【作者】 俞方圆；

【导师】 郑粉莉； 李志；

【作者基本信息】 西北农林科技大学 ， 土地资源与空间信息技术， 2011， 硕士

【摘要】 我国东北地区是气候变化最为敏感的区域,近年来旱涝灾害的频繁发生和水土流失的加剧已成为制约该区社会经济可持续发展的重要因素。因此,开展东北地区气候变化及其对流域水沙变化的影响研究对该区防灾减灾、水资源管理、农业生产和生态环境建设具有重要的现实意义。本文以松花江流域和东北三省为研究对象,基于1958-2008年东北地区温度和降水的日数据及径流量和输沙量的年数据,通过Mann-Kendall非参数检验法,森斜率估计法、双累积曲线和线性回归法等多种方法相结合的途径,分析了东北地区气候(含极端气候)的总体及季节变化趋势、变化幅度和空间变化规律,研究了松花江流域主要水文站的径流和泥沙变化过程和变化趋势,评估了气候变化和人类活动对流域径流和泥沙的影响。论文的主要结论如下:(1)分析了1958-2008年间松花江流域年均降水量和气温的整体变化趋势、季节变化规律和空间分布特征。结果表明,51年来流域年均降水量和气温分别呈微弱的下降和显著的上升趋势,二者变化幅度的空间分布大致具有东南—西北方向的变化。年均和汛期降水量的下降幅度分别为0.81 mm/yr和1.21 mm/yr;从季节变化来看,冬季和春季平均降水量分别以0.03 mm/yr和0.13 mm/yr的幅度增加,而夏季和秋季平均降水量以0.56 mm/yr和0.45 mm/yr的幅度减少。51年来松花江流域年均气温共上升了2.0℃,显著上升的突变发生在1990年。冬季平均气温上升幅度最大,达到0.06℃/yr,夏季上升的幅度最小,仅为0.02℃/yr。松花江流域的年均和四季的增温幅度远远高于全国和全球水平。(2)选取九个国际通用的极端气候变化指标(pq90,px5d,pint,pxcdd,pnl90,txq90,tnq10,txhw90,tnfd),研究了东北三省的极端降水和温度事件的时空变化特征。结果表明,东北三省极端气候变化的空间分布具有南—北方向的梯度变化。极端降水阈值pq90,极端高温阈值txq90,极端低温阈值tnq10,最大5天降水量px5d,雨天平均降雨量pint从北向南递增,而最长热波天数txhw90和霜冻天数tnfd从北向南递减。大多数站点的极端气候指标皆呈单调趋势,且显著性检验(α=0.05)结果表明:大约6-7个站点的极端降水指标、23%和68%站点的极端高温指标(txq90和txhw90)及超过90%的站点的极端低温指标(tnq10和tnfd)均通过了显著性检验。极端降水频率和强度的下降趋势以及干旱指标、极端温度指标的显著上升趋势表明51年来东北三省极端降水事件有所减少,而干旱程度加强,极端温度事件变得更加频繁和剧烈。(3)基于1958-2008年间松花江流域江桥,大贲,扶余,哈尔滨和佳木斯五个主要水文站的实测资料,探究了51年来松花江流域径流和泥沙的变化过程和变化趋势。结果表明:1958-2008年间各站点径流量均呈下降趋势,且大贲、哈尔滨和佳木斯站的减少趋势通过了α=0.05的显著性检验。对输沙量而言,江桥和佳木斯的输沙量虽有上升趋势,但未通过α=0.05显著性检验,而其余三个站表现为显著的下降趋势。五个水文站中径流量和输沙量的减少幅度分别以佳木斯和哈尔滨站最大,其减小幅度分别为5.50×108 m~3/yr和8.55×10~4 t/yr。(4)采用双累积曲线和线性回归法,评估了气候变化和人类活动对松花江流域径流和泥沙的影响。结果表明,人类活动对整个松花江流域的影响程度更大,其对径流量和输沙量的影响分别为52.80%和81.84%,而气候变化对径流量和输沙量的影响为47.20%和18.16%。20世纪90年代起,气候变化对松花江流域径流量减少的影响程度已逐渐略高于人类活动的影响程度;随着时间的推移,人类活动对松花江流域输沙量的影响程度有所减轻,而气候变化对输沙量的影响程度却逐渐加强。从流域不同区段来看,嫩江中、下游段和松花江干流中游段径流量受气候变化影响较大,其对嫩江中游段径流量的影响随着时间的推移逐渐变大;而第二松花江和松花江干流下游段径流量变化受人类活动影响较大,其对二者的影响分别为123.79%和156.32%。区段输沙量对气候变化和人类活动的响应程度和径流量对二者的响应程度并不完全对应,嫩江中、下游段和第二松花江下游段输沙量变化相对受人类活动影响更大。气候变化和人类活动对松花江干流中游段的输沙量变化影响相当,分别为52.77%和47.23%。松花江干流下游段输沙量在80年代和21世纪后受气候变化的影响更大,而在90年代明显受人类活动影响,百分比高达96.86%。更多还原

