A Multi-Resolution Model Evaluation of Pre-Flood Season Precipitation and Low-Level Flow Field Forecasts over the Guangdong-Hong Kong-Macao Region
CAO Yuran
WANG Donghai
Abstract：Based on observations from national meteorological and radiosonde stations,this study comprehensively evaluates the forecast performance of precipitation and low-level flow field over the Guangdong-Hong Kong-Macao region during the pre-flood season(April to June)from 2014 to 2018 using regional numerical weather prediction models with 9 km and 3 km horizontal resolutions.Traditional precipitation scoring methods and neighborhood technique were employed,along with various statistical indicators,to assess the differences in forecast skills between the models with different resolutions,focusing on both temporal and spatial variability.The study also analyzed the applicability of different resolutions and explored the relationship between the forecast skills for precipitation and low-level flow field,providing valuable insights for optimizing mesoscale models in future regional forecasts.The results show that:(1)Both the 9 km and 3 km resolution models exhibit relatively stable forecast performance for precipitation and low-level flow fields prior to the onset of the South China Sea summer monsoon.Both models show diurnal variations in forecasting capabilities,with improved accuracy during the 08:00 LST to 12:00 LST period,while their performance during the afternoon and night,which involve more complex physical processes,is comparatively inadequate.(2)The 9 km resolution model tends to overestimate precipitation amounts,whereas the 3 km model displays smaller temporal and spatial biases in overall forecasting,demonstrating more stable forecast skills,particularly with higher accuracy for light,moderate,and heavy rainfall events.The 3 km resolution model provides more precise predictions for precipitation following the monsoon onset and during the afternoon,with reduced forecast errors in complex terrains such as the Pearl River Delta and the northern mountainous regions of Guangdong.(3)Similarly,the 3 km resolution model excels in simulating low-level flow fields,particularly in near-surface temperature and specific humidity simulations,effectively capturing their variations during the afternoon.This model also demonstrates greater precision in simulating near-surface temperature and humidity over complex terrain areas.
Keywords：numerical modelpre-flood seasonmodel evaluationneighborhood methodGuangdong-Hong Kong-Macao Region
Publication Date：2025-10-25
Online Publishing Date：2025-11-25(First online date of this platform, not the publication date of the document)
Pages：17( 728-744 )