共查询到20条相似文献，搜索用时 15 毫秒
1.
Application of meteorological and vegetation indices for evaluation of drought impact: a case study for Rajasthan, India 总被引：3，自引：1，他引：2
Drought is a serious climatic condition that affects nearly all climatic zones worldwide, with semi-arid regions being especially
susceptible to drought conditions because of their low annual precipitation and sensitivity to climate changes. Drought indices
such as the standardized precipitation index (SPI) using meteorological data and vegetation indices from satellite data were
developed for quantifying drought conditions. Remote sensing of semi-arid vegetation can provide vegetation indices which
can be used to link drought conditions when correlated with various meteorological data based drought indices. The present
study was carried out for drought monitoring for three districts namely Bhilwara, Kota and Udaipur of Rajasthan state in India
using SPI, normalized difference vegetation index (NDVI), water supply vegetation index (WSVI) and vegetation condition index
(VCI) derived from the Advanced Very High resolution Radiometer (AVHRR). The SPI was computed at different time scales of
1, 2, 3, 6, 9 and 12 months using monthly rainfall data. The NDVI and WSVI were correlated to the SPI and it was observed
that for the three stations, the correlation coefficient was high for different time scales. Bhilwara district having the
best correlation for the 9-month time scale shows late response while Kota district having the best correlation for 1-month
shows fast response. On the basis of the SPI analysis, it was found that the area was worst affected by drought in the year
2002. This was validated on the basis of NDVI, WSVI and VCI. The study clearly shows that integrated analysis of ground measured
data and satellite data has a great potential in drought monitoring. 相似文献
2.
S. Isik 《Earth Science Informatics》2013,6(2):87-98
Estimations of annual suspended sediment loads are required for various types of water resources studies. Often estimation of the sediment load is needed for ungauged watersheds. Regionalization methods provide a practical solution to solve such problems. The purpose of this study is to classify suspended sediment yields in watersheds into homogeneous regions in order to identify their regional sediment rating curves. This study has been carried out for suspended sediment stations on 26 main basins of Turkey. Long term-scale suspended sediment rating curves of 115 gauging stations in Turkey were classified using cluster analysis on the basis of hydrological homogeneity. An agglomerative hierarchical clustering algorithm is used so that stations from different geographical locations are considered in the same cluster independently of their geographical location. 115 gauging stations were clustered into 4 different homogenous regions and the regional suspended sediment rating curve was developed for each region. The performance efficiencies of the developed regional rating curves were evaluated for 8 test stations and compared to the performances of rating curves in test sites. A regionalization model is developed for estimating suspended sediment rating curves for ungauged sites in Turkey. The developed regional rating curve models result in very close performances to those of their corresponding site rating curves. 相似文献
3.
大型灌区陆地水循环模式的参数化方案:LWCMPS_ID 总被引：2，自引：0，他引：2
地表水系统、地下水系统和土壤植物大气连续体的强烈耦合作用是大型灌区水文过程的基本特点,这导致对大型灌区的陆地水循环和水资源进行评价必须采取综合的方法,然而目前还缺少适用的模拟工具。农业灌区的水文特征与天然流域存在显著差别,常规流域水文模型和陆面过程参数化方案用于大型灌区陆地水循环的分析还存在较大的困难。LWCMPS_ID是本文提出的一个适用于大型灌区陆地水循环模式的参数化方案,采用分块集中参数模型简明地实现了地表水、地下水和土壤水的动力学耦合分析,并且包含了一个土壤水冻结融化的简化模型。对处在黄河流域的内蒙古河套灌区,用LWCMPS_ID进行20 年水文动态的模拟,取得了较好的效果。 相似文献
4.
溜河地区金矿找矿的遥感信息提取及研究 总被引：4，自引：3，他引：4
在对溜河地区TM及SPOT遥感信息处理的基础上，提取了区内与金矿成矿有关的线性构造、弧形构造、韧性剪切带构造、环形构造及蚀变异常信息。这些成矿信息的复合部位为金矿成矿的有利环境。在区内划分出4处成矿远景区，通过野外验证发现两处金矿点，为溜河地区更深层次的金矿找矿提供了重要依据。 相似文献
5.
