Sand and dust storms （SDS） are common phenomena in arid and semi-arid areas. In recent years, SDS frequencies and intensities have increased significantly in Iran. A research on SDS sources is important for understa...Sand and dust storms （SDS） are common phenomena in arid and semi-arid areas. In recent years, SDS frequencies and intensities have increased significantly in Iran. A research on SDS sources is important for understanding the mechanisms of dust generation and assessing its socio-economic and environmental impacts. In this paper, we developed a new approach to identify SDS source areas in Iran using a combination of nine related datasets, namely drought events, temperature, precipitation, location of sandy soils, SDS frequency, hu- man-induced soil degradation （HISD）, human influence index （HII）, rain use efficiency （RUE） and net primary pro- ductivity （NPP） loss. To identify SDS source areas, we firstly normalized these datasets under uniform criteria in- cluding layer reprojection using Lambert conformal conic projection, data conversion from shapefile to raster, Min-Max Normalization with data range from 0 to 1, and data interpolation by Kriging and images resampling （resolution of 1 km）. After that, a score map for the possibility of SDS sources was generated through overlaying multiple datasets under average weight allocation criterion, in which each item obtained weight equally. In the score map, the higher the score, the more possible a specific area could be regarded as SDS source area. Exceptions mostly came from large cities, like Tehran and Isfahan. As a result, final SDS source areas were mapped out, and Al-Howizeh/Al-Azim marshes and Sistan Basin were identified as main SDS source areas in Iran. The SDS source area in Al-Howizeh/Al-Azim marshes still keeps expanding. In addition, Al-Howizeh/Al-Azim marshes are now suf- fering rapid land degradation due to natural and human-induced factors and might totally vanish in the near future. Sistan Basin also demonstrates the impacts of soil degradation and wind erosion. With appropriate intensity, dura- tion, wind speed and altitude of the dust storms, sand particles uplifting from this area might have developed into extreme dust storms, especially during the summer.展开更多
遥感影像是一种平面栅格数据,以一定的地图投影方式反映地球表面的表象。常规的标准遥感影像分幅产品是以一定的规则按照景来分幅的,不同的卫星影像,景的分幅和编码规则不同。遥感影像的景没有完全与地球上的地理坐标对应。为了使长时...遥感影像是一种平面栅格数据,以一定的地图投影方式反映地球表面的表象。常规的标准遥感影像分幅产品是以一定的规则按照景来分幅的,不同的卫星影像,景的分幅和编码规则不同。遥感影像的景没有完全与地球上的地理坐标对应。为了使长时序影像更容易查询、分析和管理,本文提出遥感影像即得即用(Ready To Use,RTU)地理格网产品,即将全球影像按照定义的格网系统剖分为具有统一规则和属性的数据格网。规定了遥感影像按照经纬坐标格网和直角坐标格网的分幅与编码方法和RTU地理格网产品规范,适用于不同空间分辨率的遥感影像按照不同投影地理格网的分幅与编码和RTU地理格网产品的生产。RTU地理格网产品具有使用灵活、格网编码与空间地理坐标相一致,可以按照空间维和时间维建立数据立方体,形成空间和时间上的连续产品,便于用户直接进行空间分析和应用。本规范为遥感影像共享和遥感信息整合提供以地理格网为单元的空间参照,可用于长时序、不同空间分辨率的遥感影像综合分析和应用。展开更多
遥感数据呈现大数据特征并广泛应用于资源调查、环境监测、灾害评估等领域,但其潜在的应用价值还没有被充分挖掘出来。遥感数据工程的建立将有助于遥感数据的智能分析和信息挖掘。即得即用(Ready To Use,RTU)产品具有辐射归一化、几何...遥感数据呈现大数据特征并广泛应用于资源调查、环境监测、灾害评估等领域,但其潜在的应用价值还没有被充分挖掘出来。遥感数据工程的建立将有助于遥感数据的智能分析和信息挖掘。即得即用(Ready To Use,RTU)产品具有辐射归一化、几何标准化、剖分网格化等特点,可直接用于后续的分析应用。RTU产品的研究开发是遥感数据工程的重要内容之一。以卫星遥感数据为基础,介绍了遥感数据RTU产品的定义与组成、RTU产品的标准规范、RTU地理格网剖分等,为用户使用RTU产品提供参考。多源卫星遥感数据RTU产品将持续不断地通过CASEarth DataBank系统(databank.casearth.cn)向管理工作者、行业应用者、科学研究者以及其他公众提供共享服务。展开更多
