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著者人数: 20名, 形態: 図版あり, Number of authors: 20, Physical characteristics: Original contains illustrations, 資料番号: PA1710058000

Accurate measurements of forest biomass are important to evaluate its contribution as a source of CO2 absorption. Forest biomass correlates with forest canopy height, and thus global measurements of canopy heights lead to a better understanding of the global carbon cycle. Space-borne lidar has the unique capability of measuring forest canopy height. A vegetation lidar named MOLI (Multi-footprint Observation Lidar and Imager) has been designed to observe canopy heights more accurately, and MOLI is currently being studied in the Japan Aerospace Exploration Agency (JAXA). This paper introduces an overview of MOLI and its current status.

We conduct communication environment measurement in Chikuma city, Nagano prefecture, Japan, utilizing community bus services via private Long Range (LoRa), which is one of the low-power wide area (LPWA) communication technologies. Chikuma city has approximately 119.8 km^2 area and a population of 59,380, which is a medium-sized rural city in Japan. In this experiment, we set up LoRa relay stations at three locations in the city: the Koshoku city hall building (at the northern part of the city), the Togura municipal building (at the southern part of the city), and the Amenomiya drainage station (at the eastern part of the city). In addition, beacon transmitters are installed in the community buses (nine routes in all). The location and time information are transferred from the routes of the buses to a cloud system in real time through the relay stations. Experimental results are summarized in an area map, indicating that we succeed in communicating in 61.3% of data points on the bus routes and confirm the possibility of covering the entire city by the LPWA. We are able to expand the LoRa communication area by adding more relay stations paying attention to terrain effects.

著者人数: 17名, 形態: カラー図版あり, Number of authors: 17, Physical characteristics: Original contains color illustrations, 資料番号: PA1710059000

A diode-side-pumped laser oscillator with a Tm,Ho:YLF rod conductively cooled to −80 °C was developed. A Q-switched pulse energy of 104 mJ was achieved at a pulse repetition frequency of 70 Hz, corresponding to an average output power of 7.28 W. In addition, the maximum Q-switched pulse energy of 125 mJ was obtained at 50 Hz. Even at the maximum output level, the beam quality factor $M^{\mathrm {\mathbf {2}}}$ was measured to be $\leq $ 1.5. To the best of our knowledge, this is the highest average output power reported for a 100-mJ-class Q-switched 2- $\mu \text{m}$ laser oscillator using a conductively cooled laser head.

Rainfall velocity, raindrop size distribution (DSD), and vertical wind velocity were simultaneously observed with 2.05- and 1.54-μm coherent Doppler lidars during convective and stratiform rain events. A retrieval method is based on identifying two separate spectra from the convolution of the aerosol and precipitation Doppler lidar spectra. The vertical wind velocity was retrieved from the aerosol spectrum peak and then the terminal rainfall velocity corrected by the vertical air motion from the precipitation spectrum peak was obtained. The DSD was derived from the precipitation spectrum using the relationship between the raindrop size and the terminal rainfall velocity. A comparison of the 1-min-averaged rainfall velocity from Doppler lidar measurements at a minimum range and that from a collocated ground-based optical disdrometer revealed high correlation coefficients of over 0.89 for both convective and stratiform rain events. The 1-min-averaged DSDs retrieved from the Doppler lidar spectrum using parametric and nonparametric methods are also in good agreement with those measured with the optical disdrometer with a correlation coefficient of over 0.80 for all rain events. To retrieve the DSD, the parametric method assumes a mathematical function for the DSD and the nonparametric method computes the direct deconvolution of the measured Doppler lidar spectrum without assuming a DSD function. It is confirmed that the Doppler lidar can retrieve the rainfall velocity and DSD during relatively heavy rain, whereas the ratio of valid data significantly decreases in light rain events because it is extremely difficult to separate the overlapping rain and aerosol peaks in the Doppler spectrum.

A 2 μm Ho-doped ytrrium lithium fluoride (Ho:YLF) laser end-pumped by a 1.94 μm Tm:fiber laser was developed. A laser system of a ring resonator oscillator and amplifier was operated at repetition rates of 200–5000 Hz at room temperature. The Q-switched outputs were 7.4 W at 5000 Hz and 4.25 W at 200 Hz. Injection seeding was applied to the ring resonator, and single-mode laser emission was obtained. The Tm:fiber-laser-pumped Ho:YLF laser was first used for Doppler wind lidar measurements, and wind profiles were obtained up to ranges of about 15 km in a range resolution of 96 m and an integration time of 1 s.

The authors evaluated the effects of assimilating three-dimensional Doppler wind lidar (DWL) data on the forecast of the heavy rainfall event of 5 July 2010 in Japan, produced by an isolated mesoscale convective system (MCS) at a meso-gamma scale in a system consisting of only warm rain clouds. Several impact experiments using the nonhydrostatic four-dimensional variational data assimilation system (NHM-4DVAR) and the Japan Meteorological Agency nonhydrostatic model with a 2-km horizontal grid spacing were conducted in which 1) no observations were assimilated (NODA), 2) radar reflectivity and radial velocity determined by Doppler radar and precipitable water vapor determined by GPS satellite observations were assimilated (CTL), and 3) radial velocity determined by DWL were added to the CTL experiment (LDR) and five data denial and two observational error sensitivity experiments. Although both NODA and CTL simulated an MCS, only LDR captured the intensity, location, and horizontal scale of the observed MCS. Assimilating DWL data improved the wind direction and speed of low-level airflows, thus improving the accuracy of the simulated water vapor flux. The examination of the impacts of specific assimilations and assigned observation errors showed that assimilation of all data types is important for forecasting intense MCSs. The investigation of the MCS structure showed that large amounts of water vapor were supplied to the rainfall event by southerly flow. A midlevel inversion layer led to the production of exclusively liquid water particles in the MCS, and in combination with the humid airflow into the MCS, this inversion layer may be another important factor in its development.

