Climate Letter #2052

I have gone back and reread the three study abstracts discussed in yesterday’s letter and need to revise one of my possible conclusions—these studies do not change the conventional definition of atmospheric rivers (ARs) to quite the extent that I was hoping for.  Much of what they say about the origin and distribution of the river vapor matches that of my high-altitude PW streams, but they are ambivalent about limiting the content exclusively to the upper-level wind system in the way I do, and ambivalent about how and when precipitation is released.  In my view rain-out can occur anywhere, at any time, and much of it will go straight back into the ocean.  Landfall at the end of an ocean journey may or may not make a difference in the amount of rain.  The conventional view puts most of its emphasis on what happens upon and after landfall, which is obviously of maximum importance to people living on land.  This next link, to an article published in full just two days ago by a credible author, provides a clear representation of where the conventional view of ARs stands at this time:  https://theconversation.com/atmospheric-river-storms-can-drive-costly-flooding-and-clim,ate-change-is-making-them-stronger-128902.  It’s quite good with respect to describing the current view of how ARs respond to climate change, mainly with in terms of changes at the original source of evaporation, but has little to say about the level of atmosphere where the rivers are located, or how their movement is regulated.

Also, as I’ve said many times, no conventional view, of whatever source or content, can ever be found showing any sign of interest in the possibility that ARs could generate greenhouse energy effects from whatever their location may be.  The viewers certainly do not look for unusual effects.  As for the ordinary effects that all water vapor is supposed to have, it’s not even clear that the conventional view supports a perception that the contents held by ARs generate any greenhouse effect at all, even of the ordinary type.  In other words, while recognizing that the rivers are loaded with extreme amounts of vapor, relative to relative to surrounding locations where no rivers are in place, they fail to discern any difference in how much greenhouse energy is being delivered at the surface.  It follows that in decades to come, when their models show that climate change is likely to cause more of the kind of evaporation that should produce even larger rivers than we have today, those larger rivers will remain as impotent as the current ones when it comes to generating a greenhouse impact.  We’ll see lots more flooding, but no additional temperature change as a result of this particular activity.

If you are a long-time reader of these letters you know how much I disagree with the people who hold this view, and you also know exactly why I disagree.  It’s because I have seen solid evidence to the contrary, from the very best of credible sources.  The evidence is ongoing, not just a one-time thing.  It’s right in front of our eyes, every day.  If you are a new reader, I will take you there—right now—so you can see it for yourself.  You will need to open two websites, both of which contain daily updates of specialized maps but almost no words.  The first site contains updated maps of 5-day animation of the total flow of precipitable water (PW) over Earth’s entire surface.  It comes from a group of meteorological researchers associated with the University of Wisconsin:  http://tropic.ssec.wisc.edu/real-time/mtpw2/product.php.  Those spiky objects seen moving away from the tropical belt represent tracks that are dominated in contained volumes of total PW by concentrated streams of water vapor coursing through higher altitude parts of the atmosphere.  Atmospheric rivers, as commonly defined, create at least some of these very same tracks, if not all.  The tracks all tend to disintegrate as they progress, disappearing completely in not much more than five days, often less .There is no additional information to be found on this map.  For that we must go to another site.

The second site, called Today’s Weater Maps, is produced by a group associated with the University of Maine.  It is packed with an incredible amount of information distributed in a coordinated way via a set of many different views of a dozen different kinds of maps:  https://climatereanalyzer.org/wx/DailySummary/#t2.  One map gives you a snapshot view of total PW volumes across the globe virtually identical to the content of the last frame of PW on the animated site.  You can then compare images of entire individual streams with the various effects they have had on the planet for that particular day, by clicking on maps that specialize in many of the different effects.  You will need to go back and forth between any two maps, focusing your eyes on any location of choice as it appears on each map.  Start with PW plus precipitation.  You can easily spot the places where selected PW streams (or ARs) have dropped loads of rain or snow over the last 24 hours.  Another map comparison will reveal the way jetstream winds have an influence on the course taken by practically every PW or AR stream. The stronger the wind the greater the influence. A third pair of maps will let you compare the strength of vapor streams with temperature anomalies on surfaces directly below those streams on any given day.  This can get complicated.  At first, stick with land-only surfaces in the mid-to-upper latitudes and look for places where the overlapping of relative PW strength—by weight in kg—and the strongest of temperature anomalies–either warm or cold—is totally obvious.  It happens all the time.  The relationship is undeniable.  I’ve come to the belief that every double in PW weight creates a full 10C in temperature change (or the reverse) as long as it lasts and aside from other factors that may also have an impact for other reasons.

Carl