Robuta

https://www.nist.gov/publications/climatic-charts-surface-refractivity-germany Climatic charts of the surface refractivity for Germany: | NIST of theclimaticchartssurfacerefractivity https://ijnscfrtjournal.isrra.org/Natural_Sciences_Journal/article/view/1356 Radio Refractivity and Gradient Variations Across West Africa Climatic Zones: Implications for... west africaclimatic zonesradiorefractivitygradient