Observed Tightening of Tropical Ascent in Recent Decades and Linkage to Regional Precipitation Changes
Abstract Climate models predict that the tropical ascending region should tighten under global warming, but observational quantification of the tightening rate is limited. Here we show that the observed spatial extent of the relatively moist, rainy and cloudy regions in the tropics associated with l...
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| Format: | Article |
| Language: | English |
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Wiley
2020-02-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2019GL085809 |
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| author | Hui Su Longtao Wu Chengxing Zhai Jonathan H. Jiang J. David Neelin Yuk L. Yung |
| author_facet | Hui Su Longtao Wu Chengxing Zhai Jonathan H. Jiang J. David Neelin Yuk L. Yung |
| author_sort | Hui Su |
| collection | DOAJ |
| description | Abstract Climate models predict that the tropical ascending region should tighten under global warming, but observational quantification of the tightening rate is limited. Here we show that the observed spatial extent of the relatively moist, rainy and cloudy regions in the tropics associated with large‐scale ascent has been decreasing at a rate of −1%/decade (−5%/K) from 1979 to 2016, resulting from combined effects of interdecadal variability and anthropogenic forcings, with the former contributing more than the latter. The tightening of tropical ascent is associated with an increase in the occurrence frequency of extremely strong ascent, leading to an increase in the average precipitation rate in the top 1% of monthly rainfall in the tropics. At the margins of the convective zones such as the Southeast Amazonia region, the contraction of large‐scale ascent is related to a long‐term drying trend about −3.2%/decade in the past 38 years. |
| format | Article |
| id | doaj-art-01ba2fbf1cf84eedb6a6805f2a7be367 |
| institution | OA Journals |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2020-02-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-01ba2fbf1cf84eedb6a6805f2a7be3672025-08-20T02:31:27ZengWileyGeophysical Research Letters0094-82761944-80072020-02-01473n/an/a10.1029/2019GL085809Observed Tightening of Tropical Ascent in Recent Decades and Linkage to Regional Precipitation ChangesHui Su0Longtao Wu1Chengxing Zhai2Jonathan H. Jiang3J. David Neelin4Yuk L. Yung5Jet Propulsion Laboratory California Institute of Technology Pasadena CA USAJet Propulsion Laboratory California Institute of Technology Pasadena CA USAJet Propulsion Laboratory California Institute of Technology Pasadena CA USAJet Propulsion Laboratory California Institute of Technology Pasadena CA USADepartment of Atmospheric and Oceanic Sciences University of California, Los Angeles Los Angeles CA USADivision of Geological and Planetary Sciences California Institute of Technology Pasadena CA USAAbstract Climate models predict that the tropical ascending region should tighten under global warming, but observational quantification of the tightening rate is limited. Here we show that the observed spatial extent of the relatively moist, rainy and cloudy regions in the tropics associated with large‐scale ascent has been decreasing at a rate of −1%/decade (−5%/K) from 1979 to 2016, resulting from combined effects of interdecadal variability and anthropogenic forcings, with the former contributing more than the latter. The tightening of tropical ascent is associated with an increase in the occurrence frequency of extremely strong ascent, leading to an increase in the average precipitation rate in the top 1% of monthly rainfall in the tropics. At the margins of the convective zones such as the Southeast Amazonia region, the contraction of large‐scale ascent is related to a long‐term drying trend about −3.2%/decade in the past 38 years.https://doi.org/10.1029/2019GL085809circulationITCZprecipitationascenttighteningdrying |
| spellingShingle | Hui Su Longtao Wu Chengxing Zhai Jonathan H. Jiang J. David Neelin Yuk L. Yung Observed Tightening of Tropical Ascent in Recent Decades and Linkage to Regional Precipitation Changes Geophysical Research Letters circulation ITCZ precipitation ascent tightening drying |
| title | Observed Tightening of Tropical Ascent in Recent Decades and Linkage to Regional Precipitation Changes |
| title_full | Observed Tightening of Tropical Ascent in Recent Decades and Linkage to Regional Precipitation Changes |
| title_fullStr | Observed Tightening of Tropical Ascent in Recent Decades and Linkage to Regional Precipitation Changes |
| title_full_unstemmed | Observed Tightening of Tropical Ascent in Recent Decades and Linkage to Regional Precipitation Changes |
| title_short | Observed Tightening of Tropical Ascent in Recent Decades and Linkage to Regional Precipitation Changes |
| title_sort | observed tightening of tropical ascent in recent decades and linkage to regional precipitation changes |
| topic | circulation ITCZ precipitation ascent tightening drying |
| url | https://doi.org/10.1029/2019GL085809 |
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