Investigations of high-density urban boundary layer under summer prevailing wind conditions with Doppler LiDAR: A case study in Hong Kong

He, Yueyang; Ren, Chao; Mak, Hugo Wai Leung; Lin, Changqing; Wang, Zixuan; Fung, Jimmy Chi Hung; Li, Yuguo; Lau, Alexis Kai Hon; Ng, Edward

doi:10.1016/j.uclim.2021.100884

Cited by 29 publications

(8 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, LiDAR technologies are capable of capturing wind characteristics and profiles in complex terrain regions [ 39 ] and could also provide valuable information in research on urban ventilation, air pollution dispersion, sea breezes, heat island and flow disturbances caused by tall buildings due to urbanization [ 40 ]. Moreover, future research could employ the wind profiler radar to reveal and understand the wind characteristics of the urban boundary layer (UBL) under different circumstances [ 41 ].…”

Section: Discussionmentioning

confidence: 99%

Urbanization Effects on Surface Wind in the Guangdong–Hong Kong–Macao Greater Bay Area Using a Fan-Sector Method

Xia

Nie

Sun

et al. 2022

IJERPH

View full text Add to dashboard Cite

Surface wind directly affects human life, wind energy utilization, the atmospheric environment, and many other aspects. The Guangdong–Hong Kong–Macau Greater Bay Area (GBA) megalopolis is experiencing an accelerated progress of urbanization, which may result in the change in surface roughness and atmospheric characteristics. In this study, urbanization effects on surface wind speed (SWS) in the GBA megalopolis, particularly Zhuhai, is investigated by using long-term automatic meteorological measurements, ERA5 reanalysis, and nighttime light data. Results of the analysis show that the averaged SWS has decreased significantly at a rate of −0.53 m s−1 per decade over the past decades. With the help of observation-minus-reanalysis (OMR) method, which excludes the atmospheric circulation effects, we found that the decrease in SWS is mainly contributed by the increase in surface roughness, which may account for as much as 75.5% of the decrease. In other words, it is the rapid development of urbanization, rather than the change in large-scale circulation, that could be mainly responsible for the decrease over the GBA in the context of the increasing global SWS since 2010. In addition, a fan-sector method is established to quantitatively analyze the correspondences between urbanization and roughness changes. It is shown that the decrease in wind speed due to surface roughness change is significantly related to the increase in the nighttime light index (NLI) averaged over the 3 km upstream fan-sectors. Moreover, their correlation reaches to 0.36 (negative) when only accounting for the samples of NLI greater than 10. In general, the fan-sector method offers an additional option for assessing the urbanization effects on SWS.

show abstract

Section: Discussionmentioning

confidence: 99%

Urbanization Effects on Surface Wind in the Guangdong–Hong Kong–Macao Greater Bay Area Using a Fan-Sector Method

Xia

Nie

Sun

et al. 2022

IJERPH

View full text Add to dashboard Cite

show abstract

“…The tuning and setup of LiDAR units can be found in He et al. (2021). Each LiDAR can provide the zonal and meridional wind speed observations up to ∼3,000 m. The locations and corresponding land‐use types of three LiDAR units can be found in Figure 7d.…”

Section: Real Case Resultsmentioning

confidence: 99%

“…The Doppler LiDAR observational data measured at the Hong Kong University of Science and Technology Supersite (USTSS), Hok Tsui (HT), and King's Park (KP) are used to evaluate the performance of TKE-ACM2 (present study), ACM2, and Boulac PBL schemes. The tuning and setup of LiDAR units can be found in He et al (2021). Each LiDAR can provide the zonal and meridional wind speed observations up to ∼3,000 m. The locations and corresponding land-use types of three LiDAR units can be found in Figure 7d.…”

Section: Instantaneous Wind Speed Profilesmentioning

confidence: 99%

An Improved Non‐Local Planetary Boundary Layer Parameterization Scheme in Weather Forecasting and Research Model Based on a 1.5‐Order Turbulence Closure Model

