- Evaluation of model-derived dust vertical profiles
- Forecasting the North African dust outbreak towards Europe occurred in April 2011
Ground- and satellite-borne lidar and last generation of ceilometers are the only tools capable of inquiring about the vertical profiles of aerosol-related variables. Therefore, information provided by them may potentially be used to evaluate the vertical component of the dust fields.
Some work has already been done in this direction, as in Binietoglou et al. (2015), where dust concentration forecast by different numerical models is compared with lidar retrievals of dust mass vertical profiles obtained through the use of the Lidar/Radiometer Inversion Code (LIRIC) algorithm. However, retrieval of mass vertical profiles has limitations and now it has been opted to establish a routine comparison of extinction vertical profiles.
Contact: Enric Terradellas (email@example.com)
Four state-of-the-art dust forecast models are examined to assess their performance to predict up to 72 hours ahead an intense Saharan dust outbreak over Western Europe up to Scandinavia between 5th and 11th April 2011. The capacity of the models to predict the evolution of the dust cloud is assessed by comparing their results with aerosol optical depth from AERONET and MODIS, as well as with dust surface concentration from air-quality monitoring stations. In addition, the CALIOP vertical profiles of extinction are used to examine the predicted vertical dust distribution of each model. To identify possible reasons for the different model performance, the wind fields yield by the simulations are evaluated with 10-m winds observed at meteorological stations and the vertical wind profiles from two radio sounding stations in the source region.
Contact: Nicolás Huneeus (firstname.lastname@example.org)
Dust concentration forecast by different numerical models will be compared with retrievals from lidar co-located with sun photometers using the LIRIC algorithm.
The Lidar/Radiometer Inversion Code (LIRIC) is an algorithm that permits the retrieval of the volume concentration profiles of various atmospheric aerosol components, based on the synergy of a multi-wavelength lidar and an AERONET sun photometer. LIRIC separates the aerosol in the atmosphere in two types: fine mode (ex. smoke, urban pollution) and coarse mode (ex. Desert or Volcanic dust, Marine aerosol); if lidar depolarization measurements are also available, the coarse mode is further divided in two sub-modes, Coarse/Spherical (ex. Marine) and Coarse/Non-spherical (Dust). The LIRIC algorithm calculates the micro-physical properties and the volume concentration profiles of these components by optimizing the fit of the modeled profiles and the lidar/photometer measurements. We can thus separate the dust components of the measured aerosol and make the comparison with dust model simulations more straight-forward.
Atmos. Meas. Tech., 8, 3577-3600, doi:10.5194/amt-8-3577-2015
Contact: Ioannis Binietoglou (email@example.com)
It is proposed to conduct a in-depth case study of the small-scale extreme dust storm occurred in Tehran on 2nd June 2014, at 5:30 PM local time, lasting less than 2 hours according to public evidence. Based on public news, the dust storm caused several deaths, reduction of visibility to several tenths meters in the city, and adverse disturbance of the public traffic. The blowing wind reached 110 km/h.
According to the public information and limited observations currently available, it is hypothesized that the dust storm passing Tehran was generated by a small-scale atmospheric circulation such as a squall line or convective downdraft.
This project proposal is a response to the discussion of the SDS-WAS Regional Steering Group (RSG) for Northern Africa, Middle East and Europe (NAMEE) during its regular meeting held in Italy on June 4th, 2014, on the Tehran event. The RSG noted that eight dust models, routinely operated within the SDS WAS NAMEE Regional Node, predicted increase of dust concentration in a wider area of northern Iran, but none of them were able to predict the dust storm over Tehran due to the fact that their coarse resolution could not resolve the small scales of the storm.
Contact: Slobodan Nickovic (firstname.lastname@example.org)