2017年11月7—8日南昌市一次重度污染天气过程分析

利用地面常规观测资料、探空资料和大气污染物监测数据等资料,对2017年11月7—8日南昌市一次重度污染天气过程的大气污染物特征、天气形势及气象要素特点等进行了分析,并运用拉格朗日混合单粒子轨道模型（HYSPLIT）分析了大气污染物的后向轨迹。结果表明：1） 此次过程的首要污染物为PM2.5,空气质量呈东部劣于西部,市内劣于市郊的特点。AQI有明显的日变化特征,凌晨和上午10时各有一个AQI高峰,傍晚有一个AQI低谷,中午前后为AQI明显下降时段。2） 地面气压梯度小、风速小,不利于污染物的扩散。对流层中层有低槽东移,低层有弱切变线位于江西省北部,低层弱辐合导致周边污染物向中心辐合堆积。地面能见度与相对湿度变化呈反相关,在重度污染天气发生时多为雾和霾的混合物。南昌上空表现为“中层湿、低层干”的特点,在较干的低层有等温层和弱的逆温层,能抑制大气污染物的垂直扩散。3） 此次重度污染天气过程的大气污染物来源主要有三个,即南昌市周边环境污染、本地污染源的排放和大气污染物的外来输入,外来输入源主要为广东、广西及湖南上空的大气污染物。     

Evaluation of stratospheric ozone,temperature, and aerosol profiles from the LOANA lidar in Antarctica

We present an evaluation of observations from the Lidar Ozone and Aerosol for NDACC in Antarctica (LOANA) at the Dumont d’Urville station, Antarctica. This instrument is part of the Network for the Detection of Atmospheric Composition Change (NDACC), and ensures continuity with lidar measurements made since 1989 with the previous instrument at this site. This study is based on the dataset from 2008 to 2009, and comparisons are made with observations from balloon soundings, and from three satellite experiments: Aura/MLS, TIMED/SABER, and CALIOP/CALIPSO. The lidar ozone data are in very good agreement with the balloon sounding data (ECC sensor), revealing a bias of less than 3% between 17 and 34 km. For temperature, the lidar shows a low bias of ?3 K at 20 km when compared with Aura/MLS. Between 30 and 50 km, the bias is less than 2 K. We also present our initial results showing diurnal variations in temperature. The amplitude of these diurnal cycles is on the order of 1 K and is unlikely to account for the temperature biases between LOANA and the reference instruments. Comparisons of total attenuated backscatter reveal good qualitative agreement between LOANA and CALIOP, with differences of less than 30% in the derived optical depth.     

Integrative fuzzy set pair model for land ecological security assessment: a case study of Xiaolangdi Reservoir Region, China

Due to the increasingly serious ecological degradation of land systems, the land ecological security issues have attracted more and more attention of policy makers, researchers and citizens. Aiming at overcoming the disadvantages in subjectivity and complexity of the currently used assessment methods, an integrative fuzzy set pair model for assessing the land ecological security was developed by integrating fuzzy assessment and set pair analysis (SPA). The approximate degree of land ecological security to the optimal standard set was calculated to describe the secure level by combining multiple indices. The indices and weights were determined by a pressure-state-response model and the fuzzy analytic hierarchy process (AHP), respectively. Aided by a geographic information system, this model was applied to evaluate comprehensively the status of land ecological security in Xiaolangdi Reservoir Region, China, taking the administrative division as the assessment unit. The results showed that 20% of the total area maintained a slightly secure status, while 50% of the study area was of a middle or seriously low grade of land ecological security. The remaining portion (30%) was the most ecologically insecure. From the spatial prospective, obvious variations were observed. The land eco-security gradually decreased from the Xiaolangdi Dam to its surrounding regions. It was concluded that the status of the integral land ecological security of Xiaolangdi Reservoir Region was in the middle level, and increasingly intense human activities speeded up the degradation of regional land ecosystem in recent years and thus induced the crisis of land ecological security.     

