Constructed wetland technology and mosquito populations in Arizona     

Martin M. Karpiscak  Kenneth J. Kingsley  Roland D. Wass  Frederick A. Amalfi  John Friel  Aaron M. Stewart  Joe Tabor  Jeffrey Zauderer 《Journal of Arid Environments》2004,56(4):681

Constructed wetlands and other aquatic habitat creation or restoration efforts offer both potential benefits and problems for arid areas. An unintentional consequence of these efforts has been the potential for an increase in local adult mosquito populations. Shallow water-emergent plant zones may provide ideal conditions for mosquito larval growth, and areas of high humidity, dense vegetation, and abundant birds and other wildlife may provide ideal conditions for adult mosquitoes. Three constructed wetlands in southern Arizona were studied over a period of years before and after they were constructed and operational. Mosquito populations were sampled using a variety of methods, primarily trapping of adults with CO₂-baited traps. Populations apparently increased, sometimes by several orders of magnitude, after wetlands became operational. Several methods of mosquito abatement were initiated and their results are discussed. However, no definitive conclusions can be drawn because no untreated areas were available for comparison and many factors that may have affected mosquito populations also changed. Based on the experience gained at these three sites, mosquito control is an especially important design and management component for constructed wetlands in arid environments with low background populations of mosquitoes.  相似文献   

中国云气候特征的分析   总被引：21，自引：4，他引：21       下载免费PDF全文

刘瑞霞刘玉洁  杜秉玉 《应用气象学报》2004,15(4):468-476

利用1983年7月至2001年8月的ISCCP卫星总云量资料, 分析了我国总云量的空间分布特征, 并将全国用193个网格点表示, 采用聚类分析方法, 按照总云量年内变化规律相同的原则将中国分为3个区, 逐区讨论了总云量的年内变化特征;同时, 分析了18年来中国总云量的变化趋势。最后利用奇异值分解法(SVD)找到了我国青藏高原冬季总云量与全国夏季降水的高相关区, 证明青藏高原总云量与我国东北降水正相关密切。  相似文献   

EXPERIMENT WITH ONE DIMENSIONAL DATA FOR REPRODUCTION OF ATTRACTOR STRUCTURE IN N-DIMENSIONAL SYSTEM     

林振山  朱焰宇 《热带气象学报(英文版)》1997,3(1):105-112

Illustrated with the Rossler and Lorenz systems, the topological structure is reproduced using univariable temporal series. The study shows that there are a number of principal vectors reproduced withone-dimensional temporal series,which reflect from a certain aspect the topological structure for the system attractors.  相似文献   

Multiple time scales in rainfall variability     

Subramaniam Moten 《Journal of Earth System Science》1993,102(1):249-263

Monthly rainfall data averaged over a selected number of stations in peninsular Malaysia with a long record was subjected to singular spectrum analysis to determine the different modes of fluctuations in the rainfall. The analysis highlights the presence of fluctuations in the QBO time scale to a very long term time scale of 18–5 years which is possibly linked to lunar tidal forcing. There is also evidence of the Malaysian rainfall responding to El-Nino Southern Oscillation. An oscillation with a 7 to 10 year cycle is also evident. The annual cycle as a regular periodic oscillation is well established by the SSA.  相似文献   

旋转地球流体的一个非线性奇异孤立波精确解     

李春雁 《地球物理学报》1990,33(3):336-342

本文求出了旋转地球流体的f平面浅水波方程组的一个非线性精确解.这是一个处处连续、分片光滑的凹形孤立波,在波谷处为一尖点（奇异点）,其移速比长波速度gh^1/2略小,为（1+a/h）（gh（1+a/h））^1/2,其中a<0.其水平尺度与水深几乎无关.  相似文献   

A techno-economic model for optimum regeneration of surface mined land     

Manas K. Mukhopadhyay  Indra N. Sinha 《Environmental Geology》2006,50(5):669-676

The recent global scenario in the mineral sector may be characterized by rising competitiveness, increasing production costs and a slump in market price. This has pushed the mineral sector in general and that in the developing countries in particular to a situation where the industry has a limited capacity to sustain unproductive costs. This, more often than not, results in a situation where the industry fails to ensure environmental safeguards during and after mineral extraction. The situation is conspicuous in the Indian coal mining industry where more than 73% production comes from surface operations. India has an ambitious power augmentation projection for the coming 10 years. A phenomenal increase in coal production is proposed from the power grade coalfields in India. One of the most likely fall-outs of land degradation due to mining in these areas would be significant reduction of agricultural and other important land-uses. Currently, backfilling costs are perceived as prohibitive and abandonment of land is the easy way out. This study attempts to provide mine planners with a mathematical model that distributes generated overburden at defined disposal options while ensuring maximization of backfilled land area at minimum direct and economic costs. Optimization has been accomplished by linear programming (LP) for optimum distribution of each year’s generated overburden. Previous year’s disposal quantity outputs are processed as one set of the inputs to the LP model for generation of current year’s disposal output. From various geo-mining inputs, site constants of the LP constraints are calculated. Arrived value of economic vectors, which guide the programming statement, decides the optimal overburden distribution in defined options. The case example (with model test run) indicates that overburden distribution is significantly sensitive to coal seam gradient. The model has universal applicability to cyclic system (shovel–dumper combination) of opencast mining of stratified deposits.  相似文献   

