本文選題：極端氣候變化 + 土地利用時(shí)空變化��； 參考：《西北農(nóng)林科技大學(xué)》2017年博士論文

【摘要】：研究氣候變化和人類活動(dòng)對(duì)流域水沙變化的影響,不但為流域水沙災(zāi)害的預(yù)警提供理論支持,也為科學(xué)評(píng)價(jià)生態(tài)建設(shè)的環(huán)境效應(yīng)提供重要科學(xué)依據(jù)。本論文針對(duì)當(dāng)前極端降水變化和土地利用空間格局對(duì)流域水沙影響研究的不足,以黃河中游黃土丘陵溝壑區(qū)小理河流域?yàn)檠芯繀^(qū),采用滑動(dòng)平均、距平分析、Sen斜率估計(jì)法、Mann-Kendall非參數(shù)檢驗(yàn)和突變點(diǎn)檢驗(yàn)法等,分析了小理河流域1959-2013年極端降水、極端氣溫、徑流、泥沙的動(dòng)態(tài)變化特征;利用GIS技術(shù)和土地利用轉(zhuǎn)移矩陣、土地利用動(dòng)態(tài)度、空間自相關(guān)格局分析、景觀格局分析等方法,分析了小理河流域1990年以來(lái)土地利用的時(shí)空過(guò)程、土地利用空間自相關(guān)格局、土地利用景觀格局的時(shí)空變化及其隨地形變化的空間分異特征;基于對(duì)徑流和泥沙突變點(diǎn)檢驗(yàn),篩選了影響流域徑流和輸沙的最優(yōu)極端降水指標(biāo),利用雙累積曲線法和回歸分析法量化了極端降水變化和人類活動(dòng)對(duì)流域徑流泥沙變化的貢獻(xiàn)率;在對(duì)SWAT模型參數(shù)率定和模型驗(yàn)證的基礎(chǔ)上,通過(guò)輸入不同的土地利用和氣候情景,探討流域徑流泥沙對(duì)土地利用景觀格局變化的響應(yīng)機(jī)制,并定量研究流域徑流泥沙對(duì)氣候變化、土地利用變化和其他人類活動(dòng)的響應(yīng)特征。主要研究結(jié)論如下:(1)55 a間,年、汛期、春季、夏季、秋季降水量皆呈不顯著減少趨勢(shì),而冬季降水量呈不顯著增加趨勢(shì)。17個(gè)極端降水指標(biāo)(R10、R20、R50、R10p、R20p、R50p、R1d、R5d、SDII、R90p、R90t、R95p、R95t、R99p、R99t、CDD、CWD)中,僅最長(zhǎng)連續(xù)干旱天數(shù)CDD和平均降水強(qiáng)度SDII呈不顯著增加趨勢(shì),而其他15個(gè)極端降水指標(biāo)均呈不顯著減少趨勢(shì)。年和四季平均氣溫均呈增加趨勢(shì),其中,年、春季、冬季氣溫呈顯著增加趨勢(shì)。16個(gè)極端氣溫指標(biāo)中,冷指標(biāo)(FD、ID、TN10p、TX10p、TNn、CSDI)呈減少趨勢(shì),其中ID、TX10p、TN10p呈顯著減少趨勢(shì);暖指標(biāo)(TR、HD、SU、TN90p、TX90p、TNx、TXn、TXx、WSDI和DTR)呈增加趨勢(shì),其中SU、DTR、HD、TN90p呈顯著增加趨勢(shì),說(shuō)明流域變暖趨勢(shì)明顯。(2)流域各土地利用類型都表現(xiàn)出全局空間正自相關(guān)特性,但空間正自相關(guān)性隨著距離的增加而逐漸減弱。土地利用類型存在不同的局部空間聚集或異常特征,局部聚集區(qū)隨高程、坡度和坡向的變化呈現(xiàn)空間分異。從1990年到2009年,流域景觀格局破碎化程度增高,景觀形狀趨于復(fù)雜化,景觀類型趨于多樣化,景觀異質(zhì)性增加。景觀格局指數(shù)與高程、坡度和坡向有顯著的相關(guān)性。(3)55 a間,流域年、汛期徑流量和輸沙量呈極顯著減少趨勢(shì),年和汛期徑流量年均減少量分別為29.13×104 m3和18.6×104 m3,年和汛期輸沙量年均減少量分別為6.33×104 t和6.49×104 t。1970年為小理河流域徑流泥沙變化的突變年。據(jù)此,將整個(gè)研究時(shí)段劃分為兩個(gè)時(shí)期:1959-1970年基準(zhǔn)期(天然情景期)和1971-2013年措施期。與基準(zhǔn)期相比,措施期年和汛期徑流量分別減少近40%和50%,年和汛期輸沙量分別減少近72%。在基準(zhǔn)期,流域徑流量和輸沙量與降水量、汛期降水量和16個(gè)極端降水指標(biāo)之間相關(guān)系數(shù)變化于0.28~0.9之間,而在措施期流域徑流量和輸沙量與各降水指標(biāo)之間相關(guān)系數(shù)變化于0.18~0.62之間;說(shuō)明在基準(zhǔn)期徑流量、輸沙量受降水影響較大,而在措施期徑流量、輸沙量受到降水和人類活動(dòng)二者共同影響。在基準(zhǔn)期、措施期和整個(gè)研究期,R90p(大于1961-1990年90%分位值的降水量總量)是各降水指標(biāo)中與徑流量、輸沙量相關(guān)性最好的降水指標(biāo)。(4)以R90p作為表征極端降水的最佳降水指標(biāo),評(píng)估了極端降水變化和人類活動(dòng)對(duì)流域徑流泥沙變化的貢獻(xiàn)率。結(jié)果表明,在20世紀(jì)70、80年代和1999-2013年,人類活動(dòng)是影響流域徑流泥沙變化的主要因素,人類活動(dòng)對(duì)徑流量減少的貢獻(xiàn)率分別為57.3%、62.1%和75.4%,人類活動(dòng)對(duì)輸沙量減少的貢獻(xiàn)率分別為91.8%、92.9%和90.3%,人類活動(dòng)對(duì)輸沙量的影響大于其對(duì)徑流量的影響。而在1990-1998年,極端降水變化是影響流域徑流泥沙變化的主要因素,R90p對(duì)徑流量、輸沙量減少的貢獻(xiàn)率分別為78.2%和57.9%,極端降水變化對(duì)徑流量的影響大于其對(duì)輸沙量的影響。(5)構(gòu)建了適用于小理河流域的SWAT模型參數(shù)庫(kù),通過(guò)模型參數(shù)敏感性分析、率定和模型精度驗(yàn)證,模擬效果評(píng)價(jià)指標(biāo)R2、NSE和PBAIS分別在0.84~0.89、0.80~0.86和-7.6%~2.3%之間,說(shuō)明模型模擬效果較好�；诼识ǖ腟WAT模型,輸入不同的土地利用和氣候情景,分析了流域土地利用景觀格局變化對(duì)徑流和泥沙的影響,評(píng)估了氣候變化、土地利用變化和其他人類活動(dòng)對(duì)流域徑流泥沙變化的貢獻(xiàn)率。結(jié)果表明:流域土地利用景觀格局顯著影響流域徑流和輸沙。流域徑流量和輸沙量與斑塊數(shù)量、斑塊密度、景觀形狀指數(shù)和香農(nóng)多樣性指數(shù)呈顯著正相關(guān),而二者與最大斑塊面積比例、斑塊凝聚度、斑塊蔓延度和香農(nóng)均勻度指數(shù)呈顯著負(fù)相關(guān)。以1971-1998年為基準(zhǔn),1999-2013年氣候變化和土地利用變化對(duì)徑流減少的貢獻(xiàn)率分別為29.8%和70.2%,對(duì)輸沙量減少的貢獻(xiàn)率分別為13%和87%。同時(shí),1999-2013年土地利用變化以外的其他人類活動(dòng)(如工程建設(shè)、水保措施等)對(duì)流域徑流量、輸沙量減少的貢獻(xiàn)率分別為5.2%和3.4%。
