ECS event #34
This symposium was May 28, 2024
recording of the event
09:21:41 From Wenyu Zhou : I have a question: The 1980-2020 period presents a strong negative shift in IPO, which is a rare event in the longer observation hsitory. So it is somewhat expected that model runs rarely capture the observed trend over 1980-2020.
09:23:55 From Antonietta Capotondi : How to you diagnose the OT in the models?
09:25:25 From Maria Rugenstein : Hi Alexey, Why would the recently observed forced response pattern have the same magnitude as the first 20 years of a CO2 quadrupling? Can you elaborate a bit on how you got the observed forced response and what sets the magnitude of a pattern?
09:27:29 From Cristian Proistosescu : Hi Alexey, great talk.
One question, as some of the work of Yue Dong and Sarah Kang show, you can get a similar cooling pattern (N/S assymetry + SE pacific) from forced cooling of the Southern Ocean.
So how do we distinguish between these different mechanisms that all seem to project onto the same surface pattern (Ocean Thermostat, Aerosol, Southern Ocean forced cooling?)
09:42:12 From Thorsten Mauritsen : Great talk Emily! I was wondering if another way to estimate kappa is the current state? I looked up N in the IPCC report to be 0.79 Wm-2 for 2006-18. Then I took HadCRUT and calculated the warming since 1850-1900 which was slightly over 1 K. So kappa close to 0.8 Wm-2K-1 which you got 😀
09:42:52 From Nadir Jeevanjee : Hooray for oceanographers presenting at the ECS symposium
09:43:20 From Cristian Proistosescu : Reacted to "Hooray for oceanogra..." with 💯
09:43:25 From Daniel Feldman : Reacted to "Hooray for oceanogra..." with 💯
09:43:27 From Andrew Williams (he/him) : Reacted to "Hooray for oceanogra..." with 💯
09:43:43 From Clare Singer (she/her) : Reacted to "Hooray for oceanogra..." with 🎉
09:44:06 From Aakash Sane : Reacted to "Hooray for oceanogra..." with 😄
09:44:11 From Ivan Mitevski : Reacted to "Hooray for oceanogra..." with 🎉
09:44:50 From Emily Newsom : Reacted to "Hooray for oceanogra..." with 🎉
09:44:51 From Karsten Haustein (he/him) : Hi Emily, great talk! You showed two high OHUE models with a strong peak at 60 south (circumpolar jet region). Is the associated southern ocean warming reduced as well in those two models? And is the TCR lower accordingly?
09:45:08 From Xia Li : Reacted to "Hooray for oceanogra..." with 💯
09:45:33 From Andrew Williams (he/him) : Replying to "Hooray for oceanogra..."
Oceanographers out there, reach out! We’d love more of you to give talks here
09:45:55 From Nadir Jeevanjee : @Thorsten, here’s a paper on observational estimates of OHUE, including the time-dependence Emily was mentioning: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL100215
09:46:06 From Brandon Duran : Reacted to "Hooray for oceanogra..." with 🎉
09:46:33 From Eric DeWeaver : +1 to Nadir's comment. Maybe one issue here is the importance of the ARGO floats as an observing system, especially as we don't seem to have a long-term plan for how to sustain it.
09:47:40 From Maria Rugenstein : Thanks Emily! Do you have an idea how much of the global-mean pycnocline depth in the models is for the right reason/regions vs compensating biases? Could a more local constraint (mid-latitudes as you argue) be more physical?
09:47:42 From Emily Newsom : Great question, Karsten! I didn’t look at that but I will. I would imagine so but would be interesting to check…
09:48:03 From Karsten Haustein (he/him) : Reacted to "Great question, Kars..." with 👍
09:48:12 From Vince Cooper : Reacted to "+1 to Nadir's commen..." with 👍
09:50:42 From Emily Newsom : Maria- that’s a good question and I’m honestly not sure. Do you mean something like the depth of the pycnocline only in the mid-latitudes or something like that? We did find a strong (R>0.85) relationship between OHUE and SO isopycnal slopes, which could be argued to be more local, though I imagine that metric is also integrating biases from non-local sources.
09:52:15 From Thorsten Mauritsen : Reacted to "@Thorsten, here’s a ..." with 👍
09:52:19 From Thorsten Mauritsen : Reacted to "+1 to Nadir's commen..." with 👍
09:57:10 From Yue Dong : Replying to "Maria- that’s a good..."
The strong relationship in SO is interesting! Does it imply that the SO mean-state stratification/SSS argument may be a more plausible mechanism for OHUE spread (among other proposed theories)?
09:57:22 From Nadir Jeevanjee : Reacted to "Hooray for oceanogra..." with 💯
09:59:55 From Tim Merlis : I think I missed something important: it sounded like you said you have a simultaneous emergent constraint on CS and hydrological sensitivity. But how can surface shortwave cloud feedbacks constrain the climate sensitivity? There are CS feedback decompositions where there is spread from non-shortwave cloud feedbacks and people do process modeling studies of, say, high cloud long wave feedbacks.
10:00:45 From Thorsten Mauritsen : Reacted to "I think I missed som..." with 👍
10:01:39 From Emily Newsom : Replying to "Maria- that’s a good..."
Yes, totally I think that SO stratification matters disproportionately. I think the SSS has an important role (as discussed by Liu et al., 2023) but we also found (as have others) that there’s a really strong effect from altering mesoscale eddy diffusivity, so I think other SO processes matter too. We however found that we captured more variance in global OHUE when we looked at OHUE calculated in both mid-latitude regions (North and South), implying that some of the differences across models care about NH ventilation as well.
10:01:47 From Nadir Jeevanjee : Great session
10:02:02 From Vince Cooper : Reacted to "Great session" with 👍
10:02:27 From Antonietta Capotondi : Thanks to all speakers!
10:04:33 From Yue Dong : Replying to "Maria- that’s a good..."