The performance of a coherent 2-µm differential absorption lidar (DIAL) for simultaneously measuring water vapor (H
O) and radial wind velocity was evaluated. For measuring H
O, a wavelength locking ...technique was applied to the H
O-DIAL system. The H
O-DIAL system was evaluated under summer daytime conditions in Tokyo, Japan. H
O-DIAL measurements were compared with measurements from radiosondes. The H
O-DIAL-derived volumetric humidity values agreed with the radiosonde-derived values over the range from 11 to 20 g/m
with a correlation coefficient of 0.81 and a root-mean-square difference of 1.46 g/m
. Comparisons between the H
O-DIAL and the in-situ surface meteorological sensors demonstrated the simultaneous measurement of H
O and radial wind velocity.
cuticular hydrocarbon (CHC) as a semiochemical for recognizing their nestmates. For socially parasitic ants, deceiving the CHC is an important survival strategy. Profiling and quantifying CHC is a ...potent approach to understanding such nestmate discrimination behavior. Thus, a highly efficient, stable, and reproducible extraction method for CHC is essential for this purpose. This paper describes a method for socially parasitic ants to disguise the host species' CHC profile under laboratory conditions, as well as the extraction and measurement of CHC from ants (from a previous study). First, the artificial isotopic substance is applied to the host worker; then, the socially parasitic ant disguises the host-like CHC profile against the above host worker. Next, the CHC is extracted and fractionated from a socially parasitic ant using hexane and silica gel. After concentrating the fractionated product, this product is then used for measurement by gas chromatographymass spectrometry (GC-MS). The CHC extraction protocol described in this paper may be used for various ant species.
The first space-based Doppler wind lidar (DWL) on board
the Aeolus satellite was launched by the European Space Agency (ESA) on 22 August 2018 to obtain global profiles of horizontal line-of-sight ...(HLOS)
wind speed. In this study, the Raleigh-clear and Mie-cloudy winds for
periods of baseline 2B02 (from 1 October to 18 December 2018) and 2B10 (from
28 June to 31 December 2019 and from 20 April to 8 October 2020) were
validated using 33 wind profilers (WPRs) installed all over Japan, two
ground-based coherent Doppler wind lidars (CDWLs), and 18 GPS radiosondes
(GPS-RSs). In particular, vertical and seasonal analyses were performed and
discussed using WPR data. During the baseline 2B02 period, a positive bias
was found to be in the ranges of 0.5 to 1.7 m s−1 for Rayleigh-clear
winds and 1.6 to 2.4 m s−1 for Mie-cloudy winds using the three
independent reference instruments. The statistical comparisons for the
baseline 2B10 period showed smaller biases, −0.8 to 0.5 m s−1 for the
Rayleigh-clear and −0.7 to 0.2 m s−1 for the Mie-cloudy winds. The
vertical analysis using WPR data showed that the systematic error was
slightly positive in all altitude ranges up to 11 km during the baseline
2B02 period. During the baseline 2B10 period, the systematic errors of
Rayleigh-clear and Mie-cloudy winds were improved in all altitude ranges up
to 11 km as compared with the baseline 2B02. Immediately after the launch of
Aeolus, both Rayleigh-clear and Mie-cloudy biases were small. Within the
baseline 2B02, the Rayleigh-clear and Mie-cloudy biases showed a positive
trend. For the baseline 2B10, the Rayleigh-clear wind bias was generally
negative for all months except August 2020, and Mie-cloudy wind bias
gradually fluctuated. Both Rayleigh-clear and Mie-cloudy biases did not show
a marked seasonal trend and approached zero towards September 2020. The
dependence of the Rayleigh-clear wind bias on the scattering ratio was
investigated, showing that there was no significant bias dependence on the
scattering ratio during the baseline 2B02 and 2B10 periods. Without the
estimated representativeness error associated with the comparisons using WPR observations, the Aeolus random error was determined to be 6.7 (5.1) and 6.4 (4.8) m s−1 for Rayleigh-clear (Mie-cloudy) winds during the baseline
2B02 and 2B10 periods, respectively. The main reason for the large Aeolus
random errors is the lower laser energy compared to the anticipated 80 mJ.
