Atatacma沙漠占非常大的面积(100000多平方公里)[1],主人非常不同的气候。气候变化的主要驱动因素是太平洋的距离和高程。后一个因素是很强的,阿塔卡马沙漠覆盖了一个强大的海拔范围,从海平面到近7000,在峰会上的(奥霍斯德尔萨拉多山)[2],世界上最高的火山。最高的地区,这也恰好是进一步的大海,是干旱和多云。共同大雾天气的天气模式你提到只发生非常接近海岸,[扩大内陆只有10公里或几十公里槽低洼的山谷)[3]。和是由雾形成海洋深入内陆。叫做[浓湿雾][4],但它不会穿过海岸山脉。云的模式在整个沙漠可以使用数据集由美国宇航局的可视化(表面气象学和太阳能)[5],特别是卫星派生(平均每月晴空天)[6](即云层不到10%)22年时间(1983年7月- 2005年6月)。它的分辨率1°,这里约110公里。这意味着沙漠的中心区域是由12个细胞,但它足以看到我提到的模式。 The following figure shows the central section of the Atacama dessert using official [IGM][7] 1:500.000 maps in the left. And the mean clear skies dataset on the right for the very same area. The numbers refer to the 22-year mean clear sky days per month. [![enter image description here][8]][8] Now the interpretation will be easier if we overlay those two figures as in one as shown below: [![enter image description here][9]][9] From there you can see how there is a fairly large variability in the amount of clear sky days. From a few at the coast, to about a week over the coastal mountains to about two weeks east of the coastal mountains. Peaking at 17 days per month over the [Salar de Atacama][10] (a value surpassed only by the Sahara desert and the interior of Antarctica). Then, it is no coincidence that [ALMA observatory][11], the largest radio telescope in the world, is located there, just east of the salar de Aatacama. As mentioned before, topography is the main factor controlling this pattern. Even close to the coast, some mountain tops can have remarkable clear sky records, as is the case of the 2,635 m high [Mount Paranal][12] were the [VLT observatory][13] is located at just 15 km from the coast (falling on the lower left cell with 9 clear sky days in the figure above). Finally, going back to your question: Both the astronomers and your geography text book are right, but each one is referring to a different area of the Atacama desert. [1]: https://en.wikipedia.org/wiki/Atacama_Desert [2]: https://en.wikipedia.org/wiki/Ojos_del_Salado [3]: http://observatoriogeograficoamericalatina.org.mx/egal8/Procesosambientales/Climatologia/10.pdf [4]: https://en.wikipedia.org/wiki/Camanchaca [5]: https://eosweb.larc.nasa.gov/cgi-bin/sse/sse.cgi?skip@larc.nasa.gov [6]: https://eosweb.larc.nasa.gov/cgi-bin/sse/subset.cgi?email=skip@larc.nasa.gov [7]: https://www.igm.cl/ [8]: https://i.stack.imgur.com/DWQ9E.jpg [9]: https://i.stack.imgur.com/cDMmf.jpg [10]: https://en.wikipedia.org/wiki/Salar_de_Atacama [11]: http://www.almaobservatory.org/en/home/ [12]: https://en.wikipedia.org/wiki/Cerro_Paranal [13]: https://www.eso.org/public/teles-instr/paranal-observatory/