BassamFAIBassam 《中国地质大学学报(英文版)》2003,14(3):283-292
Gengma region, Sanjiang district is known to have some large-scale gold deposits. GIS predictive model for hydroghermal gold potential was carried out in this region using weights of evidence modeling technique. Datasets used include large-scale hydroghermal gold deposit records, geological, geophysical and remote sensing imagery. Based on the geological and mineral characteristics of areas with known gold occurrences in Sanjiang, several geological features were thought to be indicative of areas with potential for the occurrence of hydroghtermal gold deposits. Indicative features were extracted from geoexploration datasets for use as input in the predictive model. The features include host rock lithology, geologic structures, wallrock alteration and associated (volcanic-plutonic) igneous rocks. To determine which of the indicative geological features are important spatial predictors of area with potential for gold deposits, spatial analysis was done through the modeling method. The input maps were buffered and the optimum distance of spatial association for each geological feature was determined by calculating the contrast and studentized contrast. Five feature maps were converted to binary predictor patterns and used as evidential layers for predictive modeling. The binary patterns were integrated in two combinations, each of which consists of four patterns in order to avoid over prediction due to the effect of duplicate features in the two structural evidences. The two produced potential maps define almost similar favorable zones. Areas of intersections between these zones in the two potential maps placed the highest predictive favorable zones in the region. 相似文献
6.
辽西建平北部金矿床和矿点分布集中 ,具有利成矿条件。通过对该区TM图像的遥感地质解译 ,提取了线性构造、环形构造及韧性剪切带构造信息 ;利用波段比值及主成分分析等数字图像处理方法 ,对区内重点地段进行金矿化蚀变信息提取处理 ,蚀变异常在图像上以彩色晕圈显示。研究表明 ,区内线环构造、韧性剪切带构造及蚀变异常发育的复合部位 ,是金矿成矿的有利地段。根据对本区金矿成矿条件的综合分析 ,在区内圈出了 3处金矿成矿预测区 ,并在野外验证中发现 3处金矿点 ,取得了较好的找矿效果。 相似文献
7.
成熟勘探的矿集区非常有必要开展新一轮的找矿，但矿床模式的局限和大埋藏深度等困难制约了这些地区的预测性找矿发现。促进其预测性找矿发现的关键战略包括：勘查模型的创新、勘查技术的创新和各种信息的综合集成预测。勘查模型的创新必须包含基于地球动力学剖析的新成矿概念，动力学数值模拟是有效的创新手段之一；勘查技术创新的主要目的是加大探测深度和提高探测与解释的准确性，必须以详细可靠的地质资料为基础；综合信息集成是利用GIS和知识驱动及数据驱动的方法充分提取各种数据中的有用信息，集成为更加可靠的预测图。在这种思想的指导下，我们在铜陵凤凰山矿田进行了预测和勘查，并成功地发现了深部的隐伏矿床。 相似文献
8.
东北半干旱地区流域分布式水文模拟——以洮儿河流域为例 总被引：1，自引：0，他引：1
以东北半干旱地区典型流域-洮儿河流域为研究对象,应用SWAT模型对流域水文过程进行了模拟研究;选择流域上游子流域和中下游子流域分别进行参数敏感性分析,识别出影响模拟结果的敏感参数,研究发现部分参数敏感性存在空间变异性,分析主要原因在于气候和下垫面的空间异质性导致了流域上下游产流模式存在差异。采用1988-1997年水文气象数据进行模型率定和验证,结果表明：干流水文站月流量过程率定期Nash-Sutcliffe 效率系数平均值为0.78,验证期为0.72,相关系数都达到0.86以上,水量误差大多在20%以内,对日过程的模拟也有较高的精度;枯水年模拟结果较差,主要是因为流域降水站数量不够,难以反映降水的时空分布。对于水文、气象等资料相对缺乏的东北半干旱地区,SWAT模型的模拟结果总体令人满意,可以应用于与流域径流相关的各种模拟分析,研究成果对进一步加强洮儿河流域水资源综合管理提供了依据和手段。 相似文献
9.
