scholarly journals Cloud Seeding Evidenced by Coherent Doppler Wind Lidar

2021 ◽  
Vol 13 (19) ◽  
pp. 3815
Author(s):  
Jinlong Yuan ◽  
Kenan Wu ◽  
Tianwen Wei ◽  
Lu Wang ◽  
Zhifeng Shu ◽  
...  
Keyword(s):  
Layer Structure ◽  
Microwave Radiometer ◽  
Precipitation Process ◽  
Cloud Seeding ◽  
Reflectivity Spectrum ◽  
Spectrum Width ◽  
Seeding Effect ◽  
Wind Lidar ◽  
Seeding Effects ◽  
Doppler Wind Lidar

Evaluation of the cloud seeding effect is a challenge due to lack of directly physical observational evidence. In this study, an approach for directly observing the cloud seeding effect is proposed using a 1548 nm coherent Doppler wind lidar (CDWL). Normalized skewness was employed to identify the components of the reflectivity spectrum. The spectrum detection capability of a CDWL was verified by a 24.23-GHz Micro Rain Radar (MRR) in Hefei, China (117°15′ E, 31°50′ N), and different types of lidar spectra were detected and separated, including aerosol, turbulence, cloud droplet, and precipitation. Spectrum analysis was applied as a field experiment performed in Inner Mongolia, China (112°39′ E, 42°21′ N ) to support the cloud seeding operation for the 70th anniversary of China’s national day. The CDWL can monitor the cloud motion and provide windshear and turbulence information ensuring operation safety. The cloud-precipitation process is detected by the CDWL, microwave radiometer (MWR) and Advanced Geosynchronous Radiation Imager (AGRI) in FY4A satellites. In particular, the spectrum width and skewness of seeded cloud show a two-layer structure, which reflects cloud component changes, and it is possibly related to cloud seeding effects. Multi-component spectra are separated into four clusters, which are well distinguished by spectrum width and vertical velocity. In general, our findings provide new evidence that the reflectivity spectrum of CDWL has potential for assessing cloud seeding effects.

scholarly journals Validation of an Airborne Doppler Wind Lidar in Tropical Cyclones

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4288 ◽  
Author(s):  
Lisa R. Bucci ◽  
Christopher O’Handley ◽  
G. David Emmitt ◽  
Jun A. Zhang ◽  
Kelly Ryan ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Doppler Radar ◽  
Weather Prediction ◽  
Microwave Radiometer ◽  
Measurement Procedure ◽  
3 Dimensional ◽  
Wind Lidar ◽  
Mapping Techniques ◽  
Observation Space ◽  
Doppler Wind Lidar

This study presents wind observations from an airborne Doppler Wind Lidar (ADWL) in 2016 tropical cyclones (TC). A description of ADWL measurement collection and quality control methods is introduced for the use in a TC environment. Validation against different instrumentation on-board the National Oceanographic and Atmospheric Administration’s WP-3D aircraft shows good agreement of the retrieved ADWL measured wind speed and direction. Measurements taken from instruments such as the global positioning system dropsonde, flight-level wind probe, tail Doppler radar, and Stepped Frequency Microwave Radiometer are compared to ADWL observations by creating paired datasets. These paired observations represent independent measurements of the same observation space through a variety of mapping techniques that account for differences in measurement procedure. Despite high correlation values, outliers are identified and discussed in detail. The errors between paired observations appear to be caused by differences in the ability to capture various length scales, which directly relate to certain regions in a TC regime. In validating these datasets and providing evidence that shows the mitigation of gaps in 3-dimensional wind representation, the unique wind observations collected via ADWL have significant potential to impact numerical weather prediction of TCs.

scholarly journals Turbulence Detection in the Atmospheric Boundary Layer using Coherent Doppler Wind Lidar and Microwave Radiometer

2021 ◽  
Author(s):  
Pu Jiang ◽  
Jinlong Yuan ◽  
Kenan Wu ◽  
Lu Wang ◽  
Haiyun Xia
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Spatial Resolution ◽  
Microwave Radiometer ◽  
Structure Constant ◽  
New Method ◽  
Index Structure ◽  
Wind Lidar ◽  
Temporal And Spatial ◽  
Doppler Wind Lidar

Abstract. The refractive index structure constant (Cn2) is a key parameter in describing the influence of turbulence on laser transmission in the atmosphere. A new method for continuous Cn2 profiling with both high temporal and spatial resolution is proposed and demonstrated. Under the assumption of the Kolmogorov “2/3 law”, the Cn2 profile can be calculated by using the wind field and turbulent kinetic energy dissipation rate (TKEDR) measured by coherent Doppler wind lidar (CDWL) and other meteorological parameters derived from microwave radiometer (MWR). In the horizontal experiment, a comparison between the results from our new method and measurements made by a large aperture scintillometer (LAS) is conducted. Except for the period of stratification stabilizing, the correlation coefficient between them in the six-day observation is 0.8389, the mean error and standard deviation is 1.09 × 10−15 m−2/3 and 2.14 × 10−15 m−2/3, respectively. In the vertical direction, the continuous observation results of Cn2 and other turbulence parameter profiles in the atmospheric boundary layer (ABL) are retrieved. More details of the atmospheric turbulence can be found in the ABL owe to the high temporal and spatial resolution of MWR and CDWL (spatial resolution of 26 m, temporal resolution of 147 s).

