武威市极大风速气候特征分析及其推算

利用武威市观测站2005~2013年最大风速与极大风速观测数据,拟合武威市最大风速与极大风速之间关系,从而推算1980~2004年极大风速,对武威市1980年以来极大风速气候特征进行分析。结果表明,1980年以来武威市极大风速共出现4个峰值,分别出现在1984、1985、1993和2013年,尤其是1993年,极大风速达30.5 m/s,历史灾情记录显示1993年的"5.5黑风"破环力极强,给武威的农业生产带来了极大的影响,1994~2012年属于极大风速较小阶段,但由于此阶段武威市设施农业发展迅速,仍是给当地生产造成的严重的损失,利用第Ⅰ型极值分布方法推算武威市未来10、30、50、100年内可能出现的最大风速,推算结果分别为28.6、31.3、32.6、34.3m/s,在今后设施农业的规划和发展应加强大风灾害的防范。     

The effect of plastic mulch on the fate of urea-N in rain-fed maize production in a semiarid environment as assessed by 15N-labeling

A better understanding of the fate of fertilizer nitrogen (N) is critical to design appropriate N management strategies in plastic-mulched croplands. We evaluated the effects of plastic mulch on urea-N recovery by crops and loss from soil in furrow-ridge plots, with and without maize (Zea mays L.) cropping, in a semi-arid rain-fed site in China. We applied the same rate of urea-N (281 kg ha⁻¹) to all treatments during the preparation of the furrow-ridges in 2011 and 2012 but ¹⁵N-labeled the urea in 2011 only. We used transparent film to cover all soil surfaces in the mulched treatments and seeded maize in furrows in treatments with crop. In 2011, plastic mulch increased the total N uptake in the aboveground biomass of maize by 53%, whereas it decreased the in-season labeled-N uptake by 19%, compared to non-mulched treatment. At harvest in 2011, in mulched treatments the total labeled-N remaining in the 0−170 cm soil layer was 25% greater whereas unaccounted labeled-N was 69% less, than in non-mulched treatments, regardless of whether maize was cropped. In 2012 the effect of mulch on total maize N uptake was comparable to that in 2011, but the residual soil labeled-N uptake by maize was 63% higher in mulched compared to non-mulched treatment. At harvest in 2012, plastic mulch increased total labeled-N remaining in the 0−170 cm depth in cropped soils and unaccounted labeled-N in non-cropped soils, compared with no mulch. Our results indicate that plastic mulch profoundly changes the fate of urea-N in maize production in cold and dry croplands.     

武威市乌鞘岭近55年大雾天气气候特征分析

利用武威市乌鞘岭气象站1955-2008年近55a地面观测资料,统计分析了大雾天气的气候特征.研究结果发现:乌鞘岭年平均大雾日为55.5天,年大雾日总体呈逐渐减少的趋势,减少速度为0.9d/10a,二十世纪70年代中期以前和80年代末期以后年大雾日呈减少趋势,二十世纪70年代中期至80年代末期年大雾日数维持在相对较高的...     

西北地区气候暖干化对经济和特色作物的影响及应对技术

在综述西北地区现代气候变化基本特征的基础上,重点揭示了主要经济作物棉花、胡麻、冬油菜和特色作物酿酒葡萄、苹果5种作物的生长发育、产量与品质等对现代气候暖干化的响应特征,并提出应对气候暖干化的技术措施,为农业生产提供服务。     

河西走廊东部大雾气候特征及预报方法研究

运用河西走廊东部武威市1961-2008年大雾气象资料,采用统计学方法分析了河西走廊东部大雾天气发生的地理分布、气候特征。结果表明,大雾具有明显的地域特征,山区多于川区,南部多于北部;大雾呈逐年减少趋势,一年中大雾发生的频率最高在7-10月,一日内大雾发生的集中时段是20：00到次日08：00。同时运用ECMWF数值预报格点场资料,采用Press准则进行因子初选,逐步回归预报方法进行因子精选,使用最优子集回归建立大雾预报方程,最终确定了春、夏、秋季大雾预报的全局最优的显著性方程,3个季节预报方程的拟合率分别为85.5%、82.1%、81.2%。     

