黄河流域干燥度时空格局变化研究

根据国家气象局整编的1957～2001年(45 a)黄河流域93个气象站点气象资料,应用1998年FAO最新推荐的Penman-Monteith法计算干燥度中的潜在蒸散项,并在此基础上使用克里格(kriging)插值法生成黄河流域干燥度的分布图.研究结果显示,黄河流域多年平均干燥度空间分布格局受气候、地形地貌等多种因素的影响,具有明显的地域性差异,干燥度总的特点是北大南小,呈现由北向南逐渐递减趋势;从时间尺度上看,自1957年以来,干燥度总体上呈波动增大趋势,干燥度季节变化为冬季>春季>秋季>夏季,全年以7～9月份干燥度最小,11月～翌年3月最大,且不同区域之间存在着明显的差异.     

近50年岷江上游潜在蒸散量的时空变化特征

潜在蒸散量的变化对水分循环与能量平衡均具有重要的意义。文中利用1961-2010年岷江上游及周边20个气象站的逐日气象资料,采用地形矫正的Hargreaves模型计算了潜在蒸散量,并结合小波分析和M-K突变检测方法分析了其时间序列变化特征。结果表明:岷江上游潜在蒸散量呈现由西北向东南逐渐上升的趋势;年潜在蒸散量以12a为准周期变化,潜在蒸散量呈现出波动中上升的趋势,尤其是90年代以来,上升趋势更为明显;而区域内年降水量呈现明显的下降趋势。岷江上游暖干化趋势明显,尤其是近20年,暖干化趋势加剧,生态环境受到严重威胁。     

1961～2010年甘肃合作地区草地潜在蒸散量及地表湿润度变化特征

为了对青藏高原东北部边坡地带潜在蒸散量和地表湿润度的变化进行研究,利用甘肃省合作市气象站1961～2010年的地面气象观测资料,根据Penman-Monteith模型计算了合作地区草地潜在蒸散量,发现合作地区年潜在蒸散量呈明显上升的趋势,上升趋势为13.0mm/10a;地表湿润度以-0.02/10a的趋势减小,出现了明显的暖干化趋势。温度升高和相对湿度下降是造成合作地区草地潜在蒸散量上升的主要气候影响因子,同时日照时数增加、降水量减少和风速增大对合作地区草地潜在蒸散量上升也有重要影响。     

近36年天山山区潜在蒸散量变化特征及其与南、北疆的比较

在使用联合国粮农组织(FAO)推荐的Penman-Monteith公式计算出新疆各地1971-2006年潜在蒸散量的基础上,采取线性回归、最大熵谱、Mann-Kendall检测、滑动t检验和Yamamoto检验以及自然正交分解(EOF)等方法,对近36年新疆天山山区和南、北疆潜在蒸散量的变化特征及其气候成因进行对比分析.结果表明:①天山山区年潜在蒸散量的总体变化趋势与南、北疆相似,均为递减趋势,但其线性递减速率和蒸散量的多年平均值较南、北疆小,年际、年代际变化较南、北疆稳定;②天山山区潜在蒸散量的周期性变化与北疆一致,均具有4.5年的显著周期;③天山山区的潜在蒸散量于1991年发生了突变性的减小,天山山区的突变点分别较南、北疆滞后3年和5年;④天山山区和南、北疆年潜在蒸散量的主要空间分布特征均是同向变化,而反向性变化以南疆最大,天山山区居中,北疆最小;⑤新疆各区域气温均有较明显的上升趋势,但由于日照时数和年平均风速减少(小)r,降水量和空气相对湿度增多(大),受其综合影响,天山山区和南、北疆潜在蒸散量总体呈减少趋势.     

