中国降水量高度效应及全球升温对它的影响

利用中国气象中心160站点的实际观察资料,对中国半个世纪的降水变化进行了系统分析,发现中国的夏季降水量与海拔高度存在着很好的反相关关系;同时,全球升温使得降水量的高度效应增强,主要表现为高海拔降水量海拔效应明显增强,这主要是由全球升温引起环流系统增强所引起的.     

土壤侵蚀环境演变与全球变化及防灾减灾的机制

以土壤侵蚀学和环境学的交叉为基础,讨论了土壤侵蚀环境学的内涵、土壤侵蚀环境演变及其调控、全球变化及防灾减灾的机制。为揭示土壤侵蚀的实质及制定土壤侵蚀的防治对策提供了新的思想。     

Temperature niche composition change inside and outside protected areas under climate warming

Conservation of biodiversity relies heavily on protected areas but their role and effectiveness under a warming climate is still debated. We estimated the climate-driven changes in the temperature niche compositions of bird communities inside and outside protected areas in southern Canada. We hypothesized that communities inside protected areas include a higher proportion of cold-dwelling species than communities outside protected areas. We also hypothesized that communities shift to warm-dwelling species more slowly inside protected areas than outside. To study community changes, we used large-scale and long-term (1997–2019) data from the Breeding Bird Survey of Canada. To describe the temperature niche compositions of bird communities, we calculated the community temperature index (CTI) annually for each community inside and outside protected areas. Generally, warm-dwelling species dominated communities with high CTI values. We modeled temporal changes in CTI as a function of protection status with linear mixed-effect models. We also determined which species contributed most to the temporal changes in CTI with a jackknife approach. As anticipated, CTI was lower inside protected areas than outside. However, contrary to our expectation, CTI increased faster over time inside than outside protected areas and warm-dwelling species contributed most to CTI change inside protected areas. These results highlight the ubiquitous impacts of climate warming. Currently, protected areas can aid cold-dwelling species by providing habitat, but as the climate warms, the communities’ temperature compositions inside protected areas quickly begin to resemble those outside protected areas, suggesting that protected areas delay the impacts of climate warming on cold-dwelling species.     

The European land leech: biology and DNA-based taxonomy of a rare species that is threatened by climate warming

The European land leech Xerobdella lecomtei was discovered in 1868 and is one of the rarest animals on Earth. During the 1960s, several individuals of these approx. 40 mm long, cold-adapted terrestrial annelids that inhabit the moist soils of birch forests around Graz, Austria, were investigated. Only one original research paper has been published on the biology of this species. Between 2001 and 2005, we re-investigated the morphology of preserved specimens and searched for living individuals in their natural habitat that appeared to be intact. We found only one juvenile individual (length approx. 10 mm), indicating that this local leech population became largely extinct over the past four decades. The feeding behaviour of our ‘lonesome George of the annelids’ was studied and is described here in detail. After its death, the Xerobdella individual was used for chemical extraction and molecular studies (deoxyribonucleic acid [DNA] barcoding, based on one gene, the mitochondrial cytochrome c oxidase subunit I). In addition, novel DNA barcodes for a land leech from Madagascar and a recently discovered species from Europe were obtained. Our phylogenetic tree shows that X. lecomtei is not a member of the tropical land leeches (family Haemadipsidae), as previously thought, but represents a separate line of descent (family Xerobdellidae). The decline of the local leech population around Graz correlates with a rise in average summer temperatures of +3°C between 1961 and 2004. This warming led to a drastic reduction in the moisture content of the soil where X. lecomtei lives. We suggest that human-induced climate change without apparent habitat destruction can lead to the extinction of populations of cold-adapted species that have a low colonization ability.     

