황사 공급의 주원인은 바로 선상지(alluvial fans) - 지형학 저널

논문의 원제목은

 

Dust sources in arid and semiarid China and southern Mongolia:
Impacts of geomorphological setting and surface materials

 

논문번호 doi:10.1016/j.geomorph.2007.09.006

 

Dust sources in arid China and Mongolia.pdf

 

 

Abstract

Analysis of the geomorphological settings and surface materials in arid and semiarid China and southern Mongolia revealed that the dominant dust sources are ‘Gobi’ deserts and alluvial fans adjacent to Gobi deserts in the piedmonts of the Kunlun, Qilian, Helan, and Gobi Altai mountains.

 

These areas have persistent supplies of dust-sized particles, deposited by intermittent floods from the mountains, and fine materials are also generated by weathering and aeolian processes acting on the coarse fractions of Gobi surfaces. Clear spatial differences in mineral types and contents and in the salt contents of surface materials also strongly affected the intensity of dust emissions.

 

Inconsistencies in monitoring, simulation, and calculation of dust emissions in previous studies of Northern China and Mongolia may have been caused by insufficiently detailed considerations of variations in the geomorphological setting. Where the geomorphological settings in these areas are not considered in sufficient detail, deviations arise in the estimation and prediction of dust using current models.

 

Although the present study did not quantify the persistence and replenishment of dust sources in the study area, our conclusions about the importance of geomorphology can improve future studies of dust sources and controlling factors, improve assessments of the effects of climate change on dust emissions, and facilitate the interpretation of paleoclimate records.

 

 

 

논문은 2008년 5월 15일에 나온 것이니까...시간이 꽤 지났네요.

 

세계지리 교과서에서는 다룰만한 내용인데

교사인 저도 이 사실을 까맣게 모르고 있었다니....ㅠ.ㅠ

 

교과서 내용은 간략히 요약하면

'고비사막의 먼지가 날려서 대한민국에 영향을 준다'라는 것인데

 

이 먼지의 정체는 바로

사막의 먼지가 main source가 아니라

alluvial fans가 제공하는 미세먼지가 main source였다는 것입니다.

 

보통 습윤한 지역의 alluvial fans의 퇴적물이라면 불가능했겠지만

건조지형에 발달하는 alluvial fans이니까 가능했던 것 같습니다.

 

 

 

요약해서 말씀드리면

 

황사가 우리나라로 계속 날아올 수 있었던 원인은

 

1. 건조지역에

2. Kunlun, Qilian, Helan, and Gobi Altai mountains 등의 미친듯한 규모의 산맥들이 (경사 급변점)

3. 빙하 녹을때쯤 발생하는 홍수에

4. 선상지를 만들고

5. 분급효과가 좋은 유수에 의해  dust-sized particles이 끊임없이 공급되면

6. 그 먼지가 건조되어

7. 상승기류를 타고 하늘로 올라가

8. 편서풍을 타고 동쪽으로 이동한다

 

이것이 매커니즘입니다.

 

 

 

 

2005).

(A) Dust storm frequency (DSF) distribution (days) in Northern China from 1960 to 2003 (after X. Wang et al., 2006).

(B) DSF distribution (days) in Mongolia from 1937 to 1999 (after Natsagdorj et al., 2003; no latitudes and longitudes are available).

(C) Annual mean times of heavy dust production (visibility b0.5 km) averaged from 1954 to 2002 (after Zhou and Zhang, 2003).

(D) Mean dust concentration (μg m−3) averaged from 27 May 1998 to 26 May 2003 (after Shao and Dong, 2006).

(E) Annual average TOMS aerosol index (afterWashington et al., 2003).

(F) Simulation of the annual frequencies of significant dust emissions (dust flux N10−10 g cm−2 s−1) (after Laurent et al.,2005).

 

 

 

 

Fig. 2. Map of the geomorphological types of Northern China and Mongolia, showing the distribution of sandy and Gobi deserts (Modified after CAREERI, 2005). The numbers 1 to 12 indicate major sandy deserts and areas of sandy or desertified land. G-A to G-D identify the four major Gobi types described in the text. The distribution of Gobi desert in Mongolia was supplemented by the data in Murzaef (1958). S1 to S40 represent the locations of sample collection sites used for the analyses of particle sizes and of salt and CaCO3 contents (Tables 1–3). Upper and lower case letters represent the locations of the photographs in Figs. 4 and 5, respectively.

 

 

 

 

Fig. 3. Proposed source regions for the dust storms that occurred from 9 to 12 March and 9 to 11 April 2006 in Northern China and Mongolia. Arrows indicate the prevailing wind direction during the dust storm periods.

 

 

 

 

(A) Type G-A, south of the Altai Mountains.
(B) Type G-B, in the Minfeng area of the southern Taklimakan Desert.
(C) Type G-C, in the Ruoqiang area of the eastern Taklimakan Desert.
(D) Type G-D, in the Kumutage desert. The locations of these photos are identified in Fig. 2 (using the same capital letters).

 

 

 

Fig. 5. Geomorphological characteristics of alluvial fans adjacent to Gobi regions:
(A) near Keping, and
(B) cultivated land protected by plastic sheets and forest belts in Northern China. The locations of these photos are identified in Fig. 2 (using the same lower-case letters).

 

 

 

 

Fig. 6. Remote-sensing images showing the geomorphological setting of regions with high levels of dust occurrence in recent decades. Images were obtained from Google Earth (http://earth.google.com/). The scales of the images were not available, but the locations shown in the images are identified in Fig. 2. Arrows represent the direction of the prevailing wind.

 

 

 

 

Fig. 7. Geomorphological map of the Tarim Basin and the directions of surface winds responsible for dust transportation and deposition.

 

 

 

 

Fig. 8. A hypothetical framework showing the effects of glacier formation and motion on wadi and Gobi development and on the production of dust-sized particles, thereby influencing the persistence of dust sources in arid and semiarid China.