South Korea, China and Japan pool forecasting efforts and science amid worsening dust storms.
The dust-storm season in northeast Asia is expected to hit its peak next week, and this week three of the countries hardest hit met in Beijing to coordinate their response.
The storms coat cars, bury railways and facilities, and destroy crops, with the thick dust often bringing visibility down to the hundreds-of-metres range. Whipped up to heights of up to 8 kilometres, dust sometimes makes it as far as the United States.
The dust originates from the Takla Makan Desert, the Gobi Desert and other arid regions of northern China and Mongolia. It is a natural phenomenon, but accelerating desertification, caused by soil degradation and overgrazing, has made it worse. A network of 85 meteorological observatories across Japan, which each year registers an average of about a dozen dust days during the peak month of April, has noted a sharp increase since 2000.
Now, South Korea, Japan and China are pooling efforts to try to understand and tackle the storms. So far their efforts have been fragmentary and inconclusive, and forecasting, which is usually only done a few days in advance, remains unreliable.
Pioneering dust-storm researcher Hao Quan, now retired, says that this coming week might be a bad one — the seasonal peak — for dust storms. There are arid conditions in the north and a high-pressure zone in Siberia that could provide the wind, says Quan, who helped to found the Sino-Japan Friendship Centre for Environmental Protection in Beijing. But despite his decades of efforts to characterize the storms, he cannot say with any certainty. "It's just my feeling," he says.
In December 2007, the Tripartite Environment Ministers Meeting Among China, Japan, and Korea (TEMM) established two working groups that it is hoped will take some of the uncertainty out of the dust storms. A steering committee meeting in Beijing this week set up meetings in autumn in Japan for working group 1 — dedicated to monitoring and forecasting — and in the late summer in South Korea for working group 2, which aims to evaluate various measures to cut down dust storms at source.
Researchers in the first working group will pick one severe dust-storm event — most likely one that began in China in late March 2007 — and compile all available data on meteorological conditions, observed physical properties and chemical compositions of the particulate matter, as well as satellite data. They will also share LIDAR (light detection and ranging data. LIDAR involves reflecting a laser off airborne particles to estimate their density and shape. Shape is crucial for differentiating between atmospheric pollutants, which are spherical, and dust particles, which are not.
The first thing that needs to be done is to get researchers from the three countries all onto the same page, says Masataka Nishikawa, an environmental scientist at Japan's National Institute for Environmental Studies in Tsukuba who is also on working group 1. It is not clear, for example, whether the measuring devices in each country are consistent. "As much as possible, we want to share data from monitoring and chemical analyses. But are we getting accurate enough data that it can be scientifically analysed? That's the question we need to answer first," he says.
The scientists will then try to compare the countries' different forecasting models — methods for factoring in wind strength and the size of the particles has differed. "Japan, South Korea and China all have different concepts of dust storms," Nishikawa says. Once standards are set, the working group hopes to establish a region-wide monitoring network and an early-warning system.
Working group 2 will combine scientific site visits with analyses to see which strategies have been working, and, on the basis of the results of the study, expected in May 2010, will advise on which measures should be continued.
Again, efforts thus far have been fragmentary. Over the past decade, China, with assistance from various international organizations as well as South Korea, Japan and Mongolia, has, for example, planted trees to block the wind and shrubs to control the surface. Straw bundles have been spread over large swathes of land in checkerboard patterns to cut down on wind velocity at ground level. Degraded land has been fenced off to reduce grazing and laws have banned the felling of trees.
But there has been little follow-up, so the results of these initiatives are uncertain. Efforts during 2001–2003 to establish a nationwide sampling system fell apart when sudden acute respiratory syndrome (SARS) hit, Zhu Rongji, the former premier, who had personally supported Quan's mission, stepped down, and Quan retired.
The new effort also faces challenges, especially because it lacks a figure like Quan to lead it. Money may also be an issue. Working group 2 has just US$75,000 to work with for the first year. With the current financial crisis, researchers fear environmental matters may take a back seat.
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Scientific Reports (2015)