兰州大学学报(自然科学版)
蘭州大學學報(自然科學版)
란주대학학보(자연과학판)
JOURNAL OF LANZHOU UNIVERSITY(NATURAL SCIENCES)
2015年
2期
202-211,216
,共11页
龙治平%张拥军%冯松%齐玉磊%于立%柳丹
龍治平%張擁軍%馮鬆%齊玉磊%于立%柳丹
룡치평%장옹군%풍송%제옥뢰%우립%류단
西北地区%旋转经验正交函数%干湿变化%相似干旱期
西北地區%鏇轉經驗正交函數%榦濕變化%相似榦旱期
서북지구%선전경험정교함수%간습변화%상사간한기
Northwest China%rotated empirical orthogonal function%dry-wet variations%similar drought period
基于观测数据得到的帕尔默干旱指数(Dai-PDSI)和树木年轮重建的帕尔默干旱指数(MADA-PDSI),分析了中国西北干湿分布及变化特征.通过对1951?2005年夏季Dai-PDSI数据的REOF分析,可将中国西北地区划分为3个典型干旱区:南疆干旱区、北疆干旱区和西北东部干旱区.区域平均PDSI分析结果表明,自1951年以来,南疆呈现出明显的变湿趋势,北疆地区先变干后转湿,而西北东部干旱化趋势明显.近700年来的相似干旱期的分析结果显示,各类型相似干旱期都有其共性,南疆相似干旱期的主要特点是干旱从西北向东南延伸到长江中下游地区,北疆相似干旱期的严重干旱位于北疆及其北部地区,而西北东部干旱发生时中国大部分地区遭遇干旱,且严重干旱位于北方地区.20世纪以来的南疆和北疆干旱在历史时期中都有与其强度相当的相似干旱期,而西北东部历史相似干旱期与1995?2005年干旱相比,其干旱强度相对较弱,因此,1995?2005年干旱是此类型近700年来最严重的干旱.
基于觀測數據得到的帕爾默榦旱指數(Dai-PDSI)和樹木年輪重建的帕爾默榦旱指數(MADA-PDSI),分析瞭中國西北榦濕分佈及變化特徵.通過對1951?2005年夏季Dai-PDSI數據的REOF分析,可將中國西北地區劃分為3箇典型榦旱區:南疆榦旱區、北疆榦旱區和西北東部榦旱區.區域平均PDSI分析結果錶明,自1951年以來,南疆呈現齣明顯的變濕趨勢,北疆地區先變榦後轉濕,而西北東部榦旱化趨勢明顯.近700年來的相似榦旱期的分析結果顯示,各類型相似榦旱期都有其共性,南疆相似榦旱期的主要特點是榦旱從西北嚮東南延伸到長江中下遊地區,北疆相似榦旱期的嚴重榦旱位于北疆及其北部地區,而西北東部榦旱髮生時中國大部分地區遭遇榦旱,且嚴重榦旱位于北方地區.20世紀以來的南疆和北疆榦旱在歷史時期中都有與其彊度相噹的相似榦旱期,而西北東部歷史相似榦旱期與1995?2005年榦旱相比,其榦旱彊度相對較弱,因此,1995?2005年榦旱是此類型近700年來最嚴重的榦旱.
기우관측수거득도적파이묵간한지수(Dai-PDSI)화수목년륜중건적파이묵간한지수(MADA-PDSI),분석료중국서북간습분포급변화특정.통과대1951?2005년하계Dai-PDSI수거적REOF분석,가장중국서북지구화분위3개전형간한구:남강간한구、북강간한구화서북동부간한구.구역평균PDSI분석결과표명,자1951년이래,남강정현출명현적변습추세,북강지구선변간후전습,이서북동부간한화추세명현.근700년래적상사간한기적분석결과현시,각류형상사간한기도유기공성,남강상사간한기적주요특점시간한종서북향동남연신도장강중하유지구,북강상사간한기적엄중간한위우북강급기북부지구,이서북동부간한발생시중국대부분지구조우간한,차엄중간한위우북방지구.20세기이래적남강화북강간한재역사시기중도유여기강도상당적상사간한기,이서북동부역사상사간한기여1995?2005년간한상비,기간한강도상대교약,인차,1995?2005년간한시차류형근700년래최엄중적간한.
The Northwest China is one of the most arid regions in the middle latitudes, where water is scarce all the year round. The variations of summer moisture in this region were investigated using the palmer drought severity index (PDSI) derived from instrumental data (Dai-PDSI) and tree-ring records (MADA-PDSI). Based on the rotated experience and the orthogonal function (REOF) analysis of summer PDSI in the northwestern China during 1951-2005, there have been three main drought regions: the southern and northern parts of Xinjiang and eastern part of Northwest China. The area-averaged PDSI indicated a wet tendency in the southern part of Xinjiang, and a dry-wet tendency in the northern part of Xinjiang since 1951; on the contrary, the eastern part of Northwest China showed a clear tendency to be dry. An analysis of similar drought periods during the past 700 years by using MADA-PDSI showed that the similar drought periods in each region shared some common characteristics. The main characteristic of the southern part of Xinjiang drought was that it would extend from Northwest to Southeast China. Serious drought was also located in the northern part of Xinjiang and areas even north of it. When drought occurred in the eastern part of Northwest China, most areas in eastern and northern China would also suffer from dry weather. Drought in the northern and southern parts of Xinjiang during the 20 th century have had a similar pattern and intensive drought periods also happened in history. Because of its strong intensity, the drought during 1995-2005 was the most serious in the eastern part of Northwest China, though similar severe droughts also occurred in history.