The type of figurative language used in the excerpt is Personification. When the author gives the sun a human characteristic (pitiless sun), he uses the figurative language Personification to enrich the text.
Personification is a figurative language technique where objects, ideas or animals are given human characteristics or qualities. The sun, for example, can't be pitiless, as well as it can't pity. Only people can pity someone else or something because pity is a feeling or an attitude. Thus, the technique of Personification is used by the author.
That enriches the text because the sun is given movement, action. It seems like its incidence over those who face the drought, in the excerpt, is stronger and intentioned because of its Personification. The author is able to express the character's feelings and impressions without saying it literally. The figurative language creates an image and is able to express more than if the author had used descriptive language. The text adopts a poetic tone, which can cause the reader to perceive feelings and sensations. Hence, the text is enriched by the use of the figurative language Personification.