基金funded by the Small Scale Funding Agreement (UNEP/ROWA)
文摘Sand and dust storms （SDS） are common phenomena in arid and semi-arid areas. In recent years, SDS frequencies and intensities have increased significantly in Iran. A research on SDS sources is important for understanding the mechanisms of dust generation and assessing its socio-economic and environmental impacts. In this paper, we developed a new approach to identify SDS source areas in Iran using a combination of nine related datasets, namely drought events, temperature, precipitation, location of sandy soils, SDS frequency, hu- man-induced soil degradation （HISD）, human influence index （HII）, rain use efficiency （RUE） and net primary pro- ductivity （NPP） loss. To identify SDS source areas, we firstly normalized these datasets under uniform criteria in- cluding layer reprojection using Lambert conformal conic projection, data conversion from shapefile to raster, Min-Max Normalization with data range from 0 to 1, and data interpolation by Kriging and images resampling （resolution of 1 km）. After that, a score map for the possibility of SDS sources was generated through overlaying multiple datasets under average weight allocation criterion, in which each item obtained weight equally. In the score map, the higher the score, the more possible a specific area could be regarded as SDS source area. Exceptions mostly came from large cities, like Tehran and Isfahan. As a result, final SDS source areas were mapped out, and Al-Howizeh/Al-Azim marshes and Sistan Basin were identified as main SDS source areas in Iran. The SDS source area in Al-Howizeh/Al-Azim marshes still keeps expanding. In addition, Al-Howizeh/Al-Azim marshes are now suf- fering rapid land degradation due to natural and human-induced factors and might totally vanish in the near future. Sistan Basin also demonstrates the impacts of soil degradation and wind erosion. With appropriate intensity, dura- tion, wind speed and altitude of the dust storms, sand particles uplifting from this area might have developed into extreme dust storms, especially during the summer.
文摘遥感影像是一种平面栅格数据,以一定的地图投影方式反映地球表面的表象。常规的标准遥感影像分幅产品是以一定的规则按照景来分幅的,不同的卫星影像,景的分幅和编码规则不同。遥感影像的景没有完全与地球上的地理坐标对应。为了使长时序影像更容易查询、分析和管理,本文提出遥感影像即得即用(Ready To Use,RTU)地理格网产品,即将全球影像按照定义的格网系统剖分为具有统一规则和属性的数据格网。规定了遥感影像按照经纬坐标格网和直角坐标格网的分幅与编码方法和RTU地理格网产品规范,适用于不同空间分辨率的遥感影像按照不同投影地理格网的分幅与编码和RTU地理格网产品的生产。RTU地理格网产品具有使用灵活、格网编码与空间地理坐标相一致,可以按照空间维和时间维建立数据立方体,形成空间和时间上的连续产品,便于用户直接进行空间分析和应用。本规范为遥感影像共享和遥感信息整合提供以地理格网为单元的空间参照,可用于长时序、不同空间分辨率的遥感影像综合分析和应用。
文摘遥感数据呈现大数据特征并广泛应用于资源调查、环境监测、灾害评估等领域,但其潜在的应用价值还没有被充分挖掘出来。遥感数据工程的建立将有助于遥感数据的智能分析和信息挖掘。即得即用(Ready To Use,RTU)产品具有辐射归一化、几何标准化、剖分网格化等特点,可直接用于后续的分析应用。RTU产品的研究开发是遥感数据工程的重要内容之一。以卫星遥感数据为基础,介绍了遥感数据RTU产品的定义与组成、RTU产品的标准规范、RTU地理格网剖分等,为用户使用RTU产品提供参考。多源卫星遥感数据RTU产品将持续不断地通过CASEarth DataBank系统(databank.casearth.cn)向管理工作者、行业应用者、科学研究者以及其他公众提供共享服务。
