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311.
The relationship between the East Asian winter monsoon (EAWM) and East Asian summer monsoon (EASM) during the Holocene is complicated and remains controversial. In this study, analysis of grain size and benthic foraminiferal oxygen isotope, as well as accelerator mass spectrometry 14C dating was performed on a sediment core retrieved from the newly revealed muddy deposit on the northern South China Sea continental shelf. The history of the EAWM and EASM were reconstructed for the last 8200 a BP. Further analysis in conjunction with previously published paleo-climate proxies revealed that the relationship between the EAWM and EASM during the Holocene is more complex than a simple and strict anti-phase one-both negative and positive correlations were identified. The EAWM and EASM are negatively correlated around 7500, 4800, 4200, 3200, and 300 a BP (cooling periods), while positively correlated around 7100, 3700, and 2100 a BP (warm periods). In particular, both the EAWM and EASM intensified during the three positive correlation periods. However, we also found that the relationship between these two sub-monsoons is anti-phase during the final phase of particularly hot periods like Holocene Optimum and Medieval warm period. The possible impact from variations of solar irradiance on the relationship between the EAWM and EASM was also discussed. 相似文献
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1土地闲置的原因及对策1.1土地闲置的原因安丘市位于山东省中东部、潍坊市以南,辖2个街道办事处,10个镇,共计1229个行政村,人口91万,土地总面积1732km2。目前,全市共有闲置、空闲土地40.47hm2,农村村内空闲地、闲置宅基地102.31hm2。造成土地闲置的原因集中体现在以下4个方面:①乡镇合并、单位合并撤销或者迁移,造成原乡镇驻地出现空巢现象,受地形位置或房屋结构等影响,处置难度比较大。②企业改制、经营管理不善等原因,造成企业停产、破产、倒闭。③企业用地独立分散,占地面积大,不能最大限度地发挥土地利用效率。④农村村庄规划不合理或落… 相似文献
315.
常州用电负荷量气象指数初探 总被引:4,自引:4,他引:4
分析了常州市1998-1999年全市用电量变化特征,建立与其关系密切的最高气温、最低气温、相对湿度、天气状况等气象要素之间的关系,得出其回归计算方程,并分析引起用电量变化的非气象要素,将得到的预报结果进行订正。通过检验、分析,最后确定了用电负荷量指数的划分标准。 相似文献
316.
Statistical analysis of thunderstorms on the eastern Tibetan Plateau based on modified thunderstorm indices 总被引:1,自引:0,他引:1
The Tibetan Plateau, with an average altitude above 4000 m, is the highest and largest plateau in the world. The frequency of thunderstorms in this region is extremely high. Many indices are used in operational forecasting to assess the stability of the atmosphere and predict the probability of severe thunderstorm development. One of the disadvantages of many of these indices is that they are mainly based on observations from plains. However, considering the Plateau's high elevation, most convective parameters cannot be applied directly, or their application is ineffective. The pre-convective environment on thunderstorm days in this region is investigated based on sounding data obtained throughout a five-year period(2006–10).Thunderstorms occur over the Tibetan Plateau under conditions that differ strikingly from those in plains. On this basis,stability indices, such as the Showalter index(including SI and SICCL), and the K index are improved to better assess the thunderstorm environments on the Plateau. Verification parameters, such as the true-skill statistic(TSS) and Heidke skill score(HSS), are adopted to evaluate the optimal thresholds and relative forecast skill for each modified index. Lastly, the modified indices are verified with a two-year independent dataset(2011–12), showing satisfactory results for the modified indices. For determining whether or not a thunderstorm day is likely to occur, we recommend the modified SICCLindex. 相似文献
317.
中国主要矿床数据库及其应用 总被引:3,自引:0,他引:3
新近完成的“中国主要矿床数据库”利用目前最优秀的高级关系数据库管理系统软件Foxpro2.5for windows,以1993的底全国矿产储量统计表为基础,包含40种主要常见矿产,共计大,中型矿床1902处,小型矿床3384处。数据库中不但载矿床的产地,坐标,储量,品位等矿床基本数据,而且还记录了矿床的类型,成因,成矿时代,围岩时代等矿床地质信息。 相似文献
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河南省获嘉县农田水分供需特征及秸秆覆盖效果分析 总被引:3,自引:0,他引:3
秸秆覆盖可以减少土壤表面水分蒸发,提高水分利用效率.以不覆盖处理为对照,2005年10月至2007年10月在获嘉县农场对冬小麦和夏玉米生育期间进行了秸秆覆盖处理对比观测.结果表明,秸秆覆盖后近地层气象要素发生了改变,覆盖后近地层空气温度升高,水汽压降低,地表土壤温度下降;秸秆覆盖有明显的保墒、蓄水作用,提高了土壤水分利用率;同时秸秆覆盖对提高冬小麦的成穗数,增加冬小麦和玉米的千粒重有明显作用.试验期间,推广田冬小麦增产幅度为8.7%,夏玉米增产幅度为8.9%. 相似文献
320.