Annual trend, anomalies and prediction of vegetation cover behavior with Landsat and MOD13Q1 images, Apacheta micro-basin, Ayacucho Region

The region is characterized by three distinct seasonal periods: a wet season from December to March, a dry season from May to August, and an intermediate season from April to November. The climate in the area is marked by low precipitation, with an average annual accumulation of 71.09 mm, and a relatively low temperature, with a maximum air temperature of 12.73°C and a minimum air temperature of -0.35°C. The study area is situated in the headwaters of the Cachi River, in the district of Paras, province of Cangallo, and has an area of 14,348.21 ha. The region's elevation ranges from 4,112 m above sea level to 5,045 m above sea level, with an average elevation of 4,651 m above sea level. The microcuenca Apacheta is characterized by a unique combination of geography and climate, making it an ideal location for studying the impact of climate variability on vegetation cover. The study used a combination of Landsat and MOD13Q1 imagery to analyze the annual trend, anomalies, and prediction of vegetation cover behavior in the microcuenca Apacheta. The Landsat imagery was obtained from the USGS GloVis server, and consisted of 194 images from the TM, ETM+, and OLI sensors, taken between 1985 and 2020. The images were preprocessed to correct for radiometric and atmospheric effects using the Flaash method. The Normalized Difference Vegetation Index (NDVI) was calculated using the reflectance values in the near-infrared (NIR) and red (R) bands, according to the formula: NDVI = (ρNIR - ρR) / (ρNIR + ρR). The NDVI values were then used to classify the vegetation cover, which was validated using the Kappa index. The results showed a good agreement between the observed and estimated values, indicating that the Landsat imagery was suitable for monitoring vegetation cover in the microcuenca Apacheta. The study also analyzed the anomalies and prediction of vegetation cover behavior using the MOD13Q1 product. The results showed a significant increase in vegetation cover in the last 9 years, with a trend of 3,378.96 ha/year using Landsat imagery and 3,451.95 ha/year using the MOD13Q1 product. The anomalies and prediction of vegetation cover behavior also showed a significant increase in the forecasted years, 2021 and 2022. The study used the Box-Jenkins and ARIMA approaches to forecast the vegetation cover behavior, which showed a two-year future scenario that was acceptable, but with higher bias. The results of the study highlight the importance of using a combination of Landsat and MOD13Q1 imagery to analyze the annual trend, anomalies, and prediction of vegetation cover behavior in the microcuenca Apacheta. The study also emphasizes the need to consider the unique climate and geography of the region when analyzing vegetation cover behavior. The study's findings have implications for the management and conservation of the microcuenca Apacheta's natural resources. The increasing trend of vegetation cover in the region suggests that the area is becoming more productive, which could have positive impacts on the local ecosystem and economy. However, the study also highlights the need for continued monitoring and analysis of vegetation cover behavior to ensure that the region's natural resources are managed sustainably. The study's methodology and results can be applied to other regions with similar climate and geography to the microcuenca Apacheta. The use of Landsat and MOD13Q1 imagery provides a cost-effective and efficient way to monitor vegetation cover behavior over large areas, making it an ideal tool for researchers and policymakers. The study's findings also highlight the importance of considering the unique characteristics of each region when analyzing vegetation cover behavior, and the need for continued research and monitoring to ensure that the region's natural resources are managed sustainably.