Evaluating spatial patterns in precipitation trends across the Amazon basin driven by land cover and global scale forcings

• Published in: Theoretical and applied climatology Vol. 140; no. 1-2; pp. 411 - 427
• Main Authors: Haghtalab, Nafiseh, Moore, Nathan, Heerspink, Brent Porter, Hyndman, David W.
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01-04-2020; Springer; Springer Nature B.V
• Subjects: Anomalies; Aquatic Pollution; Atmospheric precipitations; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Climate; Climate science; Climatology; Deforestation; Drought; Dry season; Drying; Earth and Environmental Science; Earth Sciences; Extreme drought; Extreme values; Extreme weather; Gauges; Hydrologic cycle; Hydrological cycle; Hydrology; Land cover; Original Paper; Precipitation; Precipitation gauges; Precipitation patterns; Precipitation trends; Precipitation variability; Rain; Rain and rainfall; Rainfall; Rainfall amount; Rainfall intensity; Rainfall patterns; Rainy season; River basins; Seasonal variations; Seasonality; Trends; Waste Water Technology; Water Management; Water Pollution Control; Wet season; Amazon Basin; Precipitation indices; Climate feedbacks; Rainfall seasonality; Amazon Basin; Precipitation variations; Extreme events
• ISSN: 0177-798X; 1434-4483
• DOI: 10.1007/s00704-019-03085-3

Spatial and temporal patterns of rainfall are governed by complex interactions between climate and landscape perturbations including deforestation, fire, and drought. Previous research demonstrated that rainfall in portions of the Amazon Basin has intensified, resulting in more extreme droughts and floods. The basin has global impacts on climate and hydrologic cycles; thus, it is critical to understand how precipitation patterns and intensity are changing. Due to insufficient precipitation gauges, we analyzed the variability and seasonality of rainfall over the Amazon Basin from 1982 to 2018 using high-resolution gridded precipitation products. We developed several precipitation indices and analyzed their trends using the Mann–Kendall test (Mann
1945
; Kendall, 1975) to identify significant changes in rainfall patterns over time and space. Our results show landscape scale changes in the timing and intensity of rainfall events. Specifically, wet areas of the western Basin have become significantly wetter since 1982, with an increase of 182 mm of rainfall per year. In the eastern and southern regions, where deforestation is widespread, a significant drying trend is evident. Additionally, local alterations to precipitation patterns were also observed. For example, the Tocantins region has had a significant increase in the number of dry days during both wet and dry seasons, increasing by about 1 day per year. Surprisingly, changes in rainfall amount and number of dry days do not consistently align. Broadly, over this 37-year period, wet areas are trending wetter and dry areas are trending drier, while spatial anomalies show structure at the scale of hundreds of kilometers.