为了更加深刻地理解气候和地形条件对土地覆盖的作用机理,该研究以2001年-2009年逐年的MODIS Land Cover(MCD12Q1)为主要数据源,参考中国土地覆盖分类体系整合国际上通用的5种(IGBP、UMD、LAI-fPAR、NPP和PFT)土地覆盖分类体系,分析年...为了更加深刻地理解气候和地形条件对土地覆盖的作用机理,该研究以2001年-2009年逐年的MODIS Land Cover(MCD12Q1)为主要数据源,参考中国土地覆盖分类体系整合国际上通用的5种(IGBP、UMD、LAI-fPAR、NPP和PFT)土地覆盖分类体系,分析年际尺度上中国西北干旱半干旱地区的土地覆盖时空分异及其对气候和地形的响应。研究结果表明:IGBP较其他4种更适合年际尺度上干旱半干旱地区土地覆盖的时空分异研究。2001年-2009年,5种分类体系中农田和草地增加,水体湿地和荒漠减少,聚落保持不变,森林有增有减,并且土地覆盖类型间相互发生转换,其在空间上的转移与干旱半干旱地区的自然条件变化和人类活动相适应。6种土地覆盖类型对自然条件的响应与光、热、水在时空格局上的分配以及人类活动作用的强弱相一致。研究结果可为区域或全球土地利用和土地覆盖研究提供参考。展开更多
Floods are the most common type of natural disaster in the world and one of the most damaging.Changes in weather conditions such as precipitation and temperature result in changes in discharge.To better understand the...Floods are the most common type of natural disaster in the world and one of the most damaging.Changes in weather conditions such as precipitation and temperature result in changes in discharge.To better understand the floods and eventually develop a system to predict them,we must analyze in more detail the flow of rivers.The purpose of this article is to analyze the discharges in the upper Senegal River Basin by focusing on determining the limits of the climatic classification according to past discharges.The daily discharges from May 1,1950 to April 30,2018 were chosen as the study period.These flow data have been grouped into annual discharges and classified as very wet,moist,medium,dry and very dry each year.Then,the flow data were divided into two seasons or periods each year:high water and low water.The statistical variables used in this study are the average,the standard deviation,the coefficient of variation and the skewness.The results of the climate classification that corresponds to a log-normal distribution indicate a total of 17 years classified as averages(25%of the series),14 classified as wet(20.6%),29 classified as dry(42.6%)and 8 classified as very wet(11.8%),very dry classifications being nil.Seasonal analysis showed that the months of the high water period,such as September,had the highest flow,and the period of low water,such as May,had the lowest flow.The results of the flow analysis were then compared with changes in rainfall.The results obtained show similar climatic classifications between rainfall and flow in the basin.展开更多
文摘为了更加深刻地理解气候和地形条件对土地覆盖的作用机理,该研究以2001年-2009年逐年的MODIS Land Cover(MCD12Q1)为主要数据源,参考中国土地覆盖分类体系整合国际上通用的5种(IGBP、UMD、LAI-fPAR、NPP和PFT)土地覆盖分类体系,分析年际尺度上中国西北干旱半干旱地区的土地覆盖时空分异及其对气候和地形的响应。研究结果表明:IGBP较其他4种更适合年际尺度上干旱半干旱地区土地覆盖的时空分异研究。2001年-2009年,5种分类体系中农田和草地增加,水体湿地和荒漠减少,聚落保持不变,森林有增有减,并且土地覆盖类型间相互发生转换,其在空间上的转移与干旱半干旱地区的自然条件变化和人类活动相适应。6种土地覆盖类型对自然条件的响应与光、热、水在时空格局上的分配以及人类活动作用的强弱相一致。研究结果可为区域或全球土地利用和土地覆盖研究提供参考。
文摘Floods are the most common type of natural disaster in the world and one of the most damaging.Changes in weather conditions such as precipitation and temperature result in changes in discharge.To better understand the floods and eventually develop a system to predict them,we must analyze in more detail the flow of rivers.The purpose of this article is to analyze the discharges in the upper Senegal River Basin by focusing on determining the limits of the climatic classification according to past discharges.The daily discharges from May 1,1950 to April 30,2018 were chosen as the study period.These flow data have been grouped into annual discharges and classified as very wet,moist,medium,dry and very dry each year.Then,the flow data were divided into two seasons or periods each year:high water and low water.The statistical variables used in this study are the average,the standard deviation,the coefficient of variation and the skewness.The results of the climate classification that corresponds to a log-normal distribution indicate a total of 17 years classified as averages(25%of the series),14 classified as wet(20.6%),29 classified as dry(42.6%)and 8 classified as very wet(11.8%),very dry classifications being nil.Seasonal analysis showed that the months of the high water period,such as September,had the highest flow,and the period of low water,such as May,had the lowest flow.The results of the flow analysis were then compared with changes in rainfall.The results obtained show similar climatic classifications between rainfall and flow in the basin.
