The term "arid north" is not a widely recognized geographic term. It's possible that it's being used in a specific context or refers to a particular region that needs further clarification.

To give you a better answer, please provide more information about:

* What context are you referring to? Are you reading an article, watching a documentary, or discussing a specific topic?

* Where is this "arid north" located? Is it a continent, a country, or a region within a country?

* What are the characteristics of this area? Is it defined by its climate, geography, or culture?

Once I have more information, I can help you understand the meaning of "arid north."