Rafael Luis Bras (born 1950) is a Puerto Rican civil engineer best known for his contributions in surface hydrology and hydrometeorology,[1] including his work in soil-vegetation-atmosphere system modeling.

[6] Bras returned to MIT in July 1976, where he served for more than 32 years as a professor of Civil and Environmental Engineering and held an appointment in the Departments of Earth, Atmospheric and Planetary Sciences.

[13] Remote sensing, satellite data, and information technology can now be used to support distributed hydrologic modeling and the global mapping of water in near to real time.

[16][12] With Elfatih Eltahir he examined the role of precipitation recycling on the atmospheric branch of the water cycle of the Amazon River basin, and showed that deforestation can have serious impacts on climate.

[17][18] Bras is considered a leading authority on soil-vegetation-atmosphere system modelling and the evolution of landscapes due to climatic disturbances including global warming.