The effect of lower-laser-level lifetimes on Q-switched pulse generation in a dual-wavelength solid-state laser with a common upper laser level was numerically and experimentally investigated. A rate-equation model that accounts for finite lower-laser-level lifetimes was developed, and for a Nd:YAG laser operating at 1064 and 1319 nm, numerical simulations of dual-wavelength pulse generation were performed with and without the effects of lower-laser-level lifetimes. In the laser experiments, characteristics of the dual-wavelength Q-switched pulses agree reasonably well with theoretical predictions. As a result, we found that both the total energy of the two Q-switched pulses and the ratio of 1064–1319-nm pulse energies were strongly affected by the lower-laser-level lifetimes when the Q-switched pulse width was comparable or shorter than the lower-laser-level lifetime.

The National Institute of Information and Communications Technology (NICT) has made a great deal of effort to develop a coherent 2 μm differential absorption and wind lidar (Co2DiaWiL) for measuring CO2 and wind speed. First, coherent Integrated Path Differential Absorption (IPDA) lidar experiments were conducted using the Co2DiaWiL and a foothill target (tree and ground surface) located about 7.12 km south of NICT on 11, 27, and 28 December 2010. The detection sensitivity of a 2 μm IPDA lidar was examined in detail using the CO2 concentration measured by the foothill reflection. The precisions of CO2 measurements for the foothill target and 900, 4500 and 27 000 shot pairs were 6.5, 2.8, and 1.2%, respectively. The results indicated that a coherent IPDA lidar with a laser operating at a high pulse repetition frequency of a few tens of KHz is necessary for XCO2 (column-averaged dry air mixing ratio of CO2) measurement with a precision of 1–2 ppm in order to observe temporal and spatial variations in the CO2. Statistical comparisons indicated that, although a small amount of in situ data and the fact that they were not co-located with the foothill target made comparison difficult, the CO2 volume mixing ratio obtained by the Co2DiaWiL measurements for the foothill target and atmospheric returns was about −5 ppm lower than the 5 min running averages of the in situ sensor. Not only actual difference of sensing volume or the natural variability of CO2 but also the fluctuations of temperature could cause this difference. The statistical results indicated that there were no biases between the foothill target and atmospheric return measurements. The 2 μm coherent IPDA lidar can detect the CO2 volume mixing ratio change of 3% in the 5 min signal integration. In order to detect the position of the foothill target, to measure a range with a high SNR (signal-to-noise ratio), and to reduce uncertainty due to the presence of aerosols and clouds, it is important to make a precise range measurement with a Q-switched laser and a range-gated receiver.

A coherent 2-μm differential absorption and wind lidar (Co2DiaWiL) has been built with a high-power Q-switched Tm,Hm:YLF laser to measure CO2 concentration and radial wind speed. The performance of the Co2DiaWiL is described and analyzed, with a view to demonstrating system capabilities for remote measurements of wind velocities in the atmospheric boundary layer and free troposphere. Bias in the velocity measurements was estimated at −0.0069 m s−1 using measurements from a stationary hard target. The Co2DiaWiL achieved a velocity precision of 0.12 m s−1, derived from the magnitude of random error in radial wind velocity measurements. These measurements were made for ranges out to 20–25 km by using a horizontally fixed beam mode for average times of 1 min. Quantitative intercomparisons of 1-min averages between the Co2DiaWiL and a sonic anemometer revealed a correlation coefficient of 0.99. This study demonstrated measurements of horizontal wind profiles, by making radial wind velocity measurements with the Co2DiaWiL using conical scanning. Profile differences at higher levels could be attributed to probable large horizontal separations of the radiosondes and the low signal-to-noise ratio of the Co2DiaWiL. A pseudo-dual-Doppler technique was developed to retrieve horizontal wind components with a single-Doppler lidar and a steering mirror. Intercomparisons of the 1-min-averaged u and υ components from the pseudo-dual-Doppler lidar measurements with those from the sonic anemometer revealed correlation coefficients of 0.84 and 0.83, respectively.

We disseminated an ultra-broadband optical frequency reference based on a femtosecond (fs)-laser optical comb through a kilometer-scale fiber link. Its spectrum ranged from 1160 nm to 2180 nm without additional fs-laser combs at the end of the link. By employing a fiber-induced phase noise cancellation technique, the linewidth and fractional frequency instability attained for all disseminated comb modes were of order 1 Hz and 10-18 in a 5000 s averaging time. The ultra-broad optical frequency reference, for which absolute frequency is traceable to Japan Standard Time, was applied in the frequency stabilization of an injection-seeded Q-switched 2051 nm pulse laser for a coherent light detection and ranging LIDAR system.