【Abstract】 Northeast China is the region which is extremely sensitive to climate change, has the most vulnerable ecological environment in China. Frequent drought and flood disasters and soil erosion in Northeast China have been important factors which restrict the development of society and economy in recent years. Therefore, analyzing the change trend of climate change and assessing the effect of climate variability on water and sediment in detail can provide important information for disaster prevention and reduction, water resource management, agricultural production and ecological construction. Based on the daily series temperature, precipitation observations and the yearly series runoff and sediment load data over the period of 1958-2008, this study selected the Songhua River Basin and Northeast China as research sites, combing various research methods (non-parametric Mann-Kendall test, the estimated sen slope method, double mass curve and linear regression), to analyze the change trends and spatial distribution characteristics of meteorological and hydrological elements. The effects of climate change and human activities on runoff and sediment at different stations during different periods were assessed. The main conclusions are as follows:(1) The change trends, seasonal change, spatial distribution of average temperature and precipitation in the Songhua River Basin were analyzed. The average annual precipitation and temperature of the Songhua River Basin tended to decrease slightly and increase significantly during 1958-2008. The change range of average precipitation and temperature increased/decreased from southeast to northwest. The decreasing magnitude of average annual precipitation and precipitation in flood season were 0.81 mm/yr and 1.21 mm/yr. The average precipitation of winter and spring showed a upward trend with the change magnitude of 0.03 mm/yr and 0.13 mm/yr, while the average precipitation of summer and autumn repented a downward trend with the change magnitude of 0.56 mm/yr and0.45 mm/y. The average annual temperature which underwent abrupt change in 1990 has risen about 2.0℃during the past 51 years. The average temperature of winter increased at a faster rate (0.06℃/yr), whilst the average temperature of summer had the smallest increment—0.02℃/yr. The increasing magnitude of average annual temperature in the Songhua River Basin was much greater than the national and global level.(2) Based on the nine international extreme indices (pq90, px5d, pint, pxcdd, pnl90, txq90, tnq10, tnfd, txhw90), this study analyzed the spatial and temporal change trends of Northeast China. Results showed that the indices of extreme climate were spatially distributed with obvious gradients from the south to the north. Heavy rainfall threshold pq90, hot-day threshold txq90, cold-night threshold tnq10, greatest 5-day total rainfall px5d, simple daily rainfall intensity pint increased from north to south while the longest heatwave txhw90 and frost days tnfd decreased form north to south. Most stations had monotonic trends in extreme indices, nonetheless, the number of stations with significant trends varied greatly; only six or seven stations in precipitation-based indices had significant trends, but 23%, 68% of stations in extreme high temperature indices and over 90% of stations in extreme low temperature showed significant trends. The slight downward trends of frequency and intensity of extreme precipitation and the significant upward trend of drought indicator and extreme temperature indicated that extreme precipitation events did not change significantly, but tended to decrease slightly while the drought aggravated. Meanwhile, extreme temperature events became more severely and frequently and the length of winter shortened in Northeast China during the past 51 years.(3) Based on the measuresd data of the five main hydrological stations (Jiangqiao, Daben, Fuyu, Haerbin, and Jiamusi), the change trends of runoff and sediment were investigatived. Results showed that runoff of the five main stations presented a downward trend during 1958-2008. Among them, the decreasing trend of Daben, Haerbin and Jiamusi were significant at the 95% confidence level; the runoff of Jiamusi reduced in the rate of 5.50×108m3/yr, which is the greatest one. In the mean time, the sediment load of Daben, Fuyu and Haerbin showed significant decreasing trend while other two stations had insignificant increasing trend. The decreasing magnitude of sediment load at Harebin station was 8.55×104 t/yr, which was much larger than other stations.(4) The effects of climate change and human activeies on runoff and sediment in different stations of the Songhua River Basin during different periods were analyzed and assessed. In general, human activities play more important role in the evolutionary process of runoff and sediment, the percentage of affecting runoff and sediment load was 52.80% and 81.84%, respectively. In contrast, the changes of runoff and sediment were caused by climate change, with contribution being 47.20% for the former and 18.16% for the latter. The impact of climate change on the decrease of runoff has exceeded the impact of human activities gradually from the 1990s. The impact of human activities on sediment has been mitigated as time goes on, while climate change began to exert an increasing important influence on sediment load. In terms of regional variation, the runoff of middle and lower reaches of the Nenjiang River and the middle reaches of the main stream of the Songhua River were all greatly affected by climate change, and the influence extent of climate change on runoff tended to intensify as the years progressed. Conversely, human activities contributed 123.79% for the change of runoff in the second Songhua River and 156.32% for the lower reaches of the main stream of the Songhua River, which had greater impact than climate change. The impact of climate change and human activity on sediment load at different section is not completely corresponding exactly with the impact of the two on runoff. The impact of human activities on the change of sediment load exceeded that of climate change in the middle and lower reaches of the Nenjiang River and the lower researches of the Second Songhua River. The effect of human activities on the change of sediment load at the above three section were 94.09%, 145.74% and 86.36%. In the middle reaches of f the main stream of the Songhua River, climate change and human activities nearly had equal effect on the change of sediment load with the contribution of 52.77% and 47.23%. The sediment load in lower reaches of the main stream of the Songhua River was affected greatly by climate change in 1980s and 21st century, while human activitie play more important role for the change of sediment load in the 1990s, the percentage reach up to 96.86%.更多还原