热带太平洋SST异常对IAP-9 LAGCM 年际变率影响的模拟   总被引：3，自引：0，他引：3  

薛洪斌  张铭  王业桂 《气象科学》2006,26(1):58-65

通过1960~1989年实测的热带太平洋(30.5°N~30.5°S,120°E~70°W)SST(热带太平洋区域以外用气候平均值)强迫AGCM得到的结果,以此来研究热带SST的变化对全球大气环流年际变化的影响。首先,我们分析了南方涛动,分别给出了Tahiti和Darwin海平面气压异常及赤道附近(-5°S~5°N)外逸长波辐射(OLR)时间演变,都能很好与观测相比较。然后,讨论了全球大气环流对热带SST的变化的响应,全球主要的遥相关型都能很好地再现。最后,通过奇异值分解(SVD)技术研究了热带SST与冬季北半球500 hPa位势高度主要的耦合型,模拟的相关型与NCEP再分析资料的相关型非常相似。  相似文献   

Singular spectrum analysis and forecasting of hydrological time series     

C.A.F. Marques  J.A. Ferreira  A. Rocha  J.M. Castanheira  P. Melo-Gonçalves  N. Vaz  J.M. Dias 《Physics and Chemistry of the Earth》2006,31(18):1172-1179

The singular spectrum analysis (SSA) technique is applied to some hydrological univariate time series to assess its ability to uncover important information from those series, and also its forecast skill. The SSA is carried out on annual precipitation, monthly runoff, and hourly water temperature time series. Information is obtained by extracting important components or, when possible, the whole signal from the time series. The extracted components are then subject to forecast by the SSA algorithm. It is illustrated the SSA ability to extract a slowly varying component (i.e. the trend) from the precipitation time series, the trend and oscillatory components from the runoff time series, and the whole signal from the water temperature time series. The SSA was also able to accurately forecast the extracted components of these time series.  相似文献   

A distributed water-heat coupled model for mountainous watershed of an inland river basin in Northwest China (III) using the outputs from Mesoscale model version 5     

Ren-sheng Chen  Yan-hong Gao  Shi-hua Lu  Er-si Kang  Xi-bin Ji  Zhi-hui Zhang  Yong Yang 《Environmental Geology》2007,53(4):763-768

The distributed water-heat coupled (DWHC) model is calibrated, with the help of the Mesoscale model version 5 (MM5), by calculating the daily precipitation, the daily average air temperature at the 2.0 m heights and the daily potential evaporation in Heihe mountainous watershed area and its vicinity (96.786°∼102.284°E, 37.328°∼40.601°N, 17 × 10⁴ km²), from February 11 to June 30, 2003. The MM5 model periodically ran every 10 days in 3 km × 3 km grid resolution with an integral time step of 3 s. In the MM5 model, many scheme or options are consulted or adopted, such as the Grell scheme cumulus parameterization method, the Dudhia option, the cloud-radiation scheme, MRF PBL option and the modified Oregon State University Land-surface model (OSULSM). According to the projection transform methods, the MM5 outputs are interpolated to the 1 km × 1 km grid in Alberts projection by using triangle-based cubic interpolation (Cubic) and nearest neighbor interpolation (Nearest) methods, with which the DWHC model shares the same method. The result shows that, when the Nearest method is used, the Nash-Sutcliffe equation value of the daily average runoff is 0.79, the balance error is −0.79% and the goodness of fit R ² value is 0.81. Meanwhile, when the Cubic method is used, the Nash-Sutcliffe equation value, the balance error and the R ² value are 0.79, −0.65% and 0.80, respectively. Though the runoff simulation result is not favorable, it is still better than that using measured data at the meteorological and hydrological stations; the latter has a Nash-Sutcliffe equation value of 0.61. The MM5-DWHC model results also show that runoff mainly occurs on land surfaces and from shallow soil layers. According to model calibration results, certain outputs of MM5 are singular to some extent and the DWHC model is very sensitive to the initial values.  相似文献   

奇异摄动问题UWMCB法的非古典估计     

姜雷 《中国海洋大学学报(自然科学版)》1994,(Z2)

用ＵＷＭＣＢ法对一维的对流扩散问题进行分析，指出：当以对流为主时，可得到非古典的局部收敛估计及一致收敛估计，证实ＵＷＭＣＢ法是一种精度较高的数值解方法．  相似文献