Zhang,

Fung,

Wong

2024

JGR Atmospheres

View full text Add to dashboard Cite

Planetary boundary layer (PBL) modeling is a primary contributor to uncertainties in a numerical weather prediction (NWP) model due to difficulties in modeling the turbulent transport of surface fluxes. The Weather Research and Forecasting model (WRF) has provided many PBL schemes that may feature a non‐local transport component driven by large eddies or a one‐and‐half order turbulence closure model, but few of them possess the two features at once. In the present study, a turbulent kinetic energy (TKE)‐based eddy diffusivity/viscosity method is integrated into the non‐local Asymmetric Convective Model version 2 (ACM2) PBL scheme and implemented in WRF. The original first‐order eddy‐diffusivity term in ACM2 is discarded and an extra prognostic equation for TKE, which considers the tendency of TKE by buoyancy, wind shear, vertical transport, and dissipative processes, is supplied to calculate the diffusivity/viscosity. Non‐local transport is modeled the same as ACM2 using the transilient matrix method. Idealized tests using prescribed surface heat flux and roughness length are performed. TKE‐ACM2 displays advantages over the PBL scheme developed by Bougeault and Lacarrère (hereinafter referred to as Boulac) and ACM2 in the wind speeds (WS) profile because it better matches large‐eddy simulations results in the surface momentum flux. Real case simulations show that TKE‐ACM2 generally outperforms in the diurnal vertical profiles of WS under stable conditions. TKE‐ACM2 also produces a better alignment under moderately unstable conditions in the early nighttime at the urban LiDAR station. However, the model exhibits discrepancies more apparently under a more unstable condition during the winter daytime.

show abstract

“…Moreover, the PBLH can be associated with many interesting studies in the local context, including, but not limited to, urban climatic conditions, urban heat islands/heat waves, air pollution, etc. [67][68][69][70]. In the near future, we will conduct more work on these specific applications, like analyzing the relationship and mechanism between air pollution and the PBLH in the Jiangsu region.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Climatology of Planetary Boundary Layer Height over Jiangsu, China, Based on ERA5 Reanalysis Data

Li,

Dong,

Zhang

et al. 2023

Atmosphere

View full text Add to dashboard Cite

Based on the hourly ERA5 reanalysis dataset of the European Centre for Medium-Range Weather Forecasts (ECMWF) from 1 January 1979 to 31 December 2019, the climatology of the planetary boundary layer height (PBLH) in Jiangsu, China, is studied. The PBLH based on ERA5 is verified by using radiosonde data, and the results show that the PBLH based on ERA5 fits very well with the PBLH diagnosed by the radiosonde data. Overall, the daytime average PBLH is between 700 and 1200 m, which is higher in the north and lower in the south. It is between 100 and 400 m at night, and it is lower in the north and higher in the south. The PBLH exhibits complex spatiotemporal variation. In the daytime, the PBLH in inland areas is highest in spring, followed by fall and summer, and lowest in winter. At night, the seasonal variation in the PBLH is less obvious. The seasonal variation in the PBLH in coastal areas is higher in fall and winter and lower in spring and summer. The PBLH shows an obvious diurnal cycle, usually reaching its peak at 14:00 (LST) or 15:00 (LST). The diurnal cycle of the PBLH is significantly positively correlated with the near-surface temperature and wind speed and significantly negatively correlated with the relative humidity and lower tropospheric stability. Over these 41 years, the daytime PBLH has increased significantly in most areas. The increase in the PBLH can be attributed to the increase in near-surface temperature and the decrease in near-surface relative humidity and lower tropospheric stability.

show abstract

Investigations of high-density urban boundary layer under summer prevailing wind conditions with Doppler LiDAR: A case study in Hong Kong

Cited by 29 publications

References 57 publications

Urbanization Effects on Surface Wind in the Guangdong–Hong Kong–Macao Greater Bay Area Using a Fan-Sector Method

Urbanization Effects on Surface Wind in the Guangdong–Hong Kong–Macao Greater Bay Area Using a Fan-Sector Method

An Improved Non‐Local Planetary Boundary Layer Parameterization Scheme in Weather Forecasting and Research Model Based on a 1.5‐Order Turbulence Closure Model

Climatology of Planetary Boundary Layer Height over Jiangsu, China, Based on ERA5 Reanalysis Data

Contact Info

Product

Resources

About