How is exposure represented in the poem? Exposure is generally thought of extreme temperatures affecting a person. In the poem itself, it mentions many times just how bad the icy cold temperature is. Here are all I could find:

“Our brains ache, in the merciless iced east winds that knife us…”
What this quote has to do with exposure is when it talks about the wind that was going through their body’s again and again. And as you might of experienced before, when the wind gets cold and fast enough, it is like little spikes are being stuck in your body. They would of been experiencing this on a day to day basis, so it is understandable that he would talk about the wind like this. And the brains aching is just what happens when said winds are constantly hitting your head.
“Watching, we hear the mad gusts tugging on the wire,”
These mad gusts are just another name for the wind, and the wire is probably the barbed wire just lying across the battlefield. They can hear because, well, you know wind chimes? It’s like that.
“The poignant misery of dawn begins to grow . . .”
This line tells us how dawn is beginning, and right from the beginning it is miserable. Misery of dawn can also mean that the weather in the morning is terrible, with clouds covering the sky. And then when it is growing, it could either be about the sun moving up into the sky, or the weather getting even worse.
“We only know war lasts, rain soaks, and clouds sag stormy.”
This line is talking about how the knowledge they posses is simple. That is, the war is long, probably gotten from the endless feeling people get when they can’t remember the beginning of what they are doing, and they can’t see when the end will come. The next two pieces of information are about the weather, and how bad it is for your health. By doing it like this, it makes it obvious that he does count the war itself as a pretty bad thing for your health and otherwise, but then he says two points on the weather, making sure the reader knows where he thinks the worst enemy lays.
“Dawn massing in the east her melancholy army Attacks once more in ranks on shivering ranks of grey,”
When he talks about the weather like this, he makes it sound like the weather is the enemy they are facing off against, and that the army this weather is made from are the clouds, each one grey.
“Less deadly than the air that shudders black with snow”
The line before this one is talking about how deadly bullets are, zipping across the battlefield, killing off many of them, but it continues on with this, talking about how the weather is even more deadly that the bullets. In particular this time round, is the snow that is falling all around. I guess as this is the first time this being mentioned, that it probably started snowing around about the time of writing this part of the poem.
“With sidelong flowing flakes that flock, pause, and renew,”

“Pale flakes with fingering stealth come feeling for our faces—”
“We cringe in holes, back on forgotten dreams, and stare, snow-dazed,”
“Deep into grassier ditches. So we drowse, sun-dozed,”
“Tonight, this frost will fasten on this mud and us, Shrivelling many hands, and puckering foreheads crisp.” 
“The burying-party, picks and shovels in shaking grasp, Pause over half-known faces. All their eyes are ice,” 

Here are 3 of the language techniques used in the poem:

1. Personification “For hours the innocent mice rejoice:the house is theirs;”, “Dawn massing in the east her melancholy army.” Personification is used many times, as well as in this line. The reason this was added was because it makes it feel like everything that surrounds the soldiers have their own lives; their own power. By doing this, it makes it seem like their surroundings are human, easily capable of being the enemies of the soldiers. But the soldiers themselves are barely human, “Slowly our ghosts drag home:” This puts them at about the same level of reality. This affects our understanding by changing who we view as the enemy of the soldiers, while reaching into a large point of them poem. That the weather in this case was the enemy of the soldiers.
2. Listing “But nothing happens.” Listing is used many times throughout the poem, which drives home the point the sentence is trying to make. In this case, the sentence is trying to drive home how “nothing happens” in the war. It makes sure the reader knows how the soldiers are just sitting there. Sometimes they die from the enemy. Sometimes they die from the weather. And yet, “nothing happens.” As far as the author is concerned, even though all these other things are happening around them, nothing is happening to the soldiers themselves. At least, they are doing nothing. This impacts our understanding of the text