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.

An unusually long data set was acquired at the sodium lidar facility at Colorado State University (41N, 105W), between Sep 18 and Oct 01, 2003, including a 9‐day continuous observation. This time is long enough to average out the perturbations of gravity waves and short‐period planetary waves. As such, it can be used to define tidal‐period perturbations in temperature and horizontal wind. Assuming the sodium mixing ratio is a constant of motion, the observed tidal‐period oscillation in sodium density follows that of vertical wind. Thus, the data set defines tidal‐period perturbations of temperature and wind vector. The observed amplitudes and phases were compared to Global Scale Wave Model predictions (both GSWM00 and GSWM02). We found excellent agreement in diurnal phases and reasonable agreement in semidiurnal phases. However, GSWM02 overestimates diurnal amplitudes and both model versions underestimate observed semidiurnal amplitudes. Since the data period is long enough for the study of planetary waves and of tidal variability, we perform spectral analysis of the data, revealing a strong quasi 3‐day wave in meridional wind, a 14 hour perturbation in zonal wind, and both 14‐hour and 10‐hour periods in meridional wind, likely the result of nonlinear interactions. The observed semidiurnal amplitudes are much larger than the corresponding diurnal amplitudes above 85 km, and over a few days the diurnal and semidiurnal amplitudes vary by factors of 2–3. Causes for the observed tidal variability in terms of planetary wave modulation and tide‐gravity wave interaction are explored qualitatively.

One‐night (28 October 2003) temperature and horizontal wind measurements by a resonance sodium (Na) wind/temperature lidar at Maui (20.7°N, 156.3°W) and temperature measurement by a Rayleigh lidar at Mauna Loa Observatory (MLO, 19.5°N, 155.6°W), Hawaii, were used to study gravity wave (GW) propagation from the lower stratosphere to the lower thermosphere. A dominant wave mode was identified from 35 to 103 km. The wave was partially dissipated and propagating upward with a scale height of temperature amplitude at ∼14 km. A damping layer was present around the stratopause where the wave amplitude was small, which also corresponded to a low static stability layer. The vertical wavelengths were larger in the mesosphere (12–13 km) than in the stratosphere (6–7 km), consistent with the decreasing static stability with altitude. Hodograph analysis of the Na lidar wind data showed that the wave was propagating northward and the horizontal wavelength was 2140 km and intrinsic period was 15 h in the region 84–103 km. The apparent period was ∼6 h and consistent with Doppler shift of the background wind. It is suggested that the convective zone over the equator to the south of Hawaii provided a constant GW source that is responsible for the observed GW throughout the night.

Seasonal and interannual variations of the Quasi‐Two‐Day wave s = −3 (W3) and s = −4 (W4) modes were studied with global temperature and wind data sets during 2002–2012, observed respectively by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) and TIMED Doppler Imager (TIDI) instruments onboard the Thermosphere Ionosphere and Mesosphere Electric Dynamics (TIMED) satellite. The amplitudes of W3 and W4 are significantly enhanced during austral and boreal summer respectively. Strong W3 amplitudes are observed during January 2006 in all three components of temperature, meridional wind, and zonal wind. This is most likely related to the intensive winter planetary wave activity that led to a strong sudden stratosphere warming (SSW) event. The maximum amplitudes of W4 during the 10 years are ~8–9 K, ~40 m/s, and ~20 m/s for temperature, meridional, and zonal components respectively, nearly half as large as those of W3, with ~15 K, ~65 m/s, and ~35 m/s. In January 2008 and 2009, unusually weak W3 but strong W4 oscillations were observed, corresponding to the much weaker summer easterly jets (westward wind) than those in other years. This suggests that relatively weak summer easterly may not be able to provide sufficiently strong barotropic/baroclinic instability to amplify W3 but is favorable for the amplification of W4. The weaker magnitude values, lower peak heights, and longer life intervals of W4 than those of W3 suggest that the W4 may suffer a greater damping rate than the W3. The observations of W4 show good agreement with Rossby‐gravity (4, 0) mode, which is more easily trapped in both latitude and altitude because of its lower group velocity than that of Rossby‐gravity (3, 0) mode.

We report here a narrowband high-spectral resolution sodium temperature/wind lidar recently developed at the University of Science and Technology of China (USTC) in Hefei, China (31.5 °N, 117 °E). Patterned after the Colorado State University (CSU) narrowband sodium lidar with a dye laser-based transmitter, the USTC sodium temperature/wind lidar was deployed with a number of technical improvements that facilitate automation and ease of operation; these include a home constructed pulsed dye amplifier (PDA), a beam-steering system, a star-tracking program, and an electronic timing control. With the averaged power of $\sim 1.2\mathrm{W}$ output from PDA and the receiving telescope diameter of 0.76 m, our lidar system has a power aperture product of $\sim 0.55{\mathrm{Wm}}^2$ and is comparable to the CSU and the University of Illinois at Urbana-Champaign (UIUC) sodium lidar systems. The uncertainties of typical measurements induced by photon noise and laser locking fluctuation for the temperature and wind with a 2 km vertical and 15 min temporal resolutions under the nighttime clear sky condition are estimated to be $\sim 1.0\mathrm{K}$ and $\sim 1.5\mathrm{m}/\mathrm{s}$, respectively, at the sodium peak (e.g., 91 km), and 8 K and $10\mathrm{m}/\mathrm{s}$, respectively, at both sodium layer edges (e.g., 81 km and 105 km). The USTC narrowband sodium lidar has been operated regularly during the night since November 2011. Using the initial data collected, we demonstrate the reliability and suitability of these high resolution and precision datasets for studying the wave perturbations in the mesopause region.