A field where aerology has a practical application, but in which no navy aerologist has yet ventured, is chemical warfare. Nature has so many tricks and idiosyncrasies in her control of the movement of air masses and air currents that a good understanding of them would be most valuable in the use of chemical warfare.
Possibly the most useful and interesting feature to the navy is the phenomena of the land and sea breeze. It is well known that along the sea coast it is almost a regular occurrence for the wind to blow from the land during the night and in the daytime reverse and blow from the water back toward the beach. This local effect often extends out to sea for as much as fifteen to twenty miles, and back inland the same distance. With these conditions prevailing it is needless to say that in the early morning a unit ashore could launch a gas attack against an attacking fleet, while the fleet could not reciprocate, but if it were in the afternoon the advantage would be reversed, the fleet could launch a gas attack against a unit ashore and they could not reciprocate. Accurate information of these conditions and their extent would be most useful to the commander of a bombardment task group both in deciding how much protection must be provided against a gas attack, and whether or not it is practicable for him to arrange his plane so as to employ one himself.
In an expected engagement at sea, force and direction of the wind would play an important part in the conduct of gas warfare both offensively and defensively. If prior to the time of contact, the force and direction of the wind could be forecast over the period of contact, it might be worthwhile to plan on using a gas attack. Then the force commander could endeavor to so maneuver his ships as to make it possible to have the wind carry the attack across to the enemy, or if he found that he was unable to employ this advantage, he could make preparations for the defense against such an attack.
In both of the above uses of gas warfare one thing is most important, and that is whether or not the wind will shift just after the attack is made so that instead of the enemy feeling the effects of the gas, it results in an attack on the would-be attackers. In utilizing the land and sea breeze along the coast, the time the wind shifts can be fairly well forecast. Knowing that, sufficient allowance may be made in the planning to provide for it. But at sea it would require very accurate forecasting to anticipate a shift during an engagement.
In land warfare a knowledge of local conditions is most useful. The location of hills and valleys and their influence on the path of air currents is very important. It often happens that a certain spot or small area is so situated that while apparently it may be directly in the path of a gas barrage moving along with the wind, eddy currents may carry the gas around the area and the evil effects of the attack thus pass right around any one fortunate enough to be there. Then again it is possible for the gas to settle in a place that is seemingly well sheltered and protected. Knowing the location of these little nooks and corners would be most valuable to any one selecting a site for shelter from gas or in making any plans in which gas warfare had to be considered, such as establishing a permanent or semi-permanent battery.
Also there are places where local influences tend to cause the wind to blow practically always from the same direction. This in some cases might be an asset, in others a drawback. That, too, is an important factor worth considering in making any plans.
Further there is the tendency for air to flow down a hillside at night, and back up in the daytime. If an area in a valley were to be attacked by gas, a night attack would be effective if launched from a higher altitude, because the air flowing down into the valley would take the gas with it and settle it there, while in the daytime a valley would be comparatively free from the dangers of an attack coming down the hillside because as a rule the air rises up out of it. If an attack should get in from the same level as the valley, it would not persist for long because the gas would be fairly rapidly carried on up the slope. However, the rule is violated on an overcast day, because then not enough of the heat from the sun gets down to warm the ground and the adjacent air to cause the latter to rise, so the valley would not be invulnerable on such a day. In an attack got in under these conditions gas would settle there and the evil effects would hang on for a good while.
There is also something else which might in some way be regarded as an impossibility, but in this day and age of the rapid advancement of science and the overcoming of apparently insurmountable obstacles, it might be developed, and that is gas warfare in the air. If a gas considerably lighter than air has not already been developed, it most probably could be. Nature has provided a useful instrument, the inversion of which one frequently hears aerologists and aviators speak. It is generally known that aloft inversions exist over considerable areas of the earth’s surface and especially over the oceans. If a way could be found that a gas lighter than air could be released at the surface and rise to the level of the inversion without too much dissipation and dispersion during the ascent, at the inversion level its upward movement would be arrested, and it would be spread out by the wind at that altitude, so that the pilot of a plane coming through would find himself in a zone filled with gas. It may be only an idle dream, but the value of the results should be worth the investigation.
There is also the surface inversion that is generally found over the land in the early morning. All have seen how smoke, at times, lies along the surface and doesn’t rise as would be expected. This is caused by a surface inversion holding it down, or rather not letting it rise. Knowledge of similar conditions is important in gas warfare in that it would assist a unit commander to estimate effectiveness of a gas attack and whether or not the gas could be expected to persist for a certain period or dissipate rapidly.
These are but a few instances wherein a knowledge of local weather phenomena, a general understanding of aerology, and the use of accurate weather forecasts can be of value both in the offensive use of gas warfare and the defense against it.
It is an extremely broad subject that cannot be covered briefly, but these few instances mentioned should, it is hoped, show that aerology and gas warfare are closely related and that an efficient and successful employment of the latter can be greatly assisted by the information that an aerologist should be able to give at the time an attack is contemplated or when preparations for defense against an attack seem to be advisable.