Analysis of physicochemical characteristics in the atmospheric boundary layer over the North Plain China based on large tethered balloon and Doppler wind lidar

2020 ◽  
Author(s):  
Haijiong Sun ◽  
Yu Shi ◽  
Fei Hu ◽  
Zhe Zhang ◽  
Weichen Ding
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Vertical Profile ◽  
Layer Structure ◽  
Physicochemical Characteristics ◽  
Transport Processes ◽  
Observation Data ◽  
Tethered Balloon ◽  
Wind Lidar ◽  
Doppler Wind Lidar

<p>Physicochemical characteristics of the atmospheric boundary layer over North Plain China during the comprehensive observation experiment from 10 to 21 December 2018 were investigated in this paper. The observation data are obtained from the large tethered balloon, Doppler wind lidar, ground-level instruments. The maximum concentration of PM<sub>2.5</sub> exceeded 200 µg m-3, and the ratio value of PM<sub>2.5</sub>/PM<sub>10</sub> was basically around 0.4 (maximum has reached approximately 0.8) during the whole observation period, indicating that explosive growth of fine ode dominant aerosols during the winter heating season. The peak solar irradiance was slightly larger on the clean day, compared with the value during the pollution process. The correlation coefficient between the concentration of PM<sub>2.5</sub> and CO was highest (0.725) among the gas pollutants, and the relationship between O<sub>3</sub> and PM<sub>2.5</sub> was basically negative correlated, not simple linear relationship. Three distinctly different vertical profile types of the PM<sub>2.5</sub> were categorized according to the vertical changes based on the total 33 vertical profiles obtained by the tethered balloon. Type 1 was mainly observed in the daytime, accounted for nearly 51.5%, the PM<sub>2.5</sub> concentration decreased nearly linearly as a function of height below approximate 600 m; Type 2 shows a sharp decreasing trend from the ground to about 200 m; Type 3 shows multi-layer structure of pollutants, some pollutants suspended aloft in upper air. The vertical profile of PM<sub>2.5</sub> was closely related to the atmospheric vertical structure such as the wind, temperature and turbulent kinetic energy, caused by the diurnal variation of the boundary layer. Small wind layer and the weak turbulence activities contributed to the accumulation of pollutants. Vertical patterns of the concentration of PM<sub>2.5</sub> were also greatly affected by the local ground emission sources and regional transport processes.</p>

Eye-safe, single-frequency pulsed all-fiber laser for Doppler wind lidar

2011 ◽  
Vol 9 (9) ◽  
pp. 090604-90607 ◽  
Author(s):  
刘源 Yuan Liu ◽  
刘继桥 Jiqiao Liu ◽  
陈卫标 Weibiao Chen
Keyword(s):  
Fiber Laser ◽  
Single Frequency ◽  
Wind Lidar ◽  
Doppler Wind Lidar

scholarly journals Dust Transport Across the Atlantic Studied by Airborne Doppler Wind Lidar During the Saltrace Experiment in 2013

2016 ◽  
Vol 119 ◽  
pp. 18008
Author(s):  
Fernando Chouza ◽  
Oliver Reitebuch ◽  
Stephan Rahm ◽  
Bernadett Weinzierl
Keyword(s):  
Dust Transport ◽  
Wind Lidar ◽  
Doppler Wind Lidar

scholarly journals Integrated System for Atmospheric Boundary Layer Height Estimation (ISABLE) using a ceilometer and microwave radiometer

2020 ◽  
Vol 13 (12) ◽  
pp. 6965-6987
Author(s):  
Jae-Sik Min ◽  
Moon-Soo Park ◽  
Jung-Hoon Chae ◽  
Minsoo Kang
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Layer Structure ◽  
Microwave Radiometer ◽  
Accurate Determination ◽  
Integrated System ◽  
Lapse Rate ◽  
High Temporal Resolution ◽  
Near Surface ◽  
Boundary Layer Structure

Abstract. Accurate boundary layer structure and height are critical in the analysis of the features of air pollutants and local circulation. Although surface-based remote sensing instruments provide a high temporal resolution of the boundary layer structure, there are numerous uncertainties in terms of the accurate determination of the atmospheric boundary layer heights (ABLHs). In this study, an algorithm for an integrated system for ABLH estimation (ISABLE) was developed and applied to the vertical profile data obtained using a ceilometer and a microwave radiometer in Seoul city, Korea. A maximum of 19 ABLHs were estimated via the conventional time-variance, gradient, wavelet, and clustering methods using the backscatter coefficient from the ceilometer. Meanwhile, several stable boundary layer heights were extracted through near-surface inversion and environmental lapse rate methods using the potential temperature from the microwave radiometer. The ISABLE algorithm can find an optimal ABLH from post-processing, such as k-means clustering and density-based spatial clustering of applications with noise (DBSCAN) techniques. It was found that the ABLH determined using ISABLE exhibited more significant correlation coefficients and smaller mean bias and root mean square error between the radiosonde-derived ABLHs than those obtained using the most conventional methods. Clear skies exhibited higher daytime ABLH than cloudy skies, and the daily maximum ABLH was recorded in summer because of the more intense radiation. The ABLHs estimated by ISABLE are expected to contribute to the parameterization of vertical diffusion in the atmospheric boundary layer.

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