Improvement in the accuracy of back trajectories using WRF to identify pollen sources in southern Iberian Peninsula

Pollen grains released to the atmosphere are dispersed and/or transported through the atmosphere according to the spatial and temporal variations in the meteorological conditions as well as by the pollen physical characteristics. Due to the combination of both, pollen transport is mainly affected by atmospheric transport at micro-, meso-gamma and meso-beta scales. Atmospheric transport of pollen can be studied by atmospheric models, having special relevance in complex orography where pollen transport is widely governed by complex flows. In these cases, the accuracy of these tools to describe complex flows is mainly determined by the spatial resolution of the underlying meteorological data set. The main objective of the present work is to examine how meteorological datasets affect results from atmospheric transport models used to describe pollen transport in the atmosphere. We investigate the effect of the spatial resolution in four different meteorological datasets computing backward trajectories with the HYSPLIT model to characterize atmospheric transport of Olea pollen in a region with complex flows. We have used meteorological data sets from the Weather Research and Forecasting model (WRF-ARW) with 27, 9 and 3 km resolution and from the Global Data Assimilation System (GDAS) with 1 degree resolution. We study an olive pollen episode from 2010 detected in Cordoba city (southern Iberian Peninsula). The calculation of back trajectories shows that the complex terrain affects the trajectories and this effect varies with the four different meteorological data sets. Overall, the change from GDAS to WRF-ARW inputs improves the analyses with the HYSPLIT model, thereby increasing the understanding the pollen episode. The results suggest that a spatial resolution of at least 9km is needed to simulated atmospheric flows considerable affected by the relief of the landscape. The obtained improvement in the analysis suggests that the spatial resolution in the appropriate meteorological files should be considered when atmopsherim models are used to characterize the atmospheric transport of pollen on micro-, meso-gamma and meso-beta scales. Further than this, these results are not only useful in this research area. The increase in the accuracy of modelling results could be valuable in other atmospheric research areas, such as transport of radionuclides, as well as in the definition of nuclear-radioactivity emergency preparedness.

HERNANDEZ CEBALLOS Miguel Angel;  SKJOTH Carsten;  GARCIA MOZO Herminia;  BOLIVAR Juan Pedro;  GALAN SOLDEVILLA Carmen; 

2015-01-12

SPRINGER

JRC85637

0020-7128,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC85637,   

10.1007/s00484-014-0804-x,