Simulated enhancement of ENSO-related rainfall variability due to Australian dust
Australian dust emissions are highly episodic, and this may increase the importance of Australian dust as a climate feedback agent. We compare two 160-year coupled atmosphere-ocean simulations of modern-day climate using the CSIRO Mark 3.6 global climate model (GCM). The first run (DUST) includes an...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2011-07-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/11/6575/2011/acp-11-6575-2011.pdf |
| _version_ | 1819124145889214464 |
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| author | L. D. Rotstayn M. A. Collier R. M. Mitchell Y. Qin S. K. Campbell S. M. Dravitzki |
| author_facet | L. D. Rotstayn M. A. Collier R. M. Mitchell Y. Qin S. K. Campbell S. M. Dravitzki |
| author_sort | L. D. Rotstayn |
| collection | DOAJ |
| description | Australian dust emissions are highly episodic, and this may increase the importance of Australian dust as a climate feedback agent. We compare two 160-year coupled atmosphere-ocean simulations of modern-day climate using the CSIRO Mark 3.6 global climate model (GCM). The first run (DUST) includes an interactive treatment of mineral dust and its direct radiative effects. The second run (NODUST) is otherwise identical, but has the Australian dust source set to zero. We focus on the austral spring season, when the correlation between rainfall and the El Niño Southern Oscillation (ENSO) is strongest over Australia. The ENSO-rainfall relationship over eastern Australia is stronger in the DUST run: dry (El Niño) years tend to be drier, and wet (La Niña) years wetter. The amplification of ENSO-related rainfall variability over eastern Australia represents an improvement relative to observations. The effect is driven by ENSO-related anomalies in radiative forcing by Australian dust over the south-west Pacific Ocean; these anomalies increase (decrease) surface evaporation in La Niña (El Niño) years. Some of this moisture is advected towards eastern Australia, where increased (decreased) moisture convergence in La Niña (El Niño) years increases the amplitude of ENSO-related rainfall variability. The modulation of surface evaporation by dust over the south-west Pacific occurs via surface radiative forcing and dust-induced stabilisation of the boundary layer. The results suggest that (1) a realistic treatment of Australian dust may be necessary for accurate simulation of the ENSO-rainfall relationship over Australia, and (2) radiative feedbacks involving dust may be important for understanding natural rainfall variability over Australia. |
| first_indexed | 2024-12-22T07:19:36Z |
| format | Article |
| id | doaj.art-d7f98d3db2094fbb9e0ee9a625a8706e |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-22T07:19:36Z |
| publishDate | 2011-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-d7f98d3db2094fbb9e0ee9a625a8706e2022-12-21T18:34:19ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242011-07-0111136575659210.5194/acp-11-6575-2011Simulated enhancement of ENSO-related rainfall variability due to Australian dustL. D. RotstaynM. A. CollierR. M. MitchellY. QinS. K. CampbellS. M. DravitzkiAustralian dust emissions are highly episodic, and this may increase the importance of Australian dust as a climate feedback agent. We compare two 160-year coupled atmosphere-ocean simulations of modern-day climate using the CSIRO Mark 3.6 global climate model (GCM). The first run (DUST) includes an interactive treatment of mineral dust and its direct radiative effects. The second run (NODUST) is otherwise identical, but has the Australian dust source set to zero. We focus on the austral spring season, when the correlation between rainfall and the El Niño Southern Oscillation (ENSO) is strongest over Australia. The ENSO-rainfall relationship over eastern Australia is stronger in the DUST run: dry (El Niño) years tend to be drier, and wet (La Niña) years wetter. The amplification of ENSO-related rainfall variability over eastern Australia represents an improvement relative to observations. The effect is driven by ENSO-related anomalies in radiative forcing by Australian dust over the south-west Pacific Ocean; these anomalies increase (decrease) surface evaporation in La Niña (El Niño) years. Some of this moisture is advected towards eastern Australia, where increased (decreased) moisture convergence in La Niña (El Niño) years increases the amplitude of ENSO-related rainfall variability. The modulation of surface evaporation by dust over the south-west Pacific occurs via surface radiative forcing and dust-induced stabilisation of the boundary layer. The results suggest that (1) a realistic treatment of Australian dust may be necessary for accurate simulation of the ENSO-rainfall relationship over Australia, and (2) radiative feedbacks involving dust may be important for understanding natural rainfall variability over Australia.http://www.atmos-chem-phys.net/11/6575/2011/acp-11-6575-2011.pdf |
| spellingShingle | L. D. Rotstayn M. A. Collier R. M. Mitchell Y. Qin S. K. Campbell S. M. Dravitzki Simulated enhancement of ENSO-related rainfall variability due to Australian dust Atmospheric Chemistry and Physics |
| title | Simulated enhancement of ENSO-related rainfall variability due to Australian dust |
| title_full | Simulated enhancement of ENSO-related rainfall variability due to Australian dust |
| title_fullStr | Simulated enhancement of ENSO-related rainfall variability due to Australian dust |
| title_full_unstemmed | Simulated enhancement of ENSO-related rainfall variability due to Australian dust |
| title_short | Simulated enhancement of ENSO-related rainfall variability due to Australian dust |
| title_sort | simulated enhancement of enso related rainfall variability due to australian dust |
| url | http://www.atmos-chem-phys.net/11/6575/2011/acp-11-6575-2011.pdf |
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