塔中涡动资料不同坐标旋转方法比较分析     

李振杰  何清-  金莉莉  买买提艾力.买买提依明  赵佳伟 《沙漠与绿洲气象(新疆气象)》2019,13(3):105-111

坐标旋转是涡动协方差(EC)通量观测数据后处理当中必须进行的步骤,本文利用塔克拉玛干沙漠腹地塔中西面标校站自然沙丘上3 m高度和塔中本站32 m高度2009年4—10月湍流通量数据,对比分析了不同坐标旋转方法在塔中通量观测数据中的应用。结果表明,塔克拉玛干沙漠腹地塔中湍流各通量在旋转订正前后差别不显著,不订正造成的通量计算误差1%。塔中32 m和塔中西站3 m通量计算误差,与两个站点的采集仪器架设高度差别较大有关。即使对于相对平坦的下垫面,也必须要进行倾斜校正,以修正地势、仪器振动、安装倾斜等产生的虚假信息。本研究对塔中涡动资料进行旋转时采用了二次坐标旋转方法。此结果为塔克拉玛干沙漠腹地EC通量观测的风速仪倾斜校正提供参考。  相似文献   

新疆沙尘暴研究进展     

买买提艾力·买买提依明  霍文  杨兴华  王敏仲  杨帆  刘艳  孟露  潘红林  李红军  金莉莉  何清 《沙漠与绿洲气象(新疆气象)》2022,16(2):1-7

沙尘暴是风蚀荒漠化中的一种天气现象,既是加速土地荒漠化的重要过程,又是土地荒漠化发展到一定程度的具体体现.新疆地处我国西北干旱、半干旱区,是我国荒漠化土地最多的省区,也是风沙危害最严重的地区之一.重点论述了新疆地区沙尘暴的若干研究进展,从6个方面对沙尘暴的形成及研究现状进行综述,即新疆沙尘暴气候背景、长期变化趋势、分布...  相似文献   

The Chinese Carbon-Neutral Goal: Challenges and Prospects     

Ning ZENG  Kejun JIANG  Pengfei HAN  Zeke HAUSFATHER  Junji CAO  Daniel KIRK-DAVIDOFF  Shaukat ALI  Sheng ZHOU 《大气科学进展》2022,39(8):1229-1238

On 22 September 2020, within the backdrop of the COVID-19 global pandemic, China announced its climate goal for peak carbon emissions before 2030 and to reach carbon neutrality before 2060. This carbon-neutral goal is generally considered to cover all anthropogenic greenhouse gases. The planning effort is now in full swing in China, but the pathway to decarbonization is unclear. The needed transition towards non-fossil fuel energy and its impact on China and the world may be more profound than its reform and development over the past 40 years, but the challenges are enormous. Analysis of four representative scenarios shows significant differences in achieving the carbon-neutral goal, particularly the contribution of non-fossil fuel energy sources. The high target values for nuclear, wind, and bioenergy have approached their corresponding resource limitations, with solar energy being the exception, suggesting solar’s critical role. We also found that the near-term policies that allow for a gradual transition, followed by more drastic changes after 2030, can eventually reach the carbon-neutral goal and lead to less of a reduction in cumulative emissions, thus inconsistent with the IPCC 1.5°C scenario. The challenges and prospects are discussed in the historical context of China’s socio-economic reform, globalization, international collaboration, and development.  相似文献   

Using Portable Gamma-Ray Spectrometry for Testing Uranium Migration: A Case Study from the Wadi El Kareim Alkaline Volcanics, Central Eastern Desert, Egypt     

Osama K. DESSOUKY  Hani H. ALI 《《地质学报》英文版》2018,92(6):2214-2232

The 300±20 Ma anomalously radioactive trachytes of Wadi El Kareim, central Eastern Desert, are a significant example of U-mineralization related to the alkaline volcanics in Egypt. Extensive portable gamma-ray spectrometric data has been utilized to identify geological factors controlling uranium mobility in the geological units along the three detailed study locations of Kab Al-Abyad, South Wadi (W) Al-Tarafawy and W. Al-Farkhah; their eTh/eU ratios averaging around 4.1, 3.7 and 5.6 respectively. Quantitative analysis with the integration of mobility maps and geological studies suggest two systems controlling U-migration within the geological units (confined system and unconfined system). In the confined system, the syngenetically formed U have experienced mobility after leaching and are redistributed in the presence of an incorporation carrier during transportation (probably as carbonate complexes). Then the retardant for uranium is achieved by sorption or by coprecipitation with the aid of Fe oxy-hydroxide, and finally the formation of immobile secondary U-bearing minerals takes place along a lithogeochemical trap. In contrast to the confined system, the unconfined one is basically lacking the lithogeochemical trap which in?uences the final accumulation of U-bearing minerals. The radioactivity of the trachyte rocks arises from the radioactive minerals uranophane and beta-uranophane with U- and/or Th-bearing minerals samarskite, Th-rich REE silicates, monazite and allanite.  相似文献   

脉冲星参数统计和演化     

蔡炎  阿里塔尼  赵永恒  张承民 《天文学报》2011,52(6):449-459

统计分析了目前发现的几种脉冲星的自转周期和表面磁场以及空间的分布情况,揭示出毫秒脉冲星比普通射电脉冲星、LMXB(低质量X射线双星)比HMXB(高质量X射线双星)的空间分布要更加弥散;孤立毫秒脉冲星自转周期分布的峰值为4.7 ms,而普通脉冲星的相应值为0.6 s,双星中毫秒脉冲星这一值为3.5 ms; FERMI脉冲...  相似文献   

