Scientists from 10 countries met in Beijing last week to mull the initiation of an international programme to study a climatic phenomenon that affects a large area from central Asia to the western coast of the United States.

In the last three years particularly strong dust storms have swept across central and eastern Asia with an unprecedented frequency and impact.

Large cities like Beijing and Seoul experienced choking dust storms during the spring, the like of which have not been seen for years.

Public concern is also running high in these countries, where scientific studies of the problem have for years been independently conducted and uncoordinated.

Truly International Research

But dust storms are not confined to the territory of any specific country, said Shi Guangyu, an atmospheric physicist. Their formation, scenario and impact know no territorial boundaries.

"That makes international co-operation more necessary in this research area than any other," Shi said. "This requires truly international research."

When dust storms, originating in central Asia's desert areas swept eastwards this spring, their unwelcome presence was observed and complained about as far away as the eastern and southern Pacific regions.

Before the program was proposed at the meeting, however, no formal multi-national research had been carried out on dust storms, said Shi, a researcher at the Institute of Atmospheric Physics under the Chinese Academy of Sciences, and a key figure to promote such a program.

At the Beijing International Workshop on Dust Storms, a program entitled "DUST" was proposed and backed by many participants.

"It was a bit surprising when I first heard of such an idea, because I know many scientists and research centers have been doing work on their own," said Youngsin Chun, a researcher from the Seoul-based Meteorological Research Institute in the Republic of Korea (ROK). "But I feel the proposal comes at the right time," remarked Chun at the workshop.

"Only international co-operation can result in valuable research in this field," she added.

Chun said ROK scientists have been engaged in dust storm research for many years, but have been constantly discouraged by the lack of first-hand information and data.

It has become a consensus among scientists that most of the dust storms occurring in eastern Asia are derived from the sand or dust transported by winds from desert areas in central Asia and northwestern China, she explained.

Local ground sand or dust may be another source, but seldom plays such a significant role in the dust storms which strike the Korean Peninsula, said Chun during her presentation at the workshop.

This was confirmed by observations this March in Seoul. " We are far away from the origin (of the dust storms) and we need the co-operation of our peers in China or Kazakstan to get a complete picture of the scenario before we can investigate its cause, formation and make predictions."

China and Japan initiated the international co-operation by launching a dust storm research program two years ago.

Scientists set up an observation network under the program that stretches from the west of China, close to the edge of the Taklamakan Desert, to Tokyo in the east. The network carries out observation of dust storm movements in the hope of capturing and tracking its course.

Shi, China's leading scientist in the program, said the successful co-operation between Chinese and Japanese scientists has provided the impetus to launch a larger, multi-national effort which will invite Mongolia and Kazakstan to participate. "They are closer to the presumed origins of dust storms, but unfortunately we did not have many exchanges until recently," said Shi.

Dust storms have been a continual problem in Mongolia and relevant studies began as early as the 1960s, according to Sanjmyatav, a researcher from the Institute of Geography under the Mongolian Academy of Sciences.

Dust storms in spring, often combined with snow falls, once resulted in heavy loss of life and economic damage, particularly to the herdsman, he said.

Despite ever increasing concern and investment in this field, scientists admit there are many puzzles that remain unsolved, with even scientists themselves divided over many issues.

The disagreements are sometimes basic - even a universally accepted definition of the research has yet to be decided. "At the moment we have the terms sand storms, dust storms and yellow sand storms, aeolian dust and so on," said Shi. "There is a great discrepancy in their meaning, which may lead to different approaches and outcomes in research."

Shi, who is also an organizer of the meeting, said they had been at pains to propose a term that is scientifically acceptable and suitable to be used during the discussions.

He admitted the term currently used is a broad one that may embrace numerous research fields in relation to dust.

The dilemma Shi faces, in a sense reflects the immaturity of research in this area.

One of the biggest unresolved questions is why dust storms have increased so suddenly in frequency over the past three years in eastern Asia.

Statistics show that until three years ago the last two decades had witnessed a drastic drop in the number of dust storms in East Asia. "In fact, dust storms in spring appeared to be more frequent in the 1950s and 60s than now," said Zhang Renjian, a Chinese researcher who has worked under the Sino-Japanese dust research program.

In the 1960s, for example, dust storms occurred as often as 80 times a year, while the number went down to less than 40 in the 1980s, when the severity of the storms also decreased sharply.

The reason for the sharp decrease, followed by the recent, equally sudden increase is still far from clear, although various theories have been put forward.

One of those is that global warming might play an important role in the downward trend.

Warmer conditions in the high latitudes result in fewer cold air invasions, which are closely related to the occurrence of dust storms, according to Masatoshi Yoshino, a researcher at the University Tsukuba of Japan.

But this downward trend was broken in the last three years, when strong cold air movements, caused by spring north westerlies, triggered much severer sand storms than had occurred in the previous years.

Masatoshi believes this was caused by the shift of the cyclogenisis in Northeast Asia, but further research and investigations are needed to properly determine the causes, he said.

Although not very clear, the causes can be expected to be both multiple and complex, said Shi.

But it is essential to identify at least the major causes to make any forecast of dust storms possible, he said.

Scientists in this area have developed various models based on accumulated information which they hope will help them forecast dust storms.

But they are still subject to the test of real scenarios that often, if not always, turn out to be way off target. "Nobody believes a model but the person who writes it," Barry Huebert, a researcher from the Department of Oceanography of University of Hawaii, quipped during the meeting.

The simple reason is that the actual conditions that give rise to a storm are often not straightforward enough for scientists to build a "good" model of, said Chun.

Chun was part of a Sino-ROK research team which traveled to the Loess Plateau in northwestern China - an area where dust storms originate - this spring.

She was astonished by the geographic conditions the team found there, so much so she felt it was too complex to provide good modeling to help forecast dust storms. "With the present available technology, I don't think we can have accurate forecasts," said Chun.

Huebert, however, insisted that modeling - the devising of a model of a phenomenon - is and will remain the primary tool in dust storm research and forecasting, saying more accurate data will contribute to a better level of modeling.

With better observation statistics from countries like China and Mongolia where many dust storms originate, they will, hopefully, be able to make more accurate forecasts in the future, he said.

(China Daily November 12, 2002)