You wouldn’t have thought there is a direct correlation between parachuting and sailing but there’s is, Why? The main atmospheric air goes up to the troposphere and the surrounding ground level air is held down by the above air mass. At sea level the air pressure is one atmosphere or about 15 psi or 1 bar. As the earth rotates from west to east it produces a Coriolis effect and in the northern hemisphere it makes the air deflect to the right if you’re looking northwards.
Warm air rises cold air falls creating wind at the surface, air rushes down when the pressure is low to fill the empty air space. Sails are like aeroplane wings but set in the vertical plan they are designed to create lift and modern sails have enabled boats to sail pretty close to the wind. However, get too close to the direct wind and the sail stalls. When the sail stalls it flaps and you stop moving forward.
A parachute even the older style round parachutes use the air pressure to slow down the paratroopers descent. Modern square high performance parachutes act like aeroplane wings and create lift and offer the parachutist amazing manoeuvrability.
Military parachutes are more basic in structure and manoeuvrability, however you do have four lift webs two at the front and two at the rear. To turn right you pull down on the forward right lift web. Turn left you pull down on the forward left lift web. Like an aeroplane when you come into land it’s important that you turn into wind so you’re facing the wind and just before you land you pull down on the two rear left webs to act as air break and creates a slight stall situation and with practice you can actually do a standup landing without having to do the paratroopers roll.
Military paratroopers are trained to come down in the parachute ready landing position; chin on chest, knees and feet together and with your legs slightly bent at the knees and elbows tucked in. What’s most important is you allow the ground to come to you. Yes you do get ground rush, meaning the ground appears to come up towards you very rapidly, but you must keep nice and relaxed and wait until you make contact with the ground.
If your momentum is either forwards ,backwards or sidewards then you do a parachute roll in that direction and allow parachutes momentum to take you that way. But the secret is to always turn into wind to slow your forward motion down.
Training Drop Zones always have a windsocks blowing on the ground to let you know the wind direction. During Operational jumps,the pathfinders, they’re the soldiers who mark out the DZ before the main drop force, use orange smoke to give wind direction, if not you have to carefully watch a reference point on the ground to ascertain your drift direction to figure out which way the winds blowing.
If you get it wrong and the winds blowing behind you can come in too fast, then you could get injured. Wind speeds are critical when parachuting you can’t jump in high winds best time is either early morning or early evening at either dawn or dusk.
All that said if you were parachuting into a hot DZ and you were being fired at from the ground the last thing you’d probably be thinking about was the wind direction. But there are many cool headed characters who’d might be thinking about wind direction even if they were being shot at from the ground. The cool headed realise in combat it’s all in the “lap of gods” anyway, so why worry!
https://www.youtu.be/CYTYia9k4Tw