enso and its teleconnections - boston...
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![Page 1: ENSO and its teleconnections - Boston Universitysites.bu.edu/thompsonlab/files/2018/02/ENSOpresentation.pdf“ENSO-induced precipitation anomalies over various regions have been documented](https://reader035.vdocuments.site/reader035/viewer/2022071606/6142cb84b7accd31ec0eed90/html5/thumbnails/1.jpg)
ENSO and its teleconnectionsPresent situation and future changes
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Dai et al. 2000
Global ENSO teleconnections,
particularly precipitation anomalies, both annually and seasonally.
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Dai et al. 2000
• How does this study justify its relevance?
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Dai et al. 2000
• How does this study justify its relevance?
“ENSO-induced precipitation anomalies over various regions have been documented through analyses of rain-gauge records from land stations”
“X-A presented global maps of composite precipitation differences between warm and cold ENSO episode”
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Dai et al. 2000
• What could be a concern about the data? How is it overcome?
1900
1979 1998
Xie and Arkin
Dai et al.
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Dai et al. 2000
• What is the information that Figure 1a provides?
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Dai et al. 2000
• What is the difference between Figures 1b and 1c?
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Dai et al. 2000
• Some results fromthe plots in Figure 2are stronger and others are weaker, why?
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Dai et al. 2000
• What are the main “vehicles” of ENSO teleconnection? Where are the resulting effects more robust?
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Dai et al. 2000
• What are the main “vehicles” of ENSO teleconnection? Where are the resulting effects more robust?
“changes in the Walker circulation”
“ITCZ shift”
“shift of the South Pacific Convergence Zone”
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Dai et al. 2000
• In light of last week’s discussion, what is an underling assumption that we could rightfully doubt?
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Li, X., Ting, M. 2015
Specific teleconnection ENSO-monsoon,
and attribution of its changes over time.
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Li, X., Ting, M. 2015
• How do they separate the forcing of internal variability and radiative forcing in the relation between ENSO and monsoon?
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Simulated preindustrial SST
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Simulated preindustrial SST
EOF analysis on the (climate) noise matrix
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Simulated preindustrial SST
EOF analysis on the (climate) noise matrix
Spatial removal of (climate) noise from ensemble mean
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Simulated preindustrial SST
EOF analysis on the (climate) noise matrix
Spatial removal of (climate) noise from ensemble mean
EOF analysis on (ensemble mean – noise)
1st principal component = forced index
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Simulated preindustrial SST
EOF analysis on the (climate) noise matrix
Spatial removal of (climate) noise from ensemble mean
EOF analysis on (ensemble mean – noise)
1st principal component = forced index
𝑆𝑆𝑇𝑓𝑜𝑟𝑐𝑒𝑑 𝑥, 𝑦, 𝑡 = Cov(SST, PC1) ∙𝑃𝐶1(𝑡)
𝜎𝑃𝐶1(𝑡)
𝑆𝑆𝑇𝑛𝑎𝑡𝑢𝑟𝑎𝑙 𝑥, 𝑦, 𝑡 = 𝑆𝑆𝑇𝑡𝑜𝑡𝑎𝑙 𝑥, 𝑦, 𝑡 - 𝑆𝑆𝑇𝑓𝑜𝑟𝑐𝑒𝑑 𝑥, 𝑦, 𝑡 Niño 3.4 indices
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Li, X., Ting, M. 2015
• What do they mean with RCP8.5 scenario?
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Li, X., Ting, M. 2015
• What do they mean with RCP8.5 scenario?
Representative Concentration Pathway:
rising radiative forcing leading to 8.5 W/m2 in 2100, it’s the worst case scenario in the fifth IPCC.
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Li, X., Ting, M. 2015
• What is the effect of ENSO on the monsoon in the observation data?
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Li, X., Ting, M. 2015
• What is the effect of ENSO on the monsoon in the observation data?
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Li, X., Ting, M. 2015
• What are the differences in South-East Asia between forced and natural ENSO-monsoon relationship? And between historical data and simulations?
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Li, X., Ting, M. 2015
• How can we conclude that there is a weakening in the ENSO-monsoon relationship? Do models agree?
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