InSAR技术在南极地区的应用     

周春霞  鄂栋臣 《测绘与空间地理信息》2005,28(5):4-7

南极与全球环境变化的关系受到了全人类的关注.空间对地观测技术的发展,为人类进一步认识南极打开了新的局面.合成孔径雷达干涉测量技术（InSAR）是近十年发展起来的极具潜力的空间对地观测技术,已经成为一种用于生成数字高程模型（DEM）地图制图及地表运动监测等的有效手段.通过Grove山地区的实例研究和分析,进一步肯定了InSAR在南极研究中不仅可以用于地图制图,而且在冰川动力学、冰貌环境变化等研究领域也有巨大的潜力.  相似文献   

中国农业广义水资源利用系数及时空格局分析          下载免费PDF全文

操信春  邵光成  王小军  王振昌  何鑫  杨陈玉 《水科学进展》2017,28(1):14-21

为统一核算区域蓝水、绿水资源有效利用程度,构建了农业广义水资源利用系数（E_g）指标,核算中国31个省区粮食生产中的E_g,并基于空间自相关和通径分析方法对其时空格局及成因进行分析。中国1998-2010年E_g为0.588,大部分省区呈随时间增大趋势;E_g相似的省区在空间上显著地聚集,高值省区聚集于西部,低值省区集中于东南地区,且空间聚集现象呈减弱趋势;农业生产管理水平对E_g的影响大于气候要素,社会经济条件影响最小。结合广义水资源利用状况,西南省区可扩大粮食生产规模以发挥E_g较大优势,东北与华北粮食主产区应通过提高E_g以保障粮食安全和水资源可持续利用。研究可发展农业用水效率评价理论同时为国家粮食生产与水资源管理策略的制定提供参考。  相似文献   

Ecosystem carbon stocks across a tropical intertidal habitat mosaic of mangrove forest,seagrass meadow,mudflat and sandbar          下载免费PDF全文

Valerie X. H. Phang  L. M. Chou  Daniel A. Friess 《地球表面变化过程与地形》2015,40(10):1387-1400

Intertidal habitats provide numerous ecosystem services, including the sequestration and storage of carbon, a topic of great recent interest owing to land‐cover transitions and climate change. Mangrove forests and seagrass meadows form a continuum of intertidal habitats, alongside unvegetated mudflats and sandbars, however, studies that consider carbon stocks across these spatially‐linked, threatened ecosystems are limited world‐wide. This paper presents the results of a field‐based carbon stock assessment of aboveground, belowground and sediment organic carbon stock to a depth of 1 m at Chek Jawa, Singapore. It is the first study of ecosystem carbon stocks of both vegetated and unvegetated intertidal habitats in the tropics. Ecosystem carbon stocks were 497 Mg C ha^‐1 in the mangrove forest and 138 Mg C ha^‐1 in the seagrass meadow. Sediment organic carbon stock dominated the total storage in both habitats, constituting 62% and >99% in the mangrove forest and seagrass meadow, respectively. In the adjacent mudflat and sandbars, which had no vegetative components, sediment organic carbon stock ranged from 124–143 Mg C ha^‐1, suggesting that unvegetated habitats have a carbon storage role on the same order of importance as seagrass meadows. This study reinforces the importance of sediment in carbon storage within the intertidal ecosystem, and demonstrates the need to consider unvegetated habitats in intertidal ‘blue carbon’ stock assessments. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

