Assessment of Cloud Resources and Potential for Rain Enhancement: Case Study—Minas Girais State, Brazil

Abstract

Water scarcity due to rainfall variability, and exacerbated by climate change, is prevalent in many regions of the world. Lack of precipitation and excessive water extraction contribute to the intensification of the problem. Among different mitigation measures, rain enhancement through cloud seeding could be a tool as part of a water management strategy to replenish ground water sources. However, implementation of this technology requires proper preliminary analysis of the available cloud data and specific meteorological conditions under which rainfall forms. The aim of this paper is to assess the potential of for rain enhancement in Minas Gerais State in Brazil. The paper focuses on analysis of multiyear climate reanalysis ERA-5, upper air sounding, weather radar and ground stations data. Analysis showed that, between 2000 and 2019, precipitation declined on average by 212 mm per annum or 21% compared to the long term climatological mean. The natural precipitation, however, remains sufficiently high to implement weather modification technology. Assuming an increase of 15–20% could be achieved on a catchment area basis, the increases would be significant and could offset the recently observed decline in natural precipitation. The methodology proposed in this study can be used as a baseline for similar analysis in other vulnerable regions of the world experiencing freshwater shortages or declines. Its shortcomings and uncertainties are also discussed.

Keywords

• water scarcity
• cloud resources
• climate reanalysis ERA-5
• weather radar
• meteorological station
• rain enhancement