成都地面气温与风速年极大值的渐近分布及参数估计

利用１９３３～１９９２年期间成都地面最高气温和地面最大风速年极值的记录，通过统计推断，找出了成都地面最高气温年极值和地面最大风速年极值遵循的渐近分布——Ｗｅｉｂｕｌ分布和Ｇｕｍｂｅｌ分布，并讨论了它们的参数估计方法。     

成都日降水量年极大值的渐近分布

利用1951－1999年成都日降水量年极大值的记录，通过统计推断，找出了成都日降水量年极大值遵循的渐近分布。讨论了两种分布－皮迩逊Ⅲ型分布、对数正态分布，并比较了它们的拟合效果，最后得出成都日降水量年极大值较好地遵循对数正态分布，并讨论了它们的参数估计方法。     

成都地面风速年极值的4种分布函数拟合结果的比较

分别用Webukk分布，Gumbel分布，Pearson Ⅲ分布和对数正态分布拟合成都1993－1997年间地面风速年极大值的渐近分布，其结果表明Gumbel分布和对数正态分布拟合效果最好。     

成都地面最低气温年极值的渐近分布

利用成都１９３３～１９９２年间的地面最低气温年极值记录，采用韦伯分布和耿贝尔分布，分别对其进行了渐近分布拟合。通过统计推断，找出了成都地面最低气温年极值所遵循的最佳渐近分布——韦伯分布。     

重庆地面最高气温与最大风速年极值的渐近分布

利用重庆1951-1990年间地面最高气温和1956-1990年间地面最大风速年极值的记录,采用韦伯分布和耿贝尔分布分别对其渐近分布进行拟合.通过统计推断,找出重庆地面最高气温和地面最大风速年极值遵循的最佳渐近分布--韦伯分布.     

重庆地面最低气温年极值的渐近分布及参数估计

利用重庆 1951-1996 年间 46 年地面气温年极小值的记录,采用韦伯分布和耿贝尔分布分别进行拟合试验.通过统计推断和对比,找出重庆地面最低气温年极值遵循的最佳渐近分布--韦伯分布.     

强降水的GP分布拟合

根据极值理论中处于重要地位的GP分布模型，讨论了模型中的形状参数、位置参数及尺度参数的算法，并将其用于拟合呈偏斜状态的月和日降水量资料中强降水部分，得到强降水发生的直观年数。     

基于GOSAT卫星的全球近地面甲烷浓度时空分布特征分析

甲烷(CH_4)作为自然界最常用的燃料,分布极广。同时,甲烷作为第二大温室气体,在温室效应的过程中有重要影响。近地面甲烷受多种因素影响在高度上分布不均,影响着人类的生存和生产生活。本文利用2009年6月到2012年5月GOSAT卫星上FTS传感器的L4B级数据,研究了近地面甲烷浓度在时间和空间上的分布特征,结果表明:在时间分布方面:(1)甲烷月平均浓度处于整体上升趋势,最大增量约为2.35×10~(-8)micromol/mol;(2)从每年9月到次年2月,甲烷月平均浓度以不同增速持续增加;(3)4月到9月,甲烷月平均浓度下降,期间出现下降幅度波动,下降幅度小于上升幅度;(4)2月到4月处于阶段性峰值;(5)甲烷季节浓度的大小关系为:春季冬季夏季秋季。在空间分布方面:(1)全球近地面甲烷白天的浓度与夜晚浓度分布不同,有集聚现象;(2)从整体上分析,甲烷主要分布在北半球,南半球甲烷稀少;(3)从洲际上分析,亚欧非大陆甲烷浓度大于美洲大陆。(4)从地区分析,甲烷浓度分布不均匀;(5)从海陆分析,陆地甲烷浓度明显大于海洋。     

基于GIS技术的嘉兴市区住宅地价空间分布研究

文章根据嘉兴市区的住宅地价资料,采用GIS技术和数理统计的分析方法,揭示嘉兴市区住宅地价的空间分布规律,并结合GWR模型分析各因素对嘉兴市住宅地价的影响。     

提高GPS拟合高程精度的方法

GPS测量高程为WGS84系统的大地高,通过加入高程异常求得正常高。利用测区内几个GPS水准点上的已知高程异常进行拟合,求得该测区高程异常分布的数值模型,得到其它未知点的正常高。目前,常用的拟合方法有平面拟合法、二次曲面拟合法、多面函数法等,笔者以海阳市控制网的布设,探讨了影响GPS拟合高程精度的因素,提出了提高GPS拟合高程精度的方法。     

Characteristics of Spatial and Temporal Variations of Monthly Mean Surface Air Temperature over Qinghai-Tibet Plateau

1 Introduction The Qinghai-Tibet Plateau, known as the highest plateau with the most complex topography in the world, covers an area of more than 200km2, with a mean elevation of more than 4000m a.s.l. (Ye and Gao, 1979). Surrounded by the Earth’s highest mountains, such as the Himalayas, Pamir, Kunlun Mountains, the plateau plays a significant role in climate change in China even in the world, thus attracted great attention of researchers. Up to now, many achievements have been gained by…     

Composition and distribution of diatom assemblages in the surface sediments of the Bering Sea

