scholarly journals Effect of Rainfall Quantity on the Frequency of Severe Dust Storm in Iraq

2019 ◽  
Vol 32 ◽  
pp. 156-170
Author(s):  
Ibrahim I. Mohammed ◽  
Ahmed F. Hassoon

The dust storms and their recurrence are common phenomena in Iraq because it suffers from the exploitation of mankind to the natural environment and to the deterioration of vegetation and soil which responsible to the exposure of the soil to wind erosion leading to dust phenomena. Rain is one of the most influential climatic elements in reducing and minimizing the impact of dust storms. The amount of rainfall in Iraq is relatively small, where most of the year is not rainy. This in turn increases the dryness of the soil and increases the formation of dust storms. In this research data of (visibility, wind speed and direction and total rain amount) from the Iraqi Meteorological Organization and Seismology were analyzed for nine stations spread across the country (Mosul, Kirkuk, Haditha, Baghdad, Rutba, Nukhayb, Najaf, Amara and Nasiriya) for the period from 2001 - 2017 to compare annually severe dust storms with rainy seasons. Drought seasons were also determined using the percent of normal rainfall (PN) method. It was found that there was an inverse relationship between rainfall and severe dust storms, (according to Pearson’s correlation coefficient) where it was noticed that the highest amount of rainfall was in Mosul station with a total of 5231.6mm during the study period with only 6 severe dust storms during the same period. In other hand the lowest amount of rainfall was in Nukhayb station 1304.6mm during the study period with 62 severe dust storms.

2013 ◽  
Vol 35 (2) ◽  
pp. 131 ◽  
Author(s):  
P. Tozer ◽  
J. Leys

Dust storms are frequent in Australia and can have a large impact on the soil resource, the economy and people. There have been few economic studies of the impact of wind erosion worldwide and only one in Australia before this study. While wind erosion impacts on the soil resource at the point of the erosion, the level of economic impact rises as the population and associated infrastructure affected by dust increases. This study estimates the impact on the economy of the state of New South Wales of a single large dust storm called Red Dawn that passed over the eastern coast of Australia on 23 September 2009. Estimates for rural and urban areas are presented with both on- and off-site costs evaluated. The estimated cost is A$299 million (with a range of A$293–A$313 million) with most of the cost being associated with household cleaning and associated activities. The dust storm also impacted on many cities on the coast of the state of Queensland, but their costs are not included in this study. This study demonstrates some, but not all, of the major economic costs associated with wind erosion in Australia. Given the annual average cost of dust storms it is suggested that A$9 million per year would be a conservative estimate of the level of investment required in rural areas for dust mitigation strategies, based on improved land management that could be justified to achieve a positive impact on soil condition and reduce economic losses in rural towns and the more populous coastal cities.


2011 ◽  
Vol 378-379 ◽  
pp. 385-388
Author(s):  
Yi Bai Wang ◽  
Jian Fang Fei ◽  
Xiao Gang Huang ◽  
Xiao Ping Cheng ◽  
Yi Jun Ge

A coupled modeling system has been developed to describe the mineral dust cycle in the atmosphere. It is composed of MM5, ECIP, WE (wind erosion model) and CMAQ. A strong dust storm of North China in 2002 is simulated by this system. The modeled results show good consistent with observations and pre-existing researches in aspects of dust emission flux in source regions, distributions , vertical profiles and time variation of dust aerosol. Therefore, it can be used for further study on Asian dust storms. Furthermore, this system can be developed for further studies of the impact of dust aerosols on air quality.


2008 ◽  
Vol 8 (11) ◽  
pp. 2975-2983 ◽  
Author(s):  
C. Lin ◽  
Z. Wang ◽  
J. Zhu

Abstract. An Ensemble Kalman Filter (EnKF) data assimilation system was developed for a regional dust transport model. This paper applied the EnKF method to investigate modeling of severe dust storm episodes occurring in March 2002 over China based on surface observations of dust concentrations to explore the impact of the EnKF data assimilation systems on forecast improvement. A series of sensitivity experiments using our system demonstrates the ability of the advanced EnKF assimilation method using surface observed PM10 in North China to correct initial conditions, which leads to improved forecasts of dust storms. However, large errors in the forecast may arise from model errors (uncertainties in meteorological fields, dust emissions, dry deposition velocity, etc.). This result illustrates that the EnKF requires identification and correction model errors during the assimilation procedure in order to significantly improve forecasts. Results also show that the EnKF should use a large inflation parameter to obtain better model performance and forecast potential. Furthermore, the ensemble perturbations generated at the initial time should include enough ensemble spreads to represent the background error after several assimilation cycles.


2017 ◽  
Vol 30 (17) ◽  
pp. 6683-6700 ◽  
Author(s):  
Qingyu Guan ◽  
Xiazhong Sun ◽  
Jing Yang ◽  
Baotian Pan ◽  
Shilei Zhao ◽  
...  

