This verse is a desert scene.
The word "Hanhai" in "The vast sea is bounded by hundreds of feet of ice" is used to describe the vast ocean, but here it is used to describe the desert, expressing the vastness of the desert. "Langan" here means criss-crossing, and "Baizhangbing" describes the wide area covered by ice and snow and the size of the ice.
The "gloomy clouds" in "Gloomy clouds condense thousands of miles away" can be understood as both actual clouds and the poet's inner sorrow. "Bleak" describes the dim color of the clouds, and "Wanli Ning" means the clouds are thick and almost stagnant.