1997年和2011年春季北极臭氧损耗事件的对比分析          下载免费PDF全文

索春男  田文寿  谢飞  雒佳丽  张健恺 《Acta Meteorologica Sinica》2017,75(3):492-505

采用SLIMCAT化学传输模式以及再分析资料,对比分析了1997和2011年北极地区平流层臭氧异常偏低事件及其成因。结果表明,1997和2011年3月北极地区大气臭氧柱总量（TCO）异常值都达到了约-80 DU,并且在30-200 hPa（中下平流层）区域的大气臭氧柱总量异常约占整层大气臭氧柱总量异常的80%。分析表明发生在这两年的极端臭氧偏低事件均可能是由于上一年冬季的拉尼娜事件导致上传的行星波减少,使得北极极涡加强,平流层温度异常偏低,生成了更多极地云,引起更强的臭氧化学损耗导致的。对比这两年的大气臭氧柱总量变化发现,2011年的柱总量减少得更快。2011年北极地区上对流层下平流层（UTLS）区域臭氧下降要明显强于1997年,其主要原因应该是2010-2011冬季的拉尼娜活动更强,北太平洋海温更高,进一步减弱阿留申低压和平流层波活动。这导致2011年极涡温度异常偏低更强烈,形成了更多的极地平流层云甚至出现了第二类极地平流层云,最终加速该年春季的臭氧化学损耗引起的。  相似文献   

一种基于网络的多服务器冰箱抽样测试系统     

郭忠文  张阿娜  刘勇  王元斌 《中国海洋大学学报(自然科学版)》2003,33(6):950-954

针对冰箱企业中存在多个抽样室的情况 ,本文提出了 1种基于网络的多服务器抽样测试系统的设计方案 ,并给出了实现方法。该系统为企业类似测试系统的应用提供了 1种方案  相似文献   

Temporal Variations in the Dissolved Nutrient Stocks in the Surface Water of the Western North Atlantic Ocean     

Insaf S. Babiker  Mohamed A. A. Mohamed  Kaori Komaki  Keiichi Ohta  Kikuo Kato 《Journal of Oceanography》2004,60(3):553-562

Changes in patterns of undetectability and molar ratios of dissolved nutrients in the euphotic zone of the oligotrophic western North Atlantic Ocean were investigated utilizing the Bermuda Atlantic Time-series Study (BATS) data set of the US Joint Global Ocean Flux Study (JGOFS). Our aim was to examine the temporal dynamics of nutrient stocks over a decade (1989∼1998) and to gain insight into the interactions between the different biotic and abiotic factors underlying BATS. Patterns of nutrient undetectability clearly revealed the depleted nature of the nutrients in surface water at the BATS location, particularly phosphorous. The N:P ratio was consistently far above the nominal Redfield ratio (mean, 38.5) but was significantly lower during the 1993∼1994 period (22.1). Over the same period the proportion of samples depleted in N only increased while the proportion of samples depleted in P only decreased. This indicates an overall reduction of N relative to P in the surface water at BATS during the 1993∼1994 period, the reasons for this anomaly, though, are not clear. The correlation analysis between the biotic and abiotic variables at BATS has indicated some interesting relationships that can help understand some of the parameters affecting nutrient stocks in the euphotic zone and their consequent impacts on marine biota. Although nutrient stocks in the oligotrophic environment are limited, they might be subject to interannual variation that may become anomalous in some cases. These variations might underlay significant feedback mechanisms by affecting marine productivity, the prime factor controlling the sequestration of atmospheric CO₂ by the oceans. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

GPS接收机与PC机间串口通信的实现   总被引：8，自引：1，他引：8  

公丕波  郝金明  朱伟刚 《海洋测绘》2005,25(3):35-37,41

简要介绍了当前流行的几种串口通信程序开发模式以及GPS接收机广泛采用的NMEA0183通信协议，设计了串口通信类CSerialPortGPS，该类能够实现GPS接收机与Pc机问的串口通信，并且能够对遵循NMEA0183协议的GPS数据进行数据校验和数据提取，并成功地将该类应用到了车载定位导航系统的开发中。  相似文献   

向环境监测系统推荐SDI-12通讯标准   总被引：1，自引：0，他引：1  

廉双喜 《海洋技术学报》2001,20(2):58-64

本文推荐 的SDI－12通讯标准是近五年来欧美国家在环境监测中广泛使用的一种串行数据通讯接口协议，在该协议支持下，只要通过一根三芯电缆，即可把一台数据采记录器与多台现场多要素检测仪联系起来，且具有远距离传送，全天候防护和节省经费的优点。  相似文献   

Short-term stock assessment of Loligo gahi at the Falkland Islands: sequential use of stochastic biomass projection and stock depletion models     

Roa-Ureta  Ruben; Arkhipkin  Alexander I. 《ICES Journal of Marine Science》2007,64(1):3-17

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River–aquifer interactions in a semi‐arid environment stressed by groundwater abstraction     

