大气科学2025，Vol.49Issue(2)：587-602,16.DOI:10.3878/j.issn.1006-9895.2401.23072
利用地面格点Nudging改进华南前汛期暖区强降水的数值预报
Using Surface-Grid Nudging to Improve Numerical Prediction of Warm-Sector Heavy Rainfall Over South China during Pre-summer Rainy Season
摘要
Abstract
Significant uncertainties exist in the ability of numerical models to accurately predict heavy rainfall events during the pre-summer rainy season in southern China's warm sector.A notable instance occurred during May 29-30,2020,when heavy rain struck Guangdong Province's coastline,but all operational numerical models at the time failed to predict it.Consequently,eight experiments were conducted to assess the influence of incorporating surface-intensive observations into simulations through a technique known as nudging.The study found that the control experiment(EXP1),which nudged all surface meteorological elements,successfully replicated the development of linear convection and the spatial and temporal evolution of heavy precipitation along the Guangdong coastline.Sensitivity experiments highlighted that nudging surface water vapor was crucial for convection initiation.This was primarily attributed to a swift increase in relative humidity from 80%to near saturation(99%)within 3 hours at low levels,accompanied by a marked reduction in convective inhibition(CIN),lifting condensation level(LCL),and level of free convection(LFC).Nudging surface temperature enhanced thermal buoyancy by amplifying potential temperature perturbations,thereby influencing convection initiation and organization.Without nudging the surface temperature,convection occurred later and was less organized.Nudging surface wind helps correct the near-surface southwesterly wind direction,bringing convection evolution and rainfall into better alignment with observations.Six additional experiments examined the effect of the nudging duration on simulations.The results suggest that nudging all surface meteorological elements for 6 hours produced results similar to the control run,effectively modeling heavy rainfall along the coastline.Although water vapor surged rapidly within the first 3 hours,maintaining it for another 3 hours facilitated rapid convection development.Thus,incorporating surface-intensive observations through nudging during the initial 6 hours of model integration can enhance the numerical prediction of southern China's warm sector.关键词
地面格点Nudging/华南前汛期/暖区强降水/数值预报Key words
Surface-grid nudging/Pre-summer rainy season/Warm-sector heavy rainfall/Numerical weather prediction分类
天文与地球科学引用本文复制引用
郑宇豪,尹金方,许先煌,李丰..利用地面格点Nudging改进华南前汛期暖区强降水的数值预报[J].大气科学,2025,49(2):587-602,16.基金项目
国家自然科学基金项目42075083,国家重点研发计划项目2022YFC3003903,中国气象科学研究院发展基金项目2023KJ047 Funded by National Natural Science Foundation of China(Grant 42075083),National Key R&D Program of China(Grant 2022YFC3003903),S&T Development Fund of Chinese Academy of Meteorological Sciences(Grant 2023KJ047) （Grant 42075083）
