bdgwx

So the big question...will the IPCC AR6 stick with the likely ECS of 1.5-4.5C or refine it? Sherwood 2020's 1σ range is 2.6-3.9C and 2σ range is 2.3-4.7C. The IPCC uses 66% as the standard for "likely". Using this standard with Sherwood 2020 an argument could be made for 2.5-4.0C. That would be a big change. I'm wondering if 2.0-4.0C might be a more reasonable choice for now. With each passing decade we can constrain the lower bound further. I think at this point 1.5C is all but impossible at this point.

Sherwood 2020: An Assessment of Earth's Climate Sensitivity Using Multiple Lines of Evidence (official / free) suggests a TCR of 1.8C with 66% upper bound of 2.2C. If the PDF was normally distributed that would imply a 95% upper bound of 2.6C. However, the PDF is not normally distributed and has a long tail on the right side so 95% upper bound is likely higher than 2.6C. Sherwood 2020 is probably the most comprehensive study on climate sensitivity to date.

Some of you probably saw news articles regarding the Kramer et al 2021 publication which for the first time measures the net instantaneous radiative force using CERES and AIRS between 2003 and 2018. News Article: https://www.ecowatch.com/greenhouse-effect-nasa-study-2651319284.html Official: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL091585 Free: https://www.essoar.org/doi/10.1002/essoar.10506610.1 From the publication... Total-IRF = +0.033 W/m2/year +/- 0.007 LW-IRF = +0.027 W/m2/year +/- 0.006 SW-IRF = +0.006 W/m2/year +/- 0.003 The SOCRATES radiative transfer model predicts LW-IRF to be +0.023 W/m2/year +/- 0.003. The model computes the RF for increases in most of the GHG species found in the atmosphere. Note that measurement and modeling are consistent here. The MERRA reanalysis attributes +0.006 W/m2/year +/- 0.003 to aerosol declines. Note that this matches well with the measured value. The integrated IRF for 2003-2018 is +0.53 W/m^2 +/ 0.11 with 0.40 W/m^2 +/- 0.1 being in the LW band. Modeling predicted the LW band to be 0.35 W/m^2 +/- 0.05 over this same period which implies good agreement between theory and observation. In summary about 80% of the net heat uptake for the period 2003-2018 is the result of GHGs while 20% is the result of aerosol reductions. It used to be that aerosols were increasing which was suppressing the warming. They stabilized around 1980. But at least for this 15 year period efforts to reduce pollution are now contributing to the warming. This may explain why the EEI has increased to +0.87 W/m^2 +/- 0.12 (Schuckmann 2020) in recent years.

I could see it making a run at the low 1060's. :But I'll be extremely surprised if it hits 1070mb. There is going to be a pretty steep pressure gradient either way. The Euro actually shows slightly higher sustained winds than does the GFS even though it is much weaker with the anti-cyclone. It certainly looks like Fram export will be in high gear shortly.

There is no holding back by the GFS. The 12Z cycle is now showing a 1096mb high against a 971mb low.

https://nsidc.org/arcticseaicenews/2021/03/arctic-sea-ice-reaches-uneventful-maximum/ "On March 21, 2021, Arctic sea ice likely reached its maximum extent for the year, at 14.77 million square kilometers (5.70 million square miles), tying for the seventh lowest extent in the satellite record with 2007. This year’s maximum extent is 870,000 square kilometers (336,000 square miles) below the 1981 to 2010 average maximum of 15.64 million square kilometers (6.04 million square miles) and 360,000 square kilometers (139,000 square miles) above the lowest maximum of 14.41 million square kilometers (5.56 million square miles) set on March 7, 2017. Prior to 2019, the four lowest maximum extents occurred from 2015 to 2018."

It looks like there may have been a mesoscale boundary south of the storm that was forcing junk convection. It looks like the cell is starting outrun that now. Once it finishes ingesting this last bit of convection it looks like the inflow notch might clear out. We'll see what happens.

The spatial and temporal size of the 90 tornado ingredients contour from the 9Z SREF has doubled since last night. I'm pretty sure we've seen larger in the past, but this is high risk worthy for sure.

21Z SREF tornado ingredients product is somewhat aggressive. We've certainly seen larger spatial and temporal sizes of the 90 contour, but this one is respectable nonetheless.