A 2-micron Ho:YLF laser end-pumped by 1.94-micron Tm:fiber laser was developed. A ring resonator oscillator of 3 m length and amplifier system was adopted. The laser was operated at high repetition rates of 200-5000 Hz in room temperature. The amplifier outputs were about 7.4W in CW and more than 6 Win Q-switch operation of repetition rates more than 500 Hz. This laser was developed to be used for coherent wind and CO2 measurements. Then, injection seeding was applied to the ring resonator and single mode laser emission was obtained. The laser was used for Doppler wind lidar measurements and wind profiles were obtained.

A coherent 2-μm differential absorption and wind lidar (Co2DiaWiL) with a 2-μm single-frequency Q-switched laser with laser frequency offset locking was used for long-range CO2 measurement. The frequency stabilization of the single-frequency λ on pulsed laser was 1.0 MHz. Experimental horizontal CO2 measurement over a column range of 2.6–5.6 km and 900 shot pairs (1-min integration time) was conducted on 22 October 2009 to examine the detection sensitivity of the Co2DiaWiL. The achieved precision was less than 2.1%. The root-mean-square of the differences between the 30-min CO2 averages measured by the Co2DiaWiL and a ground-based in situ instrument was 0.9% (3.5 ppm). Experimental vertical CO2 measurements were conducted in February 2010 and January and February 2011. The partial CO2 column-averaged dry-air mixing ratios (XCO2) for an altitude between 0.4 and 1.0 km in 2010 and 2011 were 403.2 ± 4.2 and 405.6 ± 3.4 ppm, respectively. In the paper, the Co2DiaWiL results were well validated carefully against those of the airborne in situ instrument; they agreed well within the margin of error. The values of XCO2 measured in presence of cirrus clouds near the tropopause (hard target cases) show a difference of less than 4.1 ppm with the airborne measurements performed on 14 February 2010. This result demonstrates the capability of the Co2DiaWiL to measure XCO2 within a precision better than 1%.

Severe downslope winds accompanying turbulence, which are of great concern to aviation safety, often occur on the lee side of Zao mountain range in winter. Special Doppler lidar observations and numerical simulations with a grid spacing of 100 m were carried out focusing on the downslope winds around the Sendai airport on 14 February 2008. The model reproduced stationary lee waves with an approximate 20-km wavelength, consistent with the observed horizontal scale in water vapor images from the Japanese geostationary multifunctional transport satellite (MTSAT-1R). The simulated lee waves are accompanied by strong vertical shear, which leads to the separation of a vortex sheet from the surface, where small-scale vortices are generated successively. The vortex sheet is under favorable conditions for Kelvin-Helmholtz instability and may account for the generation of small-scale vortices. The simulated vortices, which are advected downstream, are accompanied by weak low-level wind patches. The Doppler lidar observation also captured the weak low-level wind patches with a horizontal scale of 1000-m moving downstream near the surface. An observed temporal variability in line-of-site wind speed decreased with increasing altitude from the surface. This feature was reproduced by the model in a qualitative sense, although the model tended to overestimate (underestimate) the variability below (above) a height of approximately 800 m.

Rayleigh and resonance lidar observations were made during the Turbopause experiment at Poker Flat Research Range, Chatanika Alaska (65° N, 147° W) over a 10 h period on the night of 17–18 February 2009. The lidar observations revealed the presence of a strong mesospheric inversion layer (MIL) at 74 km that formed during the observations and was present for over 6 h. The MIL had a maximum temperature of 251 K, amplitude of 27 ± 7 K, a depth of 3.0 km, and overlying lapse rate of 9.4 ± 0.3 K km−1. The MIL was located at the lower edge of the mesospheric sodium layer. During this coincidence the lower edge of the sodium layer was lowered by 2 km to 74 km and the bottomside scale height of the sodium increased from 1 km to 15 km. The structure of the MIL and sodium are analyzed in terms of vertical diffusive transport. The analysis yields a lower bound for the eddy diffusion coefficient of 430 m2 s−1 and the energy dissipation rate of 2.2 mW kg−1 at 76–77 km. This value of the eddy diffusion coefficient, determined from naturally occurring variations in mesospheric temperatures and the sodium layer, is significantly larger than those reported for mean winter values in the Arctic but similar to individual values reported in regions of convective instability by other techniques.

To study the wind field within the atmospheric boundary layer over the Tokyo metropolitan area, Doppler lidar observations were made 45 km north of Sagami Bay and 30 km west of Tokyo Bay, from 14 May to 15 June 2008. Doppler lidar on 27 May 2008 observed the vertical and horizontal wind structure of a well-developed sea-breeze front (SBF) penetrating from Sagami Bay. At the SBF, a strong updraft (maximum w approximately equal to 5 m s−1) was formed with a horizontal scale of about 500 m and vertical scale of 2 km. The spatial relationship between the strong updraft over the nose of the SBF and prefrontal thermal suggests that the strong updraft was triggered by interaction between the SBF and the thermal. After the updraft commenced, a collocated ceilometer observed an intense aerosol backscatter up to 2 km above ground level. The observational results suggest that the near-surface denser aerosols trapped in the head region of the SBF escaped from the nose of the SBF and were then vertically transported up to the mixing height by the strong updraft at the SBF. This implies that these phenomena occurred not continuously but intermittently. The interaction situations between the SBF and prefrontal thermal can affect the wind structure at the SBF and the regional air quality.

