Hong Kong 200m data product
Reanalyses serve a wide range of purposes, ranging from R&D in climate and weather studies, to smart city planning, renewable energy management and important decision making. There are different choices of global reanalysis data available to the public, but they are mostly in 0.25° or 1° resolution. Therefore, it is hard to apply them in Hong Kong, of which the total area is smaller than a 1°x1° cell on Earth. To meet the demand for fine resolution weather data in different sectors, we are now releasing a 200m resolution reanalysis dataset specifically for Hong Kong.
With ultra-fine resolution simulations made feasible in CPAS, this data product is created by regional simulation with 200m resolution in Hong Kong using CPAS. It covers a two-year simulation period (from 1st July 2019 to 30th June 2021), providing simulated wind in 10-minute intervals, while other variables (e.g. temperature, accumulated rain) are available hourly. As terrain complexity and spatial heterogeneity of land use are retained in the 200m resolution grid, small scale weather features that are largely influenced by the land surface, including the wind sheltering effect from mountains (Figure 1), terrain and land use effect on temperature (Figure 2), and orographic precipitation (Figure 3), can be resolved and simulated nicely in the data product.
As a result, the accuracy of this data product is found to be higher when compared to other publicly available dataset. The impact of extreme weather scenarios to Hong Kong, such as extreme temperatures and tropical cyclones, can also be simulated in the data product with better accuracy.
Figure 1. Strong northerlies sheltered by Lion Rock in the urban regions in Kowloon.
Figure 2. The 2-meter temperature is largely affected by terrain and land use.
Figure 3. The Orographic effect caused a higher amount of precipitation in Tai Mo Shan, Ma On Shan, and Lantau Island.