It is necessary to understand the aquatic chemical characteristics of natural surfacefresh water for water quality assessment. The chemical data from different kinds of water inthe central Guizhou karst area showed th...It is necessary to understand the aquatic chemical characteristics of natural surfacefresh water for water quality assessment. The chemical data from different kinds of water inthe central Guizhou karst area showed that spring water from carbonate rock cracks (crack-water) is of neutrality or meta-alkalinity and [C] Ca Ⅱ type. The amounts of all ions and theconcentrations of HCO3 and Ca2+ were higher in the autumn than in the spring. the crack-water was influenced by the infiltration of surface water in the process of erosion and/or transportation with decreasing HCO3- and increasing PH, SO, Cl, K+ and Na+ during runningin a certain distance on the land suffice. In particular, the chemical compeitions of the watersat Tianxingqiao (upper-stream), Shuiliandong (mid-waterfall) and Luoshuitan (down-pool)near the Huangguoshu Waterfall were much different from those of the crack-water. The concentrations of , Na+, Fe3+ and NO3- varied closely with seasons. The CaCO3 depositedviolently with CO2 release in the spring. In Lake Hongfeng the HCO3- /So- equivalent ratioswere only 2. 1 - 2. 4, but Ca2 + /Md+ up tO 2. 4 - 4. 2. The CI- concentration increased by afactor Of 1 and Na+ by order of magnitude relative to the spring water. These indicated the in-crease in artificial pollutant discharge in the Lake Hongfeng watershed. In addition, porewater in the soils coveing carbonate rocks belongs to strongly mineralized water. The obvious differences in water quality were controlled by carbonate despition, sulphate mineralization and nitrogen fixation as well as ammonification. It is indicated that the chemical compeitions in thewaters from the karst region were unstable and changeable.展开更多
Understanding the evolution of karst rocky desertification (KRD) quantitatively is essential to obtain objective knowledge about the concept of KRD and the form reason of KRD, and is useful to restore KRD land. Houzha...Understanding the evolution of karst rocky desertification (KRD) quantitatively is essential to obtain objective knowledge about the concept of KRD and the form reason of KRD, and is useful to restore KRD land. Houzhaihe area located in central plateau in Guizhou Province was studied here as a representative assemblage landform and its KRD’ s evolution and driving factors were studied, based mainly on high-resolution remote sensing image in 1963, 1978, 2005 and 2010. The KRD land comprises light KRD, moderate KRD and severe KRD. The results demonstrated that the evolution process of KRD can be divided into four modes such as unchanged, weakened, fluctuated and aggravated in the study area. The KRD with no changes from 1963 to 2010, namely, unchanged mode, accounted for 43.76% of the total area of the KRD in 2010;it distributed in the area with the slope of 15° - 25° and >25° basically. Furthermore, the severe KRD distributed mainly in the areas within 300 - 600 m distance from settlement;when the distance away from the rural settlements was more than 900 m, the severe KRD declined, and its proportion was 28.6% and 10.6% in 1963 and 2010 respectively. In the peak-cluster depressions, located in central study area, the slope cropland with slope of 15° - 25° was still abounding, and was seriously rocky desertification generally. So, we propose that the existence of a large number of slope croplands is still the major driving factor of land rocky desertification. Therefore, for the rocky desertification control, the authors consider that the focal point is to alter the land use of steep-slope cropland at present.展开更多
贵州高原具有少日照、多云雨和复杂下垫面的山地特殊气候和地形,准确探究该区域生态系统水分利用效率(WUE)的时空分异特征对进一步了解喀斯特地区碳水循环过程具有重要意义。本文气象站点数据用ANUSPLIN软件进行插值处理,与使用时间序...贵州高原具有少日照、多云雨和复杂下垫面的山地特殊气候和地形,准确探究该区域生态系统水分利用效率(WUE)的时空分异特征对进一步了解喀斯特地区碳水循环过程具有重要意义。本文气象站点数据用ANUSPLIN软件进行插值处理,与使用时间序列谐波分析法和质量控制文件重新构建高质量的MODIS-NDVI数据作为CASA模型的输入数据模拟植被NPP,再结合MOD16-ET数据估算WUE。综合利用Theil-Sen Median趋势分析、Mann-Kendall检验和稳定性分析等统计方法,对贵州高原2000—2014年各地貌区、植被类型WUE的时空分异特征进行对比分析。研究表明:(1)研究区近15年来WUE均值和趋势的空间格局都呈西部高于东部的特点, WUE趋势呈显著增加态势( R^2 =0.63, P <0.001)。(2)从各地貌区来看,多年WUE均值排序为:断陷盆地>岩溶峡谷>峰丛洼地>非喀斯特地貌>岩溶高原>岩溶槽谷,其中断陷盆地和岩溶峡谷呈显著( P <0.05)增加趋势。(3)从不同植被类型来看, WUE大小呈混交林>阔叶林>耕地>针叶林>草地>灌丛排序。针叶林和灌丛变异系数(CV)值较高,但前者对气候波动的抵挡能力更强,增加速率更快。草地CV值最低,变化速率最慢,不易受气候波动的影响。由于退耕还林等生态工程的实施效果显著,使耕地WUE的变化速率最快。展开更多