Andrew M. McCallum  Martin S. Andersen  Beatrice M. S. Giambastiani  Bryce F. J. Kelly  R. Ian Acworth 《水文研究》2013,27(7):1072-1085

Rivers and aquifers are, in many cases, a connected resource and as such the interactions between them need to be understood and quantified for the resource to be managed appropriately. The objective of this paper is to advance the understanding of river–aquifer interactions processes in semi‐arid environments stressed by groundwater abstraction. This is performed using data from a specific catchment where records of precipitation, evapotranspiration, river flow, groundwater levels and groundwater abstraction are analysed using basic statistics, hydrograph analysis and a simple mathematical model to determine the processes causing the spatial and temporal changes in river–aquifer interactions. This combined approach provides a novel but simple methodology to analyse river–aquifer interactions, which can be applied to catchments worldwide. The analysis revealed that the groundwater levels have declined (~ 3 m) since the onset of groundwater abstraction. The decline is predominantly due to the abstraction rather than climatic changes (r = 0.84 for the relationship between groundwater abstraction and groundwater levels; r = 0.92 for the relationship between decline in groundwater levels and magnitude of seasonal drawdown). It is then demonstrated that, since the onset of abstraction, the river has changed from being gaining to losing during low‐flow periods, defined as periods with flow less than 0.5, 1.0 or 1.5 GL/day (1 GL/day = 1 × 10⁶ m³/day). If defined as < 1.0 GL/day, low‐flow periods constitute approximately 65% of the river flows; the periods where the river is losing at low‐flow conditions are thus significant. Importantly, there was a significant delay (> 10 years) between the onset of groundwater abstraction and the changeover from gaining to losing conditions. Finally, a relationship between the groundwater gradient towards the river and the river flow at low‐flow is demonstrated. The results have important implications for water management as well as water ecology and quality. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Analysis of satellite‐based and in situ hydro‐climatic data depicts water storage depletion in North China Region     

Juana Paul Moiwo  Fulu Tao  Wenxi Lu 《水文研究》2013,27(7):1011-1020

Water storage depletion is an increasing hydrological threat to agricultural production and social stability across the globe. It is fast approaching threshold levels especially in arid/semiarid regions with low precipitation and excessive evapotranspiration (ET). This study analyses water storage dynamics in the North China Region (NCR) – an important grain‐production base in China. It uses monthly Gravity Recovery and Climate Experiment (GRACE), Global Land Data Assimilation System (GLDAS) and field‐measured precipitation data products for 2002–2009. The datasets are analysed in a basin‐scale water balance equation to determine the state of storage in the NCR study area. Based on the validated satellite‐based data products with field‐measured values, average error/bias in the datasets is <10%. The analysis also shows favourable agreements among the GRACE‐derived and flux‐based storage changes at various temporal scales. Whereas the amplitudes and phases of the precipitation and ET fluxes are largely stable for 2002–2009, those of GLDAS runoff and GRACE total water storage anomaly apparently narrow out. The linear trends in the monthly, seasonal and annual storage changes are negative for the study period, suggesting storage loss. There is an apparent seasonality of storage change in the study area; with summer storage gain, winter storage loss and an overall storage loss that is on the average of 16.8 mm/yr. Storage loss is most severe in the central floodplain region (the main irrigated production zone) of the study area. Storage depletion in this important agro‐based semi‐arid region could have negative implications for the millions of people in the region and beyond in terms of water supply, crop production, food security and social stability. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

基于C8051 F34x-DK开发平台的CF卡测试系统     

杜阁  吴小强  王正勇 《成都信息工程学院学报》2008,23(1):12-15

基于Silicon实验室的C8051 F34x-DK开发平台基础上,设计并实现了一个对CF卡等存储卡进行综合测试的一个通用测试系统。在Windows XP操作系统下,PC机通过串口发送ATA或非ATA命令来控制单片机实现对CF卡等存储卡的综合测试。详述了系统整体结构和Memory模式下读CF卡一个扇区的具体实现过程,并通过测试进行了证明。  相似文献   

Serial dependence properties in multivariate streamflow simulation with independent decomposition analysis     

Taesam Lee 《水文研究》2012,26(7):961-972

Stochastic simulation of multivariate hydrologic variables has a key role in evaluating alternative designs and operation rules of hydrologic facilities. The recently developed decomposition analysis, Independent Component Analysis (ICA), allows us to apply the simple univariate time series model to each extracted component by: (1) decomposing multivariate time series into independent components with ICA; (2) modelling and generating each component independently; and (3) mixing the generated components to come back to observational domain. However, we illustrate in the current study that fitting a univariate time series model to each extracted component might end up with the underestimation of the serial dependence that the observation data might contain. A alternative for parameter estimation is suggested to preserve the serial dependence of the observation variable using the relationship between the observation variable and the decomposed variable. The case study of the Upper Colorado River basin shows that some improvement is made through the suggested alternative. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献