Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Did dust storms make the Dust Bowl drought worse?

05.05.2008
The Dust Bowl drought of the 1930s was one of the worst environmental disasters of the Twentieth Century anywhere in the world.

Three million people left their farms on the Great Plains during the drought and half a million migrated to other states, almost all to the West. But the Dust Bowl drought was not meteorologically extreme by the standards of the Nineteenth and Twentieth Centuries.

Indeed the 1856-65 drought may have involved a more severe drop in precipitation. It was the combination of drought and poor land use practice that created the environmental disaster.

Much of the Plains had been plowed up in the decades before the 1930s as wheat cropping expanded west. Alas, while natural prairie grasses can survive a drought the wheat that was planted could not and, when the precipitation fell, it shriveled and died exposing bare earth to the winds. This was the ultimate cause of the wind erosion and terrible dust storms that hit the Plains in the 1930s. There had never been dust storms like these in prior droughts. In the worst years of the 1930s on as many as a quarter of the days dust reduced visibility to less than a mile. More soil was lost by wind erosion than the Mississippi carried to the sea. Although the numbers are not known, hundreds if not thousands of Plains residents died from 'dust pneumonia', a euphemism for clogging of the lungs with dirt. For wonderful books on the topic see Worster (1979, Dust Bowl: The Southern Plains in the 1930s) and Egan (2006, The Worst Hard Time).

But did the dust storms have a meteorological impact? There are two good reasons to ask this question. First we know from studies elsewhere in the world (e.g. the Sahel) that dust can impact circulation and precipitation. Second the Dust Bowl drought was unique in its spatial pattern - further north than is typical for a La Nina forced, or La Nina plus warm subtropical North Atlantic forced, drought. See our page "Was the Dust Bowl Predictable?". Did the dust storms impact either the intensity of the drought or its area of impact?

We have addressed this using the Goddard Institute for Space Studies atmosphere GCM which contains a dust module that can lift up dust from the surface, transport it in the atmosphere and allow it to interact with solar and longwave radiation transfer in the atmosphere. See the GISS Science Brief, "Desert Dust, Dust Storms and Climate" and the references therein.

First we ran a small ensemble of simulations with the atmosphere model forced by 1920s sea surface temperatures (SSTs) to act as our base of comparison for the simulated 1930s. Next we created a small ensemble of simulations with the model forced by 1930s SSTs. This created a drought that, as is typical for models forced by 1930s SSTs, was centered too far into the Southwest relative to the observed drought.

Then we introduced an estimate of the increased dust source from crop failure in the 1930s. This was guided by maps of wind erosion prepared in the 1930s by the newly created Soil Conservation Service. Regions of severe wind erosion were put into the model as potential dust sources although the model's dust module determines the actual lifting up, transport and deposition of the dust. The modeled dust emissions are around half the size of the scanty estimates from 1930s observations so the modeled climate impact may still be on the conservative side.

Figure 1 shows a 'box and whiskers' plot of the precipitation anomalies over the Great Plains for the modeled 1932-39 period minus the 1920s for both observations and the two model simulations. Here we have used the anomalies for each year in the observations and each year in the model run and for each of the 5 ensemble members. The boxes contain the one standard deviation spread of the anomalies and the whiskers bound the entire distribution. The distribution for the 1920s is of course spread around zero. The SST forcing alone creates a clear drought. The combination of SST forcing and interactive dust forcing intensifies the drought.

Kevin Krajick | EurekAlert!
Further information:
http://www.ldeo.columbia.edu/res/div/ocp/drought/dust_storms.shtml

More articles from Earth Sciences:

nachricht Do ice cores help to unravel the clouds of climate history?
21.06.2019 | Leibniz Institute for Tropospheric Research (TROPOS)

nachricht News from the diamond nursery
21.06.2019 | Goethe-Universität Frankfurt am Main

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fraunhofer IDMT demonstrates its method for acoustic quality inspection at »Sensor+Test 2019« in Nürnberg

From June 25th to 27th 2019, the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau (Germany) will be presenting a new solution for acoustic quality inspection allowing contact-free, non-destructive testing of manufactured parts and components. The method which has reached Technology Readiness Level 6 already, is currently being successfully tested in practical use together with a number of industrial partners.

Reducing machine downtime, manufacturing defects, and excessive scrap

Im Focus: Successfully Tested in Praxis: Bidirectional Sensor Technology Optimizes Laser Material Deposition

The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.

Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

 
Latest News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

'Sneezing' plants contribute to disease proliferation

24.06.2019 | Agricultural and Forestry Science

Researchers find new mutation in the leptin gene

24.06.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>