A numerical simulation of the strong southeasterly (SE) "Kiyokawa-dashi" wind in Yamagata, Japan on August 30, 2004, is examined and compared to the Coherent Doppler Lidar (CDL) observation. Three-dimensional numerical simulations were performed using a non-hydrostatic meso-scale model developed by the Japan Meteorological Agency. The sensitivity of the numerical simulation was examined with respect to the resolution of the horizontal and vertical grid, surface roughness, and ground surface temperature. For the case of a 1-km grid with 85 vertical layers including realistic surface settings, the observed characteristics of Kiyokawa-dashi were well reproduced: the strong SE wind (10 m s -1 ) was extremely low, about 0.1-0.5 km AGL, and the maximum wind speed over 12 m s -1 was observed at 0.1-0.2 km, AGL, under the low-level stable layer. Strong winds appeared at the foot of the final lee slope facing the Shonai Plain and 1 km south of the valley; this result was in good agreement with the CDL observation. On the basis of the stream line analysis, Kiyokawa-dashi was strongly affected by the upper SE wind, i.e., upper air on the eastern side of the mountains blew down to the middle and lower layer on the western side. The strongest wind field located 1 km south of the valley was affected by the mountain at the southwestern end of the valley. It was observed from the sensitivity experiments that the height of the jet-like flow was found to be closely related to the low-level stable layer, and the critical layer was not very important in reinforcing the low-level SE wind. This case of Kiyokawa-dashi was explained on the basis of the hydraulic theory.

Penicillium islandicum produces luteoskyrin (LUT), a yellow rice toxin that has been found frequently in rice. However, conventional analytical methods for determining LUT are limited, are complicated, and exhibit low sensitivity. In this study, an analytical method more sensitive and simple based on high-performance liquid chromatography combined with electrospray ionization mass spectrometry was developed. The cleanup procedure of the method was one step, using a solid-phase extraction cartridge. An isocratic mobile-phase system, consisting of acetonitrile-water-acetic acid (50:49:1 [vol/vol/vol]) at a flow rate of 0.2 ml/min, was utilized to obtain the best resolution. Our method showed good linearity (r = 0.9993, 0.5 to 50 ng/g) and high repeatability (relative standard deviation = 8.9 and 5.1% at levels of 0.5 and 10 ng/g, respectively) in the fortification test. The detection and quantification limits for the method in multiple-reaction monitoring mode were 0.1 and 0.3 ng/g, respectively. The average recovery of LUT in spiked rice at 0.5 and 10 ng/g was 80.7 and 85.2%, respectively. The method developed in this study should be applicable to survey LUT in rice, with high sensitivity, selectivity, and rapidity.

Over an eight-year period (1997–2005) Rayleigh lidar temperature measurements of the stratosphere and mesosphere (40–80 km) have been made at Poker Flat Research Range, Chatanika, Alaska (65°N, 147°W). The Rayleigh lidar measurements have been made between mid-August and mid-May. These measurements have yielded a total of approximately 904 hours of temperature measurements of the middle atmosphere over 116 nights. The seasonal evolution of the middle atmosphere shows an annual cycle with maximum in summer below 60 km and a reversal of the cycle with minimum in summer above 60 km. The monthly mean stratopause has a highest temperature of 273 K at an altitude of 47.5 km in May and a lowest temperature of 243 K at an altitude of 54.7 km in January. However, nightly stratopause temperatures in January and December are sometimes warmer than those in May and August. An elevated stratopause (>65 km) is observed on 5 occasions in 41 observations in January and February. The Chatanika measurements are compared with five other Arctic data sets and models. The upper stratosphere at this site is slightly colder than the zonal mean as well as sites in Greenland and Scandinavia with the largest differences found in January. We discuss the wintertime temperatures in the upper stratosphere and lower mesosphere in terms of the position of the polar vortex and the increased occurrence of stratospheric warming events during the 1997–2005 observation period.

Novel coincident 3-D radar, lidar and optical image measurements of dynamical structures in polar mesosphere summer echoes (PMSE) and noctilucent clouds (NLC) are presented. Common volume mesospheric measurements were made over central Alaska using the new Poker Flat Incoherent Scatter Radar (PFISR), a co-located Rayleigh lidar and remote, two-station digital image observations, enabling the first detailed investigation of the horizontal and vertical structures of NLC and PMSE. Coincident measurements were made of an unusual NLC display recorded on 10–11 August 2007, characterized by a broad luminous band that contained several prominent wave forms. Concurrent lidar and image measurements established the presence of NLC within the radar volume from ∼09:00 UT (01:00 LT), when the solar depression angle was 10.4°, until dawn. Strong but intermittent PMSE were detected by PFISR, with distinct patchy structures that exhibited a similar southward motion as the NLC. Detailed comparison of the 3-D PMSE structures and the NLC lidar and image data have revealed striking similarities when account was taken of the NLC layer altitude, suggesting a direct link between their small-scale spatial signatures (within the current resolution of the radar measurements). At the same time, the lidar detected a sustained increase in the backscatter signal, while the imagers revealed the development of copious short horizontal wavelength (4.9 km) billow waves. We conclude that strong wind shears associated with the Kelvin–Helmholtz billow instabilities played a key role in the development of a neutral turbulence layer in close proximity to the NLC layer resulting in the strong but intermittent PMSE detected at 450 MHz on this occasion.