近48年新疆乌-昌地区气候变化

根据新疆乌-昌地区15个气象台站1961-2008年的气候资料,采用气候倾向率、Mann-Kendall突变检测、Morlet小波、自然正交分解(EOF)和Kriging插值技术等方法,对近48年平均气温、降水量、日照时数和平均风速以及年潜在蒸散量和地表湿润指数等要素的变化趋势和特征进行了研究。结果表明:①近48年乌-昌地区年平均气温、降水量呈升高(增多)趋势,日照时数和年平均风速呈减少(小)趋势,受其影响,潜在蒸散量明显减小而地表湿润指数有所增大,气候总体呈较明显的"暖湿化"趋势。但受自然环境和城市化效应的影响,各地气候"暖湿化"的速率有明显差异;②突变检测表明,乌-昌地区年平均气温、降水量和湿润指数分别在1972年、1986年和1985年发生了显著的突变性升高,年日照时数、平均风速和潜在蒸散量分别于1972年、1979年和1985年发生了显著的突变性减小;③各气候要素分别存在4~24年的周期性变化;④各要素的主要空间分布特征均是同向变化,其中年平均气温、风速和地表湿润指数空间分布的同向性强于其他要素;⑤乌-昌地区年平均气温、降水量、日照时数、潜在蒸散量和湿润指数与地理坐标均具有极显著的多项式回归关系,这为各气候要素的栅格化处理提供了理论依据。     

基于湿润指数的新疆甘家湖地表干湿状况变化趋势

利用1953—2013年甘家湖梭梭林自然保护区内精河和乌苏气象站的逐月气象资料,采用伊凡诺夫公式计算出了逐月潜在蒸散量和湿润指数,分析了地表干湿状况的年际变化、季节变化及其主要影响因素。结果表明:1冬半年、夏半年和全年的多年平均潜在蒸散量分别为298、1 107 mm和1 407 mm,潜在蒸散量在冬半年随时间呈下降趋势,在夏半年和全年潜在蒸散量呈明显上升趋势。2春、夏季湿润指数的年际变化呈减小趋势,秋、冬季和全年湿润指数的年际变化呈增加趋势。根据湿润指数相对应的气候区划标准,春季甘家湖自然保护区为半干旱地区,夏季和秋季为极干旱区-干旱区,冬季为干旱区的亚湿润区-湿润区。3湿润指数与降水量、水汽压和相对湿度呈正相关,与风速、气温和日照时数呈负相关;相对湿度变化对湿润指数变化影响最大,其次是日照时数、气温、水汽压和降水量,影响最小的是风速。     

近50年中国干旱半干旱地区降水量与潜在蒸散量分析

在中国干旱半干旱地区日气象数据分析的基础上,依据彭曼公式计算出潜在蒸散量,以及生长季内的年平均降水量与潜在蒸散量二者的差值,利用空间分异分析,气候倾向率检测,以及时间序列MK突变检验等方法分析了降水量与潜在蒸散量的时空变化特征。结果表明:总体来看,我国干旱半干旱区50年来东、西部的气候变化有明显的差异,西北地区降水量增加,潜在蒸散量减少,干旱化程度在减轻,且变化十分显著。而东部干旱半干旱区降水量减少,潜在蒸散量增加,干旱化严重。     

京津冀地区近50年气温、降水与潜在蒸散量变化分析

利用京津冀地区22个气象站1960年到2010年逐日的气象要素观测资料,采用彭曼公式计算该地区近50年逐日的潜在蒸散量.在此基础上,利用气候倾向率检测、时间序列MK突变检验以及年代际分析等方法分析了该地区近50年气温、降水和潜在蒸散量的时空变化特征.结果表明:京津冀地区近50年来气温升高显著;大部分地区降水减少;整个地区潜在蒸散量都在减少,东南部减少的更快.气温升高和降水减少导致整个区域变得干旱化,但潜在蒸散量的减少,缓解了一部分干旱化的趋势.     