Airborne dust derived from desertification in northern China can be transported to East Asia and other regions, impairing human health and affecting the global climate. This study of northern China dust provides an understanding of the mechanism of dust generation and transportation. The authors used dust storm and climatological data from 129 sites and normalized difference vegetation index (NDVI) datasets in northern China to analyze spatiotemporal characteristics and determine the main factors controlling dust storms occurring during 1960–2007. Dust storm–prone areas are consistent with the spatial distribution of northern China deserts where the average wind speed (AWS) is more than 2 m s−1, the mean annual temperature (MAT) ranges from 5° to 10°C, and the mean annual precipitation (MAP) is less than 450 mm. Dust storms commonly occur on spring afternoons in a 3- to 6-h pattern. The three predominant factors that can affect DSF are the maximum wind speed, AWS, and MAT. During 1960–2007, dust storm frequency (DSF) in most regions of northern China fluctuated but had a decreasing trend; this was mainly caused by a gradual reduction in wind speed. The effect of temperature on DSF is complex, as positive and negative correlations exist simultaneously. Temperatures can affect source material (dust, sand, etc.), cyclone activity, and vegetation growth status, which influence the generation of dust storms. NDVI and precipitation are negatively correlated with DSF, but the effect is weak. Vegetation can protect the topsoil environment and prevent dust storm creation but is affected by the primary decisive influence of precipitation.


2010 ◽  
Vol 10 (2) ◽  
pp. 365-382 ◽  
Author(s):  
P. T. Manktelow ◽  
K. S. Carslaw ◽  
G. W. Mann ◽  
D. V. Spracklen

Abstract. A global model of aerosol microphysics is used to simulate a large East Asian dust storm during the ACE-Asia experiment. We use the model together with size resolved measurements of aerosol number concentration and composition to examine how dust modified the production of sulfate aerosol and the particle size distribution in East Asian outflow. Simulated size distributions and mass concentrations of dust, sub- and super-micron sulfate agree well with observations from the C-130 aircraft. Modeled mass concentrations of fine sulfate (Dp<1.3 μm) decrease by ~10% due to uptake of sulfur species onto super-micron dust. We estimate that dust enhanced the mass concentration of coarse sulfate (Dp>1.0 μm) by more than an order of magnitude, but total sulfate concentrations increase by less than 2% because decreases in fine sulfate have a compensating effect. Our analysis shows that the sulfate associated with dust can be explained largely by the uptake of H2SO4 rather than reaction of SO2 on the dust surface, which we assume is suppressed once the particles are coated in sulfate. We suggest that many previous model investigations significantly overestimated SO2 oxidation on East Asian dust, possibly due to the neglect of surface saturation effects. We extend previous model experiments by examining how dust modified existing particle concentrations in Asian outflow. Total particle concentrations (condensation nuclei, CN) modeled in the dust-pollution plume are reduced by up to 20%, but we predict that dust led to less than 10% depletion in particles large enough to act as cloud condensation nuclei (CCN). Our analysis suggests that E. Asian dust storms have only a minor impact on sulfate particles present at climate-relevant sizes.


2021 ◽  
Author(s):  
Diana Francis ◽  
Jean-Pierre Chaboureau ◽  
Narendra Nelli ◽  
Juan Cuesta ◽  
Noor Alshamsi

&lt;p&gt;This study investigates the underlying atmospheric dynamics associated with intense dust storms in summer 2018 over the Arabian Peninsula (AP); a major dust source at global scale. It reports, for the first time, on the formation of cyclone over the Empty Quarter Desert as important mechanism for intense dust storms over this source region. The dust direct and semi-direct radiative forcings are observed, for the first time over this source region, using high-resolution in-situ and CERES-SYN satellite observational data. The three-dimensional structure and evolution of the dust storms are inferred from state-of-the-art satellite products such as SEVIRI, AEROIASI and CALIPSO. The dynamics and thermodynamics of the boundary layer during this event are thoroughly analyzed using ERA5 reanalysis and ground based observations.&lt;/p&gt;&lt;p&gt;We found that a large dust storm by Shamal winds led up, through radiative forcing, to cyclone development over the Empty Quarter Desert, subsequent dust emissions, development of convective clouds and rain. The cyclogenesis over this region initiated a second intense dust storm which developed and impacted the AP for 3 consecutive days. The uplifted dust by the cyclone reached 5 km in altitude and altered the radiative budget at the surface, inducing both significant warming during night and cooling during day. The dust load uplifted by the cyclone was estimated by the mesoscale model Meso-NH to be in the order of 20 Tg, and the associated aerosol optical depth was higher than 3. The model simulates reasonably the radiative impact of the dust in the shortwave but highly underestimated its impact in the LW.&lt;/p&gt;&lt;p&gt;Our study stresses the importance of the dust radiative forcing in the longwave and that it should be accurately accounted for in models to properly represent the impact of dust on the Earth system especially near source areas. Missing the warming effect of dust aerosols would impact both the weather and air quality forecast, and the regional climate projections.&lt;/p&gt;&lt;p&gt;These results were published in November 2020 in the journal Atmospheric Research doi.org/10.1016/j.atmosres.2020.105364.&lt;/p&gt;


