本文利用福建省43個國家級地面氣象觀測站1981-2011年地面氣象記錄年報表 之15段年最大降雨量數據，探討福建省5-1440分鐘不同短歷時年最大雨強的時空分 佈特徵；探討太陽輻射、夜間雲輻射、地理位置及地形因素與年最大雨強發生頻次之 曰、月變化的關聯；利用NCEP/NCAR再分析高度場和風場資料，通過對內陸站2001-2011年45分鐘年最大雨強個案的天氣形勢普查，探討內陸站5-60分鐘年最大雨強 月累計頻次與月平均降水量不相稱現象的可能原因；通過天氣圖抽樣普查並結合相關 文獻，探討雨強年代際變化的可能原因；探討地形與天氣系統的不同配置對年最大雨 強空間分佈的影響。最後，結合已有研究成果，歸納不同區域雨強記錄刷新的可能天 氣背景。主要結論如下： 1.年最大雨強事件具有明顯的多時間尺度特徵。（1)日變化方面，5分鐘至90 分鐘年最大雨強有明顯的日變化，高發時段在13至18時。日變化峰點時間沿海站最 早，中部站居中，內陸站最遲。峰點時間地域差異與太陽輻射日變化地域差異密切相 關，年最大雨強發生頻次日變化的峰點較氣溫日變化峰點滯後1.5-2小時。同類站最 大雨強日變化存在季節差異，內陸站和沿海站日變化峰點夏季較梅雨季早30分鐘至 1小時，中部站夏季較梅雨季遲30分鐘；午後到傍晚的累計發生頻次，三類測站都是 夏季比梅雨季多，這是由夏季午後熱力有利條件引起；下半夜至早晨（0-8時）的累 計發生頻次，內陸站和中部站梅雨季比夏季多，這是由梅雨季雲輻射和弱冷空氣優勢 引起，沿海站夏季比梅雨季多，這是由夏季颱風過程較多、夏季夜間陸風鋒輻合線對 已有暴雨的增幅作用所致。（2)月分佈方面，5-1440分鐘年最大雨強主要出現在5-9月份。沿海站各歷時呈8月份主峰、6月份次峰的雙峰型分佈；內陸站60分鐘及以 內歷時呈6月和8月雙峰型，60分鐘以上歷時呈6月單峰型；中部站180分鐘及以內 爲8月單峰型，180分鐘以上爲6月和8月雙峰型。6月份華南滯留鋒活躍、8月份熱 帶系統活躍造成沿海地區月頻次呈雙峰型分佈；6月華南滯留鋒活躍及8月份混合積 雲、冷積雲和深厚暖雲層引起的高降水效率是內陸站60分鐘以內歷時年最大雨強事 件呈雙峰型分佈的主要原因；360分鐘及以上的4個歷時，沿海站9月份出現的頻次 與6月份相當，明顯比5月份多，內陸測站5月份出現的頻次明顯多於7-9月份； (3)年代際分佈方面，年代際變化主要有增強型、減弱型、趨緩型和兩極型等4種特 徵。閩中大山帶以東、閩江以南地區和閩江上游支流大部分測站45分鐘以上歷時爲 增強型；減弱型、趨緩型和兩極型的比例較少，主要出現在內陸和中部地區，沿海地 區較少。澳大利亞高壓和馬斯克林高壓強度年代際變化、索馬裏越赤道氣流垂直結構 的年代際變化可能是20分鐘以上歷時雨強最大值自上世紀90年代起增強的氣候背 景。 2.年最大雨強有明顯的空間分佈。（1)平均值空間分佈特徵方面，5分鐘雨強大 值區主要分佈在閩江以北；10分鐘以上至1440分鐘呈東高西低分佈，即沿海高，內 陸低，近海岸站高、遠海岸站低。（2)極大值空間分佈特徵方面，5分鐘極大值的大 值區大部分分佈在閩江以北；30-240分鐘的高值區主要分佈在閩中大山帶以東和閩江 上游以南測站，低值區分佈在閩西北；360-1440分鐘極值大致呈東西高、中間低的准 南北向分佈，最高值出現在地勢呈三面環山向南或東南開口處。（3)年最大雨強空間 分佈的影響因素包括：影響暴雨的天氣系統性質、地形及地形與天氣系統的匹配，其 中閩中大山帶是地形因素的重點，山帶以東地區重點考慮颱風環流天氣形勢下500-700百帕乾線、850百帕以下偏東風急流、邊界層弱冷空氣和海陸風輻合線等5個因 素共同作用可能造成的雨強記錄刷新現象；山帶以西地區重點考慮華南滯留鋒天氣形 勢下邊界層至地面西南暖濕氣流受武夷山脈阻擋形成的背風低壓擾動可能造成的雨 強記錄刷新現象。

Based on the precipitation data of 43 national meteorological stations in Fujian during 1980-2011, we revealed the spatial-temporal distribution of the Annual Maximum Precipitation with the Short Duration of 5 to 1440 Minutes in Fujian. We also explored the impacts of the solar radiation at daytime, cloud-radiation at nighttime, local position and topography on the distributions of diurnal and monthly variations of annual maximum precipitation occurrences. Using the NCEP/NCAR height and wind data, the synoptic situations for the annual maximum precipitation with the duration of 45 minutes in inland stations during 2000-2011 are reveled, the possible mechanisms of the unmatched phenomenon between monthly precipitation frequency and amount for the annual maximum precipitation with 5-60 minutes over inland stations are also researched. Possible causes related to the decadal changes of the precipitation intensity are discussed according to sampling synoptic chart and reference findings. The effects of different configurations of terrain and synoptic systems on the spatial distribution of annual maximum precipitation are also discussed. Finally, Synoptic backgrounds that may cause rainfall intensity record-broken are reviewed based on above analyses and reference researches. The main conclusions are shown as follows:1. The annual maximum precipitation shows remarkable multi-time scale characteristics. (1) For diurnal distributions, the events with the duration less than 90min mainly occur at the period during 13:00 to 18:00 Beijing time, and the precipitation diurnal peak time delays from coastal areas to inland stations. The regional differences of the precipitation diurnal peak time are closely related to the diurnal variation of solar radiation at daytime; the diurnal peak time of precipitation frequency lags behind 1.5-2 hours to that of temperature. Even in the same reign, the diurnal variation of the annual maximum precipitation varies with seasons. The diurnal peak time over the coastal and inland stations (middle stations) in summer is 30min-1h earlier (30min later) than in Meiyu season. Due to favorable thermal condition at summer afternoon, the occurrence frequency of the annual maximum precipitation during afternoon to evening in summer is more than in Meiyu season for all regions, meanwhile, the occurrence frequency of the annual maximum precipitation during midnight to morning (0:00-8:00 Beijing time) in the stations over central Fujian and inland areas in Meiyu season is more than that in summer for the favorable conditions as cloud radiation and weak cold flow in the Meiyu season. However, the coastal stations show opposite features due to more typhoon cases and coastal rainstorms at summer night reinforced by the land-breeze convergence line. (2)For monthly distributions, the events are concentrated from May to September. At coastal stations, the precipitation occurrence