陇东南干旱区农田土壤水分蒸散变化特征

用Peman公式计算了20世纪60~90年代陇东南旱作区农田40 a潜在蒸散值,分析了潜在蒸散的时空变化并与蒸发器实测值进行比较。结果表明:潜在蒸散值受气温、降水的支配比较大,80年代最小,其次为70、60年代,90年代增幅最大,其中关山区增幅最为明显;90年代各地各季潜在蒸散值均达到高值点,其中夏季最高,冬季最小;潜在蒸散量与实测蒸发量变化趋势基本一致;60~90年代各地平均年潜在蒸散值比实测值高30%左右,其中春、夏、秋三季潜在蒸散均大于蒸发器所测值,以夏季相差最大,达50%左右,冬季潜在蒸散则小于蒸发器所测值;90年代以来,各地土壤水分亏缺值增多,尤以春季亏缺最多,对作物生长影响较大。     

1980-2009年西藏西北部潜在蒸散时空分布特征及其影响因素

通过分析西藏西北部潜在蒸散量的时空分布以及影响潜在蒸散的气候因素.结果表明:①西藏西北部潜在蒸散呈现从西北向东南减少的分布特征,最大潜在蒸散出现在夏季,春季次之,冬季最小.近30 a来,除冬季潜在蒸散呈略微增加趋势外,其余均呈减少趋势.气温、相对湿度和降水量呈增加趋势,平均风速和日照时数呈减少趋势;潜在蒸散与气温、风速、日照时数呈正相关,与相对湿度、降水量呈负相关.②影响潜在蒸散的主要气象要素为相对湿度、平均气温和日照时数,风速对冬季潜在蒸散的影响最为显著;近30 a来,风速减小、日照时数减少、相对湿度增加是导致潜在蒸散量减少的主要气象影响因子.西藏西北部地区潜在蒸散的变化存在“蒸发悖论”现象,即在气温升高[0.55℃·(10a)-1]的背景下,潜在蒸散呈下降趋势[10.02 mm ·(10a)-1].     

农田鼠类数量统计方法的研究

目前统计大仓鼠Cricetulus triton、黑线仓鼠C.barabensis和黑线姬鼠Apodemus agrarius等地面活动的农田鼠类广泛采用夹捕法和查洞法,夹捕法又要求连续布夹三夜。本文对用一夜、连续二夜和三夜夹捕的统计结果作了对比研究,结果表明,三种夹捕方法的统计结果一致,呈极显著正相关。作者认为只用一夜捕鼠减少了工作量和样方去除效应,可在农田鼠情常规测报中代替连续三夜捕鼠法。查洞法的统计结果不能反映农田鼠类数量的季节变化,不宜在鼠情测报中使用。     

Spatial regression approach to estimate synthetic unit hydrograph by geomorphic characteristics of watersheds in arid regions

Rainfall-runoff relationship in arid regions is unique and challenging to study. Studies for bridging the hydro-meteorological knowledge gap for planning, designing and managing water resources is therefore vitally important. The objective of this study is to develop a method for estimating unit hydrograph at reasonably finer time resolutions (10-min and 1-h) which can be easily adaptable by practitioners at sub-catchment levels, especially when the focus area is ungauged. Observed wadi-flow at 5-min interval and tipping bucket rainfall measurements at 1-min interval were obtained to cover 10 major watersheds in Oman. The deconvolution method was applied to derive the unit hydrographs (UHs) from wadi-flow and excess rainfall. Key catchment characteristics such as the watershed area, length of the main wadi and the length to the centroid of the catchment area were derived from digital elevation model (DEM) data. The whole study area was then divided into 515 sub-catchments with various shapes and sizes. A strong relationship was found between the wadi length and the length to the centroid of the catchment area (R²>0.89). This relationship was then adopted to simplify the classical Snyder method to determine UHs. Moreover, several parameters of the Snyder method were calibrated to the arid environment by matching the peak-flow, lag-time and three time-widths (75%, 50% and 30% of the peak-flow) of 10-min and 1-h UHs with physical characteristics of the watersheds. All developed relationships were validated with independent rainfall and wadi-flow events. Results indicate that the calibrated parameters in these arid watersheds are quite distinct from those suggested for other regions of the world. A marked difference was found between the 10-min UHs estimated by the S-hydrograph method and the deconvolution method. Therefore, it is concluded that a method depends on natural hydro-meteorological conditions would be more practical in arid region. The proposed methodology can be used for water resources management in arid regions having similar climate and geographical settings.     