The relationship between local meteorological fields and the behaviour of airborne Asian dust that arrived in the Tokyo metropolitan area on 1 April 2007 with the passage of a synoptic-scale cold front has been investigated through Doppler lidar observations, experiments using a regional atmospheric numerical model, and analyses of surface and upper-air meteorological observations. Results of the Doppler lidar observations showed that the Asian dust passed above the metropolitan area with strong south-westerly winds with speeds of 15–26 m s−1. Meteorological fields reproduced by the numerical experiments showed the development of a surface-based stable layer in the metropolitan area caused by nocturnal radiational cooling near the ground surface and south-westerly warm air advection at upper levels. The blocking effect of the mountainous region located to the west of the metropolitan area induced an area of stagnant air inside the metropolitan area and promoted the stable layer development. Although strong downdrafts prevailed in the upper air, the airborne Asian dust did not spread to the ground when the stable layer was formed. These results strongly indicate that the developed stable layer prevented strong downdrafts from spreading to the ground, acting as an obstacle to the transport of the Asian dust particles from the upper air towards the ground. This is considered to be one of the main causes of the low appearance frequency of Asian dust phenomena near the ground in the Tokyo metropolitan area and eastern Japan.

We report observations of a noctilucent cloud (NLC) over central Alaska by a ground-based lidar and camera on the night of 9–10 August 2005. The lidar at Poker Flat Research Range (PFRR), Chatanika (65°N, 147°W) measured a maximum integrated backscatter coefficient of 2.4×10−6 sr−1 with a peak backscatter coefficient of 2.6×10−9 m−1 sr−1 corresponding to an aerosol backscatter ratio of 120 at an altitude of 82.1 km. The camera at Donnelly Dome, 168 km southeast of PFRR, recorded an extensive NLC display across the sky with distinct filamentary features corresponding to wave structures measured by the lidar. The occurrence of the maximum integrated backscatter coefficient corresponded to the passage of a bright cloud band to the southwest over PFRR. The camera observations indicate that the cloud band had a horizontal width of 50 km and a length of 150 km. The horizontal scale of the cloud band was confirmed by medium-frequency radar wind measurements that reported mesopause region winds of 30 m/s to the southwest during the period when the cloud band passed over PFRR. Comparison of these measurements with current NLC microphysical models suggests a lower bound on the water vapor mixing ratio at 83 km of 7–9 ppmv and a cloud ice mass of 1.5–1.8×103 kg. Satellite measurements show that this NLC display occurred during a burst of cloud activity that began on 5 August and lasted for 10 days. This cloud appeared 10 days after a launch of the space shuttle. We discuss the appearance of NLCs in August over several years at this lower polar latitude site in terms of planetary wave activity and space shuttle launches.

This paper presents extensive validation analyses of ozone observations from the Atmospheric Chemistry Experiment (ACE) satellite instruments: the ACE Fourier Transform Spectrometer (ACE-FTS) and the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO) instrument. The ACE satellite instruments operate in the mid-infrared and ultraviolet-visible-near-infrared spectral regions using the solar occultation technique. In order to continue the long-standing record of solar occultation measurements from space, a detailed quality assessment is required to evaluate the ACE data and validate their use for scientific purposes. Here we compare the latest ozone data products from ACE-FTS and ACE-MAESTRO with coincident observations from satellite-borne, airborne, balloon-borne and ground-based instruments, by analysing volume mixing ratio profiles and partial column densities. The ACE-FTS version 2.2 Ozone Update product reports more ozone than most correlative measurements from the upper troposphere to the lower mesosphere. At altitude levels from 16 to 44 km, the mean differences range generally between 0 and +10% with a slight but systematic positive bias (typically +5%). At higher altitudes (45-60 km), the ACE-FTS ozone amounts are significantly larger than those of the comparison instruments by up to ~40% (typically +20%). For the ACE-MAESTRO version 1.2 ozone data product, agreement within ±10% (generally better than ±5%) is found between 18 and 40 km for the sunrise and sunset measurements. At higher altitudes (45-55 km), systematic biases of opposite sign are found between the ACE-MAESTRO sunrise and sunset observations. While ozone amounts derived from the ACE-MAESTRO sunrise occultation data are often smaller than the coincident observations (by as much as -10%), the sunset occultation profiles for ACE-MAESTRO show results that are qualitatively similar to ACE-FTS and indicate a large positive bias (+10 to +30%) in this altitude range. In contrast, there is no significant difference in bias found for the ACE-FTS sunrise and sunset measurements. These systematic effects in the ozone profiles retrieved from the measurements of ACE-FTS and ACE-MAESTRO are being investigated. This work shows that the ACE instruments provide reliable, high quality measurements from the tropopause to the upper stratosphere and can be used with confidence in this vertical domain

