The goal of this paper was to present knowledge on changes in the morphodynamic structure of the Ochotnica River(Polish Carpathians)and transformations within its active river zone since the end of the 19th century.Th...The goal of this paper was to present knowledge on changes in the morphodynamic structure of the Ochotnica River(Polish Carpathians)and transformations within its active river zone since the end of the 19th century.The study used a set of archival and contemporary cartographic materials and the results of three-fold field mapping of the morphodynamic structure of the riverbed.Direct and indirect human interference with the natural environment of the catchment and the fluvial system was taken into account in the analysis.Analysis of changes in the morphodynamic structure of the Ochotnica and its active river zone since the end of the 19th century indicated significant changes in the development trend of the riverbed.The contemporary structure of the Ochotnica is more complex than in the 1980s.There has been a fragmentation of the riverbed into sections with different morphodynamic sections.The proportion of erosive sections has increased,which explains the reduced in the width of the active river zone of the Ochotnica.The average width of the active river zone of the river between 1861 and 2022 has changed from 80 m to 18 m.Human impact has been identified as the main reason for the changes in the morphodynamic structure of the riverbed and its active river zone.Currently,only the unregulated sect ion is characterised by free lateral migration of the riverbed and the widest active river zone(~28 m).展开更多
利用黄土高原无定河流域1982～1991年的水文气象、土地利用、土壤质地、数字高程和NOAA-AVHRR遥感信息,建立基于土壤-植被-大气传输机理的分布式生态水文模型,模拟流域水量平衡的时空分布.研究结果发现,该流域的年平均植被指数(NDVI)的...利用黄土高原无定河流域1982～1991年的水文气象、土地利用、土壤质地、数字高程和NOAA-AVHRR遥感信息,建立基于土壤-植被-大气传输机理的分布式生态水文模型,模拟流域水量平衡的时空分布.研究结果发现,该流域的年平均植被指数(NDVI)的年际变化不明显,但NDVI最大值的年际变化显著.该流域年累计NDVI与降水年总量关系不明显,说明该流域植被的生长并不完全受控于降水总量.模拟的实际蒸散量用无定河及其岔巴沟子流域实测降水与实测径流的差值进行验证,误差小于5%.整个流域模拟时段的平均降水量为372±53 mm yr-1,实际蒸散量为334±33 mm yr-1,其中蒸腾为130±21 mm yr-1,有明显的年际波动.地表径流的年际变化相对较小.蒸散发的季节变化特征与降雨基本一致,即7、8、9月雨季高,其他月份低.降水量和实际蒸散量呈现显著的空间分异性,表现出由东南(高NDVI)向西北(低NDVI)递减的梯度差异.地表径流的空间分异亦沿东南-西北梯度变化,但高值分散在中部.以岔巴沟子流域1991年的地表覆被度为基准,发现在全流域都覆盖上某一种植被的情况下,蒸腾和土壤蒸发的变化非常明显,地表径流和实际总蒸散的变化并不显著.只有在全流域都变成荒漠情景下,实际总蒸散才显示出较明显变化(17%),表明在西北干旱半干旱区,土地利用/覆被变化对水量平衡的影响非常复杂.展开更多
基金supported by a grant from the Faculty of Geography ang Geology under the Strategic Programme Excellence Initiative at Jagiellonian University.
文摘The goal of this paper was to present knowledge on changes in the morphodynamic structure of the Ochotnica River(Polish Carpathians)and transformations within its active river zone since the end of the 19th century.The study used a set of archival and contemporary cartographic materials and the results of three-fold field mapping of the morphodynamic structure of the riverbed.Direct and indirect human interference with the natural environment of the catchment and the fluvial system was taken into account in the analysis.Analysis of changes in the morphodynamic structure of the Ochotnica and its active river zone since the end of the 19th century indicated significant changes in the development trend of the riverbed.The contemporary structure of the Ochotnica is more complex than in the 1980s.There has been a fragmentation of the riverbed into sections with different morphodynamic sections.The proportion of erosive sections has increased,which explains the reduced in the width of the active river zone of the Ochotnica.The average width of the active river zone of the river between 1861 and 2022 has changed from 80 m to 18 m.Human impact has been identified as the main reason for the changes in the morphodynamic structure of the riverbed and its active river zone.Currently,only the unregulated sect ion is characterised by free lateral migration of the riverbed and the widest active river zone(~28 m).
文摘利用黄土高原无定河流域1982～1991年的水文气象、土地利用、土壤质地、数字高程和NOAA-AVHRR遥感信息,建立基于土壤-植被-大气传输机理的分布式生态水文模型,模拟流域水量平衡的时空分布.研究结果发现,该流域的年平均植被指数(NDVI)的年际变化不明显,但NDVI最大值的年际变化显著.该流域年累计NDVI与降水年总量关系不明显,说明该流域植被的生长并不完全受控于降水总量.模拟的实际蒸散量用无定河及其岔巴沟子流域实测降水与实测径流的差值进行验证,误差小于5%.整个流域模拟时段的平均降水量为372±53 mm yr-1,实际蒸散量为334±33 mm yr-1,其中蒸腾为130±21 mm yr-1,有明显的年际波动.地表径流的年际变化相对较小.蒸散发的季节变化特征与降雨基本一致,即7、8、9月雨季高,其他月份低.降水量和实际蒸散量呈现显著的空间分异性,表现出由东南(高NDVI)向西北(低NDVI)递减的梯度差异.地表径流的空间分异亦沿东南-西北梯度变化,但高值分散在中部.以岔巴沟子流域1991年的地表覆被度为基准,发现在全流域都覆盖上某一种植被的情况下,蒸腾和土壤蒸发的变化非常明显,地表径流和实际总蒸散的变化并不显著.只有在全流域都变成荒漠情景下,实际总蒸散才显示出较明显变化(17%),表明在西北干旱半干旱区,土地利用/覆被变化对水量平衡的影响非常复杂.
