陕西省极端无雨日数的时空分布特征

利用陕西省78个地面气象站1961—2010年的逐日降水资料,统计了四季最大连续无降水日数,采用正交函数分解、Mann-Kendall趋势检验等方法,分析了各季节极端无降水日数的空间结构和时间演变规律。结果表明：极端无雨日数最多出现在冬季,为16～45 d,最少是夏季,为8～14 d;冬、春季节的高值中心出现在陕北北部、关中的东部,冬季陕北北部达43 d以上,夏季高值中心出现在关中的东部,为11～13 d;冬、春旱陕北最多,关中次之,陕南较少,夏、秋旱关中最多,陕北次之,陕南较少;在大尺度天气系统控制下,四季极端无降水日数事件的步调基本一致,不同季节的天气系统对陕西各区域的影响具有明显的局地性和阶段性;近50 a来夏季和秋季表现为持续增多趋势,冬季和春季有部分站点呈现出反向变化趋势,其中夏季和秋季陕北局部、陕南局部干期日数增多趋势显著。     

银川市极端天气气候事件及其应对措施

近年来,随着全球气候变暖,极端天气也呈现逐渐增多的趋势。从近几年银川的天气个例中总结极端天气气候事件及其危害,从灾害中得到启示,为防灾减灾工作积累经验,并提出应对措施。     

Diving behavior of immature, feeding Pacific bluefin tuna (Thunnus thynnus orientalis) in relation to season and area: the East China Sea and the Kuroshio–Oyashio transition region

Twenty‐four archival tags were recovered from Pacific bluefin tuna previously released off Tsushima Island in the East China Sea. By analysis of the time‐series data of the pressure and the ambient and internal temperature from the 24 tags, we examined the relationship between the tuna's pattern of diving and the thermocline depth. In the East China Sea, diving and feeding events occurred throughout almost the entire day in both winter and summer, suggesting that the purpose of diving is for feeding. In summer, the feeding frequency was greater than that in winter, which corresponds to the fact that growth is more rapid in summer than in winter. During summer in the Kuroshio–Oyashio transition region, on the other hand, feeding events were much more frequent than those in the East China Sea, in spite of a lower diving frequency. The mean horizontal distance traveled was also significantly higher and it seems that in this area they may move horizontally to feed on prey accumulated at the surface. We conclude that, in addition to the ambient temperature structure, the vertical and horizontal distribution of prey species plays an important role in the feeding behavior of Pacific bluefin tuna. One bluefin tuna migrated to the Oyashio frontal area, where both the horizontal and the vertical thermal gradients are much steeper. The fish spent most of the time on the warmer side of the front and often traveled horizontally to the colder side during the day, perhaps to feed. This implies that there is a thermal barrier effect, in this case from the Oyashio front, on their behavior. The frequency of feeding events was low, although all the monitored fish dived every dawn and dusk, irrespective of the seasons or location. It is possible that these twice‐daily diving patterns occurred in response to the change in ambient light at sunrise and sunset.     

Spawning dynamics of American shad (Alosa sapidissima) in the St. Lawrence River,Canada–USA

Maltais E, Daigle G, Colbeck G, Dodson JJ. Spawning dynamics of American shad (Alosa sapidissima) in the St. Lawrence River, Canada–USA.
Ecology of Freshwater Fish 2010: 19: 586–594. © 2010 John Wiley & Sons A/S Abstract – The most northerly population of American shad (Alosa sapidissima), located in the St. Lawrence River, is considered vulnerable because of low population abundance and limited spawning habitat located at the upstream extent of the population’s anadromous migration. Here, we aimed to establish the temporal and spatial extent of spawning based on a novel hatch‐date analysis of juveniles. Spawning activity lasted from early May to early July. We found that juveniles captured downstream during the summer hatched later in the year than those captured further upstream. As a result, younger juveniles were distributed somewhat further downstream. In addition, we found significant multimodality in hatch‐date distributions at midstream and downstream sampling stations. Together, these results provide evidence that the 2‐month spawning period involved numerous spawning events that progressed in a downstream direction as the season advanced, rather than being restricted to upstream sites over the spawning season.     

我国女子持拍隔网对抗类优势项目发展研究——对潜优势项目网球的启示

运用文献资料法、对比研究法和归纳演绎法对我国女子持拍隔网对抗类项目的发展状况进行研究，总结该项群成为优势项目的成功经验，为潜优势项目发展提供借鉴。研究表明体制发展优势、奥运发展战略、完善的后备梯队建设和高水平联赛体系以及技战术创新等是乒乓球、羽毛球运动成为优势项目的主要支持。为实现潜优势项目向优势项目的过渡，应继续优化管理模式、提升教练员执教能力、完善青少年后备人才体系和竞赛机制。     

使用JDBC实现自动气象站要素信息检索

介绍了使用JDBC实现自动气象站分中心站的气象要素信息检索，程序运用B／S体系结构，遵循MVC设计思想，采用Model2模式进行开发，为了提高程序的运行速度，在数据库中创建了存储过程。     

