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21.
南昌地区风沙化土地风沙地貌发育规模和风沙活动预测 总被引：3，自引：0，他引：3
本文通过对南昌地区风沙化土地扩展方式,沙源量及人为因素在风沙地貌发育中的作用等方面的分析,初步认为本风沙地貌发育规模不会很大,且目前已接近其顶锋状态。在建立GM(1,1)和方差分析(ANOVA)联合预测模型的基础上,对厚田地区三个月的干旱程度和冬季风沙活动强度进行预测,结果令人满意。 相似文献
22.
Sultan Marsh (Turkey) is one of the largest wet lands of the Middle East and Europe. The aim of this study was to determine
average concentrations of heavy metals, variations of the obtained values in a large scale, geogenic and anthropogenic sources
of the pollution and effects of the pollution on the environment in Sultan Marsh. To these aims, a total of 176 surface soil
samples (0–10 cm depth) were collected from 80 ha land in Sultan Marsh. Using a bench-top Spectro-Xepos X-ray fluorescence
spectrometer, we analyzed all samples to determine the near-total concentrations of 26 chemical elements. Basic and multivariate
statistics were used for statistical analyses. GIS mapping, a powerful tool for identifying possible sources of pollutants,
was used to classify and identify the elements. Relatively high concentrations of the elements Fe, Pb, Zn, Sb, W, Mo, Co,
Cu, Hg, Ni, Cr, Mn and Cd were found in Sultan Marsh, surrounding rocks (geogenic sources), mines of Fe and Pb/Zn, industrial
facilities, residential and agricultural areas and major traffic routes (anthropogenic sources). 相似文献
23.
首先采用方差分析方法，研究了实际大气500 hPa高度场的月尺度可预报性，并进一步分析了不同空间尺度大气运动的可预报性及其对大气整体运动可预报性的影响；对ECMWF和国家气候中心T63谱模式分别模拟和预报的500 hPa高度场，也用同样的方法进行了研究。结果表明，欧洲中心和我国T63模式大气的可预报性均比实际大气可预报性小，特别是在对整体运动可预报性影响最大的0～3波部分，差异较大，说明改进模式对0～3波部分的预报能力，必将提高模式性能。 相似文献
24.
Ben?Harp Jeremy?Hogue Logan?Peck Drew?SpainEmail author 《Natural Resources Research》2005,14(2):101-107
An earlier investigation by the Kansas Geological Survey in central Kansas studied the movement of nitrate from fertilizer through soil into the groundwater. Nitrate concentrations in soil water were measured on samples collected at three locations during a three-year span, from sets of lysimeters buried at different depths. Although patterns seemed apparent in the resulting measurements, no statistical analyses were performed to test their significance; this re-study of the data uses analyses of variance to test for differences in nitrate concentration attributable to time and to depth in the soil. The mean nitrate concentration of samples collected in the first year of the experiment was significantly higher than the means of second and third year samples at all three locations, perhaps reflecting the confounding influence of a previous flooding experiment. ANOVAs of depth across years determined few significant differences in nitrate concentration with depth. The wintertime gap in measurements and unequal sampling through time precludes formal time-series analyses, but graphs of concentration versus time show that peak concentration occurs at later times with increasing depth, and that maximum concentration decreases with depth. These statistical analyses support the conclusions from the original investigation. 相似文献
25.
该文利用 IAP L2 AGCM1 - 1模式进行 1 7年 ( 1 980～ 1 996年 )、每年 9个单个积分的集合后报试验 ,采用方差分析的方法对试验结果进行可预报性研究 .结果表明 :在热带地区 ,海表温度 ( SST)异常引起的可预报性较高 ,50 0 h Pa高度场高值区沿热带呈带状分布 ,在热带外仅有部分相对高值区 ;在中高纬度地区 ,春季的可预报性高于夏季 ;一般来说各场的可预报性海洋高于陆地 .在北太平洋春季 ,50 0 h Pa高度场、海平面气压场和表面气温场有一可预报高值区 .在中国区域 ,降水场、海平面气压场和表面气温场的可预报性从我国南海向西北递减 . 相似文献
26.
为了解不同环境因素对水库内直链藻(Melosira)垂向分布的影响程度, 作者利用自制沉降柱实验模拟不同光照、水动力以及降雨条件对水中直链藻垂向分布的影响。通过单因素方差分析实验数据表明光照和降雨条件的改变对上浮区内直链藻的垂向分布具有显著影响, 底部出流流量的改变对下沉区内直链藻的垂向分布具有显著影响。随着水深的增加, 光照和降雨对水中直链藻垂向分布的影响减弱而水动力则对其影响增强。同时还验证了直链藻具有较强的趋光性, 宜在低光强环境内生长, 模拟测得其最适光强在3 000 lx 左右; 降雨对水中直链藻的垂向分布起到抑制作用, 降雨强度越大水中直链藻就越偏离水体表面; 在底部出流流量影响范围内, 随着出流流量的增大水中直链藻就越向水动力改变处聚集且稳定时间越短。 相似文献