河南省农业综合生产能力的构成及评价研究

通过对农业综合生产能力的构成因素分析，得出了相应的评价指标体系，利用相关分析，显著性检验和通径分析，确定了影响农业综合生产能力的重要因素，根据对１９８０～１９９３年河南省农业综合生产能力的测算结果，建立了４种模型并进行了预测。     

松花江流域极端降雨变化对流域输沙量的影响

基于松花江流域及其周边共43个气象站点1960—2014年逐日降雨数据及佳木斯水文站输沙量数据,采用Mann-Kendall非参数趋势分析方法、小波周期性分析和双累积曲线法,分析了流域内7个极端降雨指数和输沙量的动态变化趋势,在此基础上定量评估了流域极端降雨变化对输沙量的影响。结果表明:1960—2014年间,松花江流域7个极端降雨指数(最大1 d降雨量(RX1day)、连续5 d最大降雨量(RX5day)、降雨强度指数(SDII)、大于95%分位值强降雨量(P95pTOT)、大雨量(HP)、暴雨量(RSP)和汛期降雨量(FSPTOT))皆呈阶段性波动变化,存在16~20 a的大周期和5~6 a的小周期变化特征,但近55 a各极端降雨指数整体上呈不显著的变化趋势;期间佳木斯水文站输沙量的变化趋势与7个极端降雨指数的变化趋势类似。松花江流域各极端降雨指数与输沙量均存在极显著相关性(p0.01),其中RX5day、P95pTOT与输沙量的相关性最显著。双累积曲线分析显示,流域输沙量与各极端降雨指数关系的突变点均发生在1977年。与基准期(1960—1977年)相比,1978—2014年松花江流域各极端降雨指数对输沙量变化的影响在3.09%~15.24%之间,其中SDII变化对输沙量的影响最大(15.24%),其次是FSPTOT(14.81%)和RX5day(14.34%)。     

50年来湘中地区气候极值与农业气候指标动态变化趋势

利用湘中地区1961-2010年气象站逐日观测数据资料,选取与农作物密切相关的气候极值和农业气候指标,采用统计检验、趋势分析和Mann-Kendall突变检验等的方法,分析了湘中地区农业水热气候条件和气候极值,进而研究主要农业气候指标的变化倾向。研究发现：湘中地区近50年来,水热资源总体呈增加趋势;年强降水量呈增大趋势,尤其以夏季强降水量增加最为明显,表明夏季洪涝灾害的威胁加大;最高(低)气温阈值的变化表明极端高(低)温均呈缓解趋势,及其出现的天数在减少,说明由极端气候引起高温热害、低温冷害等气象灾害发生的可能性减小;≥0℃和≥10℃积温分别在1997年和2000年开始突变,上升趋势明显,表明湘中地区有效热量资源在增加;霜冻日数呈减小趋势,说明霜冻危害发生的风险在减小。这对确定合适的农业气候指标值和促进农业生产有重要的指导意义。     

1960-2009年青海省极端降水事件的变化特征

利用1960-2009年青海省26个气象台站的降水资料,采用线性倾向估计法、反距离加权法、M—K突变检测等方法,研究了青海省50a来极端降水事件变化的空间分布以及时间变化特征。结果发现,近50a来,青海省极端降水天数、最大的1d和5d降水总量、中雨天数和逐年平均降水强度均表现为增加(强)趋势,只有极端降水天数通过了0.05的置信度检验;各极端降水指数变化趋势存在空间差异,祁连山地区极端降水天数、最大的1d和5d降水总量、中雨天数和逐年平均降水强度增加趋势明显,青海省东部地区增加不明显或呈微弱减少趋势;青海省极端降水事件在0.05的置信度下发生了明显的突变现象,且各极端降水指标与年降水总量有很好的相关性。     

Projections of temperature extremes based on preferred CMIP5 models:a case study in the Kaidu-Kongqi River basin in Northwest China

The extreme temperature has more outstanding impact on ecology and water resources in arid regions than the average temperature. Using the downscaled daily temperature data from 21 Coupled Model Inter-comparison Project(CMIP) models of NASA Earth Exchange Global Daily Downscaled Projections(NEX-GDDP) and the observation data, this paper analyzed the changes in temporal and spatiotemporal variation of temperature extremes, i.e., the maximum temperature(Tmax) and minimum temperature(Tmin), in the Kaidu-Kongqi River basin in Northwest China over the period 2020–2050 based on the evaluation of preferred Multi-Model Ensemble(MME). Results showed that the Partial Least Square ensemble mean participated by Preferred Models(PM-PLS) was better representing the temporal change and spatial distribution of temperature extremes during 1961–2005 and was chosen to project the future change. In 2020–2050, the increasing rate of Tmax(Tmin) under RCP(Representative Concentration Pathway) 8.5 will be 2.0(1.6) times that under RCP4.5, and that of Tmin will be larger than that of Tmax under each corresponding RCP. Tmin will keep contributing more to global warming than Tmax. The spatial distribution characteristics of Tmax and Tmin under the two RCPs will overall the same; but compared to the baseline period(1986–2005), the increments of Tmax and Tmin in plain area will be larger than those in mountainous area. With the emission concentration increased, however, the response of Tmax in mountainous area will be more sensitive than that in plain area, and that of Tmin will be equivalently sensitive in mountainous area and plain area. The impacts induced by Tmin will be universal and farreaching. Results of spatiotemporal variation of temperature extremes indicate that large increases in the magnitude of warming in the basin may occur in the future. The projections can provide the scientific basis for water and land plan management and disaster prevention and mitigation in the inland river basin.     