The front of a sea breeze originating from Sagami Bay passed over Tokyo between 1300 LST and 1400 LST on August 10, 2006. Field observations of wind distributions over Tokyo by the use of a ground-based coherent Doppler lidar developed at the National Institute of Information and Communications Technology showed that a sharp multi-layered structure of vertical wind fields was gradually formed after the sea-breeze front passed the observation site. Numerical simulations using the Weather Research and Forecasting (WRF) model demonstrated that the multi-layered wind structure consisted of 1) the sea breeze at an altitude below 0.8 km above mean sea level (AMSL), 2) a layer of weak winds at an altitude of 0.8-1 km AMSL, 3) a return flow of the sea breeze, and 4) a northerly synoptic wind at an altitude above 3 km AMSL. This is the first direct observation of the formation of sharp multi-layered wind structure over Tokyo associated with sea-breeze circulation.

On 11 January 2006, Mount Augustine volcano in southern Alaska began erupting after 20-year repose. The Anchorage Forecast Office of the National Weather Service (NWS) issued an advisory on 28 January for Kodiak City. On 31 January, Alaska Airlines cancelled all flights to and from Anchorage after multiple advisories from the NWS for Anchorage and the surrounding region. The Alaska Volcano Observatory (AVO) had reported the onset of the continuous eruption. AVO monitors the approximately 100 active volcanoes in the Northern Pacific. Ash clouds from these volcanoes can cause serious damage to an aircraft and pose a serious threat to the local communities, and to transcontinental air traffic throughout the Arctic and sub-Arctic region. Within AVO, a dispersion model has been developed to track the dispersion of volcanic ash clouds. The model, Puff, was used operational by AVO during the Augustine eruptive period. Here, we examine the dispersion of a volcanic ash cloud from Mount Augustine across Alaska from 29 January through the 2 February 2006. We present the synoptic meteorology, the Puff predictions, and measurements from aerosol samplers, laser radar (or lidar) systems, and satellites. UAF aerosol samplers revealed the presence of volcanic aerosols at the surface at sitesmore » where Puff predicted the ash clouds movement. Remote sensing satellite data showed the development of the ash cloud in close proximity to the volcano and a sulfur-dioxide cloud further from the volcano consistent with the Puff predictions. Lidars showed the presence of volcanic aerosol with consistent characteristics aloft over Alaska and were capable of detecting the aerosol, even in the presence of scattered clouds and where the cloud is too thin/disperse to be detected by remote sensing satellite data. The lidar measurements revealed the different trajectories of ash consistent with the Puff predictions. Dispersion models provide a forecast of volcanic ash cloud movement that might be undetectable by any other means but are still a significant hazard. Validation is the key to assessing the accuracy of any future predictions. The study highlights the use of multiple and complementary observations used in detecting the trajectory ash cloud, both at the surface and aloft within the atmosphere.« less

Received 4 May 2008; revised 9 June 2008; accepted 18 June 2008; published 23 July 2008. [1] Dual-Doppler lidar and heliborne sensors were used to investigate the three-dimensional (3D) structure of the wind field over Sendai Airport in June 2007. The 3D structures of several-hundred-meter-scale horizontal convective rolls (HCRs) in the sea-breeze layer were observed by the dual-Doppler lidar. The scale of the HCRs determined by the heliborne sensors roughly agreed with that determined by the dual-Doppler lidar. Analysis of the dual-Doppler lidar data showed that the region of upward flow in the HCRs originated in near-surface low-speed streaks. This structure is consistent with the results of large-eddy simulations of the atmospheric boundary layer. The aspect ratios of the HCRs were close to those predicted by linear theories. Citation: Iwai, H., et al. (2008), Dual-Doppler lidar observation of horizontal convective rolls and near-surface streaks, Geophys. Res. Lett., 35, L14808, doi:10.1029/ 2008GL034571.

It is important to obtain the year-to-year trend of stratospheric minor species in the context of global changes. An important example is the trend in global ozone depletion. The purpose of this paper is to report the accuracy and precision of measurements of stratospheric chemical species that are made at our Poker Flat site in Alaska (65° N, 147° W). Since 1999, minor atmospheric molecules have been observed using a Fourier-Transform solar-absorption infrared Spectrometer (FTS) at Poker Flat. Vertical profiles of the abundances of ozone, HNO3, HCl, and HF for the period from 2001 to 2003 were retrieved from FTS spectra using Rodgers' formulation of the Optimal Estimation Method (OEM). The accuracy and precision of the retrievals were estimated by formal error analysis. Errors for the total column were estimated to be 5.3%, 3.4%, 5.9%, and 5.3% for ozone, HNO3, HCl, and HF, respectively. The ozone vertical profiles were in good agreement with profiles derived from collocated ozonesonde measurements that were smoothed with averaging kernel functions that had been obtained with the retrieval procedure used in the analysis of spectra from the ground-based FTS (gb-FTS). The O3, HCl, and HF columns that were retrieved from the FTS measurements were consistent with Earth Probe/Total Ozone Mapping Spectrometer (TOMS) and HALogen Occultation Experiment (HALOE) data over Alaska within the error limits of all the respective datasets. This is the first report from the Poker Flat FTS observation site on a number of stratospheric gas profiles including a comprehensive error analysis.

