玉米不同生长发育期对气温和降水的响应

降水、气温等气候因素的适宜性可以让农作物产量得到提高,在保证质量的同时,最大程度降低农户需要承担的种植风险。但气温、降水等因素难以控制,需要展开综合性的监控,以此保证种植效果,基于此,本文从玉米的生长特点入手,结合实际案例综合分析玉米在不同生长发育期对气温、降水的响应,明确具体的种植技术,以供参考。

近50年延河流域水沙变化特征及其原因分析

利用Mann—Kendall秩相关分析确定了1961～2008年近50年延河流域水沙变化趋势．结果表明，降水量、径流量和输沙量都有显著的减少趋势。进一步分析表明延河流域的径流量和输沙量在1974年和1997年均发生了突变。以1961～1973年为无人类活动影响的基准年，比对1974～1996年和1997～2008年径流量和输沙量，年均径流量分别减少0．17×10^8m^3和0．86×10^8m^3，年均输沙量减少0．17×10^8t和0．41×10^8t。双累积曲线分析表明，延河流域径流量和输沙量的变化主要受人类活动的影响。

Impacts of Climatic Factors on Runoff Coefficients in Source Regions of the Huanghe River

Runoff coefficients of the source regions of the Huanghe River in 1956-2000 were analyzed in this paper. In the 1990s runoff of Tangnaihai Hydrologic Station of the Huanghe River experienced a serious decrease, which had attracted considerable attention. Climate changes have important impact on the water resources availability. From the view of water cycling, runoff coefficients are important indexes of water resources in a particular catchment. Kalinin baseflow separation technique was improved based on the characteristics of precipitation and streamflow. After the separation of runoff coefficient （R/P）, baseflow coefficient （Br/P） and direct runoff coefficient （Dr/P） were estimated. Statistic analyses were applied to assessing the impact of precipitation and temperature on runoff coefficients （including Dr/P, Br/P and R/P）. The results show that in the source regions of the Huanghe River, mean annual baseflow coefficient was higher than mean annual direct runoff coefficient. Annual runoff coefficients were in direct proportion to annual precipitation and in inverse proportion to annual mean temperature. The decrease of runoff coefficients in the 1990s was closely related to the decrease in precipitation and increase in temperature in the same period. Over different sub-basins of the source regions of the Huanghe River, runoff coefficients responded differently to precipitation and temperature. In the area above Jimai Hydrologic Station where annual mean temperature is -3.9℃, temperature is the main factor influencing the runoff coefficients. Runoff coefficients were in inverse relation to temperature, and precipitation had nearly no impact on runoff coefficients. In subbasin between Jimai and Maqu Hydrologic Station Dr/P was mainly affected by precipitation while R/P and Br/P were both significantly influenced by precipitation and temperature. In the area between Maqu and Tangnaihai hydrologic stations all the three runoff coefficients increased with the rising of annual precipitation, while direct runoff coefficient was inversely proportional to temperature. In the source regions of the Huanghe River with the increase of average annual temperature, the impacts of temperature on runoff coefficients become insignificant.

RELATION BETWEEN PRECIPITATION AND SEDIMENT TRANSPORT IN THE DASHA RIVER WATERSHED

The study on sediment production and its relationship with climatic and hydrological factors in watershed is a major environment issue of concern in the international community. Based on the observational records covering the period from 1954 to 1999, the characteristics of precipitation changing over the Dasha River Watershed in Anhui Province and its relation to sediment yield were studied using tendency analysis and correlation analysis.Results showed that the precipitation of the Dasha River Watershed has high variability. In those 46 years, 34% of spring rainfall, 58% of summer rainfall and 30% of annual rainfall will be considered anomaly. The gray correlation analysis shows that sediment discharge correlates most closely with the frequency of the rainstorm with a daily precipitation above 100mm, secondly with the frequency of the rainstorm with a daily precipitation of 50-100mm, and thirdly with the number of rainy days. Their correlation coefficients are 0.98,0.90 and 0.85 respectively. In addition,the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.