近52年西北干旱区极端温度事件季节性时空分析

利用西北干旱区83个气象站点1961—2012年逐日最低（高）气温资料,对其极端温度事件季节性时空变化规律进行分析与预测,以期更好地为其生态保护和农业生产服务。结果表明：(1)时间趋势上,日极端低（高）温均值呈上升趋势,尤其是1981年后升幅明显增加,冬秋季升温最显著;日极端低（高）温极低（高）值有增多趋势,其中暖昼（夜）日数有增加趋势,夜（昼）指数变化最快的季节为夏秋季;1979—1986年,上述指数变化趋势发生突变（冬季先开始）;除夏季日极端低温极低值外,其他指数在2013—2020年季节变化与1961—2012年的增减趋势一致。(2)空间分布上,暖昼（夜）日数最大值、冷昼（夜）日数最小值均在北疆分区,而内蒙-宁夏分区的增减速率变化最快;2013—2020年,新疆全境春季冷昼、冷夜日数急剧减少,内蒙-宁夏分区、南疆分区夏季日最低（高）气温极值急剧降低（上升）。     

极端温度事件对我国华北农业气候资源的影响

基于均一的262个地面站逐日气温数据及RegCM4.0区域气候模式模拟数据,从观测事实和模式预估两方面,对华北区域的农业热量资源以及与农业经济相关的极端温度指标的趋势变化进行了评估.结果表明,华北区域≥15℃活动积温的趋势增加幅度均较大,≥0℃和≥10℃活动积温的趋势增加幅度均相当;而＞10℃有效积温的增加幅度较＞15℃有效积温明显.近54年来观测到的华北区域气温日较差基本呈明显的减少趋势,而模拟预估则显示出未来的日较差趋势变化并不显著.同时,极端温度指标的分析结果也表明,在未来几十年里,气温的大幅度增暖是可控的,甚至能够达到增暖幅度低于当前观测到的平缓趋势.因此,对于华北区域来说,优化种植制度是适应气候变化最重要的技术手段.     

Revealing past needle density in Pinus spp.

The number of short shoots per shoot length, or needle density, is species typical, and it shows year‐to‐year variation within species. By modification of the needle trace method, long‐term needle density chronology was produced in a Scots pine (Pinus sylvestris L.) stand, located at the northern timberline in Finland. Treewise, needle density varied between 9 and 14 short shoots per long shoot (stem internode) centimetre, the annual minimum and maximum values being 5 and 37 short shoots cm^?1. The stand‐specific long‐term average was 10.5 short shoots cm^?1, and the mean annual value varied between 17 and 8 short shoots cm^?1 in 1951 and 1984, respectively. The long‐term pattern in needle density was one of decline with time between 1950 and the mid‐1970s, then to slightly increase on entering the 1990s. The years when the density was relatively high were 1957, 1968 and 1981, indicative of some climatic extremes.     

Aardvark burrows: a potential resource for animals in arid and semi-arid environments

Arid and semi-arid environments are characterized by extreme fluctuations in temperature and low rainfall, which present significant challenges to the animals inhabiting these areas. However, the presence of burrows may allow animals to avoid climatic extremes and predators and may act as valuable foraging sites. We assessed the microhabitat conditions (maximum and minimum temperature, relative humidity and seed abundance) of aardvark (Orycteropus afer) burrows in relation to paired non-burrow areas at three sites in South Africa. We also describe the extent to which they are used as resources by other vertebrates. Maximum temperatures were significantly lower and minimum temperatures and relative humidity values were significantly higher inside the burrows than outside. The concentration of seeds inside the burrows and at the paired non-burrow sites was similar. Twenty-seven vertebrate species (21 mammals, two birds, three reptiles and one amphibian) were recorded making use of the burrows and it is likely that these species accrue benefits (e.g. a buffered microclimate) from burrow use. However, our sampling was biased towards mammals and nocturnal species. Consequently, we recommend further work to establish the overall reliance of vertebrate taxa on aardvark burrows in arid and semi-arid environments.     

近42年来东北地区夏季降水极值的时间特征分析

利用1959～2000年东北地区93站逐日降水资料,分析了东北地区夏季降水极值的时间特征,结果发现,东北地区夏季暴雨强履增强,暴雨日数略减少,tL雨量与总雨量的变化趋势一致。极端干燥事件近42年来增加显著,特别是20世纪90年代中期以来极端干甥事件发生异常频繁,是近年来东北地区干旱频繁发生及灾情严重的一个重要原因。极端连雨日总体呈较明显的减少趋势;极端连雨日是影响20世纪90年代中期之前夏季总降水量的重要因子,而降水强度是影响90年代中期之后夏季降水总量的重要因子。最大3d平均降水量无明显的年代际变化特征。