Saharan air layer？什意思

lk123

请问大佬 在查看外文论文的时候 遇到了这个 不理解 求教  Saharan air layer ？
百度解释 ：

撒哈拉空气层 ？ 实在摸不着头

   原文 ：As noted previously, it is possible that systems that follow the low-level flow are lesslikely to undergo RI because they are more likely to be embedded in the Saharan air layer, which Dunion and Velden (2002) have suggested can have a detrimental impact on TC intensity.

lk123

这是原文 ：As noted previously, it is possible that systems that follow the low-level flow are lesslikely to undergo RI because they are more likely to be embedded in the Saharan air layer, which Dunion and Velden (2002) have suggested can have a detrimental impact on TC intensity.