Regional climate model (RCM) outputs are often used in hydrological modeling, in particular for streamflow forecasting. The heterogeneity of the meteorological variables such as precipitation, temperature, wind speed and solar radiation often limits the ability of the hydrological model performance. This paper assessed the sensitivity of RCM outputs from the PRUDENCE project and their performance in reproducing the streamflow. The soil and water assessment tool was used to simulate the streamflow of the Rhone River watershed located in the southwestern part of Switzerland, with the climate variables obtained from four RCMs. We analyzed the difference in magnitude of precipitation, maximum and minimum air temperature, and wind speed with respect to the observed values from the meteorological stations. In addition, we also focused on the impact of the grid resolution on model performance, by analyzing grids with resolutions of 50 × 50 and 25 × 25 km2. The variability of the meteorological inputs from various RCMs is quite severe in the studied watershed. Among the four different RCMs, the Danish Meteorological Institute provided the best performance when simulating runoff. We found that temperature lapse rate is significantly important in the mountainous snow and glacier dominated watershed as compared to other variables like precipitation, and wind speed for hydrological performance. Therefore, emphasis should be given to minimum and maximum temperature in the bias correction studies for downscaling climatic data for impact modeling in the mountainous snow and glacier dominated complex watersheds. 相似文献
10.
甘肃黄土高原土壤水分气候特征 总被引：13，自引：0，他引：13
利用甘肃黄土高原42个气象站1961—2000年3～7月降水量和11个农业气象观测站逐年3～11月上旬的土壤重量含水率资料，分析了甘肃黄土高原土壤水分的地域和时间分布特征。结果表明：①甘肃黄土高原土壤水分从西南向东北减少，中部有一条从北向南的干舌，干旱中心在陇中北部，受六盘山的影响较大；②甘肃黄土高原分为7个气候区：陇中、陇东土壤严重缺水区，陇中、陇东土壤季节性缺水区，土壤水分适宜区，土壤水分湿润区和甘南高原土壤水分湿润区；③陇中北部和陇东北部土壤严重缺水区浅层土壤严重缺水主要出现在春季和春末夏初，深层土壤也常年处于缺水状态。季节土壤缺水区浅层主要缺水在5、6月份，深层土壤水分陇东高于陇中，适宜区和湿润区无明显土壤缺水时段。 相似文献
11.
0-1混沌测试方法是一种新的可直接作用于时间序列的混沌识别方法,不需要进行相空间重构,通过对Chebyshev映射的检验验证了有效性。运用0-1方法对中国640个气象站1960-2011年月降水序列进行混沌识别,并运用基于密度的顾及非空间属性的空间聚类方法（DBSC）对计算结果进行空间聚类。结果表明,各气象站月降水序列均表现出明显的混沌特性,且K值的空间分布具有明显的分区特征：从大尺度上看,全国可分为西北高值区、南方次高区、华北-东北中值区和青藏低值区;从小尺度上看,全国分出了29个空间簇。中国降水混沌空间聚类结果不仅与大尺度的气候类型分布相吻合,而且也反映了局部降水动力系统变化特征,这就为降水系统的时空规律研究提供了一条新的途径和方法。 相似文献
12.
Precipitation forecasting using classification and regression trees (CART) model: a comparative study of different approaches 总被引：2，自引：0，他引：2
Bahram Choubin Gholamreza Zehtabian Ali Azareh Elham Rafiei-Sardooi Farzaneh Sajedi-Hosseini Özgür Kişi 《Environmental Earth Sciences》2018,77(8):314
Interest in semiarid climate forecasting has prominently grown due to risks associated with above average levels of precipitation amount. Longer-lead forecasts in semiarid watersheds are difficult to make due to short-term extremes and data scarcity. The current research is a new application of classification and regression trees (CART) model, which is rule-based algorithm, for prediction of the precipitation over a highly complex semiarid climate system using climate signals. We also aimed to compare the accuracy of the CART model with two most commonly applied models including time series modeling (ARIMA), and adaptive neuro-fuzzy inference system (ANFIS) for prediction of the precipitation. Various combinations of large-scale climate signals were considered as inputs. The results indicated that the CART model had a better results (with Nash–Sutcliffe efficiency, NSE?>?0.75) compared to the ANFIS and ARIMA in forecasting precipitation. Also, the results demonstrated that the ANFIS method can predict the precipitation values more accurately than the time series model based on various performance criteria. Further, fall forecasts ranked “very good” for the CART method, while the ANFIS and the time series model approximately indicated “satisfactory” and “unsatisfactory” performances for all stations, respectively. The forecasts from the CART approach can be helpful and critical for decision makers when precipitation forecast heralds a prolonged drought or flash flood. 相似文献
13.
Bagher Shirmohammadi Hamidreza Moradi Vahid Moosavi Majid Taie Semiromi Ali Zeinali 《Natural Hazards》2013,69(1):389-402
Drought is accounted as one of the most natural hazards. Studying on drought is important for designing and managing of water resources systems. This research is carried out to evaluate the ability of Wavelet-ANN and adaptive neuro-fuzzy inference system (ANFIS) techniques for meteorological drought forecasting in southeastern part of East Azerbaijan province, Iran. The Wavelet-ANN and ANFIS models were first trained using the observed data recorded from 1952 to 1992 and then used to predict meteorological drought over the test period extending from 1992 to 2011. The performances of the different models were evaluated by comparing the corresponding values of root mean squared error coefficient of determination (R 2) and Nash–Sutcliffe model efficiency coefficient. In this study, more than 1,000 model structures including artificial neural network (ANN), adaptive neural-fuzzy inference system (ANFIS) and Wavelet-ANN models were tested in order to assess their ability to forecast the meteorological drought for one, two, and three time steps (6 months) ahead. It was demonstrated that wavelet transform can improve meteorological drought modeling. It was also shown that ANFIS models provided more accurate predictions than ANN models. This study confirmed that the optimum number of neurons in the hidden layer could not be always determined using specific formulas; hence, it should be determined using a trial-and-error method. Also, decomposition level in wavelet transform should be delineated according to the periodicity and seasonality of data series. The order of models with regard to their accuracy is as following: Wavelet-ANFIS, Wavelet-ANN, ANFIS, and ANN, respectively. To the best of our knowledge, no research has been published that explores coupling wavelet analysis with ANFIS for meteorological drought and no research has tested the efficiency of these models to forecast the meteorological drought in different time scales as of yet. 相似文献
14.
统计降尺度方法广泛应用于弥补大气环流模式(GCM)模拟区域气候变化能力较弱的不足。利用1960~2009年的NCEP/NCAR再分析资料和江淮流域52个站点降水观测资料,通过敏感性分析,针对4个季节分别选择10个大尺度预测因子,采用主成分分析(PCA)和支持向量机(SVM)相结合的方法,建立了江淮流域降水统计降尺度模型。检验结果表明,该模型获取的江淮流域降水的偏差显著减小,能够描述降水在月、年尺度的变化,适用于HadCM3输出的大尺度气候场,具有预测未来降水变化的能力。将统计降尺度模型应用于HadCM3在A2情景下输出的2020~2099年大尺度预测因子,分3个时段:2020~2039年,2050~2069年和2080~2099年,从年和季节两个时间尺度分析江淮流域未来降水变化。结果表明,相对1960~1999年,未来3个时段的降水有小幅增加,其中2080~2099年增幅最大,为3.6 mm;在未来3个时段的不同季节,降水变化呈现出不同特征。 相似文献
15.
P Guhathakurta Preetha Menon P M Inkane Usha Krishnan S T Sable 《Journal of Earth System Science》2017,126(8):120
Meteorological drought during the southwest monsoon season and for the northeast monsoon season over five meteorological subdivisions of India for the period 1901–2015 has been examined using district and all India standardized precipitation index (SPI). Whenever all India southwest monsoon rainfall was less than ?10% or below normal, for those years all India SPI was found as ?1 or less. Composite analysis of SPI for the below normal years, viz., less than ?15% and ?20% of normal rainfall years indicate that during those years more than 30% of country’s area was under drought condition, whenever all India southwest monsoon rainfall was –15% or less than normal. Trend analysis of monthly SPI for the monsoon months identified the districts experiencing significant increase in drought occurrences. Significant positive correlation has been found with the meteorological drought over most of the districts of central, northern and peninsular India, while negative correlation was seen over the districts of eastern India with NINO 3.4 SST. For the first time, meteorological drought analysis over districts and its association with equatorial pacific SST and probability analysis has been done for the northeast monsoon over the affected regions of south peninsular India. Temporal correlation of all India southwest monsoon SPI and south peninsular India northeast monsoon SPI has been done with the global SST to identify the teleconnection of drought in India with global parameters. 相似文献
16.
我国水文情报预报工作的主要成就及展望 总被引：2，自引：2，他引：0
新中国成立５０年来,水文情报预报工作取得了成就,在水情信息采集和传输方面,全国已有水文报汛站８０００余处,在２５处重点防洪河段和１５０座大型水库上建立了水文自动测报系统,共计有遥测站近２０００个,已有２２个省（市,区）和７个流域管理机构的水情部门通过计算机广域网互传水情信息。在水文预报技术方面,开发研制了适合中国特色的许多水文模型。随着计算机的广泛应用,水利信息中心初步建立了水雨情信息服务系统,包 相似文献
17.
