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About bdgwx

  • Birthday 10/19/1977

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    St. Louis

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  1. bdgwx

    Avoiding Hothouse Earth

    The scientific consensus doesn't claim that CO2 is the only game in town nor does it knowingly exclude any forcing mechanism. It just claims that of all radiative forcing mechanisms (both natural and anthroprogenic) CO2 happens to be a significant contributor. And in an attempt to steer the conservation back toward the topic of the thread the paper is actually focused more on what happens if the global mean surface temperature rises by 2C rather than the exact pathway of how it got there in the first place. Would a hypothetical 2C rise in the global mean surface temperature activate hothouse tipping points or not? Is there an abundance of evidence to support that hypothesis or not? The authors believe there might be. That's the focus of the paper.
  2. bdgwx

    2018 Temperatures

    Sahara Air Layer Also, I hadn't heard the phrase "atmosphere depletion" either, but enhanced ocean heat uptake at the expense of less atmospheric heat uptake is the way I understood Vice-Regent's definition. Obviously the harder your compress the spring the more it fights back. In other words, the atmosphere will eventually respond to the ocean heat uptake. It always does.
  3. This is a good point. I consider myself pretty decent at math, statistics, and probabilities and even I get hung up thinking in terms of probabilities sometimes. Some probability problems can be completely non-intuitive even for math wizards (refer to the Monty Hall problem as a prime example). Even the most trivial problems fool the general public. For example, if someone sees POPs of 33%, 33%, and 33% on Monday, Tuesday, and Wednesday they sometimes incorrectly assume there is a 100% chance of rain at some point during those 3 days. You and I know the real probability is actually 1-((1-0.33)^3) = 70%. But, even that assumes those 3 events are completely independent when in reality they probably aren't which throws yet another wrinkle in the POP game. That comes into play on your hourly example when you might see a 50% POP for 6 consecutive hours. The idea there being that if it's raining during one hour it's probably going to continue raining on the next as well. That's an example of where the hourly probabilities are dependent on each other so neither the additive nor multiplication rules apply. I personally get hung up and have to really think about how to convert the SPC's tornado probability in a 25 mile radius into a TORCON probability over a 50 mile radius. Obviously it isn't as easy as doubling the SPC value to get the TORCON equivalent. Anyway, your point is well taken because even us sciency and mathy types have to really think it about ii so I can't imagine what the general public's perception is most of the time.
  4. bdgwx

    Redding CA "firenado" rated EF3

    Here is the radar screenshot during the time.
  5. bdgwx


    Using Gough's (1981) solar luminosity formula L(t) = L(t0) / (1 + 0.4 * (1 - t/t0)) we can estimate that solar radiation was still L = 1 / (1 + 0.4 * (1 - 4.55/4.60)) = 99.5% of today's value. This yields a radiative forcing reduction of (1360 / 4) * 0.995 = -1.7 W/m2 relative to today. Using Arrhenius' (1896) original radiative forcing formula ΔF = λ * ln(C/C0) and using 5.35 W/m2 as a more conservative estimate of CO2 sensitivity parameter (the IPCC used 6.3 at one time) we can see that 1000 ppm would produce an effect of ΔF = 5.35 * ln(1000/400) = +4.9 W/m2 relative to today. So yeah, the net CO2 and solar radiative forcing 50 MYA relative to today would be around +3.2 W/m2 whereas just the CO2 forcing today at 1000 ppm would +4.9 W/m2 or about 1.5x times higher. It's obviously just a rough estimate I calculated and it doesn't factor in other climate forcing elements. The point...1000 ppm might be expected to have a bigger effect today all other things being equal because the sun is also brighter. Just food for thought...
  6. bdgwx

    Mountain West Discussion

    Here is the radar screenshot of the Redding, CA firenado.
  7. bdgwx

    July 19-20 Severe Weather

    Here is video taken from what I believe is the Showboat Branson Belle. That is a larger vessel than can weather the storm. The two boats is the video are Ride the Ducks vessels. One of them sinks. The video cuts out just before it goes under. Fair warning...this is devastating to watch. http://www.ky3.com/content/news/CAUGHT-ON-CAMERA-Viewer-captures-Ride-the-Ducks--488687431.html
  8. bdgwx

    July 19-20 Severe Weather

    It looks to me like the low was getting a tug from being in that right entrance region of that UL jet streak up there in Canada. But, on the 12Z run you can clearly tell that it wants to fully lock onto the southern flow and drift southeast instead of northeast. That is a huge change; no doubt about it. And seeing a change like this within 36-48 hours of event will definitely get a forecaster's attention.
  9. bdgwx

    Climate Emergency

    I've learned that once someone entertains the idea of conspiracy, hoax, fraud, etc. it becomes a trap in which they are forever stuck. Bona-fide evidence be damned. Whereas rational people understand the value of consilience (the idea that multiple lines of evidence from multiple sources spanning multiple disciplines of science all tend to converge on the truth) conspiracy theorists prefer anomalous pieces of evidence from questionable sources. This thread and others like it are a stain on the subforum.
  10. bdgwx

    July 19-20 Severe Weather

    There is a wide variety of solutions in model land right now. Even the GFS vs GFS/FV3 is strikingly different. And for what it's worth the FV3 has better low level setup. It also keeps interest alive on Friday further east. A lot of possibilities are still on the table at this point.
  11. Thursday could be interesting in terms of severe weather for at least the western parts of this subforum.
  12. bdgwx

    Local climate change article

    Back to the article the OP mentioned I'm definitely not understanding the explanation given. I'm playing out typical diurnal pressure and temperature perturbations in my mind and plugging them into PV=nRT and I'm just not seeing how the V or n changes much over the entire depth of the troposphere. Even on first principal reasoning it's weird to think the volume of the atmosphere is substantially different on the night side vs the day side of the planet. I mean, I acknowledge that there probably are small diurnal fluctuations in the cross sectional area of H2O and CO2 molecules (probably more so with water vapor than with carbon dioxide), but the changes aren't going to be enough to substantially alter the probability of an outgoing longwave photon getting absorbed on it's trip up to the stratosphere. Right? What am I missing?
  13. bdgwx

    Local climate change article

    By the way, an interesting extraterrestrial case study of the DTR is that of Venus. It's greenhouse effect and advective processes are so potent that the DTR there is effectively 0.
  14. bdgwx

    Local climate change article

    Yes. This reduction the diurnal temperature range is an expected and predicted behavior of a GHG forcing agent. I'm not sure I agree with the explanation given though. Based on what I've read it's actually the net effect of a lot of different things including but not limited to cloud cover, soil and vegetation evaporation rates, aerosols, urban heat islands, land use changes, etc. Different processes may dominate in different locales. But, a significant reason that is even more subtle than any of the above is that GHGs species like CO2 are mostly transparent to incoming shortwave radiation so the amount of daytime heating occurring before GHG increases isn't substantially different afterward either (all other things being equal that is). In other words, Tmax at many locales saturates out with or without GHGs at a similar pace. But, in the absence of advective processes and whereas Tmax is modulated more by incoming shortwave radiation Tmin is modulated more by outgoing longwave radiation which CO2 and other GHGs are opaque to so in that regard it's intuitive that Tmin responds more to GHGs than Tmax. Then consider that cloud cover (itself having an anthroprogenic influence) responds to both outgoing longwave radiation and incoming shortwave radiation and it should be obvious that more clouds means a smaller diurnal temperature range (DTR). Many studies pin this later simple explanation on most of the DTR observed in many regions. But, it's certainly not the whole story.
  15. Saturday might be a player as well in Missouri.