Additionally, the large representativeness error of the WPRs is probably
related to the larger Aeolus random error. Using the CDWLs, the Aeolus
random error estimates were in the range of 4.5 to 5.3 (2.9 to 3.2) and 4.8
to 5.2 (3.3 to 3.4) m s−1 for Rayleigh-clear (Mie-cloudy) winds during
the baseline 2B02 and 2B10 periods, respectively. By taking the GPS-RS
representativeness error into account, the Aeolus random error was
determined to be 4.0 (3.2) and 3.0 (2.9) m s−1 for Rayleigh-clear
(Mie-cloudy) winds during the baseline 2B02 and 2B10 periods, respectively.
Upper‐tropospheric clouds in the outflow layer of typhoons can affect the track of typhoons (tropical cyclones) through radiation effects. In this study, the microstructure of the outflow‐layer ...clouds of several typhoons was examined. Cloud radar observations of three typhoons around Japan revealed numerous protuberances in echoes along the base of the upper‐level clouds, which are referred to as mammatus‐like echoes. The horizontal and vertical scales of these mammatus‐like echoes were 0.5–3.0 and 0.3–1.5 km, respectively. Vertical observations revealed downward (upward) Doppler velocities in (between) the hanging echo regions. Upward and downward velocity maxima were estimated at 3 m s−1 around the mammatus‐like echoes. Neutral stratification developed in the dry layer beneath the cloud base in which the mammatus‐like echoes formed. These mammatus‐like structures may promote mixing along the cloud base that contributes to dissipation of the outflow‐layer clouds.
Plain Language Summary
Heating and cooling due to radiative effects associated with upper‐level clouds spreading from a typhoon have been reported to have an impact on the actual track of the typhoon. Therefore, it is important to clarify the processes of formation and dissipation of the upper‐level clouds of typhoons. However, observations of such clouds, which are formed from relatively small ice particles, are scarce and the process of their dissipation is not well understood. In this study, we used cloud radar, which can detect clouds formed of small ice particles, to observe the upper‐level clouds of three typhoons that approached Japan. At the base of the upper‐level clouds, we found many protuberance structures with 0.5–3.0 km width and 0.3–1.5 km depth. These protuberance structures were accompanied by relatively large vertical motions of approximately 3 m s−1. The temperature and water vapor distributions near the base of the upper‐level clouds of the studied typhoons were conducive to these vertical motions. The small‐scale protuberance structures might promote dissipation of upper‐level clouds along their base.
Key Points
Protuberances observed by cloud radar along the base of outflow‐layer clouds of typhoons are termed mammatus‐like echo structures
The mammatus‐like echo structures are associated with vertical motions with velocity of several meters per second
Mammatus‐like echoes occur in a layer with high potential for turbulence caused by sublimation of ice particles falling into a drier layer
Sea‐breeze front (SBF) can cause dramatic changes in weather and air quality near the coast. However, the observation and forecast of its three‐dimensional (3‐D) fine‐scale structures have been ...challenging. Using mesoscale‐to‐large eddy simulations (LES) models and high‐resolution lidar measurement over Sendai Airport, here we perform a successful simulation of the observed 3‐D structures of an SBF for the first time. We show that frontal structures are characterized by a series of lobes (spaced ~500 m apart) aligned along the raised sea‐breeze head, where the shear between sea breeze and alongshore ambient flow aloft is evident. Local strong updrafts occur both in the frontal lobes of marine cold air and in the prefrontal warm air ascending the wedge of windward lobes. Downdrafts form behind the lifted marine cold air and trap air pollutants. These fine‐scale structures and vertical motions are repeatedly strengthened by the short‐term disturbances of gravity currents that move onshore and collide with the SBF. They are also affected by buildings and determine the detailed variations of surface winds. We conclude that advanced observation and modeling systems can potentially improve the prediction of coastal weather and environment.
Plain Language Summary
When sea breeze comes, it does not come gently and often brings a sudden change in winds, temperature, and air quality. The so‐called sea‐breeze front has great influence on the environment in coastal areas around the world. This work presents a major progress to reveal its fine‐scale 3‐D structures using the state‐of‐art observations and numerical models. The dynamics and evolution of the frontal structures are further linked to the disturbances of gravity current and the effect of buildings near the coast. Some differences to the known concept of idealized sea‐breeze front are also identified. We believe that the findings have significant impacts on the research community of weather forecast, numerical modeling, and coastal environment studies.
