基于灰色关联度的区域大气环境质量影响因素研究——以秦皇岛市为例

以2004～2009年秦皇岛市相关统计数据为依据,运用灰色关联度分析法,对秦皇岛市7项大气环境质量的影响因素进行筛选,得出各项因素的主次关系。研究表明,市区人口数、园林绿地面积、港口吞吐量和煤炭使用量是影响秦皇岛市大气环境质量的重要因素。基于此,提出政府应科学确定和适当控制城市人口规模、加强城市绿化、港口煤尘治理和发展清洁能源等建议。     

基于B-P神经网络的城市大气SO2浓度预测

基于B-P神经网络的原理和方法,利用西南某市1991-2009年的统计数据,建立城市大气SO2浓度预测模型,对西南某市大气SO2浓度进行预测。结果表明,B-P神经网络方法在城市大气SO2浓度预测方面具有合理高效、精确度高、适应力强等特点,值得应用与推广。     

ENVI FLAASH和ERDAS ATCOR2的大气校正对比研究

研究分别用ENVI FLAASH模块和ERDAS ATCOR2模块对LANDSAT5-TM图像进行大气校正,进而对校正效果进行评价。结果表明,ENVI FLAASH和ERDAS ATCOR2均能很好地消除大部分大气的影响,满足试验要求。但从精度方面考虑,ENVI FLAASH要略胜于ERDAS ATCOR2。     

宁夏同心县近56年气候变化特征研究

根据宁夏同心县1951—2006年的气温和降水记录,用相关分析、统计和回归等数理统计方法进行了分析,表明56年来同心县气温有明显上升的趋势,年平均气温呈线性升高,冬季升温幅度最大、夏季微弱是气温变化的主要特征.降水量的变化不明显,但秋季降水有减少的趋势.56年来同心县呈现凉湿—凉干—暖湿—暖干的变化趋势.     

七台河市冬季大气边界层特征研究

利用实际观测的资料．对七台河市大气边界层内的风场、温度场和大气混合层高度的特征分别进行了研究,采用ATDL模式计算方法进行了风速与烟源有效高度分析,提出了浑浊气体排放的最佳时间。     

最优子集回归在武威市降水预报中的应用

选用Micaps下发的ECMWF 0～120 h格点场资料,使用差分法、天气诊断、因子组合等方法构造出能反映本地天气动力学特征的预报因子库.根据大气环流产生降水的物理机制不同,将天气形势分为西北气流型、西南气流型和不规则型3种,分别对预报因子和预报量进行线性0,1标准化处理,采用Press准则初选冈子,最优子集回归建立武威市6个站点不同天气类型的0～120 h降水预报方程,用多因子概率权重回归预测其降水概率.预报方程的降水和晴雨拟合率达0.742,0.783;投入业务试用后,0～120 h降水和晴雨预报准确率Ts 达0.653,0.813.说明该预报模型对降水天气预报能力强.其预报能力超过或接近日常业务预报,为地市级客观预报提供了有效的指导产品.业务系统与MICAPS对接,实现全自动化,输出的预报产品客观、定量.     

Yield formation of CO2-enriched hybrid rice cultivar Shanyou 63 under fully open-air field conditions

Hybrid indica rice (Oryza sativa L.) cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle and high yield potential. However, no attention has been given to its yield responses to rising atmospheric [CO₂] in conjunction with nitrogen (N) availability. Therefore we conducted a free air CO₂ enrichment (FACE) experiment at Yangzhou, Jiangsu, China (119°42′0′′E, 32°35′5′′N), in 2004–2006. A three-line hybrid indica rice cv. Shanyou 63 was grown at ambient and elevated (ca. 570 μmol mol⁻¹) [CO₂] under two levels of supplemental N (12.5 g Nm⁻² and 25 g Nm⁻²). Elevated [CO₂] had no effect on phenology, but substantially enhanced grain yield (+34%). The magnitude of yield response to [CO₂] was independent of N fertilization, but varied among different years. On average, elevated [CO₂] increased the panicle number per square meter by 10%, due to an increase in maximum tiller number under enrich [CO₂], while productive tiller ratio remained unaffected. Spikelet number per panicle also showed an average increase of 10% due to elevated [CO₂], which was supported by increased plant height and stem dry weight per tiller. Meanwhile, elevated [CO₂] caused a significant enhancement in both filled spikelet percentage (+5%) and individual grain weight (+4%). Compared with the two prior FACE studies on rice, hybrid indica rice cultivar appears to profit much more from elevated [CO₂] than japonica rice cultivar (ca. +13%), not only due to its stronger sink generation, but also enhanced capacity to utilize the carbon sources in a high [CO₂] environment. The above data has significant implication with respect to N strategies and cultivar selection under projected future [CO₂] levels.     