云南省日极端降水概率特征及时空变化研究

不同重现期的暴雨设计值是推求设计洪水的基础。选取云南省29个气象站1960―2014年日降水资料,采用极大值法和超门限峰值法2种选样方法构成研究数据序列,通过K-S检验、L-矩法和日极端降水等值线图等方法分析了云南省日极端降水的概率特征及时空变化。结果表明,Wakeby分布函数较好地拟合了云南日极端降水序列;不同重现期下,云南省日极端降水量高值区位于滇南江城、勐腊一带,低值区位于滇西北德钦、中甸一带,极端降水量从南向西北呈阶梯状递减。分别计算不同重现期下的日降水量,时段极大值法设计值均大于以日极端降水资料95th分位数作为阈值的超门限峰法设计值。多数气象站基于Wakeby分布计算出的日极端降水设计值大于PⅢ分布函数设计值。     

Impact analysis of climate data aggregation at different spatial scales on simulated net primary productivity for croplands

For spatial crop and agro-systems modelling, there is often a discrepancy between the scale of measured driving data and the target resolution. Spatial data aggregation is often necessary, which can introduce additional uncertainty into the simulation results. Previous studies have shown that climate data aggregation has little effect on simulation of phenological stages, but effects on net primary production (NPP) might still be expected through changing the length of the growing season and the period of grain filling. This study investigates the impact of spatial climate data aggregation on NPP simulation results, applying eleven different models for the same study region (∼34,000 km²), situated in Western Germany. To isolate effects of climate, soil data and management were assumed to be constant over the entire study area and over the entire study period of 29 years. Two crops, winter wheat and silage maize, were tested as monocultures. Compared to the impact of climate data aggregation on yield, the effect on NPP is in a similar range, but is slightly lower, with only small impacts on averages over the entire simulation period and study region. Maximum differences between the five scales in the range of 1–100 km grid cells show changes of 0.4–7.8% and 0.0–4.8% for wheat and maize, respectively, whereas the simulated potential NPP averages of the models show a wide range (1.9–4.2 g C m⁻² d⁻¹ and 2.7–6.1 g C m⁻² d⁻¹ for wheat and maize, respectively). The impact of the spatial aggregation was also tested for shorter time periods, to see if impacts over shorter periods attenuate over longer periods. The results show larger impacts for single years (up to 9.4% for wheat and up to 13.6% for maize). An analysis of extreme weather conditions shows an aggregation effect in vulnerability up to 12.8% and 15.5% between the different resolutions for wheat and maize, respectively. Simulations of NPP averages over larger areas (e.g. regional scale) and longer time periods (several years) are relatively insensitive to climate data aggregation. However, the scale of climate data is more relevant for impacts on annual averages of NPP or if the period is strongly affected or dominated by drought stress. There should be an awareness of the greater uncertainty for the NPP values in these situations if data are not available at high resolution. On the other hand, the results suggest that there is no need to simulate at high resolution for long term regional NPP averages based on the simplified assumptions (soil and management constant in time and space) used in this study.     

Application of the Cropping System Model (CSM)‐CROPGRO‐Soybean for Determining Optimum Management Strategies for Soybean in Tropical Environments

The determination of optimum crop management practices for increasing soybean production can provide valuable information for strategic planning in the tropics. However, this process is time consuming and expensive. The use of a dynamic crop simulation model can be an alternative option to help estimate yield levels under various growing conditions. The objectives of this study were to evaluate the performance of the Cropping System Model (CSM)‐CROPGRO‐Soybean and to determine optimum management practices for soybean for growing conditions in the Phu Pha Man district, Thailand. Data from two soybean experiments that were conducted in 1991 at Chiang Mai University and in 2003 at Khon Kaen University were used to determine the cultivar coefficients for the cultivars CM 60 and SJ 5. The CSM‐CROPGRO‐Soybean model was evaluated with data from two experiments that were conducted at Chiang Mai University. The observed data sets from farmers’ fields located in the Phu Pha Man district were also used for model evaluation. Simulations for different management scenarios were conducted with soil property information for seven different soil series and historical weather data for the period 1972–2003 to predict the optimum crop management practices for soybean production in the Phu Pha Man district. The results of this study indicated that the cultivar coefficients of the two soybean cultivars resulted in simulated growth and development parameters that were in good agreement with almost all observed parameters. Model evaluation showed a good agreement between simulated and observed data for phenology and growth of soybean, and demonstrated the potential of the CSM‐CROPGRO‐Soybean model to simulate growth and yield for local environments, including farmers’ fields, in Thailand. The CSM‐CROPGRO‐Soybean simulations indicated that the optimum planting dates from June 15 to July 15 produced maximum soybean yield in a rainfed environment. However, the planting date December 15 produced the highest yield under quality irrigation. Soybean yield was slightly improved by applying nitrogen at a rate of 30 kg N ha^?1 at planting. Soybean yield also improved when the plant density was increased from 20 to 40 plants m^?2. The results from this study suggest that the CSM‐CROPGRO‐Soybean model can be a valuable tool in assisting with determining optimum management practices for soybean cropping systems in the Phu Pha Man district and might be applicable to other agricultural production areas in Thailand and southeast Asia.