The Kiyokawa-dashi (strong local wind) was observed with a coherent Doppler lidar at the exit of the Mogami Valley, in Kiyokawa (38.80°N, 140.01°E, 20 m MSL) during the summers of 2003 and 2004. Used to define days on which the Kiyokawa-dashi wind blew were meteorological data obtained from four automatic weather stations installed at four observation sites: Kiyokawa, Karikawa (38.79 °N, 139.99°E, 15 m MSL), Mawadate (38.81°N, 139.92°E, 10 m MSL) and Hirono (38.83°N, 139.85°E, 5 m MSL). When the Kiyokawa-dashi blew, the synoptic patterns tended to be high-pressure in the east and low-pressure in the west. After the Kiyokawa-dashi was extracted, the data measured by the coherent Doppler lidar with a high spatial and temporal resolution were then utilized to investigate it. On the basis of the range height indicator and Plane position indicator scans, the coherent Doppler lidar was able to detect the three-dimensional dynamical structure of the Kiyokawa-dashi up to 8-10 km downstream from the Kiyokawa observation site. The coherent Doppler lidar clearly showed that a low-level critical layer (horizontal wind speed Approx 0 m s -1 ) existed at altitudes of 0.5-1.2 km, and that a strong easterly/southeasterly wind confined below the critical layer blows away about 10-km downstream of the Mogami Valley. Intensive upward/downward vertical motion under the critical layer was indicated by the velocity-azimuth display scan. The line-of-sight wind speeds obtained by high-frequency plane position indicator scans were high, not only near the exit of the Mogami Valley but also over the entire Shonai plain, and the distributions of the line-of-sight wind speeds were almost steady, indicating the existence of transient disturbances.

Q-switched operation of a diode-side-pumped, conduction-cooled Tm,Ho:YLF laser oscillator with 100-mJ output at a pulse repetition rate of 20 Hz and an eye-safe wavelength of 2-μm was achieved. The noncomposite Tm,Ho:YLF laser rod was conduction-cooled down to -80°C through thermal contact of In films from Cu heat sinks, and the laser diode arrays were conduction-cooled to approximately 20°C using Cu heat sinks in a vacuum container. A ring resonator of 3.86 m length with an acousto-optic Q-switch was used. The pulse width was 125 ns, and optical-to-optical efficiency was approximately 7% for an output of 100 mJ. The laser is used at 2.05 μm for applications of Doppler wind lidar measurements, COsub2/subdifferential absorption lidar measurements, and aerosol profiling.

The temperature dependence of Q-switched performance of a Tm, Ho: YLF laser was investigated. Small-signal gains and output energies were measured at 193–246 K. A quasi-four-level nature strongly affected the laser performance even in this temperature range.

The generation of stable dual-wavelength pulses from an actively Q-switched Nd:YAG laser operating at 1064 and 1319 nm was demonstrated. Pulse energies of the dual-wavelength laser were extracted by two temporally separated stimulated-emission processes for a single pumping process, thereby avoiding line competition between the two laser transitions. Total energy of the order of 20 mJ was achieved for the two pulses, and the ratio of the pulse energies of the two lasers could be selected by adjusting the output couplings. The pulse-to-pulse fluctuations for the lasers operating at 1319 and 1064 nm were 4.7%–4.8% and 1.5%–2.6%, respectively, which were almost equivalent to those for a single emission line in our system. The experimentally observed laser performance agreed reasonably well with theoretical predictions.

We accomplished a balloon observation of the high-energy cosmic-ray electrons in 10-1000GeV to reveal the origin and the acceleration mechanism. The observation was carried out for 13 days at an average altitude of 35km by the Polar Patrol Balloon (PPB) around Antarctica in January 2004. The detector is an imaging calorimeter composed of scintillating-fiber belts and plastic scintillation counters sandwiched between lead plates. The geometrical factor is about 600cm^2sr, and the total thickness of lead absorber is 9 radiation lengths. The performance of the detector has been confirmed by a test flight at the Sanriku Balloon Center and by an accelerator beam test using the CERN-SPS (Super Proton Synchrotron at CERN). The new telemetry system using the Iridium satellite, the power system supplied by solar panels and the automatic flight level control operated successfully during the flight. We collected 5.7×10^3 events over 100GeV, and selected the electron candidates by a preliminary data analysis of the shower images. We report here an outline of both detector and observation, and the first result of the electron energy spectrum over 100GeV obtained by an electronic counter.

Rayleigh lidar temperature data collected at Gadanki (13.5°N, 79.2°E) during two campaign periods in 1999 and 2000 have been analyzed to study the planetary wave activities in the stratosphere and lower mesosphere. Attention has been given to the Rossby-gravity (RG) wave, fast Kelvin wave, and slow Kelvin wave with remarkable periodicity of 3.6, 6.5, and 16 days, respectively. The well-known Lomb–Scargle periodogram (L–S) analysis was performed on the temperature profile to extract the wave characteristics. The analysis indicated the dominance of these waves in the stratosphere and mesosphere. The results obtained are consistent with other measurements based on radar, rocketsonde or satellite.

