流域水热条件和植被状况对青海湖水位的影响
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摘要
湖泊是陆地水资源的重要组成部分,也是局地气候和全球环境变化的敏感指示器之一。湖泊面积增加和水位的变化直接反映了流域内水量平衡变化过程,对区域和全球的气候变化的反映较为敏感。利用线性趋势法对青海湖流域长时间序列气象、水文资料以及流域水热条件和植被生长状况进行分析研究,利用皮尔逊相关系数法计算了各因素与湖水位的相关关系,旨在定量评估区域气象、水文、植被等要素的变化对和湖泊水位变化过程的贡献,开展细致的青海湖水位变化特征的影响因子探讨与分析。结果表明:该流域气候呈现显著的暖湿化趋势,其中流域年降水量总体上呈现弱的增加态势,气候倾向率为10.8 mm·(10 a)~(-1);流域年平均气温呈显著的升高趋势(P<0.01)。流域年可能蒸散率和年实际蒸散波动较大,年实际蒸散虽有波动但增加趋势非常明显(P<0.01)。流域净第一性生产力(NPP)平均值为2.86 t DM·hm~(-2)·a~(-1),呈现显著的增加趋势(P<0.01)。从1961年开始湖水位呈现逐年波动下降的趋势,到2004年水位最低(P<0.01);2004—2015年的近10 a连续上升,上升速率达14.4 m·(10 a)~(-1)(P<0.01)。流域气温升高、降水量增加,流域气候呈显著的暖湿化特征,入湖河流径流量也呈现出弱的增加态势;气候暖湿化特征导致流域生物温度增加,植被生长状况得到改善,NPP显著增加。年降水量增多,河流径流量增大,湖水位抬升;前一年的降水量、≥0℃积温、温度、径流量、NPP和蒸发量对湖水位的影响更大;NDVI和NPP的增加反映流域植被生长状况得到好转,从而增加了流域植被水土保持和水源涵养能力,对湖水位产生间接的影响。降水量、≥0℃积温、温度、径流量和NPP对青海湖水位起到正反馈效应,而蒸发量对湖水位主要起负反馈效应,年降水量和年径流量是湖水位变化的最直接的影响因子。
As an important part of land water resource,lake is an important indicator of local climate and global environment change.The increase of lake area and change in the lake's water level directly reflect the process of water balance change in its basin,which is sensitive to regional and global climate change.Qinghai Lake is the largest saline lake in China,with 3 190 m asl in the arid-semiarid area of the Qinghai-Tibet Plateau.The lake has experienced decline in water level and lake area over the past 50 years,but it has rebounded over the latest 10 years.This study investigated lake hydrology,climate change and hydrothermal and vegetation growth conditions in the basin,focusing on the causes for water level variation.To reveal hydrology,meteorology and vegetation change,linear trend method was used to analyze long-term data in this study.The Pearson correlation coefficient method was used to calculate relationship between various factors and the lake water level to quantitatively evaluate the lake water level change effected by regional meteorological,hydrological,and vegetation factors.The results showed that the basin climate had a significant warming and wetting trend,and the total precipitation had a weak increase trend with a climatic tendency rate of 10.8 mm·(10 a)~(-1).The annual evapotranspiration rate and annual actual evapotranspiration fluctuated greatly in the basin.Average net primary productivity(NPP) of the basin was 2.86 t DM·hm~(-2)·a~(-1),showing a significant increase trend(P<0.01).The water level was dropped during the period from 1961 to 2003,and was significantly increased from 2004 to 2015 with an increasing rate of 14.4 m·(10 a)~(-1)(P<0.01).The trend of warming and wetting of the climate was intensified and the runoff into the lake got increased,resulting in a significant rise in water level.The vegetation growth is improved and NPP is significantly increased.The amount of precipitation,the accumulated temperature(above 0 degree Celsius),annual air temperature,run-off,NPP and evaporation in the year before had even bigger impact on the lake's water level in current year.The increase of the NDVI and NPP reflected the improvement of the vegetation growth in the basin which in return enhanced the capability of the basin in the conservation of water and soil,indirectly impacting the lake's water level.The precipitation,the accumulated temperature(above 0 degree Celsius),air temperature,runoff and NPP had a positive feedback effect on the lake's water level,while evaporation has a negative feedback effect on the lake's water level.The annual precipitation and runoff were the most direct factors of the water level changes.
