新疆和田绿洲大气降尘和PM_(10)浓度变化特征分析   总被引：1，自引：0，他引：1  

张小啸  陈曦  王自发  郭宇宏  李杰 《干旱区地理》2015,38(3)

通过分析2000-2012年新疆和田绿洲环境监测记录和气象观测数据,研究该地区大气降尘强度和可吸入颗粒物浓度的变化特点,阐明其主要影响因素。结果显示:2000年以来大气降尘强度在1 300~1 500 t·km-2·a-1水平上下波动变化,春、夏两季受沙尘天气影响导致高降尘量,月平均强度均150 t·km-2;环境PM10年平均浓度在0.2~0.25 mg·mg-3之间变化,有逐渐上升的趋势,沙尘暴期间颗粒物浓度快速上升,PM10浓度极值可达到2.52 mg·m-3;超过91%的空气污染日数是由大气颗粒物造成的。因此,颗粒物是和田绿洲区的首要空气污染物。降水量波动变化剧烈,年平均值50 mm·a-1,尽管和田绿洲春、夏两季降水量增加,但降水对抑制大气颗粒物污染的湿清除作用极为有限。春、夏两季大风日数占全年大风天气总日数的84.7%以上,风蚀沙土在西北风作用下传输到绿洲区,来自塔克拉玛干沙漠的风蚀沙尘颗粒物是和田地区大气降尘和颗粒污染物的主要来源。  相似文献   

南极磷虾渔业近况与趋势分析   总被引：2，自引：0，他引：2       下载免费PDF全文

黄洪亮  陈雪忠  刘健  李灵智  吴越  杨嘉樑  周斌  齐广瑞  陈帅  徐国栋 《极地研究》2015,27(1):25-30

南极周边海域蕴藏着丰富的南极磷虾资源,其开发潜力受到世界各国的关注。为此,本研究基于南极海洋生物资源养护委员会(CCAMLR)统计数据分析了近几年南极磷虾渔业国家发展状况,并研究了南极磷虾渔业捕捞结构的变化特点。结果发现:(1)受捕捞技术及装备的限制,南极磷虾传统渔业国家——波兰、日本及乌克兰等正逐渐淡出开发行列;(2)随着挪威、中国及智利等新兴国家的加入,南极磷虾入渔船舶和渔业产量呈上升趋势;(3)南极磷虾全年均有生产,其中3—9月份渔获产量占总产量的70%—90%;(4)受综合环境因素和新的渔业管理措施影响,CCAMLR 48.1、48.2和48.3小区渔获产量年间波动变大,渔场选择难度增大;(5)传统的大规模科学调查模式已不适应该资源变化与渔业管理的要求,科学性渔业调查将成为今后南极磷虾资源调查与评估的重要补充。  相似文献   

南极磷虾商业化开发的战略性思考          下载免费PDF全文

刘勤  黄洪亮  李励年  王茜  周雨思  阮雯 《极地研究》2015,27(1):31-37

南极磷虾的区域特色、资源保有量优势和广泛的应用价值,使它成为重要的战略资源。南极磷虾商业化开发战略是海洋战略的重要组成部分,其资源特色为战略制定与实施提供了支撑,符合战略性新兴产业发展要求。基于中国海洋开发的战略环境,结合南极磷虾资源特色,评估其战略能力,确立发展目标为形成并完善南极磷虾资源开发的产业体系,确立发展战略重点为跟踪南极磷虾资源养护管理措施变化和开发利用政策、中国南极磷虾产业发展模式及风险评估、中国发展南极磷虾产业关键技术突破与产业化机制、中国发展南极磷虾产业的政策措施与保障机制研究。  相似文献   