Instructions for Authors

Instructions for Authors

Instructions for Authors     

The Nazca Group of south-central Peru: Age,source, and regional volcanic and tectonic significance

The Nazca Group, exposed east of Nazca, Peru, consists of a lower part composed of conglomerate and finer-grained clastic strata and an upper part made up of at least seven ash-flow sheets (cooling units or ignimbrites), collectively known as the Nazca Tuff. These tuffs were erupted between about 22 and 18 m.y. ago from a vent area in the vicinity of Pampa Galeras now marked by a collapse caldera. The early Miocene age of the Nazca Tuff provides additional evidence for a major pulse of largely pyroclastic felsic volcanism throughout the central Andes during the early Miocene. Recognition of the Pampa Galeras caldera supports the idea that many of these rocks were erupted from vent areas of the collapse-caldera type located near the eastern margin of the Coastal batholith.The Nazca Group overlies a major erosional surface cut on the Coastal batholith and its envelope that can be traced southward to the Chilean border. This surface is a continuation of the post-Incaic erosional surface to the north, which is overlain by conglomerate and radiometrically dated volcanic rock of late Eocene age. The post-Incaic surface therefore represents a major episode of regional uplift and pedimentation that followed early Tertiary orogeny. The absence of volcanic rocks of late Eocene/early Oligocene age overlying the Coastal batholith near Nazca and in southern Peru may reflect a general absence of post-Incaic volcanism in this portion of the Andes possibly related to differences in the angle of subduction and/or restriction of volcanic and volcaniclastic rocks of this age to depositional basins east of the batholith.     

Carbon dioxide emission reduction quota allocation study on Chinese provinces based on two-stage Shapley information entropy model

Chinese central government made a commitment to achieve a 40–45% reduction in carbon dioxide (CO₂) per unit of GDP by 2020 compared with 2005. This targeted reduction was allocated averagely among all the provinces rather than individually according to different situations of each province. Though some research has been done regarding this rough allocation, two shortcomings in previous studies exist: Firstly, CO₂ marginal abatement cost (MAC) has been ignored as one of the CO₂ emission reduction allocation indexes. Secondly, either subjective or objective method has been used rather than comprehensively of both subjective and objective method to calculate the weight of each index in the previous studies. In order to fill the gaps, this paper builds a two-stage Shapley information entropy model to allocate CO₂ emission reduction quota among the Chinese provinces based on the equity and efficiency principles. Afterward, three CO₂ emission reduction quota allocation scenarios have been proposed. The results show that the CO₂ MAC is an indispensable index in CO₂ emission reduction quota allocation, because its value of CO₂ Shapley information entropy is the highest among five indexes. CO₂ emission reduction quota of lower-MAC provinces should be allocated larger, while the quota of higher-MAC provinces should be allocated smaller. Therefore, two suggested policies have been proposed: First, differential CO₂ emission reduction quota allocation should be proposed. Second, synergetic development should be promoted.     

Design Screening Tools for Passive Funnel and Gate Systems

The funnel and gate remediation concept (Star and Cherry 1993) represents a promising, yet relatively under-developed, technology for the passive control and in situ remediation of contaminated ground water. Effective design and implementation of such a system may, however, prove difficult under conditions of large or unpredictable variations in contaminant migration or ground water flow.
Numerical modeling of two-dimensional ground water flow has been used to predict the hydraulic performance of passive, straight, or winged funnel and gate configurations over a range of hydrogeologic and ambient ground water flow conditions. The results of these analyses were used to construct generic correlation diagrams relating upstream capture zone or gale through put to the barrier, gale, and aquifer characteristics. These diagrams serve as useful screening tools to (1) quantitatively estimate the capture zone of pre-determined funnel and gale configurations, or (2) develop preliminary funnel and gale designs that will yield a desired capture zone, independent of aquifer characteristics.     

Change in the circulation regime in the stratified saline Lake Shira (Siberia,Republic of Khakassia)

The in-situ data on the vertical structure and stability of the vertical stratification of saline Lake Shira over the past decade (2007–2015) are analyzed. Simplified mathematical models have shown that strong wind in the autumn of 2014 together with rather thick ice in the winter of 2015 caused a change in the circulation regime of this water reservoir from meromictic (incomplete mixing) to holomictic (compete mixing). Based on the results obtained, a circulation regime for deep saline lakes located in the continental climate zone, in particular, in the arid zones of Southern Siberia (Khakassia, Transbaikal, and Altai) can be predicted under various climate scenarios of the future.