Developing a Vertical Wind Profile Dataset to Adapt to Extreme Hot Weather Events with Multi-location LiDAR Observations and Multi-scale Modeling (14600524) (1 Jan 25 - 30 Jun 27)
• Researchers: HE Yueyang, Francis TAM
• Funding Amount: HK$793,360
• Funding source: Research Grants Council - General Research Fund

The increasing frequency and severity of Extreme Hot Weather Events (EHWEs) pose substantial threats to the thermal comfort and well-being of urban residents. Wind, which is essential to alleviate urban overheating, plays a vital role in addressing heat-related challenges. As Hong Kong is confronting rising risks of heat-related (social) problems, a profound understanding of wind characteristics in EHWEs is needed more than ever.

The Planning Department has developed two datasets of vertical wind profiles to furnish sitespecific wind availability information for ventilation assessments. However, since extreme heat has been proven to exert significant influences on wind's magnitudes, profile shapes, and movement patterns, the existing datasets, which were primarily designed to accommodate normal, long-term-averaged weather conditions, may fall short of adequately characterizing vertical wind profiles in EHWEs.

This project aims to better describe vertical wind profiles in EHWEs by integrating a cuttingedge, ground-based Light Detection and Ranging (LiDAR) equipment network with mesoscale Numerical Weather Prediction (NWP) models. The LiDAR technique provides high-resolution and stable observations of vertical wind profiles, while NWP modeling is the only wholedomain process-based tool capable of projecting the evolution of urban boundary layer flow behaviors in response to global warming trends. The project has four objectives:

1. Using long-term multi-location LiDAR observations as a benchmark, characterize diurnal variations of vertical profiles of wind field structure in EHWEs and evaluate existing normal-condition vertical wind profile datasets.
2. Based on the LiDAR wind profiles in Objective 1, characterize the performance of NWP models in EHWEs and develop a dataset of 24-hour vertical wind profiles in current and future EHWEs in Hong Kong.
3. Using the NWP wind profile dataset in Objective 2, demonstrate the influences of current and future EHWEs on ventilation conditions in high-rise urban areas, using the ventilation assessment results in Hong Kong's typical public rental housing units as an example.
4. Based on the assessment results in Objective 3, recommend whether it is necessary to: introduce a new vertical wind profile dataset for EHWEs; establish a mechanism to monitor and reevaluate this dataset in future; update existing ventilation assessment guidance; and explore ventilation design strategies for EHWEs adaptation.

Obtaining a more accurate understanding/dataset of vertical wind profiles under "new normal" weather conditions is crucial. Such data serves as a benchmark for monitoring/modeling works of urban wind environment and evaluations of urban policies in creating a healthier and more resilient living environment in future climate change