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271.
The satellite-derived wind from cloud and moisture features of geostationary satellites is an important data source for numerical weather prediction(NWP) models. These datasets and global positioning system radio occultation(GPSRO)satellite radiances are assimilated in the four-dimensional variational atmospheric data assimilation system of the UKMO Unified Model in India. This study focuses on the importance of these data in the NWP system and their impact on short-term24-h forecasts. The quality of the wind observations is compared to the short-range forecast from the model background. The observation increments(observation minus background) are computed as the satellite-derived wind minus the model forecast with a 6-h lead time. The results show the model background has a large easterly wind component compared to satellite observations. The importance of each observation in the analysis is studied using an adjoint-based forecast sensitivity to observation method. The results show that at least around 50% of all types of satellite observations are beneficial. In terms of individual contribution, METEOSAT-7 shows a higher percentage of impact(nearly 50%), as compared to GEOS, MTSAT-2and METEOSAT-10, all of which have a less than 25% impact. In addition, the impact of GPSRO, infrared atmospheric sounding interferometer(IASI) and atmospheric infrared sounder(AIRS) data is calculated. The GPSRO observations have beneficial impacts up to 50 km. Over the Southern Hemisphere, the high spectral radiances from IASI and AIRS show a greater impact than over the Northern Hemisphere. The results in this study can be used for further improvements in the use of new and existing satellite observations. 相似文献
272.
采用WRF模式对2010年9月发生在河南省附近的一次暴雨过程进行了集合预报试验。用增长模繁殖方法(BGM)制作了集合预报方案1;为了充分利用背景场信息,结合时间滞后法,制定了集合预报方案2:滚动繁殖法;考虑到暴雨过程中天气形势的特殊性,结合区域空间特征,制定了集合预报方案3:区域繁殖法。这3组试验均对变量U、V、T、Q进行了初值扰动,加上控制预报,均产生了9个集合成员。试验结果表明:几种集合预报方法在预报效果上相较于控制预报都具有明显的改善,滚动繁殖法及区域繁殖法对增长模繁殖法都具有一定的改进作用,其中区域繁殖法的预报效果更优,与实况更为接近。 相似文献
273.
为探究冬季室温不同铁碳内电解基质下4种水生植物及其组合对人工湿地污水的净化效果,通过构建小试试验装置来探究冬季室温铁碳内电解质下菖蒲、鸢尾、金鱼藻、狐尾藻4种水生植物及菖蒲+鸢尾、金鱼藻+狐尾藻、菖蒲+鸢尾+金鱼藻+狐尾藻3种组合在不同试验时间内对污水中COD、NH_3+-N、TN、TP 4种污染物的净化效果。结果表明:冬季室温不同铁碳内电解基质下,4种植物及其组合对COD、TN、TP去除效果均较好,无显著性差异。NH3+-N净化效果较好的是菖蒲组和金鱼藻+狐尾藻组合。研究发现,铁碳内电解基质在COD、TN、TP的去除过程中发挥了主要作用。在TN去除方面,铁碳内电解质与植物的组合效果比单纯内电解质对污水的净化效果好。4种植物及其组合在NH_3+-N去除方面均发挥了重要作用,且不同处理间存在显著差异。 相似文献
274.
MIN Qingwen 《资源与生态学报(英文版)》2021,12(4):437-443
Traditional agricultural heritage research has a very long history. Programme on “The conservation and adaptive management of Globally Important Agricultural Heritage Systems (GIAHS)” initiative launched by FAO in 2002, aimed at not only preserving agricultural heritage system, but also applying the principle of dynamic conservation to promote rural development to benefit local community, to assure food security and maintaining the ecosystem. Since then, many more scientists have been enrolled in the new field focusing on the function and value, application and management, conservation and development and other aspects of these traditional agricultural systems which facilitate an emerging cross-discipline. In this paper, based on the concepts and characteristics of GIAHS and China Nationally Important Agricultural Heritage Systems (China-NIAHS), the author specifies that Agri-cultural Heritage is a compound heritage that integrates the characteristics of natural, cultural and intangible cultural heritage, and a typical social-economic-natural complex ecosystem composed of economic, biological, technological, cultural and landscape components. For their conservation and development, the joint efforts of scientists from economics, ecology, geography, history, management sciences, culturology, ethnology, sociology and other subjects are needed. Based on progresses studies and perspectives of the field, the author felt that although a good start of the research on Agri-cultural Heritage has been made, there is still much room for development which show a steady growth trend and suggested 32 priority areas in research; a new subject of Agroheritology could emerge in the near future. 相似文献
275.
