there is very little protection from ultraviolet radiation. 无法阻挡紫外线的辐射

224. At these altitudes,
     海拔如此之高
225. the sun's power can quickly turn from salvation to threat.
     太阳的热力很快从救星变成了威胁
226. The atmosphere is so thin,
     由于大气稀薄
227. there is very little protection from ultraviolet radiation.
     无法阻挡紫外线的辐射
228. By mid-morning, it's risky to linger out in the open.
     上午十点钟在开阔地带逗留就已经十分危险
229. The viscacha are forced to head for the shade.
     鼠兔被迫寻找阴凉处避暑
230. Out on the lake, there is nowhere to hide.
     而湖面上则无处可藏

来自《行星地球 第二季 第二集 Planet Earth S02E02 山脉》第 227 行