[Abstract]:The study of the effects of climate change and human activities on water and sediment changes in the basin not only provides theoretical support for the early warning of water and sediment disasters in the basin, but also provides an important scientific basis for the scientific evaluation of the environmental effects of ecological construction. The Xiali River Basin in the middle reaches of the middle reaches of the river is the study area. The dynamic changes of extreme precipitation, extreme temperature, runoff and sediment in the 1959-2013 years of the Xiaoli River Basin are analyzed by means of sliding average, anomaly analysis, Sen slope estimation, Mann-Kendall nonparametric test and mutation point test. The GIS technology and the transfer moment of land use are used. Array, land use dynamics, spatial autocorrelation analysis and landscape pattern analysis, the spatio-temporal process of land use in the Xiaoli River Basin since 1990, the spatial autocorrelation pattern of land use, spatial and temporal variation of land use landscape pattern and the spatial differentiation characteristics with the terrain change, based on the change of runoff and sediment The optimal extreme precipitation indexes affecting runoff and sediment transport are screened. The contribution rate of extreme precipitation changes and human activities to runoff and sediment changes in watershed is quantified by using double cumulative curve method and regression analysis method. On the basis of parameter rate determination and model verification of SWAT model, different land use and climate scenarios are input. The response mechanism of runoff and sediment on land use landscape pattern changes is discussed, and the response characteristics of runoff and sediment on climate change, land use change and other human activities are studied. The main conclusions are as follows: (1) 55 A, year, flood season, spring, summer, and autumn precipitation are not significantly reduced, and winter precipitation No significant increase trend of.17 extreme precipitation index (R10, R20, R50, R10p, R20p, R50p, R1d, R5d, SDII, R90p), only the longest continuous drought days and average precipitation intensity, but the other 15 extreme precipitation indexes are not significantly reduced. The cold index (FD, ID, TN10p, TX10p, TNn, CSDI) showed a decreasing trend in the year, spring, and winter temperature, in which the cold index (ID, TX10p, TN10p, CSDI) showed a decreasing trend, and the warm index (TR, HD, ID) showed an increasing trend. It shows that the trend of watershed warming is obvious. (2) all types of land use in the basin show the positive autocorrelation in the global space, but the positive autocorrelation of the space gradually decreases with the increase of distance. There are different local spatial aggregation or abnormal characteristics of the land use type, and the local agglomeration area presents the space with the elevation, the slope and the slope direction. From 1990 to 2009, landscape pattern fragmentation increased, landscape shape tended to be complex, landscape type tended to diversify and landscape heterogeneity increased. The landscape pattern index was significantly correlated with elevation, slope and slope direction. (3) 55 A, river basin year, flood season runoff and sediment transport volume showed a very significant reduction trend, year and flood period diameter The annual decrease of flow rate is 29.13 x 104 m3 and 18.6 x 104 m3 respectively. The annual and flood sediment transport annual average decrease is 6.33 x 104 T and 6.49 x 104 t.1970 year is the change year of runoff and sediment in the Xiaoli River Basin. According to this, the whole study period is divided into two periods: 1959-1970 years datum period (NATURAL scenario period) and 1971-2013 year period. Compared with the datum period, the annual and flood period runoff decreased by nearly 40% and 50% respectively, and the sediment transport in the year and flood season