Abstract Natural seeder‐feeder processes play an essential role in the formation and enhancement of precipitation. However, cloud‐seeding process from mixed‐phase clouds is still not well understood due to lack sufficient observations. (seeder clouds) lower‐lying liquid (feeder were observed on 19 occasions using ground‐based polarization lidar radiosonde measurements June 2018 2020 at a mid‐latitude plain observatory Wuhan (30.5°N, 114.4°E), China. Ice crystals originating seeder fell into...

This paper presents a two-axis AlScN-based water-immersible MEMS mirror fabricated in an 8-inch process. Compared with other studies, this device has larger optical aperture 10 mm diameter. The resonant frequencies of the are 1011 Hz air and 342 water. scanning angle reaches ±5° ±2° at water, respectively. cavitation phenomenon is observed when operating which leads to electrical failure. To address issue, reduced frequencies-246 152 water-is characterized, through bubbles can be effectively...

Multi‐response encryption materials with temperature control and time resolution have attracted widespread attention due to their unique response characteristics higher application security. The design development of photochromic crystalline multiple stimulus responses remain challenging. In this study, we report a pair responsive chiral ionic hydrogen bonded organic framework (iHOF) R/S‐iHOF‐19 controlled by both solvent through charge‐assisted synthesis. chromophore...

A new series of pH-responsive Gemini surfactants with 2-pyrrolidone head groups, N,N'-dialkyl-N,N'-di(ethyl-2-pyrrolidone)ethylenediamine (Di-C(n)P, where n = 6, 8 10, 12), were synthesized and characterized by (1)H NMR, (13)C ESI-MS, elemental analysis. The surface activity micellization behavior at acidic, neutral, basic conditions equilibrium tension fluorescence techniques. It was found that the Di-C(n)P depends on pH aqueous solutions due to protonation state surfactant molecules when...

A transient digitizer (Licel) connecting to a photomultiplier tube (PMT) can obtain lidar backscatter profiles in both photon count and analog signal. detect higher atmospheric regions by combining (gluing) simultaneous data via the slope coefficient. In this work, output of PMT has been measured with based on an intensity-stable light source. The value dynamic range profile have characterized. is determined only gain as it works linear fixed pulse height discrimination threshold. glued...

Abstract Midlevel cloud layers (2–7 km) pertinent to transported Asian dust were observed on 26 occasions from the polarization lidar measurements during period December 2012 2013 over Wuhan (30.5°N, 114.4°E), China. The events mainly occurred in winter. Cloud mostly detected (19 out of 26) top aloft layers. boundary between layer and appeared at altitudes 4–7 km. are classified into three categories: (1) category A (6 cases), supercooled liquid persistently existed without an evident sign...

Abstract. Knowledge of the convective boundary layer (CBL) and associated entrainment zone (EZ) is important for understanding land–atmosphere interactions assessing living conditions in biosphere. A tilted 532 nm polarization lidar (30∘ off zenith) has been used routine atmospheric measurements with 10 s time 6.5 m height resolution over Wuhan (30.5∘ N, 114.4∘ E). From lidar-retrieved aerosol backscatter, instantaneous (ABL) depths are obtained using logarithm gradient method Harr wavelet...

This paper reports a highly reliable piezoelectric Micro Electro Mechanical System (MEMS) Fast Steering Mirror (FSM) with large optical aperture (10 mm), which utilizes two-level-construction comprising mirror plate and actuator hidden beneath the plate, achieving high resonant frequency (⪆900 Hz) quasi-static scanning range (4 mrad). The leverage structure is adopted not only to amplify deflection angle, but also achieve fill factor (⪆50%). Moreover, compliant flexural structures are...

Abstract. The POLIPHON (polarization lidar photometer networking) method is a powerful pathway to retrieve the height profiles of dust-related particle mass and ice-nucleating (INP) concentrations. conversion factors fitted from sun observation data are major part computations, which can convert polarization-lidar-derived dust extinction coefficients into INP For central Chinese megacity Wuhan (30.5∘ N, 114.4∘ E), located at downstream area several thousands kilometers far away source...

A compact polarization Raman lidar has been designed and constructed for using it atmospheric correction measurements during satellite optical sensor calibration in areas with high altitude extremely low aerosol loading. The parameters of this lidar, such as laser wavelength, telescope diameter interference filter bandwidth, were simulated optimized the best observation performance. instrument weight, is small size, requires air cooling instead commonly used water-cooling laser. Thus,...

Abstract. Mid-level stratiform precipitations during the passage of warm fronts were detailedly observed on two occasions (light and moderate rain) by a 355 nm polarization lidar water vapor Raman lidar, both equipped with waterproof transparent roof windows. The hours-long precipitation streaks shown in signal (X) volume depolarization ratio (δv) reveal some ubiquitous features microphysical process precipitating hydrometeors. We find that for light-rain case reaches surface begins as...

Aerosol lidars play a vital role in the investigations of atmospheric pollution formation and meteorological processes. The intensity lidar return signals near range changes much faster compared with one far range, so extremely wide dynamic outputs from photomultiplier tube (PMT) are needed to avoid saturation range. Usually, obtain simultaneously, transient digitizer (Licel) is applied provide an analog detection chain for strong photon counting (PC) weak signals. However, near-range still...

This paper presents a 10mm piezoelectric MEMS fast steering mirror that integrates piezoresistive sensors. The device is fabricated using an 8-inch CMOS-compatible process, packaged into volume of 35×35×5 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , weighing 22 g, which meets the miniaturization and mass production requirements for free-space optical communication. FSM operates in double quasi-static scanning mode, with tilting...

Understory terrain is an important fundamental indicator for monitoring changes in forest ecosystems. However, in-depth analysis of the accuracy existing international open-source DEM products still lacking understory environments. The data produced by Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) carries advanced topographic LiDAR altimeter system (ATLAS) that contains elevation information ground surface as well features such vegetation above. It can reflect surface, including part...

This work presents a MEMS fast steering mirror fabricated by an 8-inch AlScN platform, with large optical aperture of up to 10 mm and high surface quality (RMS &lt; 20 nm, PV 120 nm), intended for free-space communication. The device comprises reflective plate, pillar four cantilever beams thin films. is prepared wafer-level eutectic bonding process. A reinforcement structure proposed increase the resonant frequency resistance deformation. mechanical performance, including frequency, step...

Abstract. Aerosol lidar networks can play an important role in revealing structural characteristics of the atmospheric boundary layer, urban heat island effect, and spatial distribution aerosols, especially relation to monitoring pollution megacities. To fulfill need numerical forecasting pollution, aerosol network is proposed by China Meteorological Administration which serves as part “MegaCity Experiment on Integrated Observation China” (MEMO). ensure a high standard data quality...