Evolución espacial y temporal de cultivo del olivo por efecto del ataque de plagas, utilizando sensoramiento remoto y procesamiento de imágenes satelitales

Climate change, as well as the appearance of pests and diseases, are affecting olive plantations (Olea europaea L.) and the production of olives in the world, therefore, there is an urgent need for tools to help us identify the spatial and temporal evolution of the olive groves, regarding the attack of pests, in this case, the Orthezia olivicola and the olive borer Phloeotribus scarabaeoides. In this work, we use information from freely available satellite images that allowed us to carry out spatial and temporal analysis and the combination of vegetation indices. For the studied area, according to the values of the NDVI (Normalized Difference Vegetation Index), it was identified that the surface of diseased plants ranges from 42% to 68%, moderately healthy plants from 2% to 18%, and the state of the plantation considered as very healthy plants with a tendency to zero, which means that practically 100% of the olive trees are affected by some level. The temporal variation of the NDVI, DVI, SAVI, GNDVI, EVI2, and MSAVI indices, allowed us to establish the states of affectation as mild, moderate pest attack, the severity of the pest attack added to the water deficit, and very strong pest attack and state of permanent wilting.El cambio climático, así como la aparición de plagas y enfermedades, están afectando las plantaciones de olivos (Olea europaea L.) y la producción de aceitunas en el mundo, por lo tanto, urge la necesidad de contar con herramientas que nos ayuden a identificar la evolución espacial y temporal de los olivares, respecto al ataque de plagas, como la Orthezia olivicola y el barrenillo del olivo Phloeotribus scarabaeoides. En este trabajo utilizamos información de imágenes satelitales de libre disposición que permitieron realizar el análisis espacial y temporal y la combinación de índices de vegetación. Para la zona de estudio, según los valores del NDVI (Normalized Difference Vegetation Index) se identificó que la superficie de plantas enfermas va de 42% a 68%, plantas moderadamente sanas de 2% a 18%, y el estado de la plantación considerado como plantas muy sanas con tendencia a 0%, lo que significa que prácticamente el 100% de los olivos se encuentran con algún nivel de afectación. La variación temporal de los índices NDVI, DVI, SAVI, GNDVI, EVI2 y MSAVI, permitieron establecer los estados de afectación como leve, ataque de plagas moderado, severidad del ataque de las plagas sumado al déficit hídrico y ataque de plagas muy fuerte asociado al punto de marchitez permanente

Spatiotemporal Analysis of Urban Heat Islands in Relation to Urban Development, in the Vicinity of the Atacama Desert

Near the Atacama Desert, Tacna city in Peru is among the largest arid cities with constant urban development, thus understanding of the urban surface thermal pattern is needed. We propose a comprehensive study of the urban heat island phenomenon, with the objective of (1) determining the spatial and temporal variations of the urban heat islands (UHIs), in the period 1985 to 2020; (2) analyzing the relationship between the UHI and influencing factors such as vegetation, urban area, and population, using indices calculated with satellite images. The Google Earth Engine repository was used to evaluate the corrected images from the years 1985 to 2020. The coincidence between the normalized difference vegetation index (NDVI) and normalized difference built-up index (NDBI) was good, negative between NDVI and the land surface temperature (LST), attributable to dense vegetation, and negative and very high (−0.81) between NDBI and NDVI, as massive urbanization leads to the reduction in the vegetal surface. The NDBI has a high impact on the LST; a coefficient of connections is recorded as 0.46. Tacna is a very arid region, and an increase in the time of the LST occurred with the increase in industrialization and urbanization. The land use/cover change (LUCC) evidences change in the climate in the city of Tacna; temperatures of 24.2 °C to 44.2 °C are observed in the built-up areas. In vegetated areas, the temperature remains below 24 °C, which is associated with a high rate of potential evapotranspiration. Thus, this study shows that variations in urban form and growth have produced the development of intraurban surface thermal patterns