Empirical Subseasonal Prediction of Summer Rainfall Anomalies over the Middle and Lower Reaches of the Yangtze River Basin Based on Atmospheric Intraseasonal Oscillation
The middle and lower reaches of the Yangtze River basin (MLRYB) are prone to flooding because their orientation is parallel to the East Asian summer monsoon rain belt. Since the East Asian summer monsoon presents pronounced intraseasonal variability, the subseasonal prediction of summer precipitatio...
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| Format: | Article |
| Language: | English |
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MDPI AG
2017-09-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/8/10/185 |
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| author | Zhiwei Zhu Shengjie Chen Kai Yuan Yini Chen Song Gao Zhenfei Hua |
| author_facet | Zhiwei Zhu Shengjie Chen Kai Yuan Yini Chen Song Gao Zhenfei Hua |
| author_sort | Zhiwei Zhu |
| collection | DOAJ |
| description | The middle and lower reaches of the Yangtze River basin (MLRYB) are prone to flooding because their orientation is parallel to the East Asian summer monsoon rain belt. Since the East Asian summer monsoon presents pronounced intraseasonal variability, the subseasonal prediction of summer precipitation anomalies in the MLRYB region is an imperative demand nationwide. Based on rotated empirical orthogonal function analysis, 48 stations over the MLRYB with coherent intraseasonal (10–80-day) rainfall variability are identified. Power spectrum analysis of the MLRYB rainfall index, defined as the 48-station-averaged intraseasonal rainfall anomaly, presents two dominant modes with periods of 20–30 days and 40–60 days, respectively. Therefore, the intraseasonal (10–80-day) rainfall variability is divided into 10–30-day and 30–80-day components, and their predictability sources are detected separately. Spatial-temporal projection models (STPM) are then conducted using these predictability sources. The forecast skill during the period 2003–2010 indicates that the STPM is able to capture the 30–80-day rainfall anomalies 5–30 days in advance, but unable to reproduce the 10–30-day rainfall anomalies over MLRYB. The year-to-year fluctuation in forecast skill might be related to the tropical Pacific sea surface temperature anomalies. High forecasting skill tends to appear after a strong El Niño or strong La Niña when the summer seasonal mean rainfall over the MLRYB is enhanced, whereas low skill is apparent after neutral conditions or a weak La Niña when the MLRYB summer seasonal mean rainfall is weakened. Given the feasibility of STPM, the application of this technique is recommended in the real-time operational forecasting of MLRYB rainfall anomalies during the summer flooding season. |
| first_indexed | 2024-12-19T19:03:11Z |
| format | Article |
| id | doaj.art-bc0591527aee4901ab6a6628041f3331 |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-12-19T19:03:11Z |
| publishDate | 2017-09-01 |
| publisher | MDPI AG |
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| series | Atmosphere |
| spelling | doaj.art-bc0591527aee4901ab6a6628041f33312022-12-21T20:09:31ZengMDPI AGAtmosphere2073-44332017-09-0181018510.3390/atmos8100185atmos8100185Empirical Subseasonal Prediction of Summer Rainfall Anomalies over the Middle and Lower Reaches of the Yangtze River Basin Based on Atmospheric Intraseasonal OscillationZhiwei Zhu0Shengjie Chen1Kai Yuan2Yini Chen3Song Gao4Zhenfei Hua5Key Laboratory of Meteorological Disaster, Ministry of Education (KLME)/Joint International Research Laboratory of Climate and Environment Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing 210044, ChinaJiangsu Meteorological Observatory, Nanjing 210008, ChinaWuhan Meteorological Service, Wuhan 430040, ChinaZhejiang Meteorological Observatory, Hangzhou 310017, ChinaChongqing Institute of Meteorological Sciences, Chongqing 401147, ChinaAnhui Meteorological Bureau, Hefei 230031, ChinaThe middle and lower reaches of the Yangtze River basin (MLRYB) are prone to flooding because their orientation is parallel to the East Asian summer monsoon rain belt. Since the East Asian summer monsoon presents pronounced intraseasonal variability, the subseasonal prediction of summer precipitation anomalies in the MLRYB region is an imperative demand nationwide. Based on rotated empirical orthogonal function analysis, 48 stations over the MLRYB with coherent intraseasonal (10–80-day) rainfall variability are identified. Power spectrum analysis of the MLRYB rainfall index, defined as the 48-station-averaged intraseasonal rainfall anomaly, presents two dominant modes with periods of 20–30 days and 40–60 days, respectively. Therefore, the intraseasonal (10–80-day) rainfall variability is divided into 10–30-day and 30–80-day components, and their predictability sources are detected separately. Spatial-temporal projection models (STPM) are then conducted using these predictability sources. The forecast skill during the period 2003–2010 indicates that the STPM is able to capture the 30–80-day rainfall anomalies 5–30 days in advance, but unable to reproduce the 10–30-day rainfall anomalies over MLRYB. The year-to-year fluctuation in forecast skill might be related to the tropical Pacific sea surface temperature anomalies. High forecasting skill tends to appear after a strong El Niño or strong La Niña when the summer seasonal mean rainfall over the MLRYB is enhanced, whereas low skill is apparent after neutral conditions or a weak La Niña when the MLRYB summer seasonal mean rainfall is weakened. Given the feasibility of STPM, the application of this technique is recommended in the real-time operational forecasting of MLRYB rainfall anomalies during the summer flooding season.https://www.mdpi.com/2073-4433/8/10/185atmospheric intraseasonal oscillationsubseasonal predictionsummer rainfall anomaliesmiddle and lower reaches of the Yangtze River basin |
| spellingShingle | Zhiwei Zhu Shengjie Chen Kai Yuan Yini Chen Song Gao Zhenfei Hua Empirical Subseasonal Prediction of Summer Rainfall Anomalies over the Middle and Lower Reaches of the Yangtze River Basin Based on Atmospheric Intraseasonal Oscillation Atmosphere atmospheric intraseasonal oscillation subseasonal prediction summer rainfall anomalies middle and lower reaches of the Yangtze River basin |
| title | Empirical Subseasonal Prediction of Summer Rainfall Anomalies over the Middle and Lower Reaches of the Yangtze River Basin Based on Atmospheric Intraseasonal Oscillation |
| title_full | Empirical Subseasonal Prediction of Summer Rainfall Anomalies over the Middle and Lower Reaches of the Yangtze River Basin Based on Atmospheric Intraseasonal Oscillation |
| title_fullStr | Empirical Subseasonal Prediction of Summer Rainfall Anomalies over the Middle and Lower Reaches of the Yangtze River Basin Based on Atmospheric Intraseasonal Oscillation |
| title_full_unstemmed | Empirical Subseasonal Prediction of Summer Rainfall Anomalies over the Middle and Lower Reaches of the Yangtze River Basin Based on Atmospheric Intraseasonal Oscillation |
| title_short | Empirical Subseasonal Prediction of Summer Rainfall Anomalies over the Middle and Lower Reaches of the Yangtze River Basin Based on Atmospheric Intraseasonal Oscillation |
| title_sort | empirical subseasonal prediction of summer rainfall anomalies over the middle and lower reaches of the yangtze river basin based on atmospheric intraseasonal oscillation |
| topic | atmospheric intraseasonal oscillation subseasonal prediction summer rainfall anomalies middle and lower reaches of the Yangtze River basin |
| url | https://www.mdpi.com/2073-4433/8/10/185 |
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