弱天气尺度强迫背景下的长江中下游暖区暴雨突发性强,高度非线性,难以准确预报,这时考虑不确定因素的集合预报成为重要选项,而对流尺度集合预报核心问题是积分一段时间后离散度偏低,会导致预报失败。比较包含不同尺度扰动信息的对流尺度集合预报方案间的差异性并据此优化初始扰动方案,针对2018年5月4—5日一次典型长江中下游暖区暴雨过程,分别采用动力降尺度(DOWN)、增长模繁殖法(BGM)、局地增长模繁殖法(LBGM)和混合扰动法(BLEND)等四种方法进行集合预报试验,以期探讨对离散度和预报效果的影响。结果表明,在模式积分0~6 h,具有中小尺度扰动信息的BGM和LBGM的离散度优于DOWN,其中LBGM相比于BGM具有一定程度上的改进,说明具有更准确中尺度特征的扰动能够在积分初始阶段获得有效增长,即考虑了中小尺度天气系统局地性的LBGM能弥补BGM的不足;但是,在模式积分12 h以后,具有更多大尺度特征扰动的DOWN优于区域模式中的增长模繁殖法BGM和LBGM,说明经过初始误差快速增长一段时间后,大尺度扰动开始起主要作用。而具有不同尺度扰动信息的BLEND方案则兼具LBGM和DOWN的优势,几乎在整个预报时段离散度较高且概率预报评分较好,体现出混合扰动的优越性。以上结果进一步说明,初始扰动的尺度特征在暖区暴雨的集合预报效果中具有关键性的作用,因而通过调整初始扰动的尺度信息来优化集合预报性能的混合扰动思想,在业务上具有一定的指导意义和推广价值。 相似文献
276.
277.
278.
利用江苏和安徽2012—2014年151个国家站及2 600个区域站资料,对各类自动站资料的质量及其控制方法进行初步探讨。采用缺测资料统计、气候界限值检查、气候极值检查、内部一致性检查、二次迭代的空间一致性检查、时间一致性检查、持续性检查及综合决策算法分别对国家站和区域站资料进行系统的质量控制,并根据质量控制结果进行可疑站点的标记。结果显示:国家站各要素资料缺测率远低于区域站,且资料质量总体上均明显优于区域站;自动站各要素中温、压要素的质量最好,其次是相对湿度;除了空间一致性检查中风场资料的检查结果差别不大外,其余检查中区域站资料的未通过率均远高于国家站资料;将错误资料及可疑站点信息进行及时反馈,能改善实时资料质量,并为相应测站的检修与维护提供依据。 相似文献
279.
In China, the distribution of water resources is incompatible with the development of productivity. The construction of South-to-North Water Diversion Project has achieved inter-basin water diversion, and the project can alleviate the uneven distribution of water resources phenomenon effectively. However, in recent years, the aggregate effects of water pollution and water resource shortages have been serious. Establishing transverse eco-compensation mechanisms becomes the key method to achieve sustainable use of water resources. Based on statistical and questionnaire data, this paper uses the Opportunity Costs Method and Willingness to Pay approach to establish a transverse eco-compensation standard calculation model for the Middle Route Project of the South- to-North Water Diversion. The results show that the upper and lower limits of the transverse eco-compensation standard for the Middle Route Project is $2.52 billion and $2.20 billion every year, respectively. However, the paying and receiving standards varied widely among different compensation payers and compensation receivers. Meanwhile, the significant factors influencing the paying willingness of the receiver area citizens were age, education level, average revenue per month, knowledge about the South-to-North Water Diversion Project and recognition of the importance of eco-environmental integrity. This study began with a theoretical analysis, then analysed related problems related to calculating transverse eco-compensation standards for the Middle Route Project of the South-to-North Water Diversion by an empirical study. This empirical study helps to establish effective transverse eco-compensation mechanisma and promotea the development of effective policies and legislation. 相似文献
280.
Ecological compensation plays an important role in promoting ecological protection. Identifying factors affecting the willingness of farmers to accept eco-compensation has become a focus of ecological economics. The Qianxi traditional chestnut agricultural heritage system is a typical agroforestry system in China and adapts the local environment well. However, local farmers concentrate on chestnut monocultures, driven by short-term profits. The local ecological environment is very fragile. We surveyed 100 local rural households. Based on face-to-face interviews and questionnaires and model assessment, we analyzed factors affecting the willingness of farmers to accept eco-compensation in the Qianxi chestnut agroforestry system of Hebei. We found that many factors influence farmer willingness to accept, including education level, household income, environmental awareness, environmental protection practices and knowledge of ecological compensation. This research provides helps clarify the mechanism of farmer participation in eco-compensation and provides a basis for further development of compensation standards that benefit the local environment. 相似文献