Geology

Meteorology

Amazonian

Biology

Dry season

Physical geography

Precipitation

Geography

Ecology

Programming language

Deforestation (computer science)

Computer science

Climatology

Amazon rainforest

Cartography

Forestry

Environmental science

Wet season

Journal of Geophysical Research Atmospheres

Amazonian deforestation is causing notable changes in the hydrological cycle by altering important precipitation characteristics. This study uses daily rainfall time series data from 112 rain gauges and a recent yearly 1‐km land use data set covering the period from 1974 to 2012 to evaluate the effects of the extent of deforestation at different spatial scales on the onset of the rainy season and on the duration of dry spells in southern Amazonia. Correlation analyses indicate a delay in the onset of 0.12–0.17 days per percent increase in deforestation. Analysis of cumulative probability density functions emphasizes that the likelihood of rainy season onset occurring earlier than normal decreases as the local deforestation fraction increases. In addition, the probability of occurrence of dry spells in the early and late rainy season is higher in areas with greater deforestation. The delayed onset and longer dry spell events in highly deforested areas increase the climate risk to agriculture in the region.

Effects of Deforestation on the Onset of the Rainy Season and the Duration of Dry Spells in Southern Amazonia