Ambient air concentrations of pesticides used in potato cultivation in Prince Edward Island, Canada

Ambient air concentrations of nine selected pesticides used in potato cultivation were investigated on Prince Edward Island by collecting samples during the summer of 1998 at three potato farm sites and one non-agricultural site. In 1999, air samples were collected at a single potato farm site during local application of pesticides. The fungicide chlorothalonil was the only pesticide detected in every sample in both years, even in samples with a duration as little as 5 h. In 1998, maximum (45-458 ng m(-3)) and mean (22-193 ng m(-3)) concentrations of chlorothalonil from composite 42 h samples were one to two orders of magnitude greater at agricultural sites than at the non-agricultural site (3.9 and 2.5 ng m(-3), respectively). Maximum and mean concentrations of chlorothalonil from combined 24 h samples at the farm site in 1999 were higher than those measured in 1998 (636 and 284 ng m(-3), respectively). The ubiquitous presence in air of relatively high concentrations of chlorothalonil in agricultural areas on Prince Edward Island is likely related to its repeated use on potato farms where fungicides account for 80-90% of pesticides applied. Eight of nine pesticides were detected at farm sites in 1998 and they are ranked by mean concentration from highest to lowest as follows: chlorothalonil, methamidophos, azinphos-methyl, alpha-endosulfan, beta-endosulfan, pirimicarb, metobromuron, metribuzin, metalaxyl and fluazifop-P-butyl. Concentrations of metalaxyl, pirimicarb, metobromuron and fluazifop-P-butyl in air are among the first reported values for these pesticides. Five pesticides were detected at the Summerside farm in 1999, but only two fungicides (chlorothalonil and metalaxyl) were used locally, while the presence of metribuzin, alpha-endosulfan and methamidophos in air was not associated with local application. Evidence of pesticide drift was observed for chlorothalonil, alpha-endosulfan and methamidophos, and these pesticides were identified as being of high concern in terms of potential wildlife exposure on the Island.     

土壤中210Pbex背景值含量动态平衡模型

在利用土壤侵蚀模型估算侵蚀速率的过程中,背景值点选取的好坏直接关系到结论是否可靠,如果能通过科学计算得出研究区域背景值,将大大提高背景值的准确性,对研究土壤侵蚀具有重大意义。土壤未受到侵蚀和沉积的背景区,首先假设全球大气沉降量为定值,研究把²¹⁰Pb_ex沉降过程以一年为时间尺度划分为n年,经过n年以后（n=0,1,2,…,∞）,土壤中²¹⁰Pb_ex沉降量和经过衰变减少量达到平衡,土壤中²¹⁰Pb_ex含量趋于稳定。假设各地年平均降水量为定值,通过研究发现²¹⁰Pb_ex的大气沉降通量与年降水量之间存在极显著相关（P < 0.01）,区域年降水量是影响土壤中²¹⁰Pb_ex量的主要因素,由于年平均降水量不同,全球各地土壤中²¹⁰Pb_ex含量都会达到不同的稳定值,从而建立土壤中²¹⁰Pb_ex含量与年降水量关系模型。研究²¹⁰Pb_ex来源、沉降的连续性和稳定性,提出利用区域年平均降水量来计算该地区的²¹⁰Pb_ex背景值,建立土壤中²¹⁰Pb_ex背景值含量动态平衡模型,为准确确定²¹⁰Pb_ex背景值提供了方法,对研究土壤侵蚀具有重要的意义。     

江苏暴雨事件中大气环流类型初步分析

选取江苏省近49年（1960—2008年）来64个台站暴雨资料,结合NCEP/NCAR再分析资料,选取111个典型暴雨天气过程,通过对500 hPa高度距平场进行EOF分型。结果表明近49年有影响的江苏省暴雨过程可以分为3种类型,即:两脊一槽型、纬向型和双阻型。并进一步分析各类型暴雨过程出现前一日和当日的500 hPa和700 hPa高度场、850 hPa风场和海平面气压场。分析结果表明：（1）两脊一槽型暴雨。500 hPa高度场是深厚的贝加尔湖大槽,700 hPa高度场两脊一槽的形势明显且有阶梯槽存在,高度场上等高线密集,850 hPa高度场水汽充沛,地面图上四川有低压且有东移发展成倒槽之势。此类型暴雨持续时间以一天居多。（2）纬向型暴雨。500 hPa高度场上环流较平直,多小槽活动,西南气流强盛,等高线稀疏。850 hPa高度场在苏北有风速和风向辐合区,此类型暴雨天气形势易产生持续性大范围暴雨。（3）双阻型暴雨。500 hPa高度场上中高纬度存在2个阻塞高压,贝加尔湖低槽深厚,且槽线分成南北二段,700 hPa高度场上中纬度多小槽活动,850 hPa高度场水汽输送通畅,此类型暴雨天气形势易出现持续性暴雨。