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天津盛夏降水趋势与初夏华北高压的统计分析 总被引:3,自引:1,他引:3
根据初夏(6月)的天气气候演变,预测盛夏(7~8月)的短期气候趋势,一直是急需解决的难题。文章揭示了自1958年以来天津盛夏降水趋势与初夏时节临近地区上空的环流特征之间的统计关系。结果表明,初夏华北高压强时盛夏天津降水偏少,反之盛夏天津降水偏多,不仅逐年的对应关系显著,而且变化趋势相反,转折时期也一致。初步解释了20世纪70年代以前天津(华北)盛夏多雨和80年代至今天津(华北)少雨的物理原因。以此为主要根据建立了初夏对于盛夏天津降水的短期气候预测方法,1998~2003年连续6年预报正确。 相似文献
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在气象报刊上,常常看到“气象现代化”的字样。1992年夏天,我在京参加《中国改革开放辉煌成就十四年.气象卷》编辑工作肘,陈少峰先生(《中国气象报》原社长)告诉我:语言大师吕叔湘先生曾撰文对“气象现代化”的说法提出异义,指出“气象”不能“现代化”。 相似文献
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Nutrient and Chlorophyll-a (Chl-a) concentrations were investigated monthly along three transects extending from a mariculturc area to open waters around the Zhangzi Island area from July to December 2009. The objective of this study is to illus- trate food availability to the bottom-sowed scallop Patinopecten yessoensis under the influences of the Yellow Sea Cold Water Mass (YSCWM), freshwater input and feedbacks of cultivated scallops. Significant thermal stratification was present in open waters from July to October, and salinity decreased in July and August in surface layers in the mariculture area. Nutrient concentrations increased with depth in both areas in summer, but were similar through water column in November and December. On average, nutrient in- creased from summer to autumn in all components except ammonia. Nutrient concentrations lower than the minimum thresholds for phytoplankton growth were present only in upper layers in summer, but stoichiometric nitrogen limitation existed in the entire inves- tigation period. Column-averaged Chl-a concentration was lower in open waters than in mariculture area in all months. It increased significantly in mariculturc area in August and October, and was less variable in open waters. Our results show that nutrients limita- tion to phytoplankton growth is present mainly in upper layer in association with stratification caused by YSCWM in summer. Freshwater input and upwelling of nutrients accumulated in YSCWM can stimulate phytoplankton production in mariculture area. Farming activities may change stoichiometric nutrient ratios but have less influence on Chl-a concentration. 相似文献
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The features of 30-60-day convection oscillations over the subtropical western North Pacific (WNP) were investigated, along with the degree of tropical-subtropical linkage between the oscillations over the WNP during summer 1998. It was found that 30-60-day oscillations were extremely strong in that summer over both the subtropical and tro]~ical WNP, providing a unique opportunity to study the behavior of subtropical oscillations and their relationship to tropical oscillations. Further analyses indicated that 30-60-day oscillations propagate westwards over the subtropical WNP and reach eastern China. In addition, 30-60-day oscillations in the subtropics are affected by those over the South China Sea (SCS) and tropical WNP through two mechanisms: (1) direct propagation from the tropics into the subtropics; and (2) a seesaw pattern between the tropics and subtropics, with the latter being predominant. 相似文献
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安阳林州市有两座山十分奇怪,炎热夏季山洞里不热反而结出大块的冰柱、冰凌,冬天寒冷季节则往外冒热气。夏天山洞洞口结冰的时候,揭开冰块后当地就会落下鸡蛋大小 相似文献
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In this study,we evaluate the forecast skill of the subseasonal-to-seasonal(S2S)prediction model of the Beijing Climate Center(BCC)for the boreal summer intraseasonal oscillation(BSISO).We also discuss the key factors that inhibit the BSISO forecast skill in this model.Based on the bivariate anomaly correlation coefficient(ACC)of the BSISO index,defined by the first two EOF modes of outgoing longwave radiation and 850-hPa zonal wind anomalies over the Asian monsoon region,we found that the hindcast skill degraded as the lead time increased.The ACC dropped to below 0.5for lead times of 11 days and longer when the predicted BSISO showed weakened strength and insignificant northward propagation.To identify what causes the weakened forecast skill of BSISO at the forecast lead time of 11 days,we diagnosed the main mechanisms responsible for the BSISO northward propagation.The same analysis was also carried out using the observations and the outputs of the four-day forecast lead that successfully predicted the observed northward-propagating BSISO.We found that the lack of northward propagation at the 11-day forecast lead was due to insufficient increases in low-level cyclonic vorticity,moistening and warm temperature anomalies to the north of the convection,which were induced by the interaction between background mean flows and BSISO-related anomalous fields.The BCC S2S model can predict the background monsoon circulations,such as the low-level southerly and the northerly and easterly vertical shears,but has limited capability in forecasting the distributions of circulation and moisture anomalies. 相似文献
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利用近70年(1924-1994)重庆气温资料,分析了重庆盛夏季节(7-8月)凉热的气候特点,并对其成因进行探讨,采用了均值生成函数和非线性多元回归方法建立了盛夏气温预报模型。 相似文献
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夏天是旅游旺季,今年夏天,一个具有里程碑意义的“超重量级”旅游新坐标即将闪亮登场,值得我们热切关注,那就是一被誉为“海上故宫”的国家海洋博物馆。国家海洋博物馆是中国第一座国家级、综合性、公益性的海洋博物馆,坐落于天津滨海新区,是一个集收藏保护、展示教育、科学研究、交流传播、旅游观光等功能于一体的海洋科技交流平台和标志性文化设施,其地位堪比北京故宫博物院,被誉为“海上故宫”。 相似文献