Climate Letter #2069

Science has all the tools it needs to prove whether or not all precipitable water (PW) mixtures consistently generate greenhouse energy effects, how strong the effects are, and the potential for variations in strength.  The tools and methods that are available are much better than the ones I have been using, and would provide much better results—if put into practice.  The results I get, relying only on weather map imagery, are still clear enough to serve as a reasonable source of motivation for taking the next step at the scientific level.  Is there any other source of motivation for taking this step?  Let’s consider what science already knows about the natural phenomena it calls atmospheric rivers (ARs).  It’s only in recent years that the definition of ARs has been expanded in a way that sets no limit on the magnitude of any one river.  They don’t all have to be as powerful as this latest one—https://www.bbc.com/news/world-us-canada-59324764—as long as certain basic features are present.

We know where ARs come from. We know they originate as pure water vapor, a part of which later condenses into larger-sized particles during the course of a river’s flow. Successive condensation processes transform the vapor into aerosols that are heavy enough to be precipitable, hence the new and more descriptive name given to the river’s entire mass. Some of this “water” in the PW mass is real water, some remains vapor, and some ends up as particles of ice. The “river” concept derives from the observation that all of this material is “bunched up” with an extraordinary degree of concentration, and that it keeps flowing on a distinctive pathway over a considerable distance, much like surface rivers except that everything about the flow pattern is reversed. As they flow, these rivers are gradually distributing material rather than collecting more, eventually reaching a point of complete disintegration. They are called “atmospheric” because of their unique location, on courses at least two or three miles high above the surface, each of which originates and is quickly sent aloft following the initial and continuing process of water vapor creation by evaporation.

Science knows that water vapor, all by itself, is a greenhouse gas, more powerful than the others by ordinary standards of measurement. It knows how to approximate the total greenhouse effect of all the water vapor that remains confined within the tropical belt, which may rise to very high altitudes without forming into rivers. Tropical water vapor constitutes the bulk of Earth’s total, supplemented by the vapor that stays close to the surface at all latitudes beyond the tropical belt. These latter amounts originate from local sources of evaporation, do not concentrate into river-like flows, have less tendency to elevate and no inclination toward precipitation after condensing by attachment to large surfaces. Condensation rates are closely regulated by air temperatures under a principle known as the Clausius-Clapeyron equation. What is missing from science is any kind of recognition that the concentrated PW material incorporated into the bodily flow of ARs at high altitudes may be capable of expressing greenhouse energy effects that are totally independent of the effects generated by water vapor in all of the other situations. Science as now practiced simply lumps all water vapor into a single category, treating it in much the same way as it does with other greenhouse gases. Nor is there any separate category specifically assigning greenhouse energy effects to non-gaseous agencies, such as the very fine droplet material of clouds or any of the heavier type of particles that precipitate from AR formations. This could all change upon establishing a clear view of PW in action on a day-by-day basis, which is how it actually operates, precisely what I am calling for as a first step for researchers to take.

The “research” I have personally been doing concludes that the greenhouse energy produced by PW in the ARs is very real and very powerful, but is only temporary. It can only be measured in terms of hours, at minimum, or at most a few days. This is because ARs are discrete bodies of material that have different magnitudes, are constantly in motion, and are steadily disintegrating as they flow along “streambeds” that can bend and twist in all kinds of erratic movements of their own doing. Greenhouse energy, while continuous, is dispersed accordingly, which means its effect on surface temperatures can only be observed by making deliberate, short-term observations connecting the two happenings, in the air and on the surface, in a dynamic pairing. This is the exact opposite of the way other greenhouse effects are expressed. The difference becomes yet more interesting when observations also suggest that almost every location within the mid to upper latitudes receives some amount of this kind of greenhouse energy practically all of the time, every day. The amount can vary from tiny fragments produced and shunted off by the disintegration of a previous AR to the full force generated from the healthy heart of one that is currently passing by. Even more often, the common result for a given location could be somewhere between these extremes.

The greenhouse effect from surface water vapor will vary somewhat from day to day and year to year for that same day, but seldom by a large amount.  The effect from the concentrated PW in an AR that is passing over (assuming it to be real) would almost certainly be more variable, and the relatively high concentrations of PW in overhead AR passage should result in comparably high amplifications of surface heating.  I find it possible to imagine that on an average day the amount of surface heating provided by the PW from ARs is considerably greater than the amount provided by the water vapor near the surface.  With a maximum overhead flow it could even be several times greater, with an enormous influence on energy input.  This would explain the great variations we keep observing in daily temperature anomalies, low as well as high.

Carl