江淮地区夏季对流有效位能特征  

Characteristics of convective available potential energy in summer in the Yangtze-Huaihe region

作　　者：赵文川 杨可 吴振豪 杨元建 傅云飞[1] ZHAO Wenchuan;YANG Ke;WU Zhenghao;YANG Yuanjian;FU Yunfei(School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China;School of Atmospheric Physics,Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]中国科学技术大学地球和空间科学学院,安徽合肥230026 [2]南京信息工程大学大气物理学院,江苏南京210044

出　　处：《大气科学学报》2025年第2期328-339,共12页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金项目(42230612,42275140);第二次青藏高原综合科学考察研究项目(2019QZKK0104)。

摘　　要：利用2018—2022年夏季江淮地区IGRA探空资料和ERA5再分析资料,通过线性拟合方法实现了探空数据对ERA5再分析数据对流有效位能(convective available potential energy,CAPE)的校正,以此计算得到了江淮地区夏季逐日08时和20时(北京时,下同)校正的对流有效位能,并结合地形分布,分析了江淮地区CAPE的时空分布特征。结果表明,08时CAPE的概率密度分布曲线峰值约为1200 J/kg,20时可达1500 J/kg。江淮地区夏季CAPE空间分布呈现自东南向西北、河谷向山峰递增的特征;CAPE高值中心多出现在三山(大别山、黄山和九岭山)包夹的长江河谷地带,而低值中心一般出现在山峰地域。江淮地区夏季逐日CAPE季内变化范围较大,超过1400 J/kg;其日变化曲线谷值出现在05时,约为850 J/kg,峰值出现在15时,约为1200 J/kg。此外,江淮地区夏季的CAPE与地形高度为负相关,而与地形指数为正相关关系,低海拔的陡峭地区CAPE较强。This study investigates the spatiotemporal characteristics of convective available potential energy(CAPE)in the Yangtze-Huaihe region during summer(2018-2022)using IGRA sounding data and ERA5 reanalysis data.A linear regression method was applied to develop a correction formula for ERA5 CAPE based on IGRA sounding observations,yielding a corrected dataset(CAPE_COR)for 08:00 BST and 20:00 BST on a daily scale.Correlation analysis shows that CAPE_ERA5 and CAPE_IGRA exhibit relatively strong agreement,with correlation coefficients of 0.58 at 08:00 BST and 0.59 at 20:00 BST.The scatter plot indicates that data points are densely clustered along the diagonal,confirming the accuracy of the correction.After applying the adjustment,the correlation coefficients between CAPE_COR and CAPE_IGRA slightly decrease to 0.57 and 0.58,respectively,demonstrating the reliability of the correction formula and its improved representation of the actual convective environment.Spatially,summer CAPE_COR in the Yangtze-Huaihe region exhibits a distinct geographical pattern,increasing from southeast to northwest and from river valleys to mountain peaks.High CAPE_COR values are primarily concentrated in the Yangtze River valley,particularly in areas enclosed by three major mountain ranges,while lower values are observed over higher elevations.This distribution highlights a strong correlation between CAPE and topographic features,with higher CAPE_COR values more frequently occurring in the Yangtze River valley and weaker values over elevated terrains.Further analysis reveals that CAPE_COR at both 08:00 BST and 20:00 BST is negatively correlated with terrain height and positively correlated with the terrain index,suggesting that areas with lower elevations and steeper slopes exhibit stronger convective energy.These findings emphasize the influence of topography on local convective conditions,where low-altitude valleys with pronounced terrain gradients are more conducive to the accumulation of convective energy.Temporally,CAPE_COR in the Yangtz

关 键 词：江淮地区 大气不稳定度 地形指数 对流有效位能 

分 类 号：P426.63[天文地球—大气科学及气象学]