Quercus long-term pollen season trends in the southwest of the Iberian Peninsula

• Analysis of correlation of a time series of Quercus pollen and meteorological variables.
• Model to forecast airborne Quercus pollen concentration.
• Estimation of the model parametersis proposed.

It is widely accepted the influence of meteorology to airborne pollen distribution, this concern is clearly affected by the issue of climate change. In the SW of Iberian Peninsula pollen from Quercus species is often the most abundant in the air and their flowering phenology show changes in seasonal pollination affected by meteorological parameters. This study aims to investigate airborne pollen data of Quercus from a city on the SW Iberian Peninsula over a 20 year period and to analyse the trends in these data and their relationship with meteorological parameters using time series analysis and propose a predictable model to forecast their concentration. Aerobiological sampling was conducted from 1994 to 2013 in Badajoz (SW Spain) using a 7-day Burkard spore trap. The main pollen season for Quercus pollen lasted, on average, 59 days, ranging from 31 to 80 days, from 28th March to 27th May. The model proposed to forecast the airborne pollen concentration is described by Eq. (1). This expression is composed of two terms: the first term represents the resilience of the pollen concentration trend in the air according to the average concentration of the previous 10 days; the second term is obtained from considerations of the actual pollen concentration value, which is calculated based on the most representative climatic variables multiplied by a fitting coefficient. In order to obtain the best fit the model was developed in four partial time series of 5 years, each of one with a high level of accuracy, although a general model was calculated.