四种再分析辐射资料在东南极高原适用性评价          下载免费PDF全文

傅良  卞林根  效存德  丁明虎 《极地研究》2015,27(1):56-64

利用东南极Panda-1站2011年2月至2012年1月期间的辐射观测资料,检验了四种再分析资料在该地区的适用性。结果表明:对各辐射分量ERA interim在Panda-1地区的适用性都明显好于其他三种再分析资料,这主要归因于其四维变分(4D-VAR)数据同化系统的应用、新的云预报方程和改进的参数化方案以及同化了更多的卫星资料雷达等非常规探测资料。对于向下短波辐射,NCEP-1与实测值之间偏差最大(18.7 W·m-2),可能原因是模式对大气透明度的高估和对云量的低估。对反射率模拟的偏差直接导致了各模式对净短波辐射模拟偏差。NCEP-1与JCDAS都低估了Panda-1地区的地表反射率,模式中,地表吸收了更多的向下短波辐射,最终导致对净短波辐射模拟偏高。对向下长波辐射,四种再分析资料都存在不同程度的低估,冬季偏差大于夏季,其中NCEP-1与NCEP-2偏差最大(分别为-62.6 W·m-2和-37.3 W·m-2)。四种再分析资料均不能很好地反映Panda-1地区净辐射的年变化情况,一般而言,夏季偏差小,冬季偏差大。虽然再分析资料存在明显的缺陷和不足,在广袤的东南极高原地区,观测站点稀少,实测资料无法满足需要,再分析资料仍不失为研究东南极地区气候的一种有效工具。  相似文献   

中国南极球粒陨石的高精度钾同位素研究     

蒋云  Piers KOEFOED  王昆  徐伟彪 《地质学报》2021,95(9):2878-2888

钾和其他中等挥发性元素亏损是类地行星普遍的全岩化学成分特征之一,能用来示踪不同的亏损过程.球粒陨石是组成行星的前体物质,研究球粒陨石中钾同位素的亏损和分异机制,对于太阳系物质或行星的起源、形成和演化具有十分重要的意义.本文利用近年来发展的高精度钾同位素分析技术,测试了 14 个中国南极陨石以及6 个目击型陨石(Murchison、Allende、Ningqiang、Tagish Lake、Xinyang 和Banma)的全岩钾同位素组成.结果显示,21 个碳质球粒陨石全岩δ41 K值分布范围为－0. 62‰±0. 05‰至0. 37‰±0. 08‰,平均值为－0. 32‰± 0. 24‰(2SD),比全岩硅酸盐地球(BSE)稍重.18 个普通球粒陨石全岩数据(如果异常值 GRV 021603 除外)的δ41 K值分布范围为－1. 02‰±0. 05‰到－0. 61‰±0. 02‰,平均δ41 K值为－0. 81‰±0. 15‰(2SD),比全岩硅酸盐地球稍轻.2 个目击型陨石 Murchison(CM2 型)和 Allende(CV3 型),呈现较大的内部钾同位素差异(分别为0. 22‰和0. 16‰),可能反映了水蚀变导致的钾同位素在100 mg球粒陨石全岩尺度上的不均一性.小行星母体过程(水蚀变、热变质和冲击变质)不能很好地解释球粒陨石的钾同位素分馏,母体作为一个封闭体系只是平衡均一化同一个化学群内的钾同位素成分.不同化学群球粒陨石之间的钾同位素与钾元素之间没有显示明确的相关性,这一趋势与最近国际上发表的数据在误差范围内基本一致,太阳星云的单阶段热过程如蒸发或冷凝均不能很好地解释.核合成异常是一种可能的解释,大质量恒星的星风或者超新星爆发注入可以增加一些41 K到太阳星云中,从而在原始球粒陨石中保存下来,然而这一观点需要更多研究支持.  相似文献   

干旱区绿洲地下水位调控方法与模型研究进展   总被引：1，自引：0，他引：1  

翟家齐  刘宽  赵勇  董义阳  王丽珍  姜珊 《水文》2021,41(2):1-7

适宜的地下水位是干旱区绿洲健康稳定发展的基础。从地下水生态水位的调控机理、调控方法、调控模型和应用实践入手,综述了干旱区绿洲地下水生态水位调控的研究进展:地表水与地下水相互转化规律是干旱区绿洲地下水生态水位调控的理论基础,掌握人类活动强烈影响下的地表水与地下水的响应关系是关键;地下水的补给、排泄和开发利用是实现地下水位调控的三个主要途径,不同调控方法在作用环节、适用性及效果方面存在显著差异;基于不同的研究重点,目前形成了以水资源配置、水循环过程和生态过程为核心的三类调控模型;建议继续深化强人类活动影响下干旱区绿洲生态水文响应机理与演变规律研究,构建基于调控措施-循环转化-响应反馈的地下水生态水位调控体系。  相似文献   

Grove Mountains （GRV） 024237： A new ureilite from Antarctica     

JIANG Xiaoying  WANG Guiqin  WANG Daode  MIAO Bingkui 《极地研究(英文版)》2012,23(1):25-29

