闽江流域水体氨氮降解系数实验模拟研究

本研究采用模拟实验对闽江流域氨氮的降解规律进行研究,降解系数采用稳态一维降解模型进行分析计算,闽江上游流域氨氮的平均降解系数为0.140~0.260 d-1,中下游流域氨氮的平均降解系数为0.099~0.203 d-1。结果表明,闽江上游流域氨氮自净能力比中下游流域的自净能力好,古田溪断面的氨氮平均降解系数低于全国的平均值,说明氨氮自净能力相对较弱,本研究为确定流域水环境容量和纳污能力及制定污染物总量控制提供科学依据。     

基于人类福祉视角的中部地区碳排放绩效与效应分解

碳排放绩效是当前国内外低碳经济研究的热点问题,已有研究主要针对经济发展的碳排放绩效测度展开,关注经济产出的碳排放绩效。基于人类福祉是研究碳排放绩效的新视角。首次提出碳排放绩效的概念框架及图解,据此构建了人类福祉的碳排放绩效评估模型,应用LMDI分解法建立了碳排放绩效的效应分解模型,对中部地区人类福祉的碳排放绩效及其效应进行研究发现:(1)1990年~2008年中部六省经济发展的碳排放绩效整体上先增后降;人类福祉的经济绩效与碳排放绩效整体上均呈递减趋同态势。中部地区人类福祉碳排放绩效的省际差距整体上趋向缩小;(2)1990年~2008年中部六省经济发展的碳排放绩效的总效应波动较大,驱动效应和抑制效应交替出现。经济福祉绩效效应整体递增,由抑制效应向驱动效应演进,呈现趋同趋势;(3)中部六省人类福祉的碳排放绩效主要由经济发展的碳排放绩效决定,经济发展的碳排放绩效效应是碳排放绩效总效应的决定性因素,人类福祉的碳排放绩效效应是经济发展的碳排放绩效效应和人类福祉的经济绩效效应两种效应的叠合。     

气候变化与人类活动联合影响下东江流域非一致性洪水频率

一致性假设一直是洪水频率分析的基本假设条件,但在气候变化与人类活动综合影响下,水文极值序列的一致性假设受到极大挑战。基于此,以东江流域为例,运用GAMLSS模型(广义可加模型),将时间、气候指标(北极涛动AO、北太平洋涛动NPO、太平洋年代际振荡PDO和南方涛动SOI)以及水库指标(Reservoir Index)统一纳入洪水频率分析中,并对东江流域1954―2009年年最大流量序列(AMS)进行频率分析,结果表明:1)龙川、河源和岭下站年最大流量序列均值与时间呈线性关系,方差为常量,而博罗站均值和方差与时间均呈非线性关系;2)水库对各水文站点AMS均值有显著线性影响;3)NPO对各站点AMS均值有显著线性影响,NPO值较高时,东江流域可能面临着较低的洪水风险,在一致性假设前提下,可能高估洪水设计值,反之亦然;而PDO对各站点方差有显著线性(岭下、博罗)/非线性(龙川、河源)影响;4)以时间为协变量构建非一致性模型,研究得出:龙川、河源和岭下3站T年一遇洪水设计值均呈单调下降趋势,博罗站1954―1995年左右洪水设计值呈下降趋势,而在1996―2009年呈上升趋势;以气候与水库为协变量构建非一致性模型,研究表明:龙川、河源和岭下3站T年一遇洪水设计值均因水库影响呈向下跃变;5)以气候和水库为协变量的非一致性模型对洪水频率具有良好的预测能力,为非一致条件下设计洪水的预测提供了新的预测方法。     

The atmospheric circulation patterns influencing the frequency of spring sand-dust storms in the Tarim Basin

Using NCEP/NCAR reanalysis data and the sand-storm frequency data fi＇om 37 weather stations in the Tarim Basin for the period 1961-2009, the relationship between the frequency of spring sandstorms in the Tafim Basin and the associated atmospheric circu- lation pattems is analyzed in this study. We found significantly negative correlations between sandstorm frequency and the 500-hPa geopotential height over the Paris Basin and midwestem Mongolia, while there were positive correlations over the Ural River region. The rising of the 500-hPa geopotential height in midwestem Mongolia and its falling over the Ural region corre- spond to a weakening of the large-scale wave patterns in the Eurasian region, which directly causes the frequency of the sand-dust storms in the Tarim Basin to decline. Also, the abrupt decline in the spring sandstorm frequency in the Tarim Basin observed in the last half-century is associated with profound changes in the atmospheric circulation in these key regions. At the interannual scale, the strengthened cyclonic atmospheric circulation patterns in the western part of Mongolia and the anticyclonic patterns over the East European plains at 500-hPa geopotential height, are responsible for frequent sandstorm occurrences in the Tarim Basin.     

Dating of two thermokarst lakes in Beiluhe Basin,Qinghai-Tibetan Plateau

Most of the thermokarst lakes are spread appreciably in Beiluhe Basin,Qinghai-Tibet Plateau,China,where ice-rich permafrost exists.Two typical thermokarst lakes with differing area and depth were examined to ascertain their age.We obtained lake-bottom samples of 50 cm length from lake BLH-A and 25 cm length from lake BLH-B.Environmental 137 Cs and 210 Pb and radiocarbon age dating techniques were applied to the 50 cm and 25 cm samples,respectively.The results indicate that the initiation of BLH-A is about 800-900 a B.P.,and approximately 1,450±30 a B.P.to 2,230±30 a B.P.for BLH-B.These results will provide scientific bases for sedimentological study and thermokarst activity in Beiluhe Basin.     