As an important part of land water resource,lake is an important indicator of local climate and global environment change.The increase of lake area and change in the lake's water level directly reflect the process of water balance change in its basin,which is sensitive to regional and global climate change.Qinghai Lake is the largest saline lake in China,with 3 190 m asl in the arid-semiarid area of the Qinghai-Tibet Plateau.The lake has experienced decline in water level and lake area over the past 50 years,but it has rebounded over the latest 10 years.This study investigated lake hydrology,climate change and hydrothermal and vegetation growth conditions in the basin,focusing on the causes for water level variation.To reveal hydrology,meteorology and vegetation change,linear trend method was used to analyze long-term data in this study.The Pearson correlation coefficient method was used to calculate relationship between various factors and the lake water level to quantitatively evaluate the lake water level change effected by regional meteorological,hydrological,and vegetation factors.The results showed that the basin climate had a significant warming and wetting trend,and the total precipitation had a weak increase trend with a climatic tendency rate of 10.8 mm·(10 a)~(-1).The annual evapotranspiration rate and annual actual evapotranspiration fluctuated greatly in the basin.Average net primary productivity(NPP) of the basin was 2.86 t DM·hm~(-2)·a~(-1),showing a significant increase trend(P<0.01).The water level was dropped during the period from 1961 to 2003,and was significantly increased from 2004 to 2015 with an increasing rate of 14.4 m·(10 a)~(-1)(P<0.01).The trend of warming and wetting of the climate was intensified and the runoff into the lake got increased,resulting in a significant rise in water level.The vegetation growth is improved and NPP is significantly increased.The amount of precipitation,the accumulated temperature(above 0 degree Celsius),annual air temperature,run-off,NPP and evaporation in the year before had even bigger impact on the lake's water level in current year.The increase of the NDVI and NPP reflected the improvement of the vegetation growth in the basin which in return enhanced the capability of the basin in the conservation of water and soil,indirectly impacting the lake's water level.The precipitation,the accumulated temperature(above 0 degree Celsius),air temperature,runoff and NPP had a positive feedback effect on the lake's water level,while evaporation has a negative feedback effect on the lake's water level.The annual precipitation and runoff were the most direct factors of the water level changes.
引文
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[2] 杨永岐,陈鹏狮,吉奇.气候变化对我国西北地区未来农业的影响及对策[J].辽宁气象,2001,17(4):12-15.[ YANG Yongqi,CHEN Pengshi,JI Qi.Impacts and countermeasures of climate change on future agriculture in northwest in China[J].Liaoning Meteorological Quarterly,2001,17(4):12-15.]
[3] 于秀晶,刘玉英,杜尧东,等.RCPs情景下长白山区气候变化预估分析[J].气象与环境学报,2015,31(4):65-73.[YU Xiujing,LIU Yuying,DU Raodong,et al.Projection of climate change in Changbai Mountain under RCPs scenario[J].Journal of Meteorology and Environment,2015,31(4):65-73.]
[4] 张新时,刘春迎.全球变化与生态系统[M].上海:上海科学技术出版社,1994:62-95.[ZHANG Xinshi,LIU Chunying.Global change and ecosystem[M].Shanghai:Shanghai science and Technology Press,1994:62-95.]
[5] 叶朝霞,陈亚宁,张淑花.不同情景下干旱区尾闾湖泊生态水位与需水研究——以黑河下游东居延海为例[J].干旱区地理,2017,40(5):951-957.[YE Zhaoxia,CHEN Yaning,ZHANG Shuhua.et al.Ecological water level and water demand of the rump lake in arid land under different scenarios:A case of East Juyanhai at the downstream of Heihe River[J].Arid Land Geography,2017,40(5):951-957]
[6] CUI B L,LI X Y.Stable isotopes reveal sources of precipitation in the Qinghai Lake Basin of the northeastern Tibetan Plateau[J].Science of the Total Environment,2015,527:26-37.
[7] AN Z,COLMAN S M,ZHOU W,et al.Interplay between the Westerlies and Asian monsoon recorded in Lake Qinghai sediments since 32 ka[J].Scientific Reports,2012,2:619.
[8] LI X,LIU W.Water salinity and productivity recorded by ostracod assemblages and their carbon isotopes since the early Holocene at Lake Qinghai on the northeastern Qinghai-Tibet Plateau,China[J].Palaeogeography,Palaeoclimatology,Palaeoecology,2014,407:25-33.
[9] 李新虎,宋郁东,李岳坦,等.湖泊最低生态水位计算方法研究[J].干旱区地理,2007,30(4):526-530.[LI Xinhu,SONG Yudong,LI Yuetan,et al.Calculation methods of lowest ecological water level of lake[J].Arid Land Geography,2007,30(4):526-530.]
