Michael Wehner

Just 2mph short…

I am. (And thanks for publishing this in ASCMO!)

Mundane software development and viz is pretty straightforward, almost pedestrian it is so easy. The weirdest thing we did was verify a statistical proof. We had two ideas and chat showed us which one was correct. We verified later manually, and it was right. A bit scary really...

The combined effect of extreme heat and COVID-19 on agricultural labor supply in California communities While growing bodies of scholars have examined the separate effects of extreme heat and COVID-19 on migrant farmworkers in the United States, we are unaware of any study examining their potential comb...

New(ish) paper: journals.plos.org/climate/arti...

Assessing the performance of solar radiation management geoengineering simulations - Frontiers of Earth Science Offsetting the global warming caused by anthropogenic increases in atmospheric greenhouse gases by deliberate injection of aerosols into the stratosphere is the most studied of solar radiation managem...

All currently modeled SRM schemes make seasonal drought somewhere, especially in the southern hemisphere. And the response of hurricanes (tropical storms) is highly uncertain but bound to be severe from the change in the vertical structure of the atmosphere. link.springer.com/article/10.1...

Thanks, I need to cite this is an upcoming paper.😀

I would use CGCM or AGCM depending on which class. But I am old school at this point.

I should also mention that during a California drought, it is just one beautiful day after another. Sunny and warm again...

And no rain in California since Christmas. Western US drought outlook is poor.

I have some ideas, of course…

You hit upon one of the more interesting current detection & attribution problems. While theory might suggest changes in blocking frequency and/or intensity, the signal to noise is high. If true there are still competing effects between dynamics & thermodynamics, further complicating things.

Latest paper on impact attribution. A must read for those interested in the topic doi.org/10.3389/fcli...

Not a big fan of the analogy. And not because of my LLNL background. But because it is unrelatable. Rather I think people understand death & destruction (i.e. $) more directly. And there is plenty of that to go around.

Scores are lower than last year, and the mix of mentions (colors) very different. Not sure what to make of that.

I'm glad that I played my part when I could...

I will see what I have. This was a long time ago 🤣

The 3 am warning woke me up and kept me up thinking about the leak in the basement...

Not being an actual meteorologist, I have a question about the NCEP Stage IV radar precipitation dataset. The attached picture is a snapshot of the current SoCal radar. The concentric circles at Hanford and Santa Maria are clearly artifacts. Does NCEP correct for this?

I am sure this is true but not what I want to know. What I need to know is how the risk changes for fires while parked. I would presume that parked gas cars don't ignite but parked e-cars might when charging. We sleep over our car, so fear of house fire keeps me from buying one.

Anthropogenic aerosols mask increases in US rainfall by greenhouse gases - Nature Communications The authors use rain gauge measurements to derive data-driven estimates of how climate change impacts extreme rain in the US. They find that the expected rainfall increases driven by burning fossil fu...

The companion paper doi.org/10.1038/s414...

In our recent analysis we find the influence of ENSO on seasonal mean and extreme precipitation is far less than previous estimates with about 10% of the variance explained by natural forcings. link.springer.com/article/10.1... In a companion paper, we examine the anthropogenic role. It is larger.

YouTube video by Michael Wehner Detection & Attribution of the human influence on climate: 4th US National Climate Assessment Report

Indeed. Thanks for highlighting this fact. I explained some of the nuance behind this at the 2017 AGU session on the 4th US Climate Assessment at around 4:30 in this video www.youtube.com/watch?v=pwVI...

It's happening! Canada launched two programs to recruit international researchers.

Canada Impact+ Research Chairs (1 million/yr for 8 yrs +)
Canada Impact+ Emerging Leaders.

I will do my best to facilitate the process for those interested. Hit me up.

www.canada.ca/en/impact-pl...

Physics in scream is already GPU. ERF is probably more efficient but not ready for prime time

Simulating Hurricane Katrina in the Simple Cloud‐Resolving E3SM Atmosphere Model v1 Hurricane Katrina hindcasts are evaluated for the Simple Cloud-Resolving E3SM Atmosphere Model (SCREAM) v1 and the Weather Research and Forecasting (WRF) model SCREAMv1 at 3.25 km simulated a rea...

The new models, SCREAM and ERF, run well on GPUs. See doi.org/10.1029/2025... for some recent work.

Increased U.S. coastal hurricane risk under climate change Future ocean warming in eastern tropical Pacific will enhance US hurricane risk through changes in steering flow and wind shear. 

2 of 2: And this paper: www.science.org/doi/10.1126/...

A Global Increase in Nearshore Tropical Cyclone Intensification Tropical cyclone (TC) intensification rates have increased in near coastal regions over the 42-year period 1979-2020 Increases in relative humidity along with decreases in vertical wind shear are...

1 of 2: Not surprising considering this paper: doi.org/10.1029/2023...

But no climate model calculations to assess whether it actually works or what the unintended consequences are.

"while econometric methods remain valuable for identifying current sensitivities to climate variability, they may be less reliable for long-term projection." But they provide insight, and can guide policy, even if not market investments. Wish I could be there...

Assessing the performance of solar radiation management geoengineering simulations - Frontiers of Earth Science Offsetting the global warming caused by anthropogenic increases in atmospheric greenhouse gases by deliberate injection of aerosols into the stratosphere is the most studied of solar radiation managem...

7. "SRM could exacerbate rather than ameliorate some regional changes in climate..." Seems like an understatement to me. All schemes that I examined produced seasonal drought somewhere, especially in the south. And bulk tropical cyclone metrics are highly uncertain. link.springer.com/article/10.1...