The Random Forests (RF) algorithm has recently become a fledgling method for data-driven predictive mapping of mineral prospectivity, and so it is instructive to further study its efficacy in this particular field. This study, carried out using Baguio gold district (Philippines), examines (a) the sensitivity of the RF algorithm to different sets of deposit and non-deposit locations as training data and (b) the performance of RF modeling compared to established methods for data-driven predictive mapping of mineral prospectivity. We found that RF modeling with different training sets of deposit/non-deposit locations is stable and reproducible, and it accurately captures the spatial relationships between the predictor variables and the training deposit/non-deposit locations. For data-driven predictive mapping of epithermal Au prospectivity in the Baguio district, we found that (a) the success-rates of RF modeling are superior to those of weights-of-evidence, evidential belief and logistic regression modeling and (b) the prediction-rate of RF modeling is superior to that of weights-of-evidence modeling but approximately equal to those of evidential belief and logistic regression modeling. Therefore, the RF algorithm is potentially much more useful than existing methods that are currently used for data-driven predictive mapping of mineral prospectivity. However, further testing of the method in other areas is needed to fully explore its usefulness in data-driven predictive mapping of mineral prospectivity. 相似文献
18.
青藏高原表土孢粉定量重建的气候参数探讨 总被引：1，自引：0，他引：1
孢粉在古环境研究中具有重要价值,尤其是在重建古气候方面,既可以定性地恢复过去的植被类型变化,也能定量地重建气候变化规律,是古气候研究中最常用、较可靠和较成熟的环境代用指标。现代类比法是探讨表土孢粉与气候定量关系的方法之一,适用性较为广泛。本文利用青藏高原及其毗邻地区495个现代表土样点的孢粉谱,及现代气象站点器测资料,采用现代类比法得到气候参数的模拟值,并分析模拟值与气候参数观测值之间的关系。结果表明:相关性最高的气候因子是年均降水(r=0.894),其次为年均相对湿度(r=0.863)和年均蒸发量(r=0.801),最低的是干燥度(r=0.18)。因此在重建古气候时降水的可信度较高,相对湿度和蒸发量也具有一定的可信度。并选用相关性较好的年均降水指标,分析其与11个孢粉类型之间的相关性,然后将相关性较高的孢粉组合与降水之间建立孢粉-气候函数模型,用以重建该地区过去气候变化。 相似文献
19.
The quantification of energy interactions among land surface, atmosphere, and surface vegetation is significant to comprehend the hydrological cycle in montane watersheds. Moreover, elevation change is an essential in causing variations in energy fluxes. Thus, estimating the major components of energy interactions is essential for better understanding of the hydrological process. The advanced land surface models (LSMs); the common land model (CLM) and variables infiltration capacity (VIC) are used to estimate accurate hydrometeorological variables. These hydrometeorological variables such as net radiation and sensible, latent, and ground heat fluxes were estimated using CLM and VIC at upper and lower meteorological stations in Sierra Nevada Mountain, California, USA. The estimated fluxes were compared with observations at each site. The estimated daily and monthly net radiation and sensible heat flux from both models showed good agreement with the observations (R ≥ 0.84). The CLM-modeled estimates showed lower trends during the rainfall periods, which occurred mainly during winter at both sites. In comparison, the estimated daily and monthly latent heat flux from CLM at both sites showed better results with lower RMSE and bias than that from VIC, which underestimated latent heat flux. Both models overestimated ground heat flux, and the variation trend was similar to observation. For sensitivity analysis, according to elevation change, all the estimated energy fluxes had slightly different values at the upper and lower met stations. In future studies, parameterization for the LSMs will be conducted for more robust estimations of hydrometeorological variables in montane watersheds. 相似文献
20.
选用标准化降水指数作为气象干旱指标,通过引入多标度分形理论,运用乘法级联模型,以吉林西部6个气象站点1957年1月-2010年10月的月降水量数据为基础,对吉林西部气象干旱的多标度性质进行分析。研究结果表明,吉林西部气象干旱的发生在时间尺度上均具有多标度分形特征,但在不同站点多标度分形的强度不同,表现出一定的空间差异性。其强弱次序为：长岭<通榆<白城<前郭<扶余<乾安。 相似文献