decreased by nearly 72%. in the datum period, and the correlation coefficient between the runoff and sediment discharge and the precipitation, the precipitation in the flood season and the 16 extreme precipitation indexes changed in the 0.28~0.9. The correlation coefficient between precipitation indexes varies between 0.18~0.62, indicating that in the base period runoff, sediment transport is greatly influenced by precipitation, while in the period of measure runoff, the amount of sediment is affected by the two people of precipitation and human activities. In the datum period, in the period of measure and in the whole study period, the total amount of R90p (the total amount of precipitation over 1961-1990 years 90%) is reduced. In the water index, the best precipitation index related to runoff and sediment transport is the best. (4) R90p is used as the best precipitation indicator for extreme precipitation, and the contribution rate of extreme precipitation and human activity to runoff and sediment change in river basin is evaluated. The results show that in the twentieth Century and 1999-2013 years, human activity was the influence of runoff and sediment change in the basin. The contribution rate of human activity to runoff reduction is 57.3%, 62.1% and 75.4% respectively. The contribution rate of human activities to sediment transport is 91.8%, 92.9% and 90.3%, respectively. The effect of human activity on sediment transport is greater than that of its runoff. In the 1990-1998 year, the change of extreme precipitation is the main factor affecting the change of runoff and sediment in the basin. The contribution rate of R90p to the decrease of runoff and sediment transport is 78.2% and 57.9% respectively. The influence of extreme precipitation on the runoff is greater than that of its effect on the sediment transport. (5) a parameter library of SWAT model suitable for the Xiaoli river basin is constructed, and the model parameter sensitivity analysis, rate determination and model accuracy verification, and the simulation effect evaluation index R2, NSE And PBAIS between 0.84~0.89,0.80~0.86 and -7.6%~2.3%, respectively, indicating that model simulation results are better. Based on the rate determined SWAT model, input different land use and climate scenarios, analyze the effects of landscape pattern changes on runoff and sediment, and evaluate the climate change, land use change and other human activities to the basin. The results showed that the landscape pattern of the land use landscape significantly affected the runoff and sediment transport in the basin. The runoff and sediment yield of the basin were significantly positively correlated with the number of patches, patch density, the landscape shape index and the Shannon diversity index, while the proportion of the two and the largest patch area, the degree of patch cohesion, the spread of plaque and the fragrance of the scent. The agricultural evenness index has a significant negative correlation. The contribution rate of the 1999-2013 year climate change and the land use change to the runoff reduction is 29.8% and 70.2%, respectively, and the contribution rate to the decrease of sediment transport is 13% and 87%., respectively, and other human activities other than the change of land use for 1999-2013 years (such as engineering construction and water conservation measures). The contribution rates to runoff and sediment discharge were 5.2% and 3.4%. respectively.

【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：F301.2;P333;P467
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本文編號(hào)：1896042