Climate Characteristics of the CWB Global Forecast System: Hydrological Processes and Atmospheric Circulation

This study presents the preliminary magnetic results from analyses ofthe Quaternary red-soils and the fine grain sediments within the underlyingconglomerate bed of the Linkou Terrace in northern Taiwan.Magnetic susceptibility measurements indicate that the fine grain sedimentstaken from the conglomerate bed have extremely low susceptibilitiesrelative to those of the red-soils.This phenomenon suggests that the sourceof the red-soil probably did not originate from the weathering of the conglomeratebed.From both paleomagnetic and rock magnetic results,it isthought that the red-soil bed was deposited during the period between theJaramillo normal event and the Brunhes normal epoch,or later.Stratigraphic variations of magnetic susceptibility of the red-soilsamples before and after CBD(citrate-bicarbonate-dithionite)treatmentshow the same trend:the lower part of the red-soil bed has values abouttwo times higher than those of the upper part.In addition,susceptibility ofthe upper part after CBD treatment has been reduced by more than 60%,but that of the lower part only has been reduced by less than 40%.It isknown that CBD treatment can resolve hematite,goethite and ultra finegrainedmagnetite.So,the results of this study might suggest that the upperpart has much more soil development and lateritization than the lower part.Furthermore,the major(and possibly the original)magnetic mineral ofthe red-soil is magnetite.In the area neighboring the Linkou Terrace to the north,there was alot of volcanic activity during the early Quaternary.Magnetite has beenidentified as the major magnetic mineral of the volcanic rocks.Thus,it isproposed that the source of the red-soil bed in the Linkou area developed,at least partly,from the volcanic rocks.In addition,the boundary betweenthe two groups,with distinct very different magnetic susceptibilities,mightbe used as an indicator for stratigraphic correlation in the study area.

並列關鍵字

Climate Characteristics ； Global Forecast System ； Control Simulation ； Hydrological Processes ； Atmospheric Circulation

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