ECS event #28

09:04:01 From Yen-Ting Hwang : Since I’m not talking, I can answer quick questions by typing (as long as the sick kids stay asleep).

09:04:21 From Jonah Bloch-Johnson : Reacted to "Since I’m not talkin..." with 👍

09:13:35 From Bhupendra Bahadur Singh : What causes prominent cooling (eastern P) to develop at the subsurface whereas the surface signals remain slightly weaker?

09:15:07 From Yen-Ting Hwang : After the aerosol reduction? My guess is that the air-sea flux associated with the cross-EQ cell would affect the surface.

09:15:46 From Kyle Armour : Thanks, Ting! I was wondering if this helps us understand why models can’t capture the observed eastern Pacific cooling since ~1980. They have aerosol forcing, after all. Do they have the wrong forcing magnitude, pattern, time series? Or do some other model biases (e.g., ITCZ biases?) limit the response?

09:16:10 From Deirdre Des Jardins : Any thoughts on persistent cold PDO?

09:17:06 From Yue Dong : Great talk! Does the mechanism (opposite change in tropical SST from fast to slow response) also work for SH aerosol or other thermal forcings?

09:17:33 From Karsten Haustein (he/him) : Arguably aerosols (during the recent brightening) amplifies the GHG forced tendency to cool the central Pacific (i.e. more La Niña)?

09:20:20 From Karsten Haustein (he/him) : guess my Q is obsolete sind Tue asked basically the same ;)

09:20:30 From Karsten Haustein (he/him) : Yue

09:21:10 From Deirdre Des Jardins : Eye opening talk!

09:21:34 From Yen-Ting Hwang : Thx!!

09:23:50 From Yen-Ting Hwang : @Karsten Haustein, yes, I think aerosol recovery does enhances the GHG induces hemispheric asymmetry and equatorial E-W gradient.

09:26:08 From Karsten Haustein (he/him) : Reacted to "@Karsten Haustein, y..." with 👍

09:32:58 From Jonah Bloch-Johnson : any idea why 305K Mock Walker has stronger response to aerosol changes than the cooler ones?

09:33:12 From Jonah Bloch-Johnson : (great talk btw)

09:33:18 From Yen-Ting Hwang : @Deirdre Des Jardins: The obs. trends I was referring to: https://www.dropbox.com/scl/fi/t5xxkt0edm0csrnvle2rx/SST_trend_2014vs2022.pdf?rlkey=4ac642aa6ha71roudex681fmn&dl=0

09:35:44 From Robert Wood : Guy: Are you able to reproduce (qualitatively) the Mock-Walker results using the simple WTG parameterization applied in your two-domain LES?

09:37:22 From Jonah Bloch-Johnson : thanks guy!

09:38:20 From Robert Wood : Thank you Guy. The agreement seems encouraging.

09:54:16 From Allegra N. LeGrande : The size of the LIS can have significant impacts on conditions in the North Pacific. Did you try modulating the LIS height?

09:55:13 From Robert Pincus : Neat work. Can you explain how you diagnosed effective radiative forcing?

09:55:55 From Allegra N. LeGrande : do you just plug in the reconstructed SST to a PI simulation atm-only and look at TOA changes?

09:56:33 From Allegra N. LeGrande : for determining ERF

09:57:05 From Allegra N. LeGrande : thanks!

09:57:21 From Nic Lewis : Vince: Great talk. I think Sherwood et al (2020) assumed a positive LGM pattern effect of +0.5 W/m2/K

09:58:40 From Jonah Bloch-Johnson : Jiang Zhu has a good paper on state-dependence in CAM4/5/6: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL089143

09:59:30 From Isaac Held : Suppose one is interested in the Southern Hemisphere response to CO2, rather than the global mean.  Would this ice age pattern effect change the estimate of the SH response?

10:00:35 From Kyle Armour : Replying to "Vince: Great talk. I..."

See also Ian Eisenman’s work showing that global temperature dependent feedback changes between the LGM and modern-day is smaller than assumed in Sherwood (consistent with Vince’s results). I think this is one reason that the pattern effect on feedbacks shows up as more important here. http://eisenman.ucsd.edu/papers/Eisenman-Armour-submitted-2023.pdf

10:00:49 From Isaac Held : thanks