An eye-safe airborne coherent Doppler lidar system has been developed at the National Institute of Information and Communications Technology (NICT). This system can also be used at ground level and ground-based experiments were made to evaluate the system performance at the NICT Wakkanai radio observatory. The obtained wind profiles were compared with those measured by radiosondes launched at the Wakkanai local meteorological observatory, and by a VHFR system installed by NICT near the Wakkanai airport. Although the volume measured by the coherent Doppler lidar system differed spatially and temporally from those by the radiosonde and the NICT VHF radar system, the wind profiles observed by the coherent Doppler lidar system agreed well with those observed by other instruments. The wind velocities obtained through the full correlation analysis of the VHF radar system were a little smaller than those from the coherent Doppler lidar system, which is consistent with previous statistical results for the VHF radar system. The ground-based results showed that the standard deviations of wind velocity estimates in the laser pulse accumulation seemed to approach a constant value under the real atmospheric conditions, and that the lower limit of the signal-to-noise ratio for the reliable estimate of the wind velocity decreases with the laser pulse accumulation. The ground-based experiments showed that the coherent Doppler lidar system is a reliable system for wind-related research.

We analyzed the time series data of dust vertical profiles, observed using polarization elastic lidar, from April 8 t h -21 s t , 2002, during the first intensive observation period of the Aeolian Dust Experiment on Climateimpact (ADEC), in Shapotou, Ninxia Province in China. We conducted the analysis with consideration to the upper atmospheric soundings and surface weather data. The results are summarized as follows. 1) A well-mixed dust layer dominated in the boundary layer sampled from around 11 a.m. until around 1 or 2 a.m. local time (Beijing time). Under well-mixed conditions, the mixed layers grew well with dry convections in the boundary layer, especially during the day and in the early evening. 2) Dry convections developed deeper during synoptic low-pressure conditions because of the systematic upward motions prevalent in the low-pressure systems. Vertical wind shear affected growth of the mixed layer as well, that is, weak vertical wind shear condition was favorable for the growth of the mixed layer. The deepest mixed layer was observed on April 13 t h at a thickness of about 6-km above ground, when the pressure was the lowest, the vertical wind shear was very weak, and the atmosphere was dry. The aspect ratios (horizontal/vertical scale ratios) of the convections decreased under low-pressure and weak-shear conditions. On the other hand, the aspect ratios of the convections increased dramatically under high-pressure and strong-shear conditions, because convection growth was suppressed by systematic down-drafts of the high-pressure system and by strong vertical wind shears.

We selected a reduced-pathogenicity mutant of Fusarium oxysporum f. sp. lycopersici, a tomato wilt pathogen, from the transformants generated by restriction enzyme-mediated integration (REMI) transformation. The gene tagged with the plasmid in the mutant was predicted to encode a protein of 321 amino acids and was designated FPD1. Homology search showed its partial similarity to a chloride conductance regulatory protein of Xenopus, suggesting that FPD1 is a transmembrane protein. Although the function of FPD1 has not been identified, it does participate in the pathogenicity of F. oxysporum f. sp. lycopersici because FPD1-deficient mutants reproduced the reduced pathogenicity on tomato.

We present a development and research of the 2-μm coherent lidar with a conductively-cooled laser-diode-pumped single-frequency Q-switched Tm,Ho:YLF pulse laser developed at the NICT.

We report on a design strategy for a Tm,Ho:YLF laser transmitter capable of 125 mJ pulse energy at 30 Hz. Using the results of simulations and experiments, total efficiencies were compared for two different configurations. One is the oscillator operating at 193 K, and the other is the master oscillator and power amplifier operating at 233 K. In the latter case, an extensive cooling system is not required, while the laser efficiency becomes lower. Numerical simulations were performed by using a simple rate equation model. In order to validate the results of simulations, the laser experiments were made with a conductively cooled, side-pumped Tm,Ho:YLF laser in the temperature range of 195-228 K. Based on these results, an optimum configuration to achieve the 125-mJ pulse energy are discussed.

We are developing a 2-micron Ho:YLF laser end-pumped by Tm:fiber laser. The oscillator has ring resonator of 3m length. The laser is operated at high repetition rate of 200-5000 Hz in room temperature. The oscillator and amplifier system showed outputs of about 9W in CW and more than 6W in Q-switched operation. This laser will be used for wind and CO 2 concentration measurements.

The Rayleigh lidar data collected on 119 nights from March 1998 to February 2000 were used to study the statistical characteristics of the low latitude mesospheric temperature inversion observed over Gadanki (13.5° N, 79.2° E), India. The occurrence frequency of the inversion showed semiannual variation with maxima in the equinoxes and minima in the summer and winter, which was quite different from that reported for the mid-latitudes. The peak of the inversion layer was found to be confined to the height range of 73 to 79 km with the maximum occurrence centered around 76 km, with a weak seasonal dependence that fits well to an annual cycle with a maximum in June and a minimum in December. The magnitude of the temperature deviation associated with the inversion was found to be as high as 32 K, with the most probable value occurring at about 20 K. Its seasonal dependence seems to follow an annual cycle with a maximum in April and a minimum in October. The observed characteristics of the inversion layer are compared with that of the mid-latitudes and discussed in light of the current understanding of the source mechanisms.Key words. Atmospheric composition and structure (pressure, density and temperature). Meterology and atmospheric dynamics (climatology)