THE EFFECTS OF GENERAL CIRCULATION ANOMALIES ON PRECIPITATION IN THE RAINING SEASON OF SHANDONG

Using the monthly mean reanalysis data of height, wind and vertical velocity of NCEP/NCAR from 1958 to 2003, the characteristics of 500hPa height anomalies in the Northern Hemisphere, convergence and divergence on the levels of 200hPa and 925hPa and vertical stream over the Shandong province were studied and compared with that over North China. The study shows that the teleconnection pattern called East Asia-Pacific pattern (EAP) plays important roles in the summer rainfall of Shandong. Weaker Okhotsk sea high, stronger upward stream over tropical areas and Shandong and northward location of subtropical high and stronger Indian low, are likely to lead to more rain in Shandong province in summer, but there are some flood (drought) years in which these characteristics such as the location and intensity of subtropical high change with the least extent. The difference between Shandong and North China in 500hPa height is that there is a teleconnection pattern called Europe / Asia pattern in North China, while there is a negative East Asia Pattern in Shandong during drought years. There is a teleconnection relation between Shandong summer rainfall and convective activities happening in tropical areas in spring and summer accomplished by the Rossby waves. During the flood years in Shandong, the convective activities happening in tropical India Ocean and tropical west Pacific and Walker circulation are much stronger than that during the drought years, but the convective activities happening in tropical east Pacific are weaker than those during the drought years.

Influence and Control Strategy for Local Settlement for High-Speed Railway Infrastructure

This paper discusses the main impact factors of the local settlement and differential settlement of high- speed railway lines. The analysis results show that groundwater exploitation is the direct cause of differ- ential settlement. Based on the study of ballastless track additional load and of vehicle, track, and bridge dynamic responses under different differential settlements, a control standard of differential settlement during operation is proposed preliminarily.

Climate Change and its Impact on Water Resources in the Huai River Basin

Rainfall and air temperature data from six meteorological stations above the Bengbu Sluice and hydrological and water resources evaluation data from the Bengbu Hydrological Station in the Huai River Basin from 1961 to 2008 are used to analyze the impact of changes in climatic factors on the amount of water resources in the Basin. There was a general trend of rise in its average annual air temperature, with the highest increase of 0.289℃/10a recorded at Bengbu in Anhui Province. Rising rainfall was mainly observed in the western part of the study area, while rainfall actually declined in the eastern part, i.e. the middle reaches of the Huai River. The Average rainfall in the study area was in a vaguely declining trend. In other words, the rainfall in the Basin is still much affected by natural fluctuations. On the whole, there was a trend of gradual decrease in the quantity of the Basin＇s water resources for the period under study. Water resources quantity is found to fall with decreasing rainfall and rising air temperature. Regression analysis is used to establish a mathematical model between water resources quantity and climatic factors （i.e. air temperature and rainfall） in order to explore the impact of climate change on water resources in the Basin. Moreover, various scenarios are set to quantitatively analyze the response of water resources to climate change. Sensitivity analysis shows that changes in rainfall have a much bigger impact on its water resources quantity than changes in its air temperature.

Association Between Himalayan Marmot Density and Climatic Factor

Objective:This study aims to explore the association between the density of Himalayan marmot (Marmota himalayana) and climatic factors such as temperature, precipitation, humidity, vapour pressure, sunshine percentage, wind velocity, which are closely associated with global climate change, and to provide a reference for plague prevention and control. Methods: We conducted a regression analysis to find the possible climate factors associated with the density of Himalaya marmot, and analyzed the response characters of Himalayan marmot to climate change.Results: Dailyprecipitation days(>=0.1 mm) and sunshine percentage were significantly associated with thedensityofHimalayan marmot(p<0.01). Conclusion: Climate change was associated with the risk of plague. This phenomenon is valuable for Himalayan marmot and plague prevention. More studies are needed to understand the impact of climate change on Himalayan marmot and plague.