星基多光谱分析的降水估算     

马雷凯  邢文渊 《沙漠与绿洲气象(新疆气象)》2010,4(3):59-61

<正>对从已广泛应用的全球气候模型到局地降水和洪灾的预报而言,准确估算降水的数量、时间和空间分布是至关重要的。降水作为地球水循环的一个关键组成部分,对于人类的生命财产安全有着重要的影响。从区域到全球尺度,现存的地基降水观测网络是不足的;因此,卫星提供了一种可行和吸引人的选择。很显然,  相似文献   

The tectono‐metamorphic evolution of the Balcooma Metamorphic Group,north‐eastern Australia: a multidisciplinary approach     

A. ALI 《Journal of Metamorphic Geology》2010,28(4):397-422

The sequential growth of biotite, garnet, staurolite, kyanite, andalusite, cordierite and fibrolitic sillimanite, their microstructural relationships, foliation intersection axes preserved in porphyroblasts (FIAs), geochronology, P–T pseudosection (MnNCKFMASH system) modelling and geothermobarometry provide evidence for a P–T–t–D path that changes from clockwise to anticlockwise with time for the Balcooma Metamorphic Group. Growth of garnet at ～530 °C and 4.6 kbar during the N–S‐shortening event that formed FIA 1 was followed by staurolite, plagioclase and kyanite growth. The inclusions of garnet in staurolite porphyroblasts that formed during the development of FIAs 2 and 3 plus kyanite growth during FIA 3 reflect continuous crustal thickening from c. 443 to 425 Ma during an Early Silurian Benambran Orogenic event. The temperature and pressure increased during this time from ～530 °C and 4.6 kbar to ～630 °C and 6.2 kbar. The overprinting of garnet‐, staurolite‐ and kyanite‐bearing mineral assemblages by low‐pressure andalusite and cordierite assemblages implies ～4‐kbar decompression during Early Devonian exhumation of the Greenvale Province.  相似文献   

塔克拉玛干沙漠风蚀起沙观测研究——试验介绍与观测结果初报   总被引：2，自引：0，他引：2  

何清  杨兴华  艾力·买买提明  刘新春  霍文 《中国沙漠》2011,31(2):315-322

介绍了中国气象局乌鲁木齐沙漠气象研究所在塔克拉玛干沙漠开展的风蚀起沙观测试验。对观测试验所获观测资料进行了初步分析,获得了一些有关塔克拉玛干沙漠风沙运动的特征。主要结果为,下垫面状况影响风沙流结构,塔中、若羌0~100 cm高程风沙流结构完全符合指数分布,肖塘则上部偏离指数分布;3地0~100 cm高程风沙流分别有72.4％、47.3%、62.6%的输沙量分布在0~30 cm高程内;3地风沙流输沙的粒径以细沙、极细沙、粉沙为主,其中极细沙可占到输沙量的43.8%~75.5%;风沙流中贴地层风速廓线受风沙相互作用的影响,不再符合对数分布,更加符合幂函数u=azb分布,拟合系数均大于0.93;沙尘撞击颗粒数与2 m高度风速变化趋势一致,塔中、肖塘、若羌3地的临界摩擦速度分别为0.25 m·s-1,0.27 m·s-1,0.21 m·s-1。  相似文献   

塔里木盆地一次东灌型沙尘暴环流动力结构分析   总被引：6，自引：5，他引：1  

王敏仲  魏文寿  杨莲梅  李彦华  肖书君  艾力·买买提明 《中国沙漠》2008,28(2):370-376

利用NCEP再分析资料和常规地面观测资料,对2006年4月10日塔里木盆地发生的一次东灌型沙尘暴,从气候背景、环流形势、螺旋度场、锋生次级环流、温度平流等方面进行分析,揭示了此类沙尘暴强盛期的环流动力结构。结果表明：①里咸海脊、乌拉尔脊、新地岛脊同位向叠加,西西伯利亚横槽转竖南下,引导泰米尔半岛强冷空气爆发直插新疆,东灌进入南疆盆地,造成大范围沙尘暴天气;②西西伯利亚地面冷高压爆发性南下并强烈发展是造成此次沙尘天气的根本原因;③盆地前期的干暖形势为沙尘暴的产生提供了有利的热力条件;④沙尘暴区上空螺旋度垂直分布为低层正值、高层负值,构成低空强辐合、高空强辐散的上升运动区,揭示强旋转上升运动是大范围沙尘暴发生的动力条件;⑤高空急流入口区次级环流下沉支导致高层动量下传 ,促使对流层中低层风力加大,冷锋南压,驱动沙尘天气的发生。  相似文献   

塔中地区土壤风蚀的影响因子分析   总被引：4，自引：2，他引：2  

何清  杨兴华  艾力·买买提明  刘新春 《干旱区地理》2010,33(4)

以塔中地区为例,利用野外观测数据和通过对比分析,论述了气候、地表粗糙度(包括植被覆盖)以及地表土壤特性等因子对土壤风蚀的影响,并对这些影响因子进行了量化研究。结果表明:塔中地区的年平均风蚀气候因子指数C为28.3,从季节分布上来说,夏季最大为13.9,冬季最小仅为0.7,C值与风速有着密切的指数关系;塔中地区的地表粗糙度Z0平均为6.32×10-5m,地表粗糙度小,加重了该地区的土壤风蚀程度;塔中地区的土壤类型特点、地表土壤平均粒径小、缺乏植被覆盖以及地表土壤含水率低为该地区土壤风蚀的发生提供了良好的条件。塔中地区土壤风蚀的现状是该地区气候、地表粗糙度以及地表土壤特性等因子共同作用的结果。  相似文献