Abstract. We coordinated a ground-based network that has been in use since 1997 to observe Asian dust during springtime. Huge Asian dust events that occurred in the middle of April 1998 were captured by this network. In this paper we present the organization of the network; a description of the instruments, including the lidar, sky radiometer, and optical particle counter; and the results of the observation, and offer discussions regarding the transport mechanism of Asian dust in east Asia using an on-line tracer model. We discussed the time series of the surface concentration and the height distribution of the dust. A cutoff cyclone generated during the dust episode was responsible for trapping and sedimentation during the transportation of the Asian dust, particularly in the southern parts of China and Japan. Horizontal dust images derived from NOAA/AVHRR clearly revealed the structure of the vortex. The lidar network observation confirmed the general pattern of dust height distribution in this event; the height of the major dust layer was about 3 km over Japan but was higher (4 to 5 km) in Seoul and Hefei. A thin dust layer in the upper troposphere was also commonly observed in Hefei and Japan. Evidence of the coexistence of dust and cirrus was shown by the polarization lidar. The lidar network observation of Asian dust and satellite remote sensing provide key information for the study of the transport mechanism of Asian dust. Further extension of the lidar network toward the interior of the continent and the Pacific Rim would reveal the greater global mechanism of the transportation.

A comprehensive dust aerosol model is developed and fully coupled to the U. S. Navy's operational Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS™). The model is used to simulate the Asian dust storms of 5–15 April 2001 at 27‐km resolution with 46 vertical layers. Dust was primarily generated in the Gobi and Taklamakan Deserts between 6 and 9 April and then swept across vast areas of east Asia. The model performance is verified with satellite products and by observations of PM10 and lidar data from Lanzhou, Beijing, Hefei, Tsukuba, and Nagasaki. The model simulates the right timing and strength of dust events, predicting depths and magnitudes of the boundary layer and elevated layer of dust plumes that compare well with observed values. Numerical analysis shows that the first Mongolia cyclone on the 6 and 7 April and the cold front on 8 and 9 April, accompanied by a second Mongolia low, form the major dynamic forcing patterns that mobilize, transport, and vertically redistribute the dust. Both cyclones entrain the dust and transport dust to altitudes of 8–9 km, while at the top of the cyclone, transport is anticyclonic and to the northeast. The analysis of the individual dynamic and microphysical tendency terms in the mass continuity equation reveals that in the dust generation area, mechanical and convective turbulence plays the major role in mixing dust upward to the top of the planetary boundary layer. In the downstream cyclone area, vertical advection by the model‐resolved upward motion in the cyclones is the dominant dynamic process that transports dust to high altitudes and into the westerlies, making it available for long‐range transport. The mass budget calculation for the entire simulation period reveals that about 75% of the total dust production is redeposited to the Asian deserts, 20% falls onto nondesert areas through dry and wet deposition, and 1.6% falls into the China and Japan Seas.

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An investigation of terrestrial bryophyte species diversity and community structure along an altitudinal gradient from 2,001 to 4,221 m a.s.l. in Gongga Mountain in Sichuan, China was carried out in June 2010. Factors which might affect bryophyte species composition and diversity, including climate, elevation, slope, depth of litter, vegetation type, soil pH and soil Eh, were examined to understand the altitudinal feature of bryophyte distribution. A total of 14 representative elevations were chosen along an altitudinal gradient, with study sites at each elevation chosen according to habitat type (forests, grasslands) and accessibility. At each elevation, three 100 m × 2 m transects that are 50 m apart were set along the contour line, and three 50 cm × 50 cm quadrats were set along each transect at an interval of 30 m. Species diversity, cover, biomass, and thickness of terrestrial bryophytes were examined. A total of 165 species, including 42 liverworts and 123 mosses, are recorded in Gongga mountain. Ground bryophyte species richness does not show any clear elevation trend. The terrestrial bryophyte cover increases with elevation. The terrestrial bryophyte biomass and thickness display a clear humped relationship with the elevation, with the maximum around 3,758 m. At this altitude, biomass is 700.3 g m−2 and the maximum thickness is 8 cm. Bryophyte distribution is primarily associated with the depth of litter, the air temperature and the precipitation. Further studies are necessary to include other epiphytes types and vascular vegetation in a larger altitudinal range.

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We report an 8-element spectral beam combination of Yb-doped all fiber superfluorescent sources around 1070 nm wavelength. Each source consists of a 60 mW front-end and a 1.5 kW three-stage fiber amplifier chain. The eight output beamlets are spectrally combined using a home-made polarization-independent multilayer dielectric reflective diffraction grating. 10.8 kW output power is achieved with an efficiency of 94%. Besides, both theoretical and experimental studies of dual grating dispersion compensation scheme have been performed, which is proved to be a prospective way for high brightness spectral beam combination.