兰州大学机构库 >资源环境学院
1961-2016年青藏高原极端气候事件变化特征研究
Alternative TitleStudy on the Variation Characteristics of Extreme Climate Events on the Qinghai-Tibet Plateau during 1961-2016
赵金鹏
Thesis Advisor王一博
2019-05-30
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Degree Discipline水文学及水资源
Keyword极端气候事件 极端气温 极端降水 气候变化 时空特征 概率分布 青藏高原
Abstract近年来,全球气候持续变暖,极端气候事件频繁发生,引起了各国政府和国际组织的广泛关注。青藏高原地理特征和生态环境独特,对气候变化和极端气候事件及其敏感,抵御自然灾害的能力较差。因此,探讨全球气候变化背景下青藏高原极端气候事件的变化特征,对青藏高原生态环境资源保护和应对极端气候事件及其次生灾害有重要的现实意义。本文利用青藏高原67个气象台站1961-2016年的逐日气温和降水资料,基于国际通用的13个极端温度指标和10个极端降水指标,在分析气候变化时空特征的基础上详细探讨了青藏高原极端气候事件的时空变化和概率分布特征。主要结论如下:(1)1961-2016年,青藏高原气温有明显的升高趋势,平均线性增温率为0.32 ℃/10a,年平均气温分布存在显著的空间差异,呈现出东南部和北部柴达木盆地以及青海东北部区域较高,其他区域较低的分布格局。EOF第一特征向量表征了青藏高原全区气温变化的一致性,均呈现波动上升的趋势,第二特征向量表征了青藏高原气温变化南北的差异性,主要特征为研究区南北部主要升温阶段不同。1961-2016年,青藏高原降水量整体呈波动增长的趋势,增加和减少交替出现,增加幅度为7.2 mm/10a。年平均降水量分布存在显著的空间差异性,整体表现为从东南到西北依次递减的规律。EOF第一特征向量主要表征了青藏高原中东部区域降水变化的南北差异性,主要特征为该区域降水增加阶段的不同。第二特征向量主要表征了降水变化主体区域的一致性,主要特征为高原降水量增加主要是由该区域增加引起的,主要增加阶段在20世纪90年代及其之后。(2)1961-2016年,青藏高原极端气温冷指标和气温日较差呈显著下降趋势,暖指标均呈显著上升趋势。其中,冷指标变化幅度明显大于暖指标,最低气温极小值的升高尤为显著,表现出冷暖和昼夜增温的不对称性。与中国其他区域相比,青藏高原各项极端气温指数变化趋势与其一致,除热持续指数、冷持续指数和气温日较差外,其余指数变化幅度均明显大于其他区域,相对指数尤为显著,青藏高原气候变化的“放大器”效应极其明显。同青藏高原一样,其他区域夜指数变化率也大于昼指数,最低气温极小值变化幅度远大于其他三项气温极值指标,全球变暖背景下不对称升温特征普遍存在。除气温日较差之外,青藏高原其他极端气温指数之间相关性均较好。年平均气温与各极端气温指数之间的相关性较好,极端气温指数的变化能较好地反映青藏高原的气候变化趋势。(3)青藏高原年降水量、日降水强度、强降水量、极端强降水量、低强度降水日数、中等强度降水日数、最大1日降水量和最大5日降水量均呈增加趋势,强降水量和极端强降水量的增加幅度超过了总降水量的一半以上,是青藏高原降水量增加的主要来源。连续干旱日数和连续湿润日数呈减少趋势,近几十年研究区降水变得更加均匀,干旱事件有所减少。极端降水指数变化在研究区空间分布格局更加复杂,差异性更大。呈增加趋势的极端降水指数在研究区普遍增加,但通过显著性检验的站点较少,所占比例在站点总数的30%以下。一致的是,除极端强降水量之外,这些指数显著增加的站点在高原东北部祁连山区较为集中,该区域近几十年的降水变化相对较大。(4)青藏高原极端气温事件的最优分布为广义极值分布(GEV),第二优势分布为威布尔分布(Weibull (3P)),最优分布和第二优势分布在空间上有很高的重合度。极端气温事件的最优分布具有空间差异性,广义极值分布(GEV)在青藏高原北部适用性相对较好。极端降水事件的最优分布也为广义值分布(GEV),第二优势分布为对数逻辑斯蒂分布(Log-Logistic (3P)),与极端气温事件不同,极端降水指数最优分布和第二优势分布在空间上具有很强的互补性。极端降水事件的最优分布也具有空间差异性,广义极值分布(GEV)在青藏高原中部适用性相对较好。对于极端气温和降水指标,广义极值分布(GEV)和对数逻辑斯蒂分布(Log-Logistic (3P))在研究区概率分布拟合上均具有空间互补性。
Other AbstractIn recent years, global warming and frequent extreme climate events have attracted wide attention of governments and international organizations. The Qinghai-Tibet Plateau has unique geographic characteristics and ecological environment system. It is sensitive to climate change and extreme climate events, and has poor ability to resist natural disasters. Explore the characteristics of extreme climate events in the Qinghai-Tibet Plateau under the background of global change has a practical significance for the protection of ecological environment and resources in the region and for coping with extreme climate events and secondary disasters. Based on the daily temperature and precipitation data of 67 meteorological stations in the Qinghai-Tibet Plateau from 1961 to 2016 and 13 extreme temperature and 10 extreme precipitation indices commonly used in the world, the spatiotemporal variability and probability distribution characteristics of extreme climate events over the Qinghai-Tibet Plateau were discussed in detail on the basis of analyzing the characteristics of climate change in the region. The main conclusions are as follows:(1) From 1961 to 2016, the temperature of Qinghai-Tibet Plateau has increased obviously. The average linear warming rate was 0.32 ℃/10a. There were significant spatial differences in the annual average temperature distribution, showing higher in the southeast and Qaidam basins and northeastern Qinghai, and lower in other regions. The first eigenvector of EOF indicated the consistency of temperature change in the whole region of the Qinghai-Tibet Plateau, showing a fluctuant rising trend. The second eigenvector indicated the difference of temperature change between the north and the south of the Qinghai-Tibet Plateau. The main feature was that the main warming stages were different in the north and south of the region. From 1961 to 2016, the precipitation of the Qinghai-Tibet Plateau showed a trend of fluctuating growth. Increase and decrease occurred alternately, with an increased rate of 7.2 mm/10a. There were significant spatial differences in the distribution of annual average precipitation, which showed the decreasing regulation from southeast to northwest. The first eigenvector of EOF mainly represented the North-South difference of precipitation change in the central and eastern part of the Qinghai-Tibet Plateau, and the main feature was the difference of precipitation increase stages in the region. The second eigenvector mainly represented the consistency of the main regions of precipitation change. The main feature was that the increase of precipitation in the plateau was mainly caused by the increase of the region, and the main increase stage was in the 1990s and after.