In addition we had this publication come out last year with a comprehensive analysis of the Earth Energy Imbalance. It is now up to +0.87 W/m^2. https://essd.copernicus.org/articles/12/2013/2020/essd-12-2013-2020.pdf

We've seen 3 local peaks. One on Feb 15th, one on Mar 6, and the most recent on Mar 12 with a 5D average of 14.75 per NSIDC extent. We cannot eliminate the possibility of a higher max (the 2012 max occurred on Mar 20), but with each passing day the probability decreases. It looks to me like the melt season is going to start lower than it did last year.

Copernicus reports that February 2021 was coolest since 2014. https://climate.copernicus.eu/surface-air-temperature-february-2021

JAXA data showed a pretty significant surge the last few days which puts Mar 2nd above the mid Feb peak. The winter max will almost certainly occur in Mar per NSIDC as well.

Here is the NSIDC's update regarding the sea ice data problems. https://nsidc.org/arcticseaicenews/2021/03/nsidc-continues-to-investigate-sea-ice-processing-errors/

Oh...you're right. Between both Chrome and Edge cutting off support for ftp and having to switch to WinSCP to download the data I didn't even notice that it hadn't updated.

I usually just go to NSIDC directly. https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ I did see that glitch on that site earlier today. I was assuming the glitch was isolated to that site. The data on the NSIDC site looks good.

We've seen a pretty substantial decline in the NSIDC sea ice extent the last few days. The last time the winter max occurred in February was 2015. So there is recent precedent.

We cannot eliminate the possibility that we've seen the winter max for 2021.

I don't know. That 0.03C response was for a single year. I think it is at least consistent with the hypothesis that aerosols have a big impact and that at current levels they are likely masking a lot of the GHG warming potential. Imagine if that 0.03C rate of change persisted for 10 years. That'd be a cumulative 0.3C change. I'm not really endorsing aerosols as a means of geoengineering here though. The safest thing to do would be to minimize human influence altogether. That way we aren't trying to fight one influencing factor with yet another influencing factor.

We are starting to see studies regarding just how much the pandemic influenced the global mean temperature in 2020. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL091805 About +0.03C per the study above and is attributable to reduced aerosol optical depths.

I believe it will be in March. https://www.emc.ncep.noaa.gov/users/meg/gfsv16/

Oh yeah. I totally remember. I did remove UAH and RSS from my model...just didn't add any skill no matter what weighting I gave it. In fact once I started adding other inputs UAH and RSS became more of a liability than an asset. Yes. I was running the GISTEMP code on the GHCN files. The land only index from GISTEMP actually added some skill to my model with 20% weighting. Getting the ERSST data plugged in proved very difficult at least for me. I just didn't have the time to spend on doing it. The input that mattered the most for me was Nick Stoke's TempLS dataset. I gave this input 50% weighting. When it was all said and done my model could predict the GISS update within 0.05 with 95% confidence. The guys posting as takeyourmoney and James Davis were clearly very smart. They had the modeling thing figured out long before I made my attempt. I wish those two would make an appearance on here. They were always respectful and their posts were packed full of relevant to the point information. They would be fun to engage with here.

That was me!

James Hansen says in his December update (just out today) that he thinks the warming may be accelerating as well. http://www.columbia.edu/~jeh1/mailings/2021/20210114_Temperature2020.pdf

Yes I did. It was pretty nuanced though. The rules said 2020 had to exceed 2016 by 0.01 after rounding to 2 decimal places. The quirk was that 2016 had been getting reported as 1.01. But I (along with several other people) had figured out that the recent addition of observations into the GHCN repository was going to likely flip 2016 back to 1.02. And my model had predicted that GISS would revise Nov down to 1.11 and report 0.83 for Dec. GISS officially reported 1.11 and 0.81 respectively so I had already seen the 2020 round down to 1.02 coming as well. I exploited that situation as well. In the end I learned a lot from this exercise. First...I learned that prediction markets aren't that good. Second...I learned a lot of details about GHCN, ERSST, how the GISTEMP code works, and how to create a model for predicting GISS updates with publicly available information with up to 4 weeks lead time. It was really fun. BTW...your comment above about 2010 being a good analog to 2020 kept me on my guard