Agricultural drought,characterized by insufficient soil moisture crucial for crop growth,poses significant chal lenges to food security and economic sustainability,particularly in water-scarce regions like Senegal.Thi...Agricultural drought,characterized by insufficient soil moisture crucial for crop growth,poses significant chal lenges to food security and economic sustainability,particularly in water-scarce regions like Senegal.This study addresses this issue by developing a comprehensive geospatial monitoring system for agricultural drought using the Regional Hydrologic Extremes Assessment System(RHEAS).This system,with a high-resolution of 0.05°,effectively simulates daily soil moisture and generates the Soil Moisture Deficit Index(SMDI)-based agricultural drought monitoring.The SMDI derived from the RHEAS has effectively captured historical droughts in Senegal over the recent 30 years period from 1993 to 2022.The SMDI,also provides a comprehensive understanding of regional variations in drought severity(S),duration(D),and frequency(F),through S-D-F analysis to identify key drought hotspots across Senegal.Findings reveal a distinct north-south gradient in drought conditions,with the northern and central Senegal experiencing more frequent and severe droughts.The study highlights that Senegal experiences frequent short-duration droughts with high severity,resulting in extensive spatial impact.Addition ally,increasing trends in drought severity and duration suggest evolving climate change effects.These findings emphasize the urgent need for sustainable interventions to mitigate drought impacts on agricultural productiv ity.Specifically,the study identifies recurrent and intense drought hotspots affecting yields of staple crops like maize and rice,as well as cash crops like peanuts.The developed high-resolution drought monitoring system for Senegal not only identifies hotspots but also enables prioritizing sustainable approaches and adaptive strategies,ultimately sustaining agricultural productivity and resilience in Senegal’s drought-prone regions.展开更多
Nowadays,spatiotemporal information,positioning,and navigation services have become critical components of new infrastructure.Precise positioning technology is indispensable for determining spatiotemporal information ...Nowadays,spatiotemporal information,positioning,and navigation services have become critical components of new infrastructure.Precise positioning technology is indispensable for determining spatiotemporal information and providing navigation services.展开更多
为实现遥感数字图像的快速显示,开发了基于QT和GDAL(Geospatial Data Abstraction Library)的遥感图像快速显示程序,并以ERDAS IMAGINE标准数据格式IMG图像文件为例,给出了Windows系统下IMG图像显示和坐标实时显示程序的环境配置过程、...为实现遥感数字图像的快速显示,开发了基于QT和GDAL(Geospatial Data Abstraction Library)的遥感图像快速显示程序,并以ERDAS IMAGINE标准数据格式IMG图像文件为例,给出了Windows系统下IMG图像显示和坐标实时显示程序的环境配置过程、开发框架、建立流程以及功能模块的实现。程序采用开源GDAL类库,以图形用户界面框架QT作为开发工具,Visual Studio 2008作为开发平台,采取多线程分块处理方法提取IMG数据中波段信息和坐标信息,实现IMG图像的快速显示以及坐标的实时显示。同时结合QT和GDAL进行开源程序的开发,改变了依赖于宿主软件进行二次开发的程序开发模式。研究结果表明,对于1.8 GByte遥感图像的显示,采用多线程分块处理方法,与单纯使用Raster IO()函数相比,处理时间缩短了2.7 s,提高了图像读取和显示效率以及程序开发的自主性,满足了大数据量的应用需求。展开更多
采用熔盐顶部籽晶法从K 2 Mo 3 O 10-B 2 O 3助熔剂中生长出尺寸为20 mm的优质GdAl 3(BO 3)4(简称GAB)和Nd^3+激活的自变频激光晶体。确定了GAB晶体的透光波长范围、折射率和倍频系数随波长的变化,结果表明其在整个透光范围内均可实现...采用熔盐顶部籽晶法从K 2 Mo 3 O 10-B 2 O 3助熔剂中生长出尺寸为20 mm的优质GdAl 3(BO 3)4(简称GAB)和Nd^3+激活的自变频激光晶体。确定了GAB晶体的透光波长范围、折射率和倍频系数随波长的变化,结果表明其在整个透光范围内均可实现相位匹配。测定了Nd^3+∶GAB晶体在室温下的偏振吸收、荧光光谱和荧光寿命,进行了光谱计算,测试了晶体的自变频激光性能,实现了紫外-可见光-红外-中红外多波段激光输出。展开更多
基金supported by the NASA(Grant No.80NSSC21K0403)USAID Kansas State University subcontract KSU-A20-0163-S035 with Michigan State University.