[10] LI X Y,XU H Y,SUN Y L,et al.Lake-level change and water balance analysis at Lake Qinghai,west China during recent decades[J].Water Resources Management,2007,21(9):1505-1516.
[11] 李晓东,肖建设,李凤霞,等.基于EOS/MODIS数据的近10 a青海湖遥感监测[J].自然资源学报,2012,27(11):1962-1970.[LI Xiaodong,XIAO Jianshe,LI Fengxia,et al.Remote sensing monitoring of the Qinghai Lake based on EOS/MODIS data in recent 10 years[J].Journal of Natural Resources,2012,27(11):1962-1970.]
[12] QIN B,HUANG Q.Evaluation of the climatic change impacts on the inland lake:A case study of Lake Qinghai,China[J].Climatic Change,1998,39(4):695-714.
[13] ZHANG G,XIE H,DUAN S,et al.Water level variation of Lake Qinghai from satellite and in situ measurements under climate change[J].Journal of Applied Remote Sensing,2011,5(1):053532.
[14] LI X Y,MA Y J,XU H Y,et al.Impact of land use and land cover change on environmental degradation in Lake Qinghai watershed,northeast Qinghai-Tibet Plateau[J].Land Degradation and Development,2009,20(1):69-83.
[15] XU H,HOU Z,AN Z,et al.Major ion chemistry of waters in Lake Qinghai catchments,NE Qinghai-Tibet Plateau,China[J].Quaternary International,2010,212(1):35-43.
[16] LIU X J U N,LAI Z,MADSEN D,et al.Last deglacial and Holocene lake level variations of Qinghai Lake,north-eastern Qinghai-Tibetan Plateau[J].Journal of Quaternary Science,2015,30(3):245-257.
[17] CUI B L,LI X Y.The impact of climate changes on water level of Qinghai Lake in China over the past 50 years[J].Hydrology Research,2016,47(2):532-542.
[18] 沈芳,匡定波.青海湖最近25年变化的遥感调查与研究[J].湖泊科学,2003,15(4):289-296.[SHEN Fang,KUANG Dingbo.Remote sensing investigation and survey of Qinghai Lake in the past 25 years[J].Journal of Lake Science,2003,15(4):289-296.]
[19] 李凤霞,李林,沈芳,等.青海湖湖岸形态变化及成因分析[J].资源科学,2004,26(1):38-44.[LI Fengxia,LI Lin,SHEN Fang,et al.Evolution of lakeshore shape of Qinghai Lake and its causes[J].Resources Science,2004,26(1):38-44.]
[20] 殷青军,杨英莲.基于EOS/MODIS数据的青海湖遥感监测[J].湖泊科学,2005,17(4):356-360.[YIN Qingjun,YANG Yinglian.Remote sensing monitoring of Lake Qinghai based on EOS/MODIS data[J].Journal of Lake Science,2005,17(4):356-360.]
[21] 刘瑞霞,刘玉洁.近20年青海湖湖水面积变化遥感[J].湖泊科学,2008,20(1):135-138.[LIU Ruixia,LIU Yujie.Area changes of Lake Qinghai in the latest 20 years based on remote sensing study[J].Journal of Lake Science,2008,20(1):135-138.]
[22] 沈亚文,陈华,许崇育.1973—2013年青海湖水面面积变化遥感动态分析[J].水资源研究,2013,2(5):309-315.[SHEN Yawen,CHEN Hua,XU Chongyu.Remote sensing monitoring study for the tendency of Qinghai Lake’s water area in last 41 years[J].Water Resource Research,2013,2(5):309-315.]
[23] ZOTARELLI L,DUKES M D,ROMERO C C,et al.Step by step calculation of the Penman-Monteith Evapotranspiration (FAO-56 Method)[R].Agricultural & Biological Engineering,2016.
[24] 张新时.研究全球变化的植被—气候分类系统[J].第四纪研究,1993,(2):157-169.[ZHANG Xinshi.A vegetation-climate classification system for global change studies in China[J].Quaternary Sciences,1993,(2):157-169.]
[25] 周广胜,张新时.自然植被净第一性生产力模型初探[J].植物生态学报,1995,19(3):193-200.[ZHOU Guangsheng,ZHANG Xinshi.A natural vegetatiaon NPP model[J].Chinese Journal of Plant Ecology,1995,19(3):193-200.]
[26] 周广胜.一个用气候-植被关系研究的区域蒸散模式,资源开发、全球变化与持续发展[M].北京:中国科学技术出版社,1995:570-573.[ZHOU Guangsheng.A regional evapotranspiration model based on climate vegetation relationships,resource development,global change and sustainable development[M].Beijing:China Science and Technology Press,1995:570-573.]
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