黄淮地区夏秋节气降水的时空演变与集中特征响应OA

Based on daily precipitation records from 177 national meteorological stations in the Huang-Huai re-gion from 1961 to 2024,this study systematically examines the spatiotemporal evolution and interrelationships of precipitation amount,precipitation concentration degree(PCD),and precipitation concentration period(PCP)across 12 summer and autumn solar terms.The main findings are as follows:1)From 1961 to 2024,the regional mean annual precipitation was 620.9 mm,exhibiting a weak upward trend(1.43 mm·(10 a)-1).The multiyear mean PCD was 0.41,indicating increasingly concentrated precipitation(0.004(10 a)-1).The PCP mainly oc-curred during the Minor Heat solar term and showed a tendency toward earlier timing(-0.84°·(10 a)-1).From 1961 to 1992,precipitation,PCD,and PCP all decreased,whereas from 1993 to 2024,precipitation and PCD increased and PCP was delayed.This interdecadal shift may be linked to changes in intensity of the East Asi-an summer monsoon and adjustments in the location of the western Pacific subtropical high.2)Regional precipita-tion exhibited a unimodal intra-annual pattern,with 65.47%of the total precipitation occurring between the Sum-mer Solstice and the End of Heat,peaking during Minor Heat(105.3 mm).Trends during individual solar terms differ markedly:the Summer Solstice experienced the strongest increase(4.24 mm·(10 a)-1),while Major Heat and Beginning of Autumn showed the most pronounced decreases(-1.98 mm·(10 a)-1 and-1.29 mm·(10 a)-1,respectively).3)Spatially,PCD increased from southwest to northeast.Low PCD values in the mountainous regions of western Henan likely reflect the influence of more uniformly distributed orographic pre-cipitation,whereas high values over the Jiaodong Peninsula may be associated with its proximity to the subtropi-cal high and strong land-sea thermal contrasts.In low-precipitation years,PCD values were relatively high(mean 0.45),indicating more concentrated precipitation,while high-precipitation years exhibited lower PCD(mean 0.39).During wet years,PCP advanced progressively from south to north,following the sequence Summer Sol-stice-Minor Heat-Major Heat,consistent with the northward seasonal progression of the subtropical high.4)On an annual scale,PCD exhibited a weak negative correlation with regional mean precipitation,although 95.48%of stations showed positive correlations,highlighting the contrast between local extreme events and regional aver-ages.PCP showed a weak positive correlation with regional annual precipitation.At the solar-term scale,PCD in-creased significantly with precipitation during the main flood season(Minor Heat to Beginning of Autumn).In-creased precipitation during autumn solar terms(End of Heat,White Dew,Autumn Equinox,Cold Dew)was significantly associated with delayed PCP,particularly during 1993-2024.