Impact of Lidar Data Assimilation on Analysis and Prediction of Low-level Wind Shears at Lanzhou Zhongchuan International Airport, China

2020 ◽  
Author(s):  
Lanqian Li ◽  
Aimei Shao
Keyword(s):  
Data Assimilation ◽  
Wind Shear ◽  
Weather Conditions ◽  
Experimental Results ◽  
Small Scale ◽  
Lidar Data ◽  
Low Level ◽  
International Airport ◽  
Rainy Weather ◽  
Lidar Observations

<p>Low-level wind shear could occur not only in rainy weather conditions but also in non-rainy weather conditions, which is dangerous to aircraft safety for its rapid changes in wind direction or velocity. Recently, dry wind shear occurred in non-rainy condition has drawn more and more attention. Rain-detecting Doppler radar has no capabilities in detecting dry wind shear occurred in non-rainy condition, while Doppler Lidar observations with higher spatial and temporal resolution provide valuable information for dry wind shear. For this, considering dry wind shear cases reported by pilots at Lanzhou Zhongchuan International Airport as study object, lidar observations (radial velocities) were assimilated along with surface data to improve the prediction skill of dry wind shear events.</p><p>All experiments were conducted with Weather Research and Forecasting (WRF) model and its three-dimensional variational (3D-VAR) system. Three-nested domains were employed with 1-km horizontal resolution in the innermost domain. The model was derived by the NCEP FNL data. Lidar data was processed and only assimilated in the innermost domain. Experimental results show that the low-level wind shear can not be found in the experimental results without lidar data assimilation, while lidar data assimilation experiment successfully represented wind shear small-scale characteristics and simulated radial wind pattern was close to lidar observation. In addition, assimilation cycles with short time intervals effectively improved simulation accuracy of wind shear events.</p>

scholarly journals Impact of Lidar Data Assimilation on Low-Level Wind Shear Simulation at Lanzhou Zhongchuan International Airport, China: A Case Study

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1342
Author(s):  
Lanqian Li ◽  
Ningjing Xie ◽  
Longyan Fu ◽  
Kaijun Zhang ◽  
Aimei Shao ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Wind Shear ◽  
Three Dimensional ◽  
Wrf Model ◽  
Lidar Data ◽  
Positive Role ◽  
Low Level ◽  
Wind Lidar ◽  
The Impact ◽  
Doppler Wind Lidar

Doppler wind lidar has played an important role in alerting low-level wind shear (LLW). However, these high-resolution observations are underused in the model-based analysis and forecasting of LLW. In this regard, we employed the Weather Research and Forecasting (WRF) model and its three-dimensional variational (3D-VAR) system to investigate the impact of lidar data assimilation (DA) on LLW simulations. Eight experiments (including six assimilation experiments) were designed for an LLW process as reported by pilots, in which different assimilation intervals, assimilation timespans, and model vertical resolutions were examined. Verified against observations from Doppler wind lidar and an automated weather observing system (AWOS), the introduction of lidar data is helpful for describing the LLW event, which can represent the temporal and spatial features of LLW, whereas experiments without lidar DA have no ability to capture LLW. While lidar DA has an obviously positive role in simulating LLW in the 10–20 min after the assimilation time, this advantage cannot be maintained over a longer time. Therefore, a smaller assimilation interval is favorable for improving the simulated effect of LLW. In addition, increasing the vertical resolution does not evidently improve the experimental results, either with or without assimilation.

scholarly journals Low-Level Wind Shear Identification along the Glide Path at BCIA by the Pulsed Coherent Doppler Lidar

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 50
Author(s):  
Hongwei Zhang ◽  
Xiaoying Liu ◽  
Qichao Wang ◽  
Jianjun Zhang ◽  
Zhiqiang He ◽  
...  
Keyword(s):  
Wind Shear ◽  
Vertical Direction ◽  
Small Scale ◽  
Observation Data ◽  
Doppler Lidar ◽  
Low Level ◽  
Glide Path ◽  
Coherent Doppler Lidar ◽  
Scanning Strategies ◽  
Meteorological Phenomenon

Low-level wind shear is usually to be a rapidly changing meteorological phenomenon that cannot be ignored in aviation security service by affecting the air speed of landing and take-off aircrafts. The lidar team in Ocean University of China (OUC) carried out the long term particular researches on the low-level wind shear identification and regional wind shear inducement search at Beijing Capital International Airport (BCIA) from 2015 to 2020 by operating several pulsed coherent Doppler lidar (PCDL) systems. On account of the improved glide path scanning strategy and virtual multiple wind anemometers based on the rang height indicator (RHI) modes, the small-scale meteorological phenomenon along the glide path and/or runway center line direction can be captured. In this paper, the device configuration, scanning strategies, and results of the observation data are proposed. The algorithms to identify the low-level wind shear based on the reconstructed headwind profiles data have been tested and proved based on the lidar data obtained from December 2018 to January 2019. High spatial resolution observation data at vertical direction are utilized to study the regional wind shear inducement at the 36L end of BCIA under strong northwest wind conditions.

scholarly journals Low-Level Wind Shear Characteristics and Lidar-Based Alerting at Lanzhou Zhongchuan International Airport, China

