Progress of Geological Survey Using Airborne Hyperspectral Remote Sensing Data in the Gansu and Qinghai Regions

Hyperspectral remote sensing is now a frontier of the remote sensing technology. Airborne hyperspectral remote sensing data have hundreds of narrow bands to obtain complete and continuous ground-object spectra. Therefore, they can be effectively used to identify these grotmd objects which are difficult to discriminate by using wide-band data, and show much promise in geological survey. At the height of 1500 m, have 36 bands in visible to the CASI hyperspectral data near-infrared spectral range, with a spectral resolution of 19 nm and a space resolution of 0.9 m. The SASI data have 101 bands in the shortwave infrared spectral range, with a spectral resolution of 15 nm and a space resolution of 2.25 m. In 2010, China Geological Survey deployed an airborne CASI/SASI hyperspectral measurement project, and selected the Liuyuan and Fangshankou areas in the Beishan metallogenic belt of Gansu Province, and the Nachitai area of East Kunlun metallogenic belt in Qinghai Province to conduct geological survey. The work period of this project was three years.

Working in Remote Areas Services are scarce in mountainous regions

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Apparent diffusion coefficient evaluation for secondary changes in the cerebellum of rats after middle cerebral artery occlusion

Supratentorial cerebral infarction can cause functional inhibition of remote regions such as the cerebellum, which may be relevant to diaschisis. This phenomenon is often analyzed using positron emission tomography and single photon emission CT. However, these methods are expensive and radioactive. Thus, the present study quantified the changes of infarction core and remote regions after unilateral middle cerebral artery occlusion using apparent diffusion coefficient values. Diffu- sion-weighted imaging showed that the area of infarction core gradually increased to involve the cerebral cortex with increasing infarction time. Diffusion weighted imaging signals were initially in- creased and then stabilized by 24 hours. With increasing infarction time, the apparent diffusion co- efficient value in the infarction core and remote bilateral cerebellum both gradually decreased, and then slightly increased 3-24 hours after infarction. Apparent diffusion coefficient values at remote regions （cerebellum） varied along with the change of supratentorial infarction core, suggesting that the phenomenon of diaschisis existed at the remote regions. Thus, apparent diffusion coefficient values and diffusion weighted imaging can be used to detect early diaschisis.

Causal effects of shelter forests and water factors on desertification control during 2000–2010 at the Horqin Sandy Land region, China

The Horqin Sandy Land（HSL）, the largest sandy land in the semi-arid agro-pastoral ecotone of Northeast China, has been subject to desertification during the past century. In response, and to control the desertification,government implemented the Three-North Shelter/Protective Forest Program, world＇s largest ecological reforestation/afforestation restoration program. The program began in1978 and will continue for 75 years until 2050. Understanding the dynamics of desertification and its driving forces is a precondition for controlling desertification.However, there is little evidence to directly link causal effects with desertification process（i.e., on the changing area of sandy land） because desertification is a complex process,that can be affected by vegetation（including vegetation cover and extent of shelter forests） and water factors such as precipitation, surface soil moisture, and evapotranspiration.The objectives of this study were to identify how influencing factors, especially shelter forests, affected desertification in HSL over a recent decade. We used Landsat TM imagery analysis and path analysis to identify the effects of spatiotemporal changes in water and vegetation parameters during2000–2010. Desertification was controlled during the study period, as indicated by a decrease in desert area at a rate of163.3 km2year-1and an increase in the area with reduced intensity or extent of desertification. Total vegetation cover in HSL increased by 10.6 % during the study period and this factor exerted the greatest direct and indirect effects on slowing desertification. The contribution of total vegetation cover to controlling desertification increased with the intensity of desertification. On slightly and extremely severe desertified areas, vegetation cover contributed 5 and 42 % of the desertification reduction, respectively. There were significant correlations between total vegetation cover and water conditions（i.e., evapotranspiration and precipitation）and the area of shelter forests（P ／ 0.0001）, in which water conditions and the existence of shelter forests contributed49.7 and 12.8 % to total vegetation cover, respectively. The area of shelter forests increased sharply due to program efforts, but only shrub forests had significant direct effects on reducing the area of desertification categorized as slightly desertified. The reason for the lack of direct effect of increased arbor forests（accounting for 95.3 % of the total increase in shelter forests） on reducing desertification might be that the selected arbor species were not suited to water conditions（low precipitation, high evapotranspiration） prevailing at HSL. The establishment of shelter forests aided control of desertification in the HSL region, but the effect was less than expected. Effective control of desertification in the HSL region or other similar sandy areas will require greater improvements in vegetation cover. In particular,shrub species should be selected for plantation with reference to their potential to survive and reproduce in the harsh climatic and weather conditions typical of desertified areas.