全球海岸带国家蓝碳资源价值与类型研究          下载免费PDF全文

冯翠翠  龚语嫣  叶观琼  曾江宁  唐剑武  方秦华  杜建国 《应用海洋学学报》2024,43(1):001-011

海岸带蓝碳生态系统已成为应对气候变化重要的基于自然的解决方案。本研究梳理了全球海岸带蓝碳生态系统的分布、碳封存量和封存价值,并根据经济、科技、蓝碳封存量三个指标对各海岸带国家和地区进行分类。海岸带蓝碳生态系统分布最广的国家是澳大利亚、印度尼西亚、墨西哥和美国,而印度尼西亚、澳大利亚、马来西亚和巴西碳埋藏量最高。全球每年蓝碳埋藏价值在碳交易和碳税价格下分别为3.47×109美元和2.35×109美元。中国拥有丰富的海岸带蓝碳资源,生态系统面积排名第10,年封存量排名第21;然而蓝碳自然资源的赋存禀赋与现有碳价格体系下的价值匹配性较差,基于碳交易价格的中国海岸带蓝碳埋藏价值全球排名第27,基于碳税价格仅排名第39。碳价格低迷将会导致在国际蓝碳交易中处于劣势,中国后续应不断完善碳排放交易市场。中国具有在蓝碳研究以及修复投入与实践方面的优势,以及贝藻养殖、海洋牧场等特色蓝碳资源,可结合不同类型的蓝碳国家经济科技条件与自然条件制定多元合作策略。  相似文献   

三沙永乐龙洞洞内侧壁礁体矿物和元素组成及其晚更新世以来的形成演化   总被引：1，自引：0，他引：1  

罗珂  田元  傅亮  孙晓霞  毕乃双  范德江  杨作升 《海洋与湖沼》2019,50(5):1014-1021

三沙永乐龙洞深度在300m左右,是目前全球已知最深的海洋蓝洞,但是对其性质和成因了解极其有限。本研究使用X射线粉晶衍射仪、X射线荧光光谱仪、AMS14C测年等分析测试方法对采自不同深度的洞壁礁体的矿物物相、元素含量和形成年代进行了测定,探讨了洞壁性质和龙洞的演化。研究结果表明:三沙永乐龙洞洞内侧壁矿物均属于碳酸盐矿物,包括文石、高镁方解石和低镁方解石,平均含量分别为49.0%、46.6%、14.3%,它们主要来自钙质生物碎屑;洞内侧壁的主要元素是Ca、Mg、Sr,平均含量分别为36.8%、0.98%、0.48%。三沙永乐龙洞是一个复合体,17m以上岩石年龄晚于7.5cal kaBP,是全新世海平面上升时期形成的现代珊瑚礁体,没有经历过海平面下降引起的成岩作用; 17—35m岩石形成时代早于25cal ka BP,是经历了大气淡水成岩作用的晚更新世喀斯特溶洞,且在高海平面时期于17—23m以浅的空间内广泛发育洞内珊瑚礁。  相似文献   

海带CRY-DASH基因的克隆与转录表达分析     

李璐  张朋艳  姚建亭  段德麟 《海洋科学》2019,43(4):1-7

利用cDNA末端快速克隆(RACE)技术,获得海带(Saccharina japonica) CRY-DASH基因(SjCRYDASH)全长序列,结构分析发现,其ORF区长1779 bp,编码592个氨基酸。进行氨基酸同源序列比对,其与其他藻类和高等植物间存在两个重要辅基MTHF和FAD结合的保守域。通过不同光质照射诱导海带幼孢子体,发现蓝光、白光诱导1h后,均能使SjCRY-DASH转录水平上升,且SjCRY-DASH对蓝光的响应更强烈。本研究结果为研究大型褐藻-海带CRY-DASH受光诱导调控功能打下基础。  相似文献   

太湖蓝藻爆发与水温的关系的MODIS遥感   总被引：15，自引：4，他引：11  

王得玉  冯学智  周立国  郝景燕  徐晓雄 《湖泊科学》2008,20(2):173-178

利用MODIS高光谱遥感数据动态监测太湖地区蓝藻水华发展过程,并结合水温环境因子,探讨蓝藻爆发的环境条件.首先,通过简单的比值植被指数,实现蓝藻生物量的遥感估算;根据六期遥感估算结果,监测太湖蓝藻动态发展过程.然后,利用MODIS热红外波段(31和32),采用分裂窗算法,同步反演出的太湖表面水体温度,探讨蓝藻爆发的水温条件,及蓝藻生长与水-温度之间的关系.研究结果表明,在水体富营养化前提下,水体温度是影响蓝藻生长的重要环境因子;合适的水体温度(24-30℃)是蓝藻爆发的必要条件;大于30℃的高温,对蓝藻的生长有明显的抑制作用.  相似文献   

Porewater-derived dissolved inorganic carbon and nutrient fluxes in a saltmarsh of the Changjiang River Estuary     