2020 ◽  
Vol 34 (3) ◽  
pp. 633-645 ◽  
Author(s):  
Lanqian Li ◽  
Aimei Shao ◽  
Kaijun Zhang ◽  
Nan Ding ◽  
Pak-Wai Chan
Keyword(s):  
Wind Shear ◽  
Low Level ◽  
International Airport ◽  
Shear Characteristics

scholarly journals Predicting Low-Level Wind Shear Using 200-m-Resolution NWP at the Hong Kong International Airport

2020 ◽  
Vol 59 (2) ◽  
pp. 193-206 ◽  
Author(s):  
Kai-Kwong Hon
Keyword(s):  
Hong Kong ◽  
Wind Shear ◽  
Weather Prediction ◽  
Model Performance ◽  
Characteristic Analysis ◽  
Relative Operating Characteristic ◽  
Low Level ◽  
International Airport ◽  
Wind Shears ◽  
Hong Kong International Airport

Abstract“Low-level wind shear” is a known aviation safety hazard and refers to a sustained change in head wind encountered by an aircraft during takeoff or landing. Because of their small spatiotemporal scales and high variability, automatic alerting of wind shears at airports around the world is almost exclusively detection based (using remote sensing equipment). Numerical modeling studies so far mainly cover individual cases and lack systematic validation. This paper presents the first statistical evaluation of numerical weather prediction (NWP) model performance in predicting low-level wind shear at a major international airport over a 2-yr continuous period. The 200-m-resolution Aviation Model (AVM) of the Hong Kong Observatory is used to generate runway-specific wind shear forecasts at 1-min output intervals for the Hong Kong International Airport (HKIA), known for its susceptibility to wind shear occurrence. The AVM forecasts are then validated against over 800 actual reports of wind shear by aircraft pilots over the two major arrival runway corridors, 07LA and 25RA, at HKIA between 2014 and 2015 using a verification scheme with the same level of spatiotemporal stringency as operational alerting systems at HKIA. With “relative operating characteristic” analysis, positive skill is consistently observed across both runway corridors throughout the study period and across all considered forecast lead times out to 6 h ahead. This study serves to establish and document the current capability of fine-resolution NWP in predicting the phenomenon of low-level wind shear for aviation weather applications.

scholarly journals Overview of Low-Level Wind Shear Characteristics over Chinese Mainland

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 628
Author(s):  
Caiyan Lin ◽  
Kaijun Zhang ◽  
Xintao Chen ◽  
Sheng Liang ◽  
Junjie Wu ◽  
...  
Keyword(s):  
Wind Shear ◽  
Weather Conditions ◽  
Chinese Mainland ◽  
Steady Increase ◽  
Low Level ◽  
Air Traffic Controllers ◽  
Shear Characteristics ◽  
Strong Winds ◽  
Almost All ◽  
The Impact

The characteristics of low-level wind shear (LLWS) over the Chinese mainland were investigated using reports from pilots, air traffic controllers and the number of arriving/departing flights from 2016 to 2020. A preliminary analysis of the impact of the flights on the LLWS reports was carried out, and the cause of LLWS was also investigated. LLWS reports from most airports indicate that LLWS is most likely to occur within 600 m AGL with a higher density below 300 m, but with some exceptions, as wind shear is reported at higher altitudes at some airports. Airports with a high frequency of LLWS reports are almost all located in or around regions with complex topography and in regions with prevailing weather conditions favorable to LLWS. The variation in overall LLWS reports displays a steady increase from 2016 to 2019 and a decrease from 2019 to 2020, consistent with the trend in the number of flights, but with no evidently similar trends for individual airports. Seasonal variations in LLWS reports are observed and demonstrate no notable impact caused by the number of flights, implying that the main cause is the monthly variation of weather conditions. Diurnal variation is also evident and largely associated with the variation in number of flights during the busy period in addition to weather conditions, such as common strong winds, in the afternoon.

scholarly journals Airport low-level wind shear lidar observation at beijing capital international airport

2018 ◽  
Vol 176 ◽  
pp. 06013
Author(s):  
Hongwei Zhang ◽  
Songhua Wu ◽  
Qichao Wang ◽  
Bingyi Liu ◽  
Xiaochun Zhai
Keyword(s):  
Wind Shear ◽  
Doppler Lidar ◽  
Low Level ◽  
Lidar Observation ◽  
International Airport ◽  
Glide Path ◽  
Coherent Doppler Lidar

Ocean University of China lidar team operated a pulse coherent Doppler lidar (PCDL) for the low level wind shear monitoring at the Beijing Capital International Airport (BCIA) in 2015. The experiment configuration, observation modes is presented. A case study shows that the low level wind shear events at the southern end of 18R/36L runway were mainly caused by the trees and buildings along the glide path under strong northwest wind conditions.

scholarly journals Airport low-level wind shear lidar observation at Beijing Capital International Airport

2019 ◽  
Vol 96 ◽  
pp. 113-122 ◽  
Author(s):  
Hongwei Zhang ◽  
Songhua Wu ◽  
Qichao Wang ◽  
Bingyi Liu ◽  
Bin Yin ◽  
...  
Keyword(s):  
Wind Shear ◽  
Low Level ◽  
Lidar Observation ◽  
International Airport
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