1970年以来湖北省气候变化与旱涝灾害响应分析

湖北省是中国亚热带地区的内陆省区,具有气候变化响应的特殊性。依据湖北省分布较为均匀的17个气象站点1970-2013年的逐月气温和降水数据,运用线性回归、插值分析、Mann-Kendall突变检验、Morlet小波分析和标准化降水指数SPI等数理分析统计方法,对湖北省近44年来气候变化的时空分异规律以及旱涝灾害响应特征进行分析,结果显示:(1)近44年来,湖北省年降雨量呈减少趋势,其减少的速率为16.16 mm/10a,年平均气温呈波动上升趋势,其上升的速率为0.30℃/10a,整体呈暖干化趋势;(2)通过对年均温做Mann-Kendall突变检验后发现,湖北省气温在1994年前后发生突变,之后呈现出较大幅度的增温趋势;(3)就旱涝灾害来说,湖北省旱涝灾害频繁,中度、重度和极端旱涝灾害发生频率高达31.8%。研究证明:在暖干化趋势的背景下,湖北省气候变化响应体现出显著的阶段性特征,具有特殊性,其旱涝灾害也因气候变化体现出周期性干湿变化规律,当前几年正处于偏干旱阶段,旱灾较多。     

A climatic reversal at the last interglacial-last glacial transition recorded in the loess section at Zhaitang, Beijing

A weakly developed paleosol was identified at S1-L1 transition of the loess section of Zhaitang, Beijing. This paleosol may represent a climatic reversal which is associated with the strengthening in summer monsoon and correlated well with the climatic regression event documented in the paleoclimate records from Greenland ice, marine sediments and European pollen at the last interglacial-last glacial transition.     

The evidence of fossil carbon isotopes of the climatic event at the beginning of Quaternary

Tooth enamel of mammalian fossils can efficiently preserve the original carbon isotopic mposition when they lived. The ungulate fossils, especially equids in the early Early Pleistocene Bajiazui fauna from Qingyang, Gansu are studied. According to the enriched relation of carbon isotopes between mammalian tooth enamel and grass diets, the fractions of C₃ and C₄ plants in this region at that time are reconstructed, which indicates that C₃ grass occupied a dominant position. Because C₃ grass adapts itself to cold and clamp climates, cur analytic results show that the time of the Bajiazui fauna was in a critical state between a glacial stage beginning and a summer monsoon retreat, and it was a reflection to the turning cold event of the global climate at the beginning of the Quaternary.     

基于改进人工蜂群算法的大青杨晚材率预测

为了更加准确地预测人工林大青杨(Populus ussuriensis)晚材率,通过对标准人工蜂群算法(artificial bee colony, ABC)的蜜源更新公式进行改进,提出了分段式蜜源搜索半径公式,并用改进的人工蜂群算法(AABC)对径向基(radial basis function, RBF)神经网络的初始参数进行优化,提出一种基于改进的人工蜂群算法和径向基神经网络算法结合的预测模型,并与粒子群(partical swarm optimization, PSO)优化的RBF神经网络预测结果进行对比。结果表明:传统的RBF预测模型不仅收敛速度慢,而且预测精度不高。基于改进的ABC算法优化RBF神经网络预测模型整体比PSO优化的效果相对较好,收敛速度从42步提升至28步,预测的平均相对误差从2.54%降低到0.95%。可见对ABC算法的改进是可行的,而且提高了晚材率预测的精度。     

汽车环境风洞和环境舱流场品质的对比研究

汽车环境风洞和环境舱的流场品质直接影响汽车的各项热气动性能测试结果的准确性。采用试验与计算流体动力学（CFD）仿真相结合的方法研究对比了环境风洞和环境舱的流场品质。试验测试了环境风洞和环境舱试验段特定区域的风速均匀性、边界层厚度、轴向静压梯度和动压稳定性等流场参数,使用CFD方法对环境风洞和环境舱进行流场三维数值模拟。通过对比环境风洞和环境舱的整体流场特征,分析了影响环境风洞和环境舱内流场差异的原因。试验和数值仿真结果表明：汽车环境风洞试验段流场的风速均匀性、边界层、轴向静压梯度、动压稳定性以及气流和风速分布等流场品质明显优于汽车环境舱。     

Periodicity of Holocene climatic variations in the Huguangyan Maar Lake

There exist five primary periods of 2 930, 1 140, 490, 250 and 220 a in the Holocene climatic variations in the Huguangyan Maar Lake, according to the energy-spectrum and filter analyses of high-resolution time sequences (10–15 a) of the sediment dry density. The peak values of the three temperature-decreasing periods with the 2 930 a cycle occur at about 7 300, 4 250 and 1 200 Cal. aBP. There are 7–8 temperature-decreasing periods with the 1 140 a cycle, and the climate fluctuation range is largest in the early Holocene, and reduces gradually in the middle and late Holocene. The millennial-scale climatic change in the Holocene may adjust the global water cycle and the thermohaline circulation intensity through the harmonic tones of the earth’s precession cycle, which in turn influences the global climate change.     

世界气候分类

文中提出的分类法根据全球大气环流形势及其季节变化把全球气候划分为 5个气候带 :热带、副热带、温带、副极地带和极地带 ;除了极地带外的每一个气候带再划分为 4个气候型 :海洋性气候、过渡性气候、大陆性气候和高地气候 ;每一个气候型由若干个气候副型组成 .极地带根据其最暖月气温划分为两个气候型 .最后设计湿润指数 I =P/ ( EP.S)和第三个字母进行第三级划分     

辽东半岛几个长记录站的温度变化

根据丹东,熊岳、营口和大连站１９０５－１９８８年温度记录资料,计算了冬季,夏季和年平均温度距平和线性趋势,对温度年际和长期变化特点做拓辽东半岛的这４个站记录,冬季平均温度在本世纪内部明显上升了,夏屯平均温度除营口外本世一般呈现变凉,营口和大连两个记录连续的年平均温度存在长期增覆趋势。对温度变化的可能原因也做了初步讨论。     

区域气候灾害管理分析系统的建立与应用研究

将已建立的区域气候灾害管理分析系统应用于三江平原丘陵区的研究工作中,初步实现了数据共享和区域气候灾害分析自动化与半自动化。     

再建气候环境演化历史的碳同位素技术

稳定碳同位素是再建气候环境变化历史最重要手段。简要回顾了碳同位素分馏的主要影响因素。介绍了碳同位素变化与生态环境变迁的可能关系 ;重点探讨了利用碳同位素再建古大气CO2 的原理和方法