Key Points
Lidar observations capture well the fine‐scale 3‐D structures and evolution of a typical sea‐breeze front
A novel local prediction system can reproduce frontal lobes/clefts and updrafts at high accuracy and resolution
Gravity current disturbances control the short‐term variations of frontal structures, while coastal buildings affect detailed features
Abstract
Rainfall velocity, raindrop size distribution (DSD), and vertical wind velocity were simultaneously observed with 2.05- and 1.54-
μ
m 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.
Polyrhachis lamellidens is a temporary social parasitic species. When a newly mated queen encounters a host worker, it opens its jaws and then mounts and rubs the body of the host worker, called ...rubbing behaviour. This behaviour is different from aggressive behaviour and is considered to be a preparatory action before invasion of the host colony. However, it is unclear what cues trigger rubbing behaviour. Therefore, in this study, we used glass beads that imitated the insect body surfaces and searched for triggers. Although P. lamellidens did not respond to the cuticular compounds only, cuticular compounds and chitin coatings on glass beads elicited responses that were similar to those towards live samples. The rubbing behaviour of P. lamellidens was elicited in response to a cuticle-like surface that mimicked a procuticle by combining the compounds with chitin. These results suggest that host recognition and nest-mate recognition are supported by different mechanisms. This article has an associated First Person interview with the first author of the paper.
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.
While most ant species establish a colony independently, some socially parasitic ants build the foundation of their colony by invading other ant (host) colonies and utilizing their labor forces. Many ...socially parasitic ants disguise their cuticular hydrocarbon (CHC) profile, which is also known as signature mixture for nestmate discrimination, when invading the host colony. Since the strategy of chemical disguise is widespread in socially parasitic ants, elucidating the mechanism of chemical disguise will promote knowledge on the evolutionary history of social parasitism. However, detailed knowledge is still lacking, as the relevant information has only originated from circumstantial evidence, which was obtained from ecological observations. In this study, we investigated the mechanism of chemical disguise in a new queen of a temporary socially parasitic spiny ant (
Polyrhachis lamellidens
) by measuring its CHC profile, performing a tracing assay with labeled substances, and analyzing gene expression levels. First, after rubbing behavior was observed against the host workers, the CHC profile in
P. lamellidens
shifted to pronounced peaks that closely resembling that of the host workers. We also observed a reduction in aggressive behaviors by the host ant against
P. lamellidens
after rubbing behavior was performed. In addition,
P. lamellidens
acquired artificially-applied labeling substances from host workers through their rubbing behaviors, while gene expression profiling showed the expression of CHC synthesis-related genes did not change during this behavior. These results suggest that
P. lamellidens
directly obtains host CHCs through rubbing behavior, and these host CHCs enables
P. lamellidens
to remain disguised during colony invasion.
During the Tokyo Metropolitan Area Convection Study for Extreme Weather Resilient Cities (TOMACS), many isolated convective storms developed in the southern Kanto Plain on August 17, 2012. The aim of ...this study was to clarify the dynamics leading to the convection initiation of one of them using different remote sensing instruments. Before the convection initiation, a southeasterly flow transported water vapor inland from Tokyo Bay and the well-mixed and a cumulus-cloud-topped convective boundary layer developed. A convergence line in the form of a sea breeze front (SBF) also moved inland from Tokyo Bay. A near-surface air parcel was lifted to its lifting condensation level (LCL) by an updraft in a convergence zone with a 3 km horizontal scale, which formed the west edge of the convergence line. The saturated air parcel at the LCL was then lifted to its level of free convection (LFC) by the updrafts associated with thermals below the cumulus cloud base. A Ku-band radar detected the first echo of hydrometeors about 6 minutes after the air parcel reached its LFC, then the convective cell developed rapidly. When an SBF arriving from Sagami Bay passed under the cell, the updraft over the nose of the SBF triggered a new precipitation cell, but no intensification of the preexisting cell was observed.
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