Distribution and current status of permafrost in the highest volcano in North America: Citlaltepetl (Pico de Orizaba), Mexico

Abstract

espanolSe enfatiza la presencia de permafrost en el volcan Citlaltepetl y se actualiza su cubertura. Mediante el analisis empirico-estadistico de variables topo-climaticas y con base en el modelo de regresion lineal fue posible determinar que el limite inferior de permafrost continuo se ubica por encima de 4,880 msnm en la ladera norte y por arriba de 4,963 msnm en su ladera sur; por su parte, porciones discontinuas y aisladas inician a partir de 4,780 y 4,863 msnm al norte y sur del cono volcanico respectivamente. Se encontro una alta correlacion entre la temperatura de los perfiles del suelo y la del aire en su altitud correspondiente. Las condiciones de temperatura del permafrost permiten considerarlo como “calido”, tal como sucede en montanas de mediana y baja latitud, y al mismo tiempo se puede clasificar como “comprometido” y potencialmente inestable. No obstante la degradacion que presenta a partir de su primera estimacion en los anos 1970, se estima que este indicador de cambio climatico de alta montana permanezca al menos durante algunas decadas una vez que el glaciar del Citlaltepetl se haya extinguido. EnglishThe occurrence of permafrost in the Citlaltepetl volcano was emphasized and its coverage was updated. Through an empirical and statistical analysis of topo-climatic variables and based on linear regression it was found that the lower limit of continuous permafrost is positioned above 4,880 masl on its northern slope and at 4,963 on the southern slope; on the other hand, discontinuous and isolated patches start at 4,780 and 4,863 meters in the north and south respectively. A high correlation was found between the temperature of the ground profiles and the air temperature at their corresponding altitude. The temperature found in the permafrost classifies it as “warm” permafrost as in most mountains of medium and low latitude and at the same time it is classified as “compromised” and potentially unstable. In spite of the degradation observed from its first estimation during the 1970s, it is estimated that this indicator of climatic change in high mountains will remain at least for a few decades after the Citlaltepetl s glacier has been extinguished.