HR: 0800h
AN: GC21A-0131    [Abstracts]
TI: A case study of mineral dusts from China and Mongolia: satellite remote sensing, meteorological analysis and model simulation
AU: Tsunekawa, A
EM: a.tsunekawa@gmail.com
AF: Tottori University, Hamasaka 1390, Tottori, 6800001, Japan
AU: * Zhang, B
EM: baolin@alrc.tottori-u.ac.jp
AF: Tottori University, Hamasaka 1390, Tottori, 6800001, Japan
AU: Tsubo, M
EM: tsubo@alrc.tottori-u.ac.jp
AF: Tottori University, Hamasaka 1390, Tottori, 6800001, Japan
AB: We used MODIS L1B data to monitor the dust events during April 6—11, 2001; then employed the NCEP/NCAR reanalysis Project daily dataset to analyze the physical mechanism of dust emission, transport and deposition process. And finally, we introduced RegCM into Asian dust simulation. The study area is northern China and southern Mongolia (between 70–150°E and 20–60°N), where are regarded as the main dust sources in Asia. During April 6—11, huge dust storms developed from the south of Mongolia and the north of China, sweeping across northern China, southeastern Russia, Korean Peninsula, Japan, North Pacific Ocean. In this period, the dust events consisted of 2 episodes. One was mainly from southeast of Mongolia (Dundgovi and Dornogovi) and the middle of Inner Mongolia (Otintag sandy land), China. The other was mainly from Taklimakan Desert. In the first episode, the dust was raised from the southeast of Mongolia on April 6, and moved eastward. On April 7, the dust blow across Otintag sand land of Inner Mongolia, China; the loose, plentiful dust materials here and the funneling cased by the mountain ranges of Xinganling to the east strengthened the dust; the dust storm almost covered the whole northeast of China. In the following days, the dust storm moved northeastward slowly, went across southeast of Russia and then to the North Pacific Ocean. This episode was associated with Mongolian cyclone. On April 5 (00:00), a trough was to the east of Lake Baikal. Under the influence of cold air from north, a Mongolian cyclone formed here around 12:00 April 5, with a center of 995 geopotential height (gpm). This cyclone deepened, while it moved quickly eastward. When this cyclone swept across the south of Mongolia and the middle of Inner Mongolia, strong dust storm occurred. Although another cyclone formed to the southwest of Lake Baikal around 06:00, April 7, the first cyclone was relatively stronger. The uprising air of this cyclone can also be well explained by positive vorticity at 500 hpa. The positive vorticity area lay in the east of Mongolia and the east of Inner Mongolia, China, where is just between on the transport pathway of the dust storm originated from south of Mongolia and middle of Inner Mongolia, as shown by satellite images of April 6 and April 7. The strong wind, surface convergence and upper divergence derived from NNRP1 data also explained this episode well. The second episode mainly originated from Takalimakan Desert. On April 8, strong local wind developed in the basin; and carried dust out of the basin, across Mongolia and northern China on April 9, to the northeastern China on April 10 and the North Pacific Ocean on April 11. The circulation of strong local wind brought dust from the edges of the desert out of the basin through the east exit on the border of Xinjiang, Gansu of China, where lies between Tianshan Mountains (average elevation >3500 meters) and Mazongshan Mountains (average elevation between 1000 and 3500 meters). This episode demonstrated a northeastward transport of dust from Taklimakan Desert, as differs from previous reports. This episode was caused cold front, associated upper trough-ridge system. The NNRP1 derived negative divergence over the northeast rim of Taklimakan Desert well explained the dust sources. RegCM was used to simulate these dust events. The results showed that dust module may overestimate the dust emission from some deserts, especially Gurban Tonggut Desert, and underestimate dust emission from Gobi desert and sandy land, which have been identified as the main contributor to Asian dust.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0468 Natural hazards
DE: 0480 Remote sensing
DE: 1610 Atmosphere (0315, 0325)
DE: 6015 Dust
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting