Publications

Melo, KD; Delgado, RC; Mendonça, APT (2025). Precipitation Trends and Andean Snow Cover: Climate Interactions and Hydrological Impacts in the Acre River Basin (1982-2023). ATMOSPHERE, 16(3), 249.

Abstract
The state of Acre, located in the Western Amazon, has been more intensely affected in recent years by extreme weather events, especially those of a hydrological nature. These are rainy seasons with major floods and record water levels and, later in the same year, severe droughts that last for more months than is normal for the dry season. In this sense, remote sensing acts as an important tool for monitoring the meteorological variables involved in this dynamic, and for predicting future climate trends. Different temporal lengths reflect the availability of reliable data for each variable, and statistical methods were applied separately to ensure robust analyses despite these differences. Our research used data on rainfall (1982-2023), air temperature (2001-2020), fire foci, vegetation, and snow cover (2001-2023) for these purposes. Snow cover data were obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) product MOD10CM (MODIS/Terra Snow Cover Monthly L3 Global Climate Modeling Grid). The MOD10CM product was used to quantify snow cover in an area close to the state, connected to one of the main river basins in Acre. The results showed an increase in the amount of rainfall for the month of February and a reduction in the amount for months of the dry season, as well as an extension of the same. A reduction in the percentage of snow cover was also observed in the region, which may have a direct impact on water availability for several populations, including the city of Rio Branco. The Mann-Kendall test reinforced this reduction, with a Z index of -1.98 for the month of June. Principal Component Analysis (PCA) highlighted key relationships among variables. For the first principal component (PC1), rainfall, snow cover, maximum temperature, and minimum temperature had the strongest contributions, capturing over 56% of the total variance across all datasets. A negative relationship was observed between rainfall and minimum temperature, indicating that higher minimum temperatures are associated with reduced rainfall in the region. Conversely, the second principal component (PC2), which explained approximately 29% of the variance, revealed a strong positive relationship between fire foci and maximum temperature, suggesting that higher maximum temperatures significantly increase the number of fire foci. These results reinforce the role of climatic extremes in shaping environmental dynamics in Acre. The level of statistical significance (p-value) adopted for the data was up to 0.10.

DOI:
10.3390/atmos16030249

ISSN:
2073-4433