Observed trends in clouds and precipitation (1983–2009): implications for their cause(s)
<p>Satellite observations (International Satellite Cloud Climatology Project (ISCCP), 1983–2009) of linear trends in cloud cover are compared to those in global precipitation (Global Precipitation Climatology Project (GPCP) pentad V2.2, 1983–2009), to investigate possible cause(s) of the linea...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/21/4899/2021/acp-21-4899-2021.pdf |
| Summary: | <p>Satellite observations (International Satellite Cloud Climatology Project (ISCCP), 1983–2009) of linear trends in cloud cover are compared to those
in global precipitation (Global Precipitation Climatology Project (GPCP) pentad V2.2, 1983–2009), to investigate possible cause(s) of the linear
trends in both cloud cover and precipitation. The spatial distributions of the linear trends in total cloud cover and precipitation are both
characterized primarily by a broadening of the major ascending zone of Hadley circulation. Our correlation studies suggest that global warming,
Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO) can explain 67 %, 49 % and 38 %, respectively, of the
spatial variabilities in the linear trends in cloud cover, but causality is harder to establish. Further analysis of the broadening of the major
ascending zone of Hadley circulation shows that the trend in global temperature, rather than those in AMO and PDO, is the primary contributor to the
observed linear trends in total cloud cover and precipitation in 1983–2009. The underlying mechanism driving this broadening is proposed to be the
moisture–convection–latent-heat feedback cycle under global warming conditions. The global analysis is extended by investigating connections
between clouds and precipitation in China, based on a large number of long-running, high-quality surface weather stations in 1957–2005. This
reveals a quantitative matching relationship between the reduction in light precipitation and the reduction in total cloud cover. Furthermore, our
study suggests that the reduction in cloud cover in China is primarily driven by global temperature; PDO plays a secondary role, while the
contribution from AMO and Niño3.4 is insignificant, consistent with the global analysis.</p> |
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| ISSN: | 1680-7316 1680-7324 |