How quickly it rains down depends on a few factors, and we can tip those in our favor:
--> Humid Rise—humidity (just the h2o molecule) is only 18g/mol, while oxygen molecules are 32g/mol, so humid air is quite buoyant! Especially considering that water vapor reflects heat (infrared) back to the ground, creating a heat bulge beneath it. The result is that, once humidity begins to rise, it naturally pulls air in from all around it, along the ground. It begins to drive convection. Yet! That humid rise is normally billowy and easily dispersed by cross-breezes, which means that the humidity cannot rise high quickly; it mostly travels far overland, or stays in place. Your rain wanders to an unexpected location! We want to form rain clouds nearby, instead, so we need that humidity to rise really high, quickly, without being torn apart by cross-breezes. That’s where the solar concentrators help, with their tall tower at 1200C and radiant, they blast infrared into all the water vapor around them, pummeling a plume high up, carrying that vapor. Up high enough, the air pressure drops, which is key for causing a rapid cooling, and the formation of nice heavy clouds. The faster we take air from the ground up to a few kilometers, the more water it’ll still be holding. [[Only a fraction of one gram per m3 is needed for the thinnest clouds, but we could toss a few grams up and it’ll come down soon. We want the water to rain, evaporate, and rain down again, in as many cycles as it can. That gives plants time to grab it, in numerous locations, as well as time for the ground to catch some.]] When we look at water-demand for plants in the wild vs. water-resilient greenhouses, we can drop water demand ten-fold because nine-tenths of the water was lost in the leaves to evapotranspiration! As a result, if that leaf-sweat keeps rising and falling as rain as it travels further South, then the same bucket of water ends up getting ten times the use (assuming ground water is eventually used, as well).
--> Albedo—the desert rock is pretty bright, so the addition of vegetation and especially any water-bodies (!) will multiply the solar absorption, which will drive that heat-bulge and evaporation for humidity-buoyancy, to help loft water vapor and form clouds. This is how the Amazon does it—most of her clouds are her armpit fog, caused by solar-to-thermal foliage!
--> Vortices—the solar concentrators themselves can be rigged with a few flanges, to nudge their inflowing convection as it quickens toward the center, to spin that up-draft, helping it stay coherent and push higher, for rains nearby. Any Youtube video on Rocket Stoves by Robert Murray-Smith is best for enjoying such a vortex!
--> Swales—I love swales. I’ve been preaching swales since 2010. I heard, almost immediately, when Sepp Holzer started pitching his “crater gardens” … which were dug by an excavator, four feet deep. I was aghast—my favorite swales are micro-swales, a few inches deep, in flakey soils that rain seasonally, to catch it as it dribbles. That’s what they’re doing in the Sahel, south of Sahara, to stop the deserts. By halting the flow of water along the ground, keeping it for seep, roots, and another evaporation, you prolong the residence-time of each ton of water, leading to a greater equilibrium stock—that is, a high normal lake line, because each ton of water rarely ever leaves.
And, as to infrastructure before success—California could probably boost rains enough to help farmers and forests, here, without needing to conquer an entire desert the size of Europe!
How quickly it rains down depends on a few factors, and we can tip those in our favor:
--> Humid Rise—humidity (just the h2o molecule) is only 18g/mol, while oxygen molecules are 32g/mol, so humid air is quite buoyant! Especially considering that water vapor reflects heat (infrared) back to the ground, creating a heat bulge beneath it. The result is that, once humidity begins to rise, it naturally pulls air in from all around it, along the ground. It begins to drive convection. Yet! That humid rise is normally billowy and easily dispersed by cross-breezes, which means that the humidity cannot rise high quickly; it mostly travels far overland, or stays in place. Your rain wanders to an unexpected location! We want to form rain clouds nearby, instead, so we need that humidity to rise really high, quickly, without being torn apart by cross-breezes. That’s where the solar concentrators help, with their tall tower at 1200C and radiant, they blast infrared into all the water vapor around them, pummeling a plume high up, carrying that vapor. Up high enough, the air pressure drops, which is key for causing a rapid cooling, and the formation of nice heavy clouds. The faster we take air from the ground up to a few kilometers, the more water it’ll still be holding. [[Only a fraction of one gram per m3 is needed for the thinnest clouds, but we could toss a few grams up and it’ll come down soon. We want the water to rain, evaporate, and rain down again, in as many cycles as it can. That gives plants time to grab it, in numerous locations, as well as time for the ground to catch some.]] When we look at water-demand for plants in the wild vs. water-resilient greenhouses, we can drop water demand ten-fold because nine-tenths of the water was lost in the leaves to evapotranspiration! As a result, if that leaf-sweat keeps rising and falling as rain as it travels further South, then the same bucket of water ends up getting ten times the use (assuming ground water is eventually used, as well).
--> Albedo—the desert rock is pretty bright, so the addition of vegetation and especially any water-bodies (!) will multiply the solar absorption, which will drive that heat-bulge and evaporation for humidity-buoyancy, to help loft water vapor and form clouds. This is how the Amazon does it—most of her clouds are her armpit fog, caused by solar-to-thermal foliage!
--> Vortices—the solar concentrators themselves can be rigged with a few flanges, to nudge their inflowing convection as it quickens toward the center, to spin that up-draft, helping it stay coherent and push higher, for rains nearby. Any Youtube video on Rocket Stoves by Robert Murray-Smith is best for enjoying such a vortex!
--> Swales—I love swales. I’ve been preaching swales since 2010. I heard, almost immediately, when Sepp Holzer started pitching his “crater gardens” … which were dug by an excavator, four feet deep. I was aghast—my favorite swales are micro-swales, a few inches deep, in flakey soils that rain seasonally, to catch it as it dribbles. That’s what they’re doing in the Sahel, south of Sahara, to stop the deserts. By halting the flow of water along the ground, keeping it for seep, roots, and another evaporation, you prolong the residence-time of each ton of water, leading to a greater equilibrium stock—that is, a high normal lake line, because each ton of water rarely ever leaves.
And, as to infrastructure before success—California could probably boost rains enough to help farmers and forests, here, without needing to conquer an entire desert the size of Europe!