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排序方式: 共有344条查询结果,搜索用时 31 毫秒
91.
双热带气旋相互作用的研究   总被引:7,自引:1,他引:6  
田永祥  寿绍文 《气象学报》1998,56(5):584-593
采用无基本气流的无辐散正压模式模拟了双热带气旋的运动。应用非对称理论研究了双热带气旋的相互作用。双热带气旋中的每个热带气旋主要由通过其中心的非对称气流(即通风气流)作用而移动。这股非对称气流是由其自身的线性和非线性效应产生的非对称涡旋与其配对热带气旋形成的非对称涡旋相叠加而引起的。  相似文献   
92.
OntheForcingoftheRadial-verticalCirculationwithinCyclones—Part1:ConceptsandEquationsD.R.JohnsonandZhuojianYuanSpaceScienceand...  相似文献   
93.
In the context of a model of tropical cyclone intensity based on an improved meso-scale atmospheric model, numerical simulation is performed of the track and intensity variation of tropical cyclones(TC) arising from sea surface temperature(SST) variation over a specified sea region. Evidence suggests that the model is capable of modeling quite welt the track and intensity of TC:SST variation leads to an abrupt change in the cyclone intensity:the response of the cyclone to the abrupt SST change lasts 8-12 h.  相似文献   
94.
The characteristics of the mid-latitude Pacific cyclones that produce precipitation over California are investigated statistically to determine their role in governing precipitation receipt. From all cyclones occurring over the Pacific Ocean from December through March and between 1965–1990 inclusive, we identify a subset of cyclones likely to produce precipitation over California. The characteristics analyzed are track, frequency, duration, speed, central pressure, and proximity. These are related to monthly precipitation for the entire period and are also used to explain the difference in precipitation received during the earlier (wet) and latter (dry) halves of the 1980s. Results indicate that the winter cyclones responsible for precipitation over California originate in the southeast quadrant of the region influenced by the Aleutian Low and decay south of the Gulf of Alaska. The extent of cyclonic activity over the east Pacific Ocean near California diminished during the dry period. There were fewer cyclones, they were significantly weaker, and they traveled along a more meridional track during the dry period.  相似文献   
95.
With the OLR data,the landfall and activity of tropical cyclones(TC) in southern China over a 20-year period(1975~1994) are studied.The result shows that the variation of the monthly anomalous OLR is somewhat teleconnected with the TC activity in southern China.The former is used to predict short-term climate for the latter over months with frequent or no TC influence.To some externt,the relationship between the TC activity in southern China and the monthly mean OLR anomalies is dependent on the climatological location of the subtropical high in northwestern Pacific region.  相似文献   
96.
This study explores two different tropical cyclone rainfall (TCR) problems: first, the identification of areas where TCR is highly concentrated and, second, the contribution of tropical cyclones (TCs) to the climatology of Puerto Rico for the period 1970–2010. A total of 86 storms within a 500-km radius of Puerto Rico were analyzed. Daily and monthly rainfall data from 32 weather stations were used to generate interpolated surfaces. Two geostatistical interpolation techniques were implemented: ordinary kriging and ordinary cokriging. Results show that rainfall from most TCs tends to be clustered in the eastern, southeastern, and central regions of the island, with a decrease in values toward the west. TCs closer to Puerto Rico (≤230 km) and embedded in high moisture environments (≥44.5 mm) exhibited the highest rainfall values, with most concentrated in the high elevation areas of the southeastern region of the island. Months with the largest TC contributions to rainfall (20–30%) were August and September, while the lowest contributions were found in June and November. For August, stations in the southern and eastern portions of the island had TCR contributions of >20%, with some stations in the southern coastal plains exhibiting 30%.  相似文献   
97.
西北太平洋温带气旋爆发性发展的热力-动力学分析   总被引:8,自引:4,他引:4  
利用天气、位涡分析和导出的Lagrangian型广义Z-O发展方程的诊断分析,考查了两个西北太平洋温带气旋爆发件发展的主要强迫机制和热力一动力空;司结构。结果表明,热力强迫对爆发性气旋发展起主要控制作用,当反映大气斜乐性的Laplacian温度平流、积云对流和湍流加热为主的热力强迫共同作用使地转相对涡度急剧增长时,气旋便出现了爆发性发展,其中积二尺度的对流加热贡献更大。Laplacian绝热冷却、大气向海洋的感热输送和摩擦效应起阻滞发展的作用,也是控制气旋衰亡的主要过程。爆发性发展启动同子因例而异,涡度平流、Laplacian温度平流和Laplacian大尺度加热均可成为主要启动因子。垂直积分平均分布和垂直结构考查进一步佐证了诊断分析的结果,并揭示了气旋爆发性发展过程中一些重要的热力-动力学分布特征。  相似文献   
98.