文摘Agricultural drought,characterized by insufficient soil moisture crucial for crop growth,poses significant chal lenges to food security and economic sustainability,particularly in water-scarce regions like Senegal.This study addresses this issue by developing a comprehensive geospatial monitoring system for agricultural drought using the Regional Hydrologic Extremes Assessment System(RHEAS).This system,with a high-resolution of 0.05°,effectively simulates daily soil moisture and generates the Soil Moisture Deficit Index(SMDI)-based agricultural drought monitoring.The SMDI derived from the RHEAS has effectively captured historical droughts in Senegal over the recent 30 years period from 1993 to 2022.The SMDI,also provides a comprehensive understanding of regional variations in drought severity(S),duration(D),and frequency(F),through S-D-F analysis to identify key drought hotspots across Senegal.Findings reveal a distinct north-south gradient in drought conditions,with the northern and central Senegal experiencing more frequent and severe droughts.The study highlights that Senegal experiences frequent short-duration droughts with high severity,resulting in extensive spatial impact.Addition ally,increasing trends in drought severity and duration suggest evolving climate change effects.These findings emphasize the urgent need for sustainable interventions to mitigate drought impacts on agricultural productiv ity.Specifically,the study identifies recurrent and intense drought hotspots affecting yields of staple crops like maize and rice,as well as cash crops like peanuts.The developed high-resolution drought monitoring system for Senegal not only identifies hotspots but also enables prioritizing sustainable approaches and adaptive strategies,ultimately sustaining agricultural productivity and resilience in Senegal’s drought-prone regions.
文摘Nowadays,spatiotemporal information,positioning,and navigation services have become critical components of new infrastructure.Precise positioning technology is indispensable for determining spatiotemporal information and providing navigation services.
文摘为实现遥感数字图像的快速显示,开发了基于QT和GDAL(Geospatial Data Abstraction Library)的遥感图像快速显示程序,并以ERDAS IMAGINE标准数据格式IMG图像文件为例,给出了Windows系统下IMG图像显示和坐标实时显示程序的环境配置过程、开发框架、建立流程以及功能模块的实现。程序采用开源GDAL类库,以图形用户界面框架QT作为开发工具,Visual Studio 2008作为开发平台,采取多线程分块处理方法提取IMG数据中波段信息和坐标信息,实现IMG图像的快速显示以及坐标的实时显示。同时结合QT和GDAL进行开源程序的开发,改变了依赖于宿主软件进行二次开发的程序开发模式。研究结果表明,对于1.8 GByte遥感图像的显示,采用多线程分块处理方法,与单纯使用Raster IO()函数相比,处理时间缩短了2.7 s,提高了图像读取和显示效率以及程序开发的自主性,满足了大数据量的应用需求。
文摘采用熔盐顶部籽晶法从K 2 Mo 3 O 10-B 2 O 3助熔剂中生长出尺寸为20 mm的优质GdAl 3(BO 3)4(简称GAB)和Nd^3+激活的自变频激光晶体。确定了GAB晶体的透光波长范围、折射率和倍频系数随波长的变化,结果表明其在整个透光范围内均可实现相位匹配。测定了Nd^3+∶GAB晶体在室温下的偏振吸收、荧光光谱和荧光寿命,进行了光谱计算,测试了晶体的自变频激光性能,实现了紫外-可见光-红外-中红外多波段激光输出。
文摘由于全球气候变暖造成海平面上升,致使沿海城市面临将来被海水淹没的威胁。利用GDAL(geospatial data abstraction library)和OpenCV(open source computer vision library)开发了淹没算法和模拟系统,使用GDAL库处理Landsat卫星数据和ASTRE GDEM(advanced spaceborne thermal emission and reflection radiometer global digital elevation model)高程数据,同时OpenCV Mat数据结构作为底层数据结构。系统实现了有源淹没算法及其可视化。该模拟系统可以为海岸城市淹没灾害预警提供有效的支持。