文摘It is necessary to understand the aquatic chemical characteristics of natural surfacefresh water for water quality assessment. The chemical data from different kinds of water inthe central Guizhou karst area showed that spring water from carbonate rock cracks (crack-water) is of neutrality or meta-alkalinity and [C] Ca Ⅱ type. The amounts of all ions and theconcentrations of HCO3 and Ca2+ were higher in the autumn than in the spring. the crack-water was influenced by the infiltration of surface water in the process of erosion and/or transportation with decreasing HCO3- and increasing PH, SO, Cl, K+ and Na+ during runningin a certain distance on the land suffice. In particular, the chemical compeitions of the watersat Tianxingqiao (upper-stream), Shuiliandong (mid-waterfall) and Luoshuitan (down-pool)near the Huangguoshu Waterfall were much different from those of the crack-water. The concentrations of , Na+, Fe3+ and NO3- varied closely with seasons. The CaCO3 depositedviolently with CO2 release in the spring. In Lake Hongfeng the HCO3- /So- equivalent ratioswere only 2. 1 - 2. 4, but Ca2 + /Md+ up tO 2. 4 - 4. 2. The CI- concentration increased by afactor Of 1 and Na+ by order of magnitude relative to the spring water. These indicated the in-crease in artificial pollutant discharge in the Lake Hongfeng watershed. In addition, porewater in the soils coveing carbonate rocks belongs to strongly mineralized water. The obvious differences in water quality were controlled by carbonate despition, sulphate mineralization and nitrogen fixation as well as ammonification. It is indicated that the chemical compeitions in thewaters from the karst region were unstable and changeable.
文摘Understanding the evolution of karst rocky desertification (KRD) quantitatively is essential to obtain objective knowledge about the concept of KRD and the form reason of KRD, and is useful to restore KRD land. Houzhaihe area located in central plateau in Guizhou Province was studied here as a representative assemblage landform and its KRD’ s evolution and driving factors were studied, based mainly on high-resolution remote sensing image in 1963, 1978, 2005 and 2010. The KRD land comprises light KRD, moderate KRD and severe KRD. The results demonstrated that the evolution process of KRD can be divided into four modes such as unchanged, weakened, fluctuated and aggravated in the study area. The KRD with no changes from 1963 to 2010, namely, unchanged mode, accounted for 43.76% of the total area of the KRD in 2010;it distributed in the area with the slope of 15° - 25° and >25° basically. Furthermore, the severe KRD distributed mainly in the areas within 300 - 600 m distance from settlement;when the distance away from the rural settlements was more than 900 m, the severe KRD declined, and its proportion was 28.6% and 10.6% in 1963 and 2010 respectively. In the peak-cluster depressions, located in central study area, the slope cropland with slope of 15° - 25° was still abounding, and was seriously rocky desertification generally. So, we propose that the existence of a large number of slope croplands is still the major driving factor of land rocky desertification. Therefore, for the rocky desertification control, the authors consider that the focal point is to alter the land use of steep-slope cropland at present.
文摘贵州高原具有少日照、多云雨和复杂下垫面的山地特殊气候和地形,准确探究该区域生态系统水分利用效率(WUE)的时空分异特征对进一步了解喀斯特地区碳水循环过程具有重要意义。本文气象站点数据用ANUSPLIN软件进行插值处理,与使用时间序列谐波分析法和质量控制文件重新构建高质量的MODIS-NDVI数据作为CASA模型的输入数据模拟植被NPP,再结合MOD16-ET数据估算WUE。综合利用Theil-Sen Median趋势分析、Mann-Kendall检验和稳定性分析等统计方法,对贵州高原2000—2014年各地貌区、植被类型WUE的时空分异特征进行对比分析。研究表明:(1)研究区近15年来WUE均值和趋势的空间格局都呈西部高于东部的特点, WUE趋势呈显著增加态势( R^2 =0.63, P <0.001)。(2)从各地貌区来看,多年WUE均值排序为:断陷盆地>岩溶峡谷>峰丛洼地>非喀斯特地貌>岩溶高原>岩溶槽谷,其中断陷盆地和岩溶峡谷呈显著( P <0.05)增加趋势。(3)从不同植被类型来看, WUE大小呈混交林>阔叶林>耕地>针叶林>草地>灌丛排序。针叶林和灌丛变异系数(CV)值较高,但前者对气候波动的抵挡能力更强,增加速率更快。草地CV值最低,变化速率最慢,不易受气候波动的影响。由于退耕还林等生态工程的实施效果显著,使耕地WUE的变化速率最快。