Jia  Zuo  Ren  Fumin  Zhang  Dalin  Ding  Chenchen  Yang  Mingjen  Feng  Tian  Chen  Boyu  Yang  Hui 《中国科学:地球科学(英文版)》2020,63(1):27-36
Recently, a track-similarity-based Dynamical-Statistical Ensemble Forecast(LTP_DSEF) model has been developed in an attempt to predict heavy rainfall from Landfalling Tropical cyclones(LTCs). In this study, the LTP_DSEF model is applied to predicting heavy precipitation associated with 10 LTCs occurring over China in 2018. The best forecast scheme of the model with optimized parameters is obtained after testing 3452 different schemes for the 10 LTCs. Then, its performance is compared to that of three operational dynamical models. Results show that the LTP_DSEF model has advantages over the three dynamical models in predicting heavy precipitation accumulated after landfall, especially for rainfall amounts greater than 250 mm. The model also provides superior or slightly inferior heavy rainfall forecast performance for individual LTCs compared to the three dynamical models. In particular, the LTP_DSEF model can predict heavy rainfall with valuable threat scores associated with certain LTCs, which is not possible with the three dynamical models. Moreover, the model can reasonably capture the distribution of heavier accumulated rainfall, albeit with widespread coverage compared to observations. The preliminary results suggest that the LTP_DSEF model can provide useful forecast guidance for heavy accumulated rainfall of LTCs despite its limited variables included in the model.  相似文献   
99.
Response based analysis (RBA) is used to establish the design metocean conditions (DMCs) of a generic weather-vaning FPSO off the North West Shelf (NWS) of Australia for determining greenwater severity. A vessel heading prediction tool, an essential component of the RBA analysis for weather-vaning vessels, is developed and evaluated by comparing with full-scale measurements from an operating FPSO. Locations at the bow, amidships and the stern of the vessel are found to be susceptible to greenwater risks and the vessel is often exposed to oblique waves during tropical cyclones. Long-term extrapolation is performed to estimate 1 in. N-year return relative wave-vessel motions represented by both the most probable maximum relative wave-vessel motion within a storm rmp, and the maximum individual relative wave-vessel motion rMax. It is observed that rMax ˜ (1.1–1.2) rmp. The use of rMax allows for the variability of the short term maxima per storm and also the fact that the peak in response might not come in the most severe sea-state. Given the focus on greenwater rather than wave severity, the slightly larger value of rMax at a given return period is used for assessment of greenwater risk. The sea-states that lead to rMax at a 1 in 100 year level are identified and subsequently used for characterising the wave groups causing maximum relative wave-vessel motion at various locations around the vessel. For a given location, the shapes of the wave time histories which give rise to extreme relative wave-vessel motions in a set of design metocean conditions are similar, indicating that a ‘design wave’, derived within the framework of linear wave theory, may be a useful approach to tackle highly nonlinear and complex greenwater overtopping problems.  相似文献   
100.
利用1981—2010年期间的热带气旋实况数据、ERA-Interim逐月和逐日的再分析资料及NOAA提供的向外长波辐射月数据,采用合成分析方法及天气学方法,对强度快速增强气旋活跃年份及不活跃年份的海温条件、向外长波辐射、垂直风切变、100 hPa位势高度距平场及季风槽进行了特征分析,结果表明:(1)RITC活跃年份-不活跃年份的海温距平场多表现为厄尔尼诺特征,即活跃年份的整个赤道中东太平洋海温较不活跃年份明显偏高;(2)RITC活跃年份所对应的赤道大部分地区(140°E以东)向外长波辐射值更低,表明对流活动明显东移;(3)RITC活跃年份的垂直风切变较小区域较不活跃年份总体偏东10~15个经度;(4)RITC活跃年份的南亚高压主体东端出现明显的扩展;(5)RITC活跃年份的季风槽为偏东型,不活跃年份的季风槽则为西北型。同时,对具有代表性的1983年第10号热带气旋"Forrest"的物理量场进行分析后发现:在该气旋强度快速增长阶段,气旋的整个中低层增暖增湿效果明显;表征积云对流发展的大范围的对流有效位温高值区存在于气旋及其周围,尤其是前进方向上;该阶段仍存在较强的垂直风切变,但强度及范围明显变弱、变小;各通道的水汽条件充沛。  相似文献   
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