Rising Air Delivers Precipitation!

Precipitation of moisture in the air is the primary way that new safe water is delivered everywhere. Nearly all of this precipitation happens naturally as part of what we call the Water Cycle. If we could raise air artificially or manually, we could deliver safe water anywhere!
Air Circulation

Rising and descending air
Source - adapaonline.org

Large-scale rising and dropping air is a characteristic of the atmosphere. 
The location of both rising and descending air vary by location (by latitude and longitude) and by season (as the axis of the earth changes relatively to the sun as the Earth rotates around the sun.
The wettest areas are seen in the areas where air is 'naturally' rising i.e. at the equator and the mid-latitudes  40-60 degrees North and South.
The driest areas are seen where air is naturally descending: 20-30 degree North and South latitudes and around the poles.
Drivers of Rising and Falling air

Causes of Rising and Falling air
Source - cmmap.org

The primary causes of air circulation are surface heating, terrain changes, convergence of air masses. There is more rainfall on higher elevations of mountains and as weather patterns create turbulence in the atmosphere.
The rising and falling air moves northwards or southwards by season i.e. how the earth is oriented relative to the sun.
Like mountains, the presence of large bodies of water also influences incidence and rates of precipitation.
Adiabatic Cooling

Source - cmmap.org

As air mass rise, pressure on the air mass drops and the air mass cools.

Source - ww2010.atmos.uiuc.edu

Source - ww2010.atmos.uiuc.edu

As rising continues, so does the cooling, till water vapor molecules condense and coalesce to form water droplets.

Intensity of precipitation increases as the depth of the rising air mass increases.

Is there any way for us to artificially raise large bodies of air that we know are full of water vapor?

Fog Collection System in Cactus

Many naturally-occurring Biological Structures have the ability to extract liquid water from air. The common cactus that lives and thrives in arid locations is quite drought tolerant because it can collect liquid water droplets contained in fog.
The Opuntia Microdasys Cactus

Source -
en.wikipedia.org/wiki/Opuntia microdasys

Spine Clusters
Source - commons.wikipedia.org

The surface skin of this species of cactus is covered with micro- and nano-scale structures. These consist of clusters of spines and appendages (called trichomes) that are uniformly distributed all over the cactus' skin.

Source - Article titled "A multi-structural and multi-functional integrated
fog collection system in cactus by 

Jie Ju,

Hao Bai,

Yongmei Zheng,

Tianyi Zhao,

Ruochen Fang

& Lei Jiang

nature communications Journal

Study and analyses of cactus spines under an electronic microscope reveal the existence of wide and narrow grooves along the length of each spine and the existence of grooves and barbs on each trichome (figures on the left).
These specific designs are the reasons why cacti can extract water droplets from fog and do so with extreme efficiency.
Experiments in the laboratory have shown that the initial deposition of the water droplets in fog happen on the barbs on each spine and this water droplet falls down to the base of each spine while growing in size.
The trichome's job is to absorb the water arriving at the base of the spine. Thus, multiple spine clusters and trichomes working in close cooperation deliver water adequate for a cactus to thrive in very arid climates.
Two Underlying Science Phenomena
The gradient of surface-free energy and the gradient of Laplace pressure are the two mechanisms that come into play when cacti harvest water droplets from fog.

Surface -free EnergySource - wikipedia.org

Surface-Free Energy:
This is the amount of free energy on a surface and this energy increases as the area of a surface increases.
Folds in surfaces, thus, increase surface free energy. For isotropic materials this energy is the same as surface tension.
The gradient is the direction in which surface-free energy increases: as the spine is conical in shape, the surface area closer to the bottom of the spine is greater than that closer to its tip. Thus a natural gradient exists forcing water droplets to move from the tip to the base of each spine.
Laplace Pressure

Laplace Pressure
Source - hyperphysics. phy-astr.gsu.edu

Laplace pressure is the pressure difference between the inside and the outside of a surface.
As this difference gets greater, moisture droplets outside a surface get absorbed into the body through the surface.
This is the phenomenon underlying the trichome's ability to absorb water droplets captured and delivered by the spines.

How can we replicate nature's phenomenon to capture water droplets contained in fog ingeniously everywhere on Earth? That's the task - development and deployment of artificial fog collectors - before humanity today!

The First Building That Will Extract Water-From-Air

Imagine the Common Laser Pointer Delivering Drinking Water!

Local precipitation of water vapor in the air to produce rain (when needed and in necessary amounts) would be a god-send to humanity. Most common approaches so far have been ways to "seed" condensation of the water vapor in the air. Recent research has, however, surfaced the possibility of using lasers to promote condensation.
Traditional "Seeds" of Condensation

Dry Ice
Source - en.wikipedia.org

Silver Iodide crystal
Source - en.wikipedia.org

Dispersing tiny particles of dry ice, silver iodide and other salts is the traditional approach to seeding clouds to encourage precipitation in the form of rain.
The efficiency of this approach is, however, a bone of serious contention because the success of this approach is never predictable to any level of acceptable confidence.
Laser Filaments

A Laser Filament
Source - large.stanford.edu

A narrow column of plasma is known as a laser filament.

A Laser Filament
Source - large.stanford.edu

A column of plasma forms when a laser pulse self-focuses and when its self-focused intensity is high enough to ionize the medium the pulse is traversing through. At this point in time and location, the column of medium is actually a column of plasma aka a laser filament.
As the energy required for continued ionization detracts from the pulse energy, the filament steadily dissipates over time.
Air is as medium for laser beam propagation and, thus, for the formation of filaments.
Typical filaments are a few meters long but filaments with lengths in the hundreds of meters are not uncommon.
Inside a Laser Filament

HNO3
Source - ffden-2.phys.uaf.edu

The local chemical composition of the atmosphere appears to be altered by the existence of a laser filament.
In particular, at relative humidity levels higher than 70%, the HNO3 amounts inside a laser filament are found to be over 1,000 times the levels at which HNO3 is known to stabilize water droplets, increase their growth and increase their rate of growth.
The most interesting finding from experiments is that this higher concentration outlives the laser filament by orders of magnitude i.e. the water-producing effects of increased concentration can continue to make water droplets larger for as long as 15-20 minutes.

The eventual result: rain!