26 November 2007


A few days ago, I heaped some scorn on a scheme that the (now outgoing!) Australian government has adopted to the tune of $A10 million; an unproven technology to make rain, even when there are no clouds. As presented, the details on the whole endeavor were sketchy, from how the technology was supposed to work to the funding and decision making process. Well, another news item has appeared with a few clues about how the device is supposed to work which confirms my earlier suspicion that this is complete and utter nonsense. In addition, a cloud physics expert and member of the WMO Weather Modification panel is quoted. He basically says (albeit much more diplomatically) that we, the Australian people, have been hornswoggled! Sold up the river by a deceitful MP (who unfortunately was re-elected), apparently in an effoty to line his campaign donor's pockets.

Here is a quote from this new article, focusing on how it (allegedly) is supposed to work. I will give a few of my own scientific criticisms afterward (My graduate research was on cumulus and storm dynamics, so I do have some insight into this...)

Scientists involved in testing the Australian Rain Corporation technology, including Professor Jürg Keller of the University of Queensland, say the ionisation system uses a ground-based device to attract water molecules.

These condense, generating heat that, in turn, triggers an up-draft of the kind that occurs when clouds form naturally.

The basic idea here just seems fanciful, not reality-based. Excuse me for being technical (for background, here is Wiki's cloud physics article, though it is not particularly insightful...), but some problems that I see with this are:

  • Where is this moisture coming from? From the moisture in the air above the device, or is it attracting it from10s to 100s of km away, an alluring siren's song that the water vapor molecules just can't resist?

  • With the most hydrophilic of cloud condensation nuclei, you might get an extremely small drop at say 90% RH (relative humidity). This is very rare. Generally, a small supersaturation (i.e. 100+%) is required to get a small drop to form and grow. If, as claimed, it can produce rain “under a blue sky” (i.e. presumably not 100% RH), how do the drops grow to precipitation size in this?

  • Generally in a cumulus cloud (which would appear to be the model they are working off of...), the updraft comes before the water condenses and droplets form, not after as suggested here. In fact, the water is often detrimental to the kinetic energy of the updraft. It doesn't follow that because water condenses, an updraft and rain will form. Think of fog. Think of cumulus clouds that don't rain.

  • An unstable environment is required for cumulus clouds. The influence of the broader environment doesn't even seem to be considered here.

These are just a few of the more obvious problems with this. The whole idea seems vaguely reminiscent of the whole cosmic ray/climate connection which has been posited but is in fact generally unsupported by either careful theoretical considerations or the data. There is very little correlation between the temperature trends and cosmic ray activity.

The scandal here is not with proposing new ideas and hypotheses. Rather the issue is way it has been done. It all seems very underhanded and 'hush-hush'. Apparently, no one with any genuine expertise was consulted on this. If they were consulted , their advice was ignored. By all means, let's apply science and innovation to help mitigate our climate problems . But not large handouts to campaign donors with half-baked ideas (and please, let's not dump stuff into the ocean). The appearance of impropriety is too strong (please, let's have an inquiry into this). It is very difficult to get research funding in Australia and there are numerous innovative and unfunded researchers whose projects offer a genuine chance at making a contribution. Let's fund those, rather than chasing mirages in the desert.

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