Dust events in the Middle East are becoming more frequent and intense in recent years with impacts on air quality, climate, and public health. In this study, the relationship between dust, as ...determined from Aerosol Optical Depth (AOD) and meteorological parameters (precipitation, temperature, pressure and wind field) are examined using monthly data from 2000 to 2015 for desert areas in two areas, Iraq-Syria and Saudi Arabia. Bivariate regression analysis between monthly temperature data and AOD reveals a high correlation for Saudi Arabia (R = 0.72) and Iraq-Syria (R = 0.64). Although AOD and precipitation are correlated in February, March and April, the relationship is more pronounced on annual timescales. The opposite is true for the relationship between temperature and AOD, which is evident more clearly on monthly time scales, with the highest temperatures and AOD typically between August and September. Precipitation data suggest that long-term reductions in rainfall promoted lower soil moisture and vegetative cover, leading to more intense dust emissions. Superimposed on the latter effect are more short term variations in temperature exacerbating the influence on the dust storm genesis in hot periods such as the late warm season of the year. Case study analysis of March 2012 and March 2014 shows the impact of synoptic systems on dust emissions and transport in the study region. Dust storm activity was more intense in March 2012 as compared to March 2014 due to enhanced atmospheric turbulence intensifying surface winds.
•The relationship between dust and meteorological are examined from 2000 to 2015.•Bivariate regression analysis between temperature and AOD reveals high correlation.•Synoptic map analysis shows, atmospheric turbulence intensify dust emissions.•The effects of temperature on AOD are more observed at monthly time scales.•The effects of precipitation, on AOD are more observed over annual time scales.
Lake Urmia (LU) once was the second largest hypersaline lake in the world, covering up to 6000km2, but has undergone catastrophic desiccation in recent years resulting in loss of 90% of its area and ...extensive coverage by playas and marshlands that represent a source of salt and dust. This study examines daily Aerosol Optical Depth (AOD) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) between 2001 and 2015 over northwestern Iran, which encompasses LU. Intriguingly, salt emissions from the LU surface associated with ongoing desiccation do not drive the study region's AOD profile, whereas pollution transported from other regions and emissions around LU are more important. Signatures of increasing local crustal emissions are most evident outside of the peak dust season (January, February, and October) and on the periphery of LU. AOD has generally increased in the latter half of the study period with the onset of the AOD ramp-up starting a month earlier in the spring season when comparing 2009–2015 versus earlier years. Results indicate that suppression of emissions on the LU border is critical as the combined area of salt and salty soil bodies around LU have increased by two orders of magnitude in the past two decades, and disturbing these areas via activities such as grazing and salt harvesting on the lake surface can have more detrimental impacts on regional pollution as compared to benefits. These results have important implications for public health, climate, the hydrological cycle, and pollution control efforts.
Display omitted
•AOD characteristics examined over Lake Urmia in northwestern Iran between 2001 and 2015.•No significant relationship found between lake water level and AOD.•Interannual AOD variability driven mainly by transport from upwind regions.•Enhanced emissions from salty/soil areas around the lake in the latter years•Activities like grazing can disturb the remaining playa and lead to salt emissions.
Introduction: In this study, the dust schemes implemented in the model WRF/Chem have been investigated for a severe dust storm as a case study over the Middle East. Materials and methods: There are ...three main dust schemes in the model WRF/Chem, which are named GOCART, AFWA, and UoC. All of these dust schemes use the same dust source function, based on a topographical method, which plays a crucial role in the simulation of dust emission from the ground. Results: The results of model for dust distribution are validated by the EUMETSAT MSG dust product, and furthermore the capabilities of the model are investigated by comparing the model output with the measured PM10 concentrations of 3 air pollution monitoring stations. The AFWA dust scheme showed better capability in the simulation of dust behavior considering dust distribution. Although the GOCART dust scheme shows a remarkable coincidence between modeled and measured dust concentration, its results are with a considerable overestimation over the study domain. The UOC dust scheme, except Kerman station, shows a drastic underestimation in dust concentration as well as dust distribution. Conclusions: The results show appropriate estimates of dust distribution and its movement through east. The model WRF/Chem as a state of the art numerical model could be applied in the operational forecast systems for the hazardous
Introduction: Nowadays, air pollution is one of the most important problems, leading to serious financial and human health concerns. On the 15th to 17th days of November, 2016 an intense air ...pollution episode occurred in Tehran, Iran. Materials and methods: In this study, the meteorological data, pollutant concentration, and the data related to this severe air pollution episode, required to implement the model, besides, a brief account, pertinent to the configuration of atmospheric model WRF and air quality model LASAT is presented and certain meteorological quantity are studied. Results: Statistical analysis indicates in this case study, negative wind speed anomaly and positive mean temperature anomaly related to the average 65 years for Novembers. The minimum visibility, is reported for the two days of November 15 and 16. Atmospheric vertical structure analysis shows the temperature inversion at 950 hPa height on November 14th, 2016, it causes stable atmospheric conditions. Conclusions: Running WRF model, with YSU boundary layer scheme, shows that it can well simulate the atmospheric quantities, however, the 10 m wind speed has more errors among the quantities. In this case study LASAT Model is applied for simulation of different pollutant concentrations. The results indicate the underestimation of model by using the output of WRF as atmospheric model is not dependent on the meteorological data, whereas the reference error is driven either from the parameterization, or from the estimation of pollutants emission related to ground level.
PDF
