Diagnosing ISO Forecast from GloSea5 Using Dynamic-Oriented ISO Theory
A Madden–Jillian oscillation (MJO) and boreal summer intraseasonal oscillation (BSISO) are important climate variabilities, which affect a forecast of weather and climate. In this study, the MJO and the BSISO hindcasts from the Global Seasonal Forecast System, version 5 (GS5) were diagnosed using dy...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-01-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/12/1/114 |
| _version_ | 1827600759159521280 |
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| author | Young-Min Yang Taehyoun Shim Ja-Yeon Moon Ki-Young Kim Yu-Kyung Hyun |
| author_facet | Young-Min Yang Taehyoun Shim Ja-Yeon Moon Ki-Young Kim Yu-Kyung Hyun |
| author_sort | Young-Min Yang |
| collection | DOAJ |
| description | A Madden–Jillian oscillation (MJO) and boreal summer intraseasonal oscillation (BSISO) are important climate variabilities, which affect a forecast of weather and climate. In this study, the MJO and the BSISO hindcasts from the Global Seasonal Forecast System, version 5 (GS5) were diagnosed using dynamic-oriented theories. We additionally analyzed the GS5 climatological run to identify whether the weakness of the GS5 hindcast results from the model physics or initialization processes. The GS5 hindcast captures three-dimensional dynamics and thermodynamics structure of MJO eastward propagation well in the Indian Ocean. The model produces the boundary layer (BL) moisture convergence anomalies to the east of the MJO deep precipitation with easterly anomalies associated with the Kelvin wave. The enhanced BL moisture convergence increases upward transport of moisture from the surface to the lower troposphere, inducing the moist lower troposphere and the positive convective instability by destabilization of the lower atmosphere and, thus, generating the next convection to the east of MJO deep convection and promoting MJO eastward propagation. However, the signal for eastward propagation is relatively weak in the Maritime Continent (MC) and the Western Pacific (WP). To improve the MJO eastward propagation in the MC and WP, improved heating induced by shallow (or congestus) clouds interacting with enhanced BL dynamics may be required. On the other hand, the GS5 hindcast reproduces the BSISO northward propagation reasonably well in the Indian Ocean, which is attributed to positive vorticity anomalies induced by strong vertical shear. |
| first_indexed | 2024-03-09T04:42:40Z |
| format | Article |
| id | doaj.art-1ae48c478ce14bf491e1406fa2110753 |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-03-09T04:42:40Z |
| publishDate | 2021-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atmosphere |
| spelling | doaj.art-1ae48c478ce14bf491e1406fa21107532023-12-03T13:18:57ZengMDPI AGAtmosphere2073-44332021-01-0112111410.3390/atmos12010114Diagnosing ISO Forecast from GloSea5 Using Dynamic-Oriented ISO TheoryYoung-Min Yang0Taehyoun Shim1Ja-Yeon Moon2Ki-Young Kim3Yu-Kyung Hyun4Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters and Earth System Modeling Center, Key Laboratory of Meteorological Disaster of Ministry of Education, Joint International Research Laboratory of Climate and Environment Change, Department of Atmospheric Science, Nanjing University of Information Science and Technology, Nanjing 210044, ChinaResearch Institute, 4D Solution, Co., Ltd., Seoul 08511, KoreaResearch Institute, 4D Solution, Co., Ltd., Seoul 08511, KoreaResearch Institute, 4D Solution, Co., Ltd., Seoul 08511, KoreaOperational Systems Development Department, National Institute of Meteorological Sciences (NIMS)/Korea Meteorological Administration (KMA), Jeju 63568, KoreaA Madden–Jillian oscillation (MJO) and boreal summer intraseasonal oscillation (BSISO) are important climate variabilities, which affect a forecast of weather and climate. In this study, the MJO and the BSISO hindcasts from the Global Seasonal Forecast System, version 5 (GS5) were diagnosed using dynamic-oriented theories. We additionally analyzed the GS5 climatological run to identify whether the weakness of the GS5 hindcast results from the model physics or initialization processes. The GS5 hindcast captures three-dimensional dynamics and thermodynamics structure of MJO eastward propagation well in the Indian Ocean. The model produces the boundary layer (BL) moisture convergence anomalies to the east of the MJO deep precipitation with easterly anomalies associated with the Kelvin wave. The enhanced BL moisture convergence increases upward transport of moisture from the surface to the lower troposphere, inducing the moist lower troposphere and the positive convective instability by destabilization of the lower atmosphere and, thus, generating the next convection to the east of MJO deep convection and promoting MJO eastward propagation. However, the signal for eastward propagation is relatively weak in the Maritime Continent (MC) and the Western Pacific (WP). To improve the MJO eastward propagation in the MC and WP, improved heating induced by shallow (or congestus) clouds interacting with enhanced BL dynamics may be required. On the other hand, the GS5 hindcast reproduces the BSISO northward propagation reasonably well in the Indian Ocean, which is attributed to positive vorticity anomalies induced by strong vertical shear.https://www.mdpi.com/2073-4433/12/1/114MJOGloSea5BSISOeastward propagationnorthward propagation |
| spellingShingle | Young-Min Yang Taehyoun Shim Ja-Yeon Moon Ki-Young Kim Yu-Kyung Hyun Diagnosing ISO Forecast from GloSea5 Using Dynamic-Oriented ISO Theory Atmosphere MJO GloSea5 BSISO eastward propagation northward propagation |
| title | Diagnosing ISO Forecast from GloSea5 Using Dynamic-Oriented ISO Theory |
| title_full | Diagnosing ISO Forecast from GloSea5 Using Dynamic-Oriented ISO Theory |
| title_fullStr | Diagnosing ISO Forecast from GloSea5 Using Dynamic-Oriented ISO Theory |
| title_full_unstemmed | Diagnosing ISO Forecast from GloSea5 Using Dynamic-Oriented ISO Theory |
| title_short | Diagnosing ISO Forecast from GloSea5 Using Dynamic-Oriented ISO Theory |
| title_sort | diagnosing iso forecast from glosea5 using dynamic oriented iso theory |
| topic | MJO GloSea5 BSISO eastward propagation northward propagation |
| url | https://www.mdpi.com/2073-4433/12/1/114 |
| work_keys_str_mv | AT youngminyang diagnosingisoforecastfromglosea5usingdynamicorientedisotheory AT taehyounshim diagnosingisoforecastfromglosea5usingdynamicorientedisotheory AT jayeonmoon diagnosingisoforecastfromglosea5usingdynamicorientedisotheory AT kiyoungkim diagnosingisoforecastfromglosea5usingdynamicorientedisotheory AT yukyunghyun diagnosingisoforecastfromglosea5usingdynamicorientedisotheory |