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交叉检验是验证基础性地理国情监测成果质量的一种方法,本文针对交叉检验工作的特点,介绍了基础性地理国情监测成果的检验内容和方法,分析了检验过程中出现的普遍质量问题,并给出了今后交叉检验工作顺利开展和提高成果质量的意见。 相似文献
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The community structure and seasonal dynamics of plankton in Bange Lake,northern Tibet,China 总被引：1，自引：1，他引：0
The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in the saline Bange Lake, northern Tibet, China. Sampling was carried out between one to three times per month from May 2001 to July 2002. Salinity ranged from 14 to 146. The air and water temperature exhibited a clear seasonal pattern, and mean annual temperatures were approximately 4.8°C and 7.3°C, respectively. The lowest water temperature occurred in winter from December to March at-2°C and the highest in June and July at 17.7°C. Forty-one phytoplankton taxa, 21 zooplankton, and 5 benthic or facultative zooplankton were identifi ed. The predominant phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Dunaliella salina, and Spirulina major. The predominant zooplankton species included H olophrya actra, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, and A rctodiaptomus salinus. The mean annual total phytoplankton density and biomass for the entire lake were 4.52×10~7 cells/L and 1.60 mg/L, respectively. The annual mean zooplankton abundance was 52, 162, 322, and 57, 144 ind./L, in the three sublakes. The annual mean total zooplankton biomass in Lakes 1–3 was 1.23, 9.98, and 2.13 mg/L, respectively. The annual mean tychoplankton abundances in Bg1, 2, and 3 were 47, 67, and 654 ind./L. The annual mean tychoplankton biomass was 2.36, 0.16, and 2.03 mg/L, respectively. The zooplankton biomass(including tychoplankton) in the lake was 9.11 mg/L. The total number of plankton species in the salt lake was signifi cantly negatively correlated with salinity. 相似文献
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在概述了元胞数组的基础上,对元胞数组的定义以及一些基本操作进行了回顾总结。并针对现有的各种数据类型无法一次性传递多维数据的问题提出了解决方法,即在MATLAB中将元胞数组与循环结合使用一次传递多维数据。 相似文献
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基于若尔盖地区天然牧草1983～2013年生育期观测资料和近50年地面气象观测资料,通过趋势分析、相关分析、M-K突变检验和积分回归等数学方法分析了研究区气候变化特征及其对天然牧草高原早熟禾生育期的影响,以揭示若尔盖湿地天然牧草生育期对气候变化的响应规律。结果表明:(1)研究区年降水量有微弱下降趋势,牧草生长关键期5～9月有效降水日数下降趋势最为显著;年均气温、最高气温、最低气温升高趋势显著;牧草生长季4～9月逐月积温有显著增加的趋势;草地干燥指数以0.0256/10a的速率上升,1990s中期后暖干化加剧。(2)2000s牧草返青期、分蘖期、抽穗期较1980s提前,开花期较1990s延后了4天、黄枯期较1980s提前了12天,较1990s延迟了9天、生长期较1980s减少了20天,较1990s增加了8天。(3)3月≥0℃积温、4月和6月≥3℃积温的显著增加,导致了牧草返青期、分蘖期、抽穗期提前;除返青期外有效降水日数越多,生育期越提前,反之亦然;(4)牧草生长期对平均温度、气温日较差、有效降水日数等气象因子敏感;在牧草生长关键期7月不出现干旱或干旱程度较轻的情况下,气候变暖将导致生长期延长。 相似文献