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 Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

nachricht Modeling magma to find copper
13.01.2017 | Université de Genève

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>