亚马逊网络书店的信息检索

文章论述了亚马逊网络书店的特征，从图书信息，检索速度，检索途径，检索的交互性等分析了其特的价值．对我国网络书店和图书馆有一定的启示。     

Smoking rain clouds over the Amazon

Heavy smoke from forest fires in the Amazon was observed to reduce cloud droplet size and so delay the onset of precipitation from 1.5 kilometers above cloud base in pristine clouds to more than 5 kilometers in polluted clouds and more than 7 kilometers in pyro-clouds. Suppression of low-level rainout and aerosol washout allows transport of water and smoke to upper levels, where the clouds appear "smoking" as they detrain much of the pollution. Elevating the onset of precipitation allows invigoration of the updrafts, causing intense thunderstorms, large hail, and greater likelihood for overshooting cloud tops into the stratosphere. There, detrained pollutants and water vapor would have profound radiative impacts on the climate system. The invigorated storms release the latent heat higher in the atmosphere. This should substantially affect the regional and global circulation systems. Together, these processes affect the water cycle, the pollution burden of the atmosphere, and the dynamics of atmospheric circulation.     

Selective logging in the Brazilian Amazon

Amazon deforestation has been measured by remote sensing for three decades. In comparison, selective logging has been mostly invisible to satellites. We developed a large-scale, high-resolution, automated remote-sensing analysis of selective logging in the top five timber-producing states of the Brazilian Amazon. Logged areas ranged from 12,075 to 19,823 square kilometers per year (+/-14%) between 1999 and 2002, equivalent to 60 to 123% of previously reported deforestation area. Up to 1200 square kilometers per year of logging were observed on conservation lands. Each year, 27 million to 50 million cubic meters of wood were extracted, and a gross flux of approximately 0.1 billion metric tons of carbon was destined for release to the atmosphere by logging.     

《土地利用现状分类》修改浅议

通过全国土地资源第二次普查工作实践体会及各行业专业工作的普遍反映,分析了当前发布执行的《土地利用现状分类》国家标准存在各方面的缺憾,尤其表现在分类方法和分类标准上不一致,同一级别类型概念外延和内涵互相交叉重叠不严密,从属与平行逻辑关系比较混乱。为此,对《土地利用现状分类》提出了进一步修改完善的具体建议,力求遵循分类学分类原则、方法和标准,从行业专业和国土管理两个层面进行优化衔接,真正实现一套标准统计数据能够全面反映各行各业的土地利用及发展动态。     

DEM在土地利用总体规划中的应用

通过提取DEM中的海拔、坡度信息,在ArcGIS环境中运用密度分析的思路生成实验区地貌区,以期对划分土地用途区、科学编制土地利用总体规划有一定的参考作用。     

Amazon rain-forest fires

Charcoal is common in the soils of mature rain forests within 75 kilometers of San Carlos de Rio Negro in the north central Amazon Basin. Carbon-14 dates of soil charcoal from this region indicate that numerous fires have occurred since the mid-Holocene epoch. Charcoal is most common in tierra firme forest Oxisols and Ultisols and less common in caatinga and igapo forest soils. Climatic changes or human activities, or both, have caused rain-forest fires.     

The 2010 Amazon drought

In 2010, dry-season rainfall was low across Amazonia, with apparent similarities to the major 2005 drought. We analyzed a decade of satellite-derived rainfall data to compare both events. Standardized anomalies of dry-season rainfall showed that 57% of Amazonia had low rainfall in 2010 as compared with 37% in 2005 (≤-1 standard deviation from long-term mean). By using relationships between drying and forest biomass responses measured for 2005, we predict the impact of the 2010 drought as 2.2 × 10(15) grams of carbon [95% confidence intervals (CIs) are 1.2 and 3.4], largely longer-term committed emissions from drought-induced tree deaths, compared with 1.6 × 10(15) grams of carbon (CIs 0.8 and 2.6) for the 2005 event.