(2) From 1961 to 2016, the extreme temperature cold indices and daily range of temperature (DTR) in the Qinghai-Tibet Plateau showed a significant decreased trend, while the warm indices showed a significant raised trend. Among them, the change trend of cold index was obviously higher than that of warm index, especially the minimum of minimum temperature (TNn), which showed the cold-warm asymmetry of temperature increasing. Compared to other regions in China, the trend of extreme temperature indices in the Qinghai-Tibet Plateau was consistent with that in other regions. Except for the daily range of temperature (DTR), the warm spell duration index (WSDI) and the cold spell duration index (CSDI), the range of other indices was obviously larger than that in other regions, especially the relative indices. The "amplifier" effect of climate change in the Qinghai-Tibet Plateau was extremely obvious. Similar to the Qinghai-Tibet Plateau, the range of night indices in other regions was larger than that of day indices, and the minimum of minimum temperature (TNn) was much larger than the other three extreme temperature indices. The asymmetric warming characteristics were widespread under the background of global warming. Except for the daily range of temperature (DTR), the other extreme temperature indices in the Qinghai-Tibet Plateau had high correlation. The correlation between annual average temperature and extreme temperature indices was good, and the change of extreme temperature indices can better reflect the climate change trend of the Qinghai-Tibet Plateau.(3) The total precipitation amount (PRCPTOT), simple daily intensity index (SDII), heavy precipitation (R95p), extremely heavy precipitation (R99p), weak precipitation days (R10mm), weak or moderate precipitation days (R20mm), maximum 1-day precipitation (RX1day) and maximum 5-day precipitation (RX5day) of the Qinghai-Tibet Plateau all showed an increasing trend. The increase of heavy precipitation (R95p) and extremely heavy precipitation (R99p) were more than half of the total precipitation, which were the main source of precipitation increased in the Qinghai-Tibet Plateau. The maximum consecutive dry days (CDD) and maximum consecutive wet days (CWD) tended to decrease. In recent decades, the precipitation in the study area became more homogeneous, and the drought events were reduced. The spatial distribution pattern of extreme precipitation index changed in the study area was more complex and the difference was greater. The increased extreme precipitation index generally increased in the study area, but only fewer stations which amount below 30% of the total stations passed the significance test. Consistently, except for extremely heavy precipitation (R99p), the stations with significant increases in these indices were concentrated in the Qilian Mountains in the northeastern part of the plateau, and the precipitation variations in this region were relatively large in recent decades. (4) The optimal distribution of extreme temperature events in the Qinghai-Tibet Plateau was the Generalized Extreme Value Distribution (GEV), and the second dominant distribution was Weibull Distribution (Weibull (3P)). The optimal distribution and the second dominant distribution had high spatial coincidence. The optimal distribution of extreme temperature events had spatial differences, and the Generalized Extreme Value Distribution (GEV) was relatively suitable for the northern Qinghai-Tibet Plateau. The optimal distribution of extreme precipitation events was also Generalized Extreme Value Distribution (GEV), and the second dominant distribution was Logarithmic Logistic Distribution (Log-Logistic(3P)). Unlike extreme temperature events, the optimal distribution of extreme precipitation events and the second dominant distribution had strong spatial complementarity. The optimal distribution of extreme precipitation events also had spatial differences. Generalized Extreme Value Distribution (GEV) had relatively good applicability in the central Qinghai-Tibet Plateau. For extreme temperature and precipitation indices, the Generalized Extreme Value Distribution (GEV) and Logarithmic Logistic Distribution (Log-Logistic(3P)) had spatial complementarity in fitting probability distribution in the study area.
Pages79
URL查看原文
Language中文
Document Type学位论文
Identifierhttp://ir.lzu.edu.cn/handle/262010/344335
Collection资源环境学院
Affiliation资源环境学院
First Author AffilicationCollege of Earth Environmental Sciences
Recommended Citation
GB/T 7714
赵金鹏. 1961-2016年青藏高原极端气候事件变化特征研究[D]. 兰州. 兰州大学,2019.
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