Spatiotemporal variations of maximum seasonal freeze depth in 1950s–2007 over the Heihe River Basin, Northwest China

Investigation on spatiotemporal variations of maximum seasonal freeze depth （MSFD） over the Heihe River Basin is of great importance for systematic understanding of regional climate and environmental change, ecological-hydrological processes, water resources assessment, construction and resource development. Based on soil and air temperatures at the meteorological stations of the China Meteorological Administration （CMA） over the Heihe River Basin, MSFDs time series are structured into a composite time series over the 1960-2007 period. Evaluating the averaged MSFD time series for 1960 2007 reveals a statistically significant trend of 4.0 cm/decade or a net change of-19.2 cm for the 48-year period over the basin. The MSFD had significantly negative correlation with mean annual air temperature （MAAT）, winter air temperature, mean annual ground surface temperature （MAGST）, degree days of thawing for the air （DDTa） as well as for the surface （DDTs）, and degree days of freezing for the surface （DDFs）. While there was significantly positive correlation between DDF,. and MSFD time series, MSFD was deeper and changed greatly in the Heihe River source area. It was shallower in the east-central basin and gradually deepened in other sections of the basin. The MSFD distribution pattern in 2003-2005 is consistent with that of averaged degree days of freezing for air （DDFa） in 1960-2007. However, the maximum of MSFD may not be accurate, because there is no long term observation data in the deep seasonally frozen ground regions near the lower boundary of permafrost. With increasing elevation, averaged DDFa increased at a rate of 51.6 ℃-day/100m, therefore, the MSFG and the date reaching MSFG became deeper and later, respectively.     

鄂尔多斯盆地东缘大宁—吉县地区山西组页岩岩相与沉积相特征

以鄂尔多斯盆地东缘大宁—吉县地区二叠系山西组为研究对象,综合应用岩心、薄片及测井资料,开展山32亚段岩相类型、岩相组合和沉积相研究,研究结果表明:山32亚段包括粉砂质泥岩/页岩相、纹层状层理含粉砂泥岩/页岩相、透镜状层理粉砂质泥岩/页岩相、钙质页岩相、煤层、碳质页岩相、黑色页岩相、波状层理泥质粉砂岩相、交错层理中—细砂...     

南黄海盆地南五凹阜宁组“广湖咸水”烃源岩及其油气勘探意义

通过对南五凹钻井所揭示的阜宁组进行岩性、地球化学、古生物及地震相等综合分析证实,南五凹阜宁组发育中深湖相泥质烃源岩,且该套烃源岩形成于"广湖咸水"沉积环境。"广湖"即湖盆分布广泛,中深湖相泥质烃源岩在凹陷深洼处和缓坡带均有发育,平面上面积大,纵向上厚度大,具备生成油气的物质基础。"咸水"即烃源岩形成时期湖盆受到了海侵影响,致使水体性质偏咸。南五凹与中国东部古新世—始新世期间曾遭受海侵影响的其他湖盆类似,其形成的咸化烃源岩具有"排烃早"的特征。南五凹阜宁组湖相烃源岩"广湖咸水"沉积特征对于油气勘探具有重要意义。     

南黄海盆地中部隆起的形成与演化

南黄海盆地是在前震旦系克拉通基础上发育的中、古生界海相与中、新生界陆相多旋回叠合盆地。通过地震资料解释,结合邻区钻井与区域地质资料,对南黄海盆地中部隆起中、古生代地层及其形成演化进行了研究,结果表明,南黄海盆地中部隆起沉积了较全的中、古生界海相地层,发育第四系—新近系、中—下三叠统青龙组、上二叠统、下二叠统—上泥盆统、中—下志留统,奥陶系—震旦系和前震旦系变质岩系等7套地震地质层序;主要经历了前震旦纪基底形成、震旦纪—早古生代克拉通发育、晚古生代—中三叠世稳定台地—陆内裂陷、晚三叠世—古近纪形成与抬升剥蚀及新近纪-第四纪坳陷沉降5个阶段。     

南黄海盆地烃源潜力比较性评价

南黄海中—新生代盆地经历了中生代印支运动以来的多期构造运动改造,凹陷分隔性强,各凹陷烃源岩发育条件差异大。利用地质调查获得的最新资料,从烃源岩有机质丰度、类型、成熟度以及成熟烃源岩体积参数等方面,重点探讨了中—新生代陆相盆地生烃条件好和较好的7个凹陷的烃源潜力及中—古生界海相烃源岩的演化特征。结果表明,北部坳陷的北部凹陷、东北凹陷以及南部坳陷的南四凹陷属于一类生烃凹陷,北部坳陷的南(西)部凹陷、南部坳陷的南五凹陷属于二类生烃凹陷,而北部坳陷的中—东部凹陷以及南部坳陷的南七凹陷为三类生烃凹陷。印支构造面之下的中—古生界海相层系是盆地内另一套重要烃源岩,其有机质热演化程度分异明显,在中—新生代凹陷间低凸起区最低,坳陷周围的隆起区最高,新生代凹陷区"基底层"内热演化程度介于上述两者之间。