Regional representation of glaciers in Chandra Basin region,western Himalaya,India

Hamtah and Chhota Shigri are two nearby,well monitored glaciers of western Himalaya,lying in the same climatic zone and driven by the same climatic conditions.In this study,topographical characteristics of both the glacier have been explored to understand the role of topography in controlling the glacier response.Further,their topographical characteristics and possible response towards climatic variations have been compared with each other and also with that of the other glaciers in the basin to find out the suitability of these two glaciers to be considered as representative of the region.Multi sensor and multi temporal remote sensing data have been used to carry out to fulfill the objectives.It is found that being in the same climatic zone,the mean accumulation area ratio of Chhota Shigri is 54%and Hamtah is 11%between 1980 and 2014.In comparison to Hamtah,Chhota Shigri glacier has a small upslope area,low compactness ratio indicating the ability of the glacier to receive direct precipitation and solar radiation.The analysis revealed that the Chhota Shigri glacier has a closer resemblance with the other glaciers in the region than Hamtah glacier.Also,the topographical settings of Chhota Shigri glacier are suitable for recording and reflecting year-to-year climatic variations.

Background levels of OCPs,PCBs,and PAHs in soils from the eastern Pamirs,China,an alpine region influenced by westerly atmospheric transport

Long-range atmospheric transport(LRAT)plays a crucial role in the occurrence of persis-tent organic pollutants(POPs)in remote regions.When studying the LRAT of POPs on the Tibetan Plateau,westerly-controlled regions have received insufficient attention compared with regions influenced by the Indian monsoon or air flow from East Asia.We investigated the residual levels of POPs in soils from the eastern Pamirs and used air backward trajectory analysis to elucidate the influence of potential source regions via LRAT.Organochlorine pes-ticides(OCPs,mainly comprising DDTs,HCHs,and HCB),polychlorinated biphenyls(PCBs,mainly comprising penta-and hexa-CBs),and polycyclic aromatic hydrocarbons(PAHs,mainly comprising three-and four-ring)were detected at low concentrations of 40-1000,<MDL-88,and 2100-34,000 pg/g,respectively.We elucidated three major geographical dis-tribution patterns of POPs,which were influenced by(1)the distribution of total organic carbon and black carbon in soil,(2)historical use of pesticides in the Tarim Basin,and(3)continuous emissions.Central Asia and the Tarim Basin were major potential source regions of POPs reaching the eastern Pamirs via LRAT.Historical use of technical HCH or lindane and technical DDT in potential source regions may contribute to the accumulation of HCHs and DDTs in the eastern Pamirs,respectively.Local sources seem to play a more important role in the occurrence of PAHs in the study area.By being under the control of less contaminated westerly air flow,the eastern Pamirs are more pristine than the core of the Tibetan Plateau where the Indian and East Asia monsoons deliver contaminants from highly industrialized areas in East China and India.

Estimation model of winter wheat disease based on meteorological factors and spectral information

Wheat scab(WS,Fusarium head blight),one of the most severe diseases of winter wheat in Yangtze-Huaihe river region,whose monitoring and timely forecasting at large scale would help to optimize pesticide spraying and achieve the purpose of reducing yield loss.In the present study,remote sensing monitoring on WS was conducted in 4 counties in Yangtze-Huaihe river region.Sensitive factors of WS were selected to establish the remote sensing estimation model of winter wheat scab index(WSI)based on interactions between spectral information and meteorological factors.The results showed that:1)Correlations between the daily average temperature(DAT)and daily average relative humidity(DAH)at different time scales and WSI were significant.2)There were positive linear correlations between winter wheat biomass,leaf area index(LAI),leaf chlorophyll content(LCC)and WSI.3)NDVI(normalized difference vegetation index),RVI(ratio vegetation index)and DVI(difference vegetation index)which had a good correlation with LAI,biomass and LCC,respectively,and could be used to replace them in modeling.4)The estimated values of the model were consistent with the measured values(RMSE=5.3%,estimation accuracy=90.46%).Estimation results showed that the model could efficiently estimate WS in Yangtze-Huaihe river region.