Ridge-furrow mulching system in semiarid Kenya: A promising solution to improve soil water availability and maize productivity

In semiarid Kenya, field productivity of maize has been at a low integrity level due to insufficient use of rainwater use. From 2012 to 2013, an innovative ridge-furrow mulching system (RFMs) was tested using local maize (Zea mays L.) hybrid, KCB in KARI-Katumani Farm, Kenya in long and short rainy seasons. Field experiments were conducted in a randomized complete block design with four treatments: 1) RFMs with transparent polyethylene film (RFT), 2) RFMs with black polyethylene film (RFB), 3) RFMs with grass straw mulching (RFS), and 4) RFMs without mulching (CK). Soil moisture & temperature, grain yield, water use and economic benefit were determined and analyzed. The results indicated that both RFT and RFB treatments significantly increased soil water storage amount in the depth of 0–60 cm. Grain yield and water use efficiency (WUE) in both treatments were increased by 66.5–349.9% and 72.9–382% respectively, compared with those of CK over two growing seasons. In addition, grain yield and WUE in RFS treatment were only increased by from 4.2–127.1% compared with those of CK. Particularly, two types of plastic films displayed different effects on modifying topsoil temperature. Transparent film mulching significantly increased topsoil temperature by 1.3 °C (p < 0.05) higher than CK, to facilitate growth and grain formation in long (but cool) growing season. In contrast, black film mulching lowered soil temperature by 0.3 °C lower than CK in short (but warm) growing season, which led to better soil thermal balance. Overall, RFMs with film mulching could serve as an effective solution to increase maize productivity, and hence a promising strategy to cope with food security under climate change in semiarid Kenya.     

基于DEM的甘肃省降水资源分析

对甘肃省80个气象站近30 a(1971～2000)的降水量资料,利用地理信息系统(GIS)技术进行数据栅格化,采用趋势面分析、逐步回归、宏观地理因子模拟与小地形订正等方法,建立全省降水空间分布的数学模型.从推算结果看:甘肃省降水资源分布差异很大,从100 mm以下到800 mm以上均有分布,而且基本上呈现由东南向西北逐级减少的趋势;甘肃省干旱区(r<300 mm)面积最大,达到184 144.01 km2,占到全省面积的46.6%.     

ArcGIS在气象灾害短临监测预警业务系统中的应用

尝试利用移动手机短信结合GIS技术开展气象灾害的监测预警,有效发挥手机短信快捷便利、不受时空限制的优势和GIS技术准确定位的作用,建立气象灾害防御的快速联动机制。武威市气象灾害短临监测预警业务系统考虑了区域气象站资料获取、气象灾害阈值检索、气象灾害点在地理信息图上落点和等值线分析因素,以区域气象站观测资料、地理信息作为输入数据,通过设定气象灾害监测阈值进行监测预警;从系统框架模型、系统体系结构、数据处理流程、分析流程、数据访问、系统功能6个方面进行设计;利用ArcGIS强大的分析功能与移动通讯相结合,实现了气象数据收集、处理、输出于一体的气象灾害监测预警,增强了气象灾害防御的主动性和时效性。     

武威市雷暴气候特征及预报方法研究

利用武威市1961～2008年5个气象站雷暴实况资料,采用统计学方法,分析了该市雷暴天气时空分布、日变化和持续性等气候特征。结果表明,雷暴具有明显的地域特征,雷暴日数山区多于川区,南部多于北部;年代、年雷暴日数总体呈减少趋势,雷暴主要发生在5～9月,12:00～23:00是雷暴发生的集中时段,雷暴的持续时间一般为10～40 min。运用2003～2007年4～10月逐日20:00 ECMWF数值预报格点场资料,采用Press准则进行因子初选,逐步回归进行因子精选,使用最优子集回归建立雷暴预报方程,采用CSC双评分准则确定了各县区西北气流型、西南气流型、不规则型雷暴的全局最优显著性方程,预报方程通过了α=0.01信度检验。预报方程均达到了较高的概括率和拟合率,为雷暴业务预报提供了客观有效的指导产品。