2018 ◽  
Vol 31 (22) ◽  
pp. 9107-9124 ◽  
Author(s):  
Asha K. Jordan ◽  
Anand Gnanadesikan ◽  
Benjamin Zaitchik

North Africa is the world’s largest source of mineral dust, and this dust has potentially significant impacts on precipitation. Yet there is no consensus in published studies regarding the sign or magnitude of dust impacts on rainfall in either the highly climate-sensitive Sahel region of North Africa or the neighboring tropical Atlantic Ocean. Here the Geophysical Fluid Dynamics Laboratory (GFDL) Climate Model 2 (GFDL CM2.0) with Modular Ocean Model, version 4.1 (MOM4.1), run at coarse resolution (CM2Mc) is applied to investigate one poorly characterized aspect of dust–precipitation dynamics: the importance of sea surface temperature (SST) changes in mediating the atmospheric response to dust. Two model experiments were performed: one comparing Dust-On to Dust-Off simulations in the absence of ocean–atmosphere coupling, and the second comparing Dust-On to Dust-Off with the ocean fully coupled. Results indicate that SST changes in the coupled experiment reduce the magnitude of dust impacts on Sahel rainfall and flip the sign of the precipitation response over the nearby ocean. Over the Sahel, CM2Mc simulates a net positive impact of dust on monsoon season rainfall, but ocean–atmosphere coupling in the presence of dust decreases the inflow of water vapor, reducing the amount by which dust enhances rainfall. Over the tropical Atlantic Ocean, dust leads to SST cooling in the coupled experiment, resulting in increased static stability that overrides the warming-induced increase in convection observed in the uncoupled experiment and yields a net negative impact of dust on precipitation. These model results highlight the potential importance of SST changes in dust–precipitation dynamics in North Africa and neighboring regions.


Nature ◽  
1969 ◽  
Vol 223 (5204) ◽  
pp. 391-391
Author(s):  
M. MADDEN
Keyword(s):  

Author(s):  
Kaifeng Li ◽  
Hongyan Xie ◽  
Huixin Jin ◽  
Qiang Zhang ◽  
Yaqing Zhang ◽  
...  

Author(s):  
W. Ernst Eder

Students learning design engineering at times need a good example of procedure for novel design engineering. The systematic heuristic-strategic use of a theory to guide the design process — Engineering Design Science — and methodical design process followed in this case study is only necessary in limited situations. The full procedure should be learned, such that the student can select appropriate parts for other applications. Creativity is usually characterized by a wide search for solutions, especially those that are innovative. The search can be helped by this systematic and methodical approach. This case example is presented to show application of the recommended method, and the expected scope of the output, with emphasis on the stages of conceptualizing. The case follows a novel design problem of a smoke gas dust precipitation process and the necessary technical system, including a sub-problem of a rapper for dust removal.


Nature ◽  
1969 ◽  
Vol 223 (5204) ◽  
pp. 391-391
Author(s):  
E. H. LENAERTS
Keyword(s):  

2021 ◽  
pp. 47-56
Author(s):  
Ali Al-Dousari ◽  
Noor Al-Dousari

AbstractA dust storm is meteorologically defined whenever visibility is less than 1,000 meters (Al-Kulaib 1990). Al-Dousari (2009) lists Kuwait as having one of the highest dust precipitation rates in the world. Safar (1980) states that the annual average number of dusty days due to dust storms or rising dust or suspended dust in Kuwait is 255.4. Forty-seven sampling sites representing all the geomorphological and sedimentological provinces in Kuwait were selected for the installation of dust traps to measure the average annual amount of deposited dust during 2009–2010 and 2010–2011 in tons.km-2.


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