Detection of beet yellows virus in sugarbeet plants by enzyme-linked immunosorbent assay (ELISA)

Beet yellows virus can be detected in leaf extracts of infected sugarbeet plants by ELISA. The use of discs was studied and proved to be a valuable and qualitatively reliable method. Leaf material could be stored at 4^o or 22°C for at least six days without affecting the detection of this virus by ELISA. A dramatic decrease in ELISA values was found when leaf extracts were frozen.In an analysis of the distribution of virus over the plant it was found that young leaves present at the moment of infection and those which had still to develop after infection will contain virus. Symptoms produced by systemic virus invasion occur on the oldest leaves containing virus.Samenvatting Het bietevergelingsvirus kan op betrouwbare wijze met de ELISA methode in geïnfecteerde bieteplanten worden aangetoond. Een aanzienlijke vereenvoudiging van de procedure kan worden bereikt met de zogenaamde disc-method, waarbij intacte ponsstukjes in de putjes van de ELISA-plaat worden geïncubeerd. Hierbij komt voldoende virus uit de ponsstukjes voor ELISA vrij. Bladmateriaal kon op verschillende wijzen bewaard worden zonder dat de mogelijkheid om het virus aan te tonen achteruitging. Met bladextracten die ingevroren waren, werden echter slechte resultaten verkregen.In een analyse naar de verdeling van het virus over het loof bleek het virus voor te komen in de geïnoculeerde bladeren, in die bladeren die op het tijdstip van inoculatie minder dan de helft van hun uiteindelijke lengte bereikt hadden en in de bladeren die nog moesten verschijnen. De symptomen ontwikkelden zich op de oudste systemisch geïnfecteerde bladeren.     

浅淡单点校正法和标准曲线法及其在农药分析中的应用

本文从单点校正法和标准曲线法的适用前提条件出发，运用数学方法，探讨了单点校正法代替标准曲线法的条件，并为在农药分析中选择单点校正法和标准曲线法提供依据，从而简化正常农药分析步骤，避免一些分析误差。     

吐伦球坚蚧在杏树上的分布及抽样方法研究

为确定吐伦球坚蚧在杏树上的分布格局及其田间虫口数量估计的最佳抽样方法,以最近邻体法分别对吐伦球坚蚧越冬若虫、成虫和越夏若虫在杏树上的分布进行研究,并比较五点法、棋盘式、双对角线、Z字形、平行线5种抽样方法与总体平均数的差异显著性及各抽样方法的误差率。结果表明：吐伦球坚蚧越冬若虫、成虫和越夏若虫在杏树上的分布均为聚集型。Z字形抽样方法对田间吐伦球坚蚧越冬若虫和成虫进行抽样最可靠;越夏若虫以平行线抽样法最具代表性且最为可靠。     