Xiaogang Chen  Jinzhou Du  Xueqing Yu  Xiaoxiong Wang 《海洋学报(英文版)》2021,40(8):32-43

Saltmarshes are one of the most productive ecosystems, which contribute significantly to coastal nutrient and carbon budgets. However, limited information is available on soil nutrient and carbon losses via porewater exchange in saltmarshes. Here, porewater exchange and associated fluxes of nutrients and dissolved inorganic carbon(DIC) in the largest saltmarsh wetland(Chongming Dongtan) in the Changjiang River Estuary were quantified. Porewater exchange rate was estimated to be(37±35) cm/d during December 2017 using a radon(~(222)Rn) mass balance model. The porewater exchange delivered 67 mmol/(m~2·d), 38 mmol/(m~2·d) and 2 690 mmol/(m~2·d) of dissolved inorganic nitrogen(DIN), dissolved silicon(DSi) and DIC into the coastal waters,respectively. The dominant species of porewater DIN was NH_4~+ (99% of DIN). However, different with those in other ecosystems, the dissolved inorganic phosphorus(DIP) concentration in saltmarsh porewater was significantly lower than that in surface water, indicating that saltmarshes seem to be a DIP sink in Chongming Dongtan. The porewater-derived DIN, DSi and DIC accounted for 12%, 5% and 18% of the riverine inputs, which are important components of coastal nutrient and carbon budgets. Furthermore, porewater-drived nutrients had obviously high N/P ratios(160–3 995), indicating that the porewater exchange process may change the nutrient characteristics of the Changjiang River Estuary and further alter the coastal ecological environment.  相似文献   

Temporal and spatial changes of blue water and green water in the Taihang Mountain Region,China, in the past 60 years     

Junkai Du  Chunfeng Hao  Yaqin Qiu  Cunwen Niu  Huan Liu 《水文科学杂志》2019,64(16):2040-2056

ABSTRACT

Appropriate allocation of limited freshwater resources to humans and ecosystems is an important issue hampering sustainable development in mountainous regions. The Taihang Mountain Region (TMR), including the Yellow and Hai river basins, is an important water source area for the North China Plain. The distributed hydrological model Water and Energy transfer Processes in Large river basins (WEP-L) was used to simulate the water cycle processes and to summarize the temporal and spatial changes in the blue and green water in the TMR from 1956 to 2015. The results show that in the period 2011–2015 the annual average blue water decreased by 7.31 × 10⁹ m³, while the annual average green water increased by 13.60 × 10⁹ m³ compared to 1956–1960. At the inter-annual time scale, the blue water exhibited a downward trend while the green water exhibited an upward trend. The amount of seasonal blue water in the TMR is ranked in descending order: summer, autumn, spring and winter, while for green water, the rank is summer, spring, autumn and winter. The amounts of blue and green water are higher on the windward than on the leeward slopes. The blue water yield is generally higher in forests and grasslands than in farmland, while the green water exhibits the opposite response. A greater emphasis should be placed on the widening gap between blue water and green water due to climate warming, and on soil and water conservation measures.  相似文献   

Hydrological modelling of the Vistula and Odra river basins using SWAT   总被引：3，自引：1，他引：2  

M. Piniewski  M. Szcześniak  I. Kardel  T. Berezowski  T. Okruszko  R. Srinivasan 《水文科学杂志》2017,62(8):1266-1289

This paper presents a large-scale application of the SWAT model for water balance and natural streamflow simulation in the entire basins of the Vistula and the Odra, covering most of the territory of Poland. A tailored calibration approach was designed to achieve satisfactory goodness-of-fit across a range of catchment sizes. Model calibration and evaluation driven by high-resolution climate data showed overall good behaviour for 80 benchmark catchments divided into eight clusters, and spatial evaluation for 30 gauges showed that the designed regionalization scheme performed well (median KGE of 0.76). Basin-averaged estimates of blue and green water flow and green water storage estimated using the calibrated model were 185, 517 and 206 mm, respectively. This study provides a basis for future work, such as assessing climate change impacts on hydrology, assessing flow alterations, and water quality simulation. The model output is publicly available through an online research data archive (doi:10.4121/uuid:b8ab4f5f-f692-4c93-a910-2947aea28f42).