Methane Fluxes in West Siberia: 3-D Regional Model Simulation

The West Siberian region is one of the main contributors of theatmospheric greenhouse gas methane due to the large areas ofwetlands, rivers, lakes and numerous gas deposits situated there.But there are no reliable estimations of integral methane flux fromthis area into the atmosphere. For assessment of methane fluxes inWest Siberia the specially constructed 3-D regional chemicaltransport model was applied. The 3-D distribution of methane iscalculated on the basis of the current meteorological data fields(wind, temperature, geopotential) updated 4 times a day. The methaneconcentrations measured near the main gas fields of West Siberia inthe summer season of 1999, were used for correction of methane fluxintensity estimates obtained previously by comparison ofmeasurements carried out in summer 1993 and 1996 with modelledmethane mixing ratio distribution. This set of field and modelexperiments confirmed the preliminary conclusion about low leakageintensity: anthropogenic methane flux does not exceed 5–15% oftotal summer methane flux, estimated as 11–12 Mt CH₄ in summer from this region, in spite of the large areas of gas deposits located there.     

Natural bitumens versus oil pollution in the Vlasina lake peat

Free and associated bitumens were isolated by sequential extraction from Vlasina lake peat (SE Serbia) and were investigated in order to differentiate between oil pollution and natural bitumens. Four peat samples were collected at different depths, on a peat island. Gas chromatographic (GC) and gas chromatography/mass spectrometry (GC/MS) analysis revealed the presence of three markedly different bitumen fractions. Here we show that the free bitumens are representing the native peat bitumens. The two associated bitumens are mainly the products of bacterial rework of organic substance, which were then trapped by two differing mechanisms. The bitumens characteristics and association features exclude a contribution of oil pollution.Selected article from the Regional Symposium on Chemistry and Environment Krusevac, Serbia, June 2003, organised by Dr. Branimir Jovancicevic.     

Heavy Metal Distribution in Valley Sediments in Wadi Al-Karak Catchment Area, South Jordan

Valley sediments samples collected from the major and minor valleys of Al-Karak catchment area (southern Jordan) were leached with hot dilute HCl and analysed for their heavy metals content. The results of leachable metal concentrations indicated the absence of anomalous values for metal occurrences. However, appreciable contamination of the sediments with Cu, Zn, Pb, Cd and Cr was observed. Using an index of pollution the extent of contamination was better delineated. The geographical distribution of the samples showed higher Cu, Zn, Pb, Cd and Cr concentrations mainly around heavily inhabited areas indicating an anthropogenic source of contamination. Lithological influence indicated from the anomalies of Fe and Mn was found to be very low.     

Global Grids from Recursive Diamond Subdivisions of the Surface of an Octahedron or Icosahedron

In recent years a number of methods have been developed for subdividing the surface of the earth to meet the needs of applications in dynamic modeling, survey sampling, and information storage and display. One set of methods uses the surfaces of Platonic solids, or regular polyhedra, as approximations to the surface of the earth. Diamond partitions are similar to recursive subdivisions of the triangular faces of either the octahedron or icosahedron. This method views the surface as either four (octahedron) or ten (icosahedron) tessellated diamonds, where each diamond is composed of two adjacent triangular faces of the figure. The method allows for a recursive partition on each diamond, creating nested sub-dimaonds, that is implementable as a quadtree, including the provision for a Peano or Morton type coding system for addressing the hierarchical pattern of diamonds and their neighborhoods, and for linearizing storage. Furthermore, diamond partitions, in an aperture-4 hierarchy, provide direct access through the addressing system to the aperture-4 hierarchy of hexagons developed on the figure. Diamond partitions provide a nested hierarchy of grid cells for applications that require nesting and diamond cells have radial symmetry for those that require this property. Finally, diamond partitions can be cross-referenced with hierarchical triangle partitions used in other methods.     

全球气候变化情景下的河北省区域减灾建设

全球气候变化将导致一些地区自然灾害加剧,并将影响到区域的可持续发展.加强区域减灾建设,及早采取相应措施,是适应未来全球气候变化的明智选择.鉴于全球气候变化的影响存在区域差异,不同区域采取的对策也有所区别.本文以河北省为例,分析了该区域自然灾害的类型、历史时期和现在灾害的特点、发生规律及其原因,并根据该区域未来的全球气候变化趋势,提出了一些需要及早实施的战略性减灾对策.