10%溴虫氟苯双酰胺SC对草地贪夜蛾的控制效果

为探索新型杀虫剂溴虫氟苯双酰胺对草地贪夜蛾的防治效果,采用喷雾法和浸叶法在室内研究了10%溴虫氟苯双酰胺悬浮剂(SC)对草地贪夜蛾的杀虫性,并用喷雾法进行了田间控制效果研究。室内试验结果表明,10%溴虫氟苯双酰胺SC喷雾处理对草地贪夜蛾卵的孵化率无明显影响,但能显著提高初孵幼虫的死亡率(P<0.05),各处理校正死亡率均高于78.26%。同时,10%溴虫氟苯双酰胺SC对3龄和5龄幼虫均有较强的活性,处理72 h后的校正死亡率均高于90%,并且随着浓度的增加,死亡率升高。田间药效试验表明,不同浓度的10%溴虫氟苯双酰胺SC处理后1 d和7 d防效均可达96.33%以上,显著高于对照药剂5.7%甲维盐微乳剂(ME)和200 g/L氯虫苯甲酰胺SC;药后14 d各处理防效为41.71%～66.32%,其中10 mL/667m~2处理与对照药剂5.7%甲维盐ME防效相当。研究表明,10%溴虫氟苯双酰胺SC可以有效控制草地贪夜蛾,且速效性和持效性较好,建议每667 m~2使用制剂10～15 mL,防治适期为草地贪夜蛾卵孵化盛期及低龄幼虫期。     

药剂对小麦叶锈菌生物活性试验方法的研究

应用人工接菌方法,小麦叶锈菌能在含有６－苄基氨基嘌呤洋菜培养基中的感病离体小麦叶段上产生夏孢子堆。它在药剂生物活性测定中反应较为灵敏,与室内活体生物测定有较高的相关性,但也存在一定差异。如果两者结合使用,则可取长补短,避免漏筛。     

A general multi-objective programming model for minimum ecological flow or water level of inland water bodies

Assessment of ecological flow or water level for water bodies is important for the protection of degraded or degrading ecosystems caused by water shortage in arid regions, and it has become a key issue in water resources planning. In the past several decades, many methods have been proposed to assess ecological flow for rivers and ecological water level for lakes or wetlands. To balance water uses by human and ecosystems, we proposed a general multi-objective programming model to determine minimum ecological flow or water level for inland water bodies, where two objectives are water index for human and habitat index for ecosystems, respectively. Using the weighted sum method for multi-objective optimization, minimum ecological flow or water level can be determined from the breakpoint in the water index–habitat index curve, which is similar to the slope method to determine minimum ecological flow from wetted perimeter–discharge curve. However, the general multi-objective programming model is superior to the slope method in its physical meaning and calculation method. This model provides a general analysis method for ecological water uses of different inland water bodies, and can be used to define minimum ecological flow or water level by choosing appropriate water and habitat indices. Several commonly used flow or water level assessment methods were found to be special cases of the general model, including the wetted perimeter method and the multi-objective physical habitat simulation method for ecological river flow, the inundated forest width method for regeneration flow of floodplain forest and the lake surface area method for ecological lake level. These methods were applied to determine minimum ecological flow or water level for two representative rivers and a lake in northern Xinjiang of China, including minimum ecological flow for the Ertix River, minimum regeneration flow for floodplain forest along the midstream of Kaxgar River, and minimum ecological lake level for the Ebinur Lake. The results illustrated the versatility of the general model, and can provide references for water resources planning and ecosystem protection for these rivers and lake.     

Dynamics of ecosystem carbon stocks during vegetation restoration on the Loess Plateau of China

In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with vegetation restoration in this region are poorly understood. This study examined the changes of carbon stocks in mineral soil(0–100 cm), plant biomass and the ecosystem(plant and soil) following vegetation restoration with different models and ages. Our results indicated that cultivated land returned to native vegetation(natural restoration) or artificial forest increased ecosystem carbon sequestration. Tree plantation sequestered more carbon than natural vegetation succession over decades scale due to the rapid increase in biomass carbon pool. Restoration ages had different effects on the dynamics of biomass and soil carbon stocks. Biomass carbon stocks increased with vegetation restoration age, while the dynamics of soil carbon stocks were affected by sampling depth. Ecosystem carbon stocks consistently increased after tree plantation regardless of the soil depth; but an initial decrease and then increase trend was observed in natural restoration chronosequences with the soil sampling depth of 0–100 cm. Moreover, there was a time lag of about 15–30 years between biomass production and soil carbon sequestration in 0–100 cm, which indicated a long-term effect of vegetation restoration on deeper soil carbon sequestration.