003–2019
title_full_unstemmed Impacts of the Saharan air layer on the physical properties of the Atlantic tropical cyclone cloud systems: 2003–2019
title_sort impacts of the saharan air layer on the physical properties of the atlantic tropical cyclone cloud systems: 2003–2019
publishDate 2021
url https://doi.org/10.5194/acp-2021-462
https://acp.copernicus.org/preprints/acp-2021-462/
genre North Atlantic
genre_facet North Atlantic
op_source eISSN: 1680-7324
op_relation doi:10.5194/acp-2021-462
https://acp.copernicus.org/preprints/acp-2021-462/
op_doi https://doi.org/10.5194/acp-2021-462
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