几种全球加权平均温度模型的精度验证与分析

利用IGRA提供的全球593个无线电探空站2014年的探空资料,对Bevis 经验公式、GTm-Ⅱ和GTm-Ⅲ模型进行精度验证,对各模型随纬度、季节的变化规律进行分析研究。结果表明,在全球范围内,GTm-Ⅲ模型的总体精度（MAE=3.26 K, RMS=4.10 K）要优于另外两个模型;3种模型的精度在中低纬度地区较高,高纬度地区较低;Bevis公式和GTm-Ⅱ模型的精度在南北半球具有不对称性;各模型精度的季节性变化规律基本一致,模型的RMS在不同季节相差2~3 K。     

A Catalog of Luminous Infrared Galaxies in the IRAS Survey and Second Data Release of SDSS

We selected a sample of luminous infrared galaxies by cross-identification of the Faint Source Catalogue (FSC) and Point Source Catalogue (PSC) of the IRAS Survey with the Second Data Release of the SDSS. The size of our sample is 1267 for FSC and 427 for PSC by using the 2σ significance level cross-section. The "likelihood ratio" method is used to estimate the individual's reliability and for defining two more reliable subsamples (908 for FSC and 356 for PSC). A catalog of infrared, optical and radio data is compiled and will be used in further work. Some statistical results show that luminous infrared galaxies are quite different from ultra-luminous infrared galaxies. The AGN fractions of galaxies at different infrared luminosities and the radio-infrared correlations are consistent with the previous studies.     

植物与大气间的湍流交换——新方法介绍研究状况综述*

植物与大气之间的湍流交换是地球和大气系统中能量和物质循环的一个重要环节,也是土壤-植物-大气系统的重要研究内容之一。揭示这一交换环节的物理机制,了解地气系统中能量、水分和C_0.2等物质的运动和转换规律,对于农业生产、数值气象预报,环境生态和气候变化等研究工作有诸多方面的意义,是地学界所共同关心的问题。近十年来,植物与大气之间相互作用的研究有了许多重要进展,传统的局地湍流交换模式的局限性已逐渐被认识,一些新的方法在这一领域中出现,其中高阶闭合模式和流轨模式是比较重要的探索途径。     

南方冬小麦三叶——抽穗期干物重与叶面积动态耦合计算探讨

根据实测资料,尝试性地提出了一种南方麦区冬小麦三叶到抽穗期的干物重与叶面积动态的耦合计算方法,经检验效果尚好。另外,初值灵敏度试验表明苗期生长状况的优劣对于其后生育阶段的干物重与叶面积动态影响似乎不大。     

1990年以来中国小麦农业气象灾害时空变化特征(英文)

Agro-meteorological disasters(AMD) have become more frequent with climate warming. In this study, the temporal and spatial changes in the occurrence frequency of major meteorological disasters on wheat production were firstly explored by analyzing the observed records at national agro-meteorological stations(AMS) of China from 1991 to 2009. Furthermore, impact of climate change on AMD was discussed by comparing the warmer decade(2000–2009) with another decade(1991–2000). It was found that drought was the most frequent disaster during the last two decades, with a highest proportion of 79%. And the frequency of AMD increased significantly with climate change. Specifically, the main disasters occurred more frequently in the reproductive period than in the vegetative period. Besides, the spatial changes in the AMD frequency were characterized by region-specific. For example, the wheat cultivation areas located on the Loess Plateau and the middle-lower reaches of the Yellow River suffered mainly from drought. All these results were strongly linked to climate change in China. Therefore, sound adaptation options should be taken based on the latest changes of AMD under global warming to reduce agricultural damages.     

Trophic ecology of small yellow croaker (Larimichthys polyactis Bleeker): stable carbon and nitrogen isotope evidence

The trophic ecology of the small yellow croaker (Larimichthys polyactis) was studied using stable isotope analyses. Samples were collected from July to September 2009 and 34 individuals from eight sites were examined for stable carbon and nitrogen isotopes. Stable carbon isotope ratios (δ13C) ranged from -20.67 to -15.43, while stable nitrogen isotope ratios (δ15N) ranged 9.18-12.23. The relationship between δ13C and δ15N suggested high resource partitioning in the sampling area. Significant differences in stable isotope values among the eight sampling sites may be linked to environmental diversities involving various physical processes (such as ocean current, wind and tide) and different carbon sources. Furthermore, the stable isotope ratios may also explain the ontogenetic variability in diet and feeding, because δ13C and δ15N varied significantly with increasing body size. The findings are consistent with other studies on diet analyses in small yellow croaker. It was also demonstrated that stable isotope analysis could be used to estimate the trophic characters of small yellow croaker in feeding patterns and migrating habits.     

Assessment of Surface Ecological Quality of Grassland Mining Area and Identification of Its Impact Range

Natural Resources Research - High-intensity coal mining in grasslands has negative impact on the surface ecology of the mining area and its surroundings. This impact shows spatio-temporal...     

Densities of Huanghe River estuary and Bohai Bay waters

The densities of 36 water samples from the Huanghe River estuary and Bohai Bay were determinedby a magnetic float densimcter under three temperatures from 15℃ to 25℃.All the measured densities ofsamples were greater than that of the values calculated from the International Equation of State of Seawater.The differences between the measured and calculated densities increased with the decrease of salinities.The dif-ferences appeared exponentially correlated with[Ca~(2+)]/s,[Mg~(2+)]/s and[SO_4~(2-)]/s,and had"s"type curverelationship with the alkalinity in all salinity range.But in the salinity ranging from 25.72 to 31.57,therelationships were all linear.The density difference can be estimated from the equation △ρ（10~3kg·m~(-3)）=（-2.79+236.5([Ca~(2+)]/s)/(-9.7464×10~（-3）+[Ca~(2+)]/s).It was the high alkalinity and[Ca~(2+)]/s that resulted in the measured densi-ties of seawaters being higher than the calculated densities in the Huanghe estuary and Bohai Bay.     

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Comparison of ecophysiological characteristics between introduced and indigenous mangrove species in China

Due to its rapid growth, the introduced mangrove species Sonneratia apetala from Bangladesh has been widely used in mangrove restoration in southeastern China since 1985. As an indigenous mangrove species in Hainan, China, Sonneratia caseolaris was also planted in Guangdong Province for afforestation purposes. Both species have developed well in their new habitats, but their ecophysiological differences with the native mangrove species have not been studied. In this study, leaf gas exchange, water and nitrogen use efficiencies of two Sonneratia species were compared with those of selected native mangrove species (Avicennia marina, Aegiceras corniculatum, Kandelia candel, and Excoecaria agallocha) in Hainan and Shenzhen. The introduced S. apetala maintained lower carbon assimilation rate (A) and photosynthetic nitrogen use efficiency (PNUE) than the indigenous S. caseolaris. In Shenzhen, the two introduced Sonneratia had comparable photosynthetic rates and water use efficiency (WUE) with the native mangrove species, except that PNUE in S. caseolaris was significantly higher than in the native mangrove species. The two Sonneratia species showed significant overlap in PNUE and long-term WUE. Photosynthetic parameters derived from leaf photosynthetic light–response curves and A–C_i curves also suggested lower carbon assimilation capacities for the introduced Sonneratia than for the native mangrove species in both study sites. The lower light compensation point (LCP) of two introduced Sonneratia in both study sites also indicated a better adaptation to a low light regime than the native mangrove species. The results of photosynthetic capacities indicated that the introduced mangrove species have little competitive advantage over local native mangrove species in their respective new habitats.