Ureilites share the characteristics of differentiated meteorites and of primary chondrites. GRV 024237 is a ureilite, which was found in the 19th Chinese National Antarctic Research Expedition （CHINARE）, at the No. 4 moraine, Grove Moun- tains, Antarctica. GRV 024237 consists mainly of coarse-grained olivine （60 vol%）, pigeonite （30 vol%） and opaque minerals （10 vol% ）. Tri-junction texture between olivine and pigeonite is common. Carbonaceous materials with minor amounts of troilite and nickel-iron metal were observed as interstitial phases. The Fa value of olivine composition varies from 6.2 to 16.8 from rim to core, but pyroxene is homogeneous in composition, with Fs 14.0 to 15.5. Both olivine and pyroxene have normal extinctions. Net-like iron or limonite veins filled in the fractures of olivine and pyroxene, and no diamond was observed. Based on petrographic and mineralogical features, GRV 024237 is a Type I and Group 2 monomict ureilite.  相似文献   

Development of the geodetic coordinate system in Antarctica     

ZHANG Shengkai  E Dongchen 《极地研究(英文版)》2012,(3):181-186

Defining a universal geodetic coordinate system is one of the fundamental challenges of geodesy. We present a review of the basic general coordinate systems -- the space rectangular coordinate system, the geodetic coordinate system, the topocentric coordinate system, and the plane coordinate system. We then look ： t the World Geodetic System WGS72 and WGS84 and the In- ternational Terrestrial Reference Frames ITRF2000 and 1TRF2005, which were introduced when space technology became avail- able. The history of international geodetic coordinate systems in the Antarctic region is briefly reviewed and the development of the geodetic coordinate systems in the Chinese Great Wall Station and Zhongshan Station in Antarctica is outlined. Finally, the issue of coordinate system transformation is discussed.  相似文献   

An analysis of oasis evolution based on land use and land cover change: A case study in the Sangong River Basin on the northern slope of the Tianshan Mountains     

Qi Zhang  Geping Luo  Longhui Li  Miao Zhang  Nana Lv  Xinxin Wang 《地理学报(英文版)》2017,27(2):223-239

This study investigated oasis evolution and the changes of peripheral desert in the Sangong River Basin since the 1950s by rebuilding seven land cover maps derived from black-and-white aerial photographs (1958, 1968, and 1978), a color-infrared aerial photograph (1987), Landsat Thematic Mapper (TM) imagery (1998), Satellite Pour l’Observation de la Terre (SPOT) imagery (2004), and Landsat Operational Land Imager (OLI) imagery (2014). The results showed that: (1) Since 1950, the oasis consecutively expanded more than four times from an alluvial fan to an alluvial plain, causing the shrinkage of desert landscapes that were dominated by a Haloxylon ammodendron Bunge community (HBC) and a Tamarix chinensis Lour community (TLC). Furthermore, the primary (1958–1968) and final (2004–2014) stages were the most important periods, during which agricultural land experienced the most rapid expansion during the period 1958–1968, and the built-up area showed the most rapid expansion after the 2000s. (2) Two basic management modes, a “local mode” formed by the local governments and a “farm management mode” developed by Xinjiang Production and Construction Corps, together promoted oasis evolution under various land-use and landcover (LULC) stages. (3) The evolution of the modern oasis during the 1950s–2004 showed the general features of an arid oasis, while during the period of 2004–2014 it was characterized by a large-scale inter-basin water diversion or the import of new water sources. (4) The oasis expanded at the expense of desert vegetation, resulting in distinct variation in the structure of the desert plant community, which will make it more difficult to protect the desert ecosystem.  相似文献   

Coincidence of abandoned settlements and climate change in the Xinjiang oases zone during the last 2000 years   总被引：1，自引：0，他引：1  

Dan Jia  Xiuqi Fang  Chengpeng Zhang 《地理学报(英文版)》2017,27(9):1100-1110

The study on the relationship of abandoned settlements and climate change in the oases could provide a historical reference for understanding human responses to present and future global warming in the arid zone. A total of 554 abandoned historical settlements in Xinjiang Uygur Autonomous Region, China, were used to examine the relationship between abandoned settlements and temperature change over the past 2000 years. The analysis covered dynastic epochs from the Han Dynasty (206BC–220AD) to the Qing Dynasty (1644AD–1911AD) in the oases of Xinjiang. Greater density of settlements was found at the oases larger than 2000 km², which were more stable and less sensitive to climate change compared to smaller oases. Settlements flourished at small oases and the middle and lower reaches of rivers during warm periods and shrank back to piedmont basins and upstream alluvial fans during cold periods. These results demonstrated responses of oasis agriculture to climate change.  相似文献