Diatoms collected from the top 1 cm of the surface sediment layer at seven Bering Sea stations during the Fourth Chi- nese National Arctic Research Expedition （4th CH1NARE-Arctic） in 2010 were studied. In total, 101 taxa belonging to 38 genera were found. The species were divided into four groups： eurythermal species, boreal-temperate species, polar species, and sea-ice species. The diatom assemblages at the stations in the southwestern basin area were primarily composed of boreal-temperate species, such as Neodenticula seminae, Thalassiosira trifulta, Rhizosolenia hebetata f. hiemalis, and Actinocyclus curvatulus. The northeastern shelf stations were dominated by polar species, including Fragilariopsis oceanica, Thalassiosira antarctica spora, Thalassiosira nordensldoeldii, and Thalassiosira hyalina. The overall abundance was highest at the basin stations with 3.7 ×10^6 cells·g^-1 of wet sediment, whereas the eastern shelf stations had the lowest abundance of 0.7×10^6 cells·g^-1 of wet sediment （excluding the resting spores of Chaetoceros spp.）. The relationship between the distribution of the surface sediment diatom assemblages and the environment is discussed.     

青藏高原-热带印度洋地区大气热源的时空变化特征

为了寻求青藏高原一热带印度洋地区大气热源空间变化的敏感区,进一步深入研究季风的形成、变异和预测,利用NCEP1979-2008年的再分析资料计算分析了青藏高原一热带印度洋地区30年来不同季节大气热源分布的气候特征,并且利用经验正交函数分解研究了该区大气热源在夏、冬季的时空变化特征。结论如下：春季大气热源有明显的经向差异;夏季的热源明显比春季的热源强度强,范围广,热源最强中心在孟加拉湾北部大陆边缘;秋季热源区域明显南缩,热源强度较夏季明显减弱;冬季大气热源呈西西南一东东北方向分布,大气热源位置继续南移。对于夏季,前3个模态分别反映了青藏高原一热带印度洋地区大气热源的纬向差异型、经向差异型、西北一东南分布型。对于冬季,前3个模态分别反映了青藏高原一热带印度洋地区大气热源的经向差异主导型、经向差异型、纬向差异型。     

Composition and distribution of planktonic ciliates in the southern South China Sea during late summer: Comparison between surface and 75 m deep layer

Ciliates are very important components in most marine ecosystem.They are trophic link between the microbial food web and grazing food chain.In this study,ciliates were collected from 11 sites in the southern South China Sea(SCS) during August 25 to September 28,2011.Their composition and distribution at the surface and 75 m deep depth of the ocean were studied.A total of 30 species belonging to 22 genera were identified,and 22 species of 15 genera were Tintinnids.Eutintinnus fraknoii and E.stramentus were the most common species.The other dominants were strombidiids ciliates including Strombidium conicum and S.globosaneum,which were followed by the tide form,Mesodinium pulex.Ciliates abundance ranged from 46 ind L~(-1) to 368 ind L~(-1) in the open sites,46–368 ind L~(-1) at surface and 73–198 ind L~(-1) at 75 m deep layer.In the Yongshu reef,ciliates abundance ranged from 167 ind L~(-1) to 365 ind L~(-1) in the water column,similar to that in Sanya coral reef waters.Ciliates composition showed obvious difference between surface and 75 m deep layer at station S2(P 0.05),while no similar result was observed at other sites.At 75 m deep layer,salinity was negatively related to mixed layer depth(P 0.05),but positively to chlorophyll a concentration(P 0.05),indicating that the change of vertical mixing in water column influenced vertical distribution of ciliates in the southern SCS.     

Analysis on monthly-averaged distribution of sea surface wind and wave over the seas southeast of Asia using ERS-2 scatterometer data

The wind system over the seas southeast of Asia (SSEA) plays an important role in China's climate variation. In this paper, ERS scatterometer winds covering the period from January 2000 to December 2000 and the area of 2-41 °N, 105- 130°E were analyzed with a distance-weighting interpolation method and the monthly mean distribution of the sea surface wind speed were given. The seasonal characteristics of winds in the SSEA were analyzed. Based on WAVEWATCH Ⅲ model, distribution of significant wave height was calculated.     

典型山区SRTM3与ASTER GDEM数据精度对比分析——以青藏高原东麓深切河谷区为例

目前广泛应用的数字高程模型(DEM)包括SRTM和ASTER GDEM,但在地形影响下,两类数据的误差分布并不均匀。本文选用1:5万地形图DEM及河流要素作为参照,在青藏高原东麓山区开展实验,分别采用"河流-河谷"位置偏移量与高程中误差来评价两类数据的平面精度与垂直精度,结果表明:(1)实验区内SRTM3存在向西南方向的水平位置偏移,平均偏移量为127.8 m,ASTER GDEM则以正西方向偏移为主,平均偏移量为104.1 m,该区域ASTER GDEM的总体平面精度较好;(2)SRTM3数据样本的绝对误差分布相对集中,高程中误差为35.3 m,小于ASTER GDEM样本的高程中误差50.2 m,总体垂直精度优于ASTER GDEM;(3)在平均高程大于4500 m的高海拔区域,两类数据的中误差与高程值正相关,SRTM3中误差随高程增速较慢,垂直精度较ASTER GDEM高;(4)两组数据垂直精度对坡度有较大依赖性,中误差随坡度近似指数曲线增长,在平缓区域SRTM3中误差小于ASTER GDEM。本研究为该类数据在山区的选用及误差修正提供依据。