frequency with the duration of 5-1440min shows double peak pattern with a primary peak in August and a secondary peak in June. At inland stations, the monthly occurrence frequency of the precipitation with the duration of less than 60min (more than 60min) shows double peak pattern with one in June and the other in August, (single peak with peak in June). At middle stations, the precipitation occurrence frequency with the duration less than 180min (more than 180min) shows single peak in August (double peaks with one in June and the other in August). Huanan quasi- stationary front being active in June and subtropical system being active in August lead to the double peak pattern over the coastal stations. The characteristic of Huanan quasi- stationary front also results in the precipitation frequency peak in June over the inland stations. Another peak in August of the precipitation with the durations of 5-60min over the inland stations is mainly due to the high precipitation efficiency caused by mixed cumulus, cold cumulus, and thick warm clouds. In the coastal 二〇一八年 黃麗娜等 doi: 10.3966/025400022018094603002 stations, the precipitation frequency in September is comparable to that in June and is more than that in May obviously. However, in the inland stations, the precipitation frequency in May is more than that in Jul-Sep. (3) For the decadal distributions, the decadal variation of the annual maximum precipitation in Fujian may be divided into four patterns as Strengthen-pattern, Weaken-pattern, Stabilized-pattern, and Polarized-pattern. The annual maximum rainfall with the duration more than 45min over most stations located at south to Mingjiang and east to mountain belt of central Fujian Province, or near the tributaries of upper Reaches of Mingjiang shows Strengthen-pattern. The station proportions of other patterns (Weaken-pattern and Stabilized-pattern and Polarized pattern) are less and mainly located in inland and middle areas of Fujian and seldom located in coastal regions. The climatic background of the decadal strengthening may be related to the decadal variations of the Australia anticyclone, Mascarene anticyclone and the vertical structure of Somalia cross-equatorial flow. 2. The spatial distributions of the annual maximum rainfall intensity are distinct.(1) Mean value of the annual maximum precipitation with the duration of 10-1440min shows the pattern of high in east and low in west with high (low) values mainly located at coastal areas (regions west to mountain belt of central Fujian Province). In addition, for the stations located in the regions east to mountain-belt of central Fujian Province, stations close to coastline show higher values than the stations far from the coastline. However, for precipitation with the duration of 5min, higher values are mainly located at regions north to Mingjiang River.(2) For spatial distribution of extreme maximum values, higher values for the precipitation with the duration of 5-min are mainly located at the regions north to Mingjiang River, which is similar to that of mean values; higher values for the precipitation with the duration of 30-240min are located at regions east to mountain belt of central Fujian Province and regions south to the upper reaches of Mingjiang, however, lower values are located at Northwest Fujian; the distribution of the precipitation with the duration of 3601440min shows a pattern of ‘quasi south-north5 with higher values in east and west regions than that in the middle region and the highest values are mainly located at bell mouthed terrain with entrance toward south or southeast.(3)Factors affecting the spatial distributions of annual maximum rainfall intensity include weather system, topography, and configuration of terrain and synoptic system. Mountain belt of central Fujian Province is the main factor of topography. For the regions east to Mountain belt of central Fujian Province, new historical record might be caused by typhoon circulation together with multiple factors as dry line at 500-700hPa levels, weak cold flow in boundary layer, and sea-land breeze convergence line, thus, the synoptic background as above should be focused on. However, for the regions west to the Mountain belt of central Fujian Province, new historical record might be caused by quasi- stationary front together with low pressure disturbance at the leeward slope, which is formed by southwest warm wet flow of levels from surface to boundary layer being blocked by Wuyi Mountain, thus the synoptic background should also be focused on.