Typica Geomorphic Extraction In Karst Basin Based On Multi-source Information

Yanrong landform also known as Karst, formed by surface landform andunderground landform. In southern China distributes a large number of karst landform,due to the formation of karst landform always inseparable from the water which candissolve karst limestone, so the karst landform often gathered in a river basin. Thispaper according to the Changhe River basin in Jiangxi province which belong toRuichang-Pengze karst development zone as the study area, by multi-sourceinformation to seek the distribution rule of karst landform, the target is that throughthis study which can provide the scientific methods to a wide range of exploring karstlandform in the future.Firstly, using the GIS method to hydrological analysis based on DEM data in theChanghe River basin, extract river network information of the basin, compares theextraction of river network with the river network information which get by artificialfield on-the-spot investigation, after comparing found that they are approximatelycoincidence, at the same time,there are small difference, main is the river networkwhich extract by the software is connectivity, but the river network which extract byartificial field investigation in some places appear cutoff, in the meantime, not faraway from the cutoff there will be short river, combine there belong toRuichang-Pengze karst development zone in Jiangxi,suggesting the region is likely toexist underground river.Secondly extract geomorphic information by remote sensing images. On the onehand, extract the surface temperature in the Changhe River basin through the thermalinfrared band of Landsat-7image data in September14,2000, search abnormaltemperature area, eliminate interference of the mountain slope, water, lakes and otherfactors, combining the field survey data, infer the surface karst landform is most likelyto distribution in the surface temperature of27degrees Celsius to32degrees Celsius.On the other hand, through Landsat-8image data in July24,2013, afterpretreatment, according the vegetation luxuriant degree of the earth’s surface tosupervised classification, due to the karst landform surface water shortage andvegetation is sparse, extraction of the distribution of the surface karst landform.Integrated surface temperature information and supervised classification information,finally get surface karst landform distribution range of Changhe River basin. Finally, make use of the typical karst landform information which get by the fieldinvestigation of the Changhe River in July2013and April2014, verify and correct thedistribution range of karst landform in the Changhe River basin. As a result,underground river distribution area which extract by the river network and surfacekarst landform area which extract by supervised classification, degree of accuracyboth very high. but extract the surface temperature in the Changhe River basinthrough the thermal infrared band to identify the distribution of the aven location isdifficult, may be by the interference of image resolution and all kinds of landform. Inaddition, according to field investigation and supervised classification information, byreflecting dry and wet conditions of land surface, miscanthus has great instructionsignificance to karst landform.