简介：

简介：调查土壤侵蚀的原因处于由于另外的因素的存在的自然条件是困难的。没有简化试验性的条件，当考虑象植被盖子，地形学，和降雨那样的因素时，与它的众多的参数学习土壤行为是困难的并且处于大多数条件不可能。模拟途径的应用程序因此是必要的简化原型。在这研究，象质地和前身那样的物理土壤因素的效果玷污潮湿，与土地斜坡一起，使用伊朗阴谋的一个降雨模拟器和土壤侵蚀并且植被盖子在Taleghan分水岭被评估，。为这个目的，89u，生产30min持续时间的24.5和32mm/h降雨紧张的120厘米降雨模拟器学习区域的一个普通条件，与95u的尺寸在土壤侵蚀阴谋上在144个地点被使用125厘米。阴谋有1220和2030%，不同土壤质地，不同先前的土壤潮湿，和媒介的斜坡课到差的植被盖子条件。为24.5和32mm/h降雨紧张，沉积收益有高关联，这被发现?0.771并且?0.796分别地与植被盖子和与土地的0.045和0.029的细微关联倾斜。为预言沉积收益的回归方程也为不同条件被开发。

简介：Inthisstudy,thepracticalmethodologiesaredescribedforthedeterminationofthefactorsfortheselfabsorptioneffect(Fs),spectralinterferences(Fcsi),andtruecoincidencesummingeffects(Fcoi),whichareusedindirectgamma-spectrometricmeasurementofradionuclidessuchas210Pb,238U,234Th,226Ra,214Pb,228Ac,208Tl,214Bi,137Csand40Kinsamples.Tovalidatetheappliedmethods,certifiedreferencematerials(CRMs)oflakeandstreamsedimentsweremeasuredwithann-typeGermanium(Ge)detector-calibratedusingamultinuclidereferencesource.Thehighestself-absorptioncorrectionfactorsrangedfromFs1.44-2.10for46.5keVpeak(210Pb)andFs?1.25-1.60for63.3keVpeak(234Th)lyinginthelowenergyregionofthespectrum.Thesystematicinfluencewasobservedfor186.2keV(226Ra)peakduetospectralinterferenceswiththe235Ucontribution.Forthispeak,Fcsiischangedfrom0.921to0.955.Additionally,thepresentstudysuggeststhattruecoincidencesumming(TCS)effectsarenotdominant,exceptfor208Tland214BiforwhichFcoirangedfrom1.179to1.192anrangedfrom1.140to1.151,respectively.

简介：Theresponseofsedimentdischargeratetothefollowingfourecohydrologicalfactors:temperature,rainfall,evapotranspiration(ET),andstreamflowwasevaluatedbyconductingwaveletanalysisonLuergousmallcatchmentdatarangingfrom1982to2000.Forsedimentdischargerate,therewasanoveralltrendofreductionthatincludedaperiodicoscillationof6to7yearspercycle.Rainfallalsohadanoveralltrendofreductionthatincludedtwoperiodicoscillationsof7yearspercycleand2yearspercycle,respectively.Streamflowhadthesametrendasrainfallbuthadoneperiodicoscillationof6to7yearspercycle.Incontrastwithrainfallandstreamflow,thetrendsfortemperatureandETeachshowedanoverallincreasingtendency,andbothhadthesametwoperiodicoscillationsof6to7yearspercycleand4yearspercycle,respectively.Thesedimentdischargeratehadsignificantrelationshipswiththefourecohydrologicalfactors,withstreamflowandrainfallhavingpositivecorrelations,whileETandtemperaturehadnegativecorrelations.ThecorrelationbetweenETandsedimentdischargeratebecamestrongerwhenETwascomparedtothesedimentdischargerateofthefollowingyear.Therelationshipbetweensedimentdischargerateandthefourecohydrologicalfactorswasfurtherexpressedbythemulti-linearregressionmodelthatwasconstructed,whichmakessedimentdischargerateafunctionofstreamflow,rainfall,ET,andtemperature.

简介：TheperformanceofalinearresuspensionmodeldevelopedintheBalticSeawasstudiedintheconditionsofaeutrophicLakeKirkkoj(a|¨)rvi(southernFinland).Themodelpredictssedimentresuspensionrateusingdataonvegetationcover,windandsedimentqualityasaninput.Whentheoriginalmodelcoefficientswereused,themodelresultedonaverage1.8foldoverestimationoftheresuspensionrateinKirkkoj(a|¨)rvi.Thiswasduetolowerfetchandwaterdepth,andlessconsolidatedsedimentofKirkkoj(a|¨)rvicomparedwiththeBalticSeastudysite.WhencoefficientswereadjustedforKirkkoj(a|¨)rvi,themodelpredictionswere1.1timesthemeasuredvalues.Duetothecontinuousresuspension,theeffectofthewindterminthemodelwassolowthatitcouldbeexcludedwithoutaffectingtheaccuracyofmodelpredictions.Thestudydemonstratedthatinashalloweutrophiclakeaccuratepredictionsonresuspensionratecanbemadeusingonlydataonsedimentqualityandonfactorsinhibitingresuspension(macrophytes).Themodelresidualsincreasedwithincreasingresuspensionrateandhighratesofresuspensionwereunderestimatedbythemodel.DuetothefluffysedimentinKirkkoj(a|¨)rvi,erosionofsedimentincreasesmorethanlinearwithincreasingshearstress.Thusinsuchconditions,evenbetterpredictionscouldbeachievedbyanon-linearresuspensionmodel.

简介：在上面的黄河的Sanhuhekou-Toudaoguai活动范围的河床上的沉积免职搜索的年度变化从Sanhuhekou和Toudaoguai水文学车站基于流量和沉积运输观察在年1952-2010期间被调查。象水库操作，支流流入，以及来自Shidakongdui区域的流量和沉积负担那样的多重影响因素被分析。尽管沉积从主要来源，装载，结果显示出那特别自从2000年代，象象Qingshui河和Zuli河那样的在上游的支流一样的Shidakongdui区域由于提高的水土壤保存措施和植被盖子的改进减少了，学习活动范围通常仍然在累积沉积的地位。这主要由于Liujiaxia水库和Longyangxia水库的联合操作，它显著地在SanhuhekouCrosssection减少了年度流量和沉积负担。水库显著地也改变了学习活动范围的夏天洪水特征，导致变化从的年度流动曲线的形状一进一座双山峰单个山峰。这些引申严厉地减少了大量涌入产出超过90%沉积的夏天洪水季节的沉积运输能力装载，导致在水和沉积之间的一种失衡的关系。另外，SanhuhekouCrosssection的估计的到来的沉积系数从0.003到0.004kgs/m6作为不平的批评价值被建议决定scour或学习活动范围的免职地位的0.014kgs/m6,。