2020 ◽  
Author(s):  
Claire Newman ◽  

&lt;p&gt;Measurements of near-surface winds on Mars are vital to understand momentum, heat, and gas exchange (e.g. water vapor, methane) at the surface; to interpret surface aeolian features, from wind streaks to dunes; to understand the conditions required for raising dust from the surface; to combine with other observations of atmospheric phenomena such as baroclinic waves, convective vortices, and clouds; to test and improve atmospheric models, which may then be used with greater confidence for other locations and epochs; to provide ground truth for Entry-Descent-Landing, the Mars2020 helicopter, and Ascent Vehicles; and finally, to help quantify the conditions that will be faced by future human explorers of Mars.&lt;/p&gt;&lt;p&gt;Despite this, however, good wind datasets are very rare for Mars. The Viking Landers provided valuable information on seasonal and diurnal variations in wind speed and direction, including the impact of dust storms, but recorded high frequency winds only a small portion of the time. Mars Pathfinder lasted only a few months on the surface and recorded wind directions but could not produce calibrated wind speeds. Phoenix similarly had a short lifetime and only measured intermittently at low temporal resolution and accuracy, although provided both wind speed and direction. Spirit and Opportunity carried no wind sensors at all. The ongoing Mars Science Laboratory mission&amp;#8217;s Curiosity Rover carried the first wind sensor to operate in a region of strong topography (Gale Crater); however, electronic noise and damage upon landing resulted in many data gaps and biases in the wind dataset, and the wind sensor was permanently lost after fewer than three Mars years due to further damage.&lt;/p&gt;&lt;p&gt;InSight carries the TWINS wind sensor, consisting of two booms facing in opposite directions. The wind speed and direction at any time is obtained by selecting the boom with the least interference by lander components or heating. By the time of this presentation, InSight should have measured wind continuously at ~1.2m above the surface for over 500 Mars sols (nearly three-quarters of a Mars year), with the majority of this dataset available at a frequency of 1Hz.&lt;/p&gt;&lt;p&gt;We will present the InSight wind dataset and describe how it has already helped Mars scientists to make progress in a range of fields. These include understanding the origins of aeolian features and inferring thresholds for sand motion or dust lifting, as well as quantifying the impact of topography and dust loading on modifying the regional circulation. Comparison with the winds predicted by atmospheric models has shown areas of disagreement, pointing to places where a different model setup or boundary condition (e.g. resolution, roughness map) may be needed, or where the model&amp;#8217;s parameterizations of sub-grid scale physical processes (e.g. vertical mixing) need to be improved. Finally, given InSight&amp;#8217;s proximity to the Curiosity Rover, we will show how winds in some seasons provide information on the regional flow before it reaches Gale Crater, and hence aid in interpreting Curiosity&amp;#8217;s more complex wind dataset.&lt;/p&gt;


2018 ◽  
Author(s):  
Reza Modarres

Abstract. Climate variability and change in arid regions are important factors controlling emission, frequency and movement of dust storms. This study provides robust statistical methods to detect trends in dust storm frequency across arid regions of Iran in relation to climate variability and trend in recent decades. The univariate trend assessment based on block bootstrapping method and three bivariate trend assessment methods, Covariance Inversion Test, Covariance Sum Test and The Covariance Eigenvalue Test are applied in this study to find if change in dust storm frequency can be attributed to changes in climatic variables. In this regard, the annual number of dust storms from 25 stations in central arid and semi-arid regions of Iran were selected. In addition, five major climatic variables including annual rainfall, annual maximum and average wind speed, annual maximum and average temperature were also collected. The univariate trend test indicates both increasing and decreasing trend in dust storm frequency and climate variables. The bivariate trend test shows a strong and statistically significant relationship between trend of climate variables and dust storm frequency for most of the stations across the region. Among climate variables, rainfall change has an inverse impact on dust storm frequency while wind speed and temperature have direct covariance structure with dust storm frequency. The wind speed also seems to be the most effective climate driver on dust storm frequency in arid regions of Iran, followed by temperature. The results also shows that local conditions that are not considered in this study may also play significant role in dust storm emission in some parts of the region.


2010 ◽  
Vol 10 (4) ◽  
pp. 8899-8925 ◽  
Author(s):  
Q. Ma ◽  
Y. Liu ◽  
C. Liu ◽  
J. Ma ◽  
H. He

Abstract. Mineral dust comprises of a significant fraction of the globe's aerosol loading. Yet it remains the largest uncertainty in future climate predictions due to the complexity in its components and physico-chemical properties. Multi-analysis methods, including SEM-EDX, FTIR, BET, TPD/mass, and Knudsen cell/mass, were used in the present study to characterise Asian dust storm particles. The morphology, element fraction, source distribution, true uptake coefficient of SO2 and hygroscopic behaviour were studied. The major components of Asian dust storm particles were found to consist of aluminosilicate, SiO2, and CaCO3, which were coated with organic compounds and inorganic nitrate. The dust storm particles have a low reactivity to SO2 (true uptake coefficient of 5.767×10−6) which limits the conversion of SO2 to sulfate during a dust storm period. The low reactivity also demonstrated that the heterogeneous reaction of SO2, in both dry and humid air conditions, had little effect on the hygroscopic behaviour of the dust particles. These results indicate that the impact of dust storms on atmospheric SO2 removal should not be overestimated.


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