Seasonal snow cover is a key global climate and hydrological system component drawing considerable attention due to glob-al warming conditions.However,the spatiotemporal snow cover patterns are challenging in western ...Seasonal snow cover is a key global climate and hydrological system component drawing considerable attention due to glob-al warming conditions.However,the spatiotemporal snow cover patterns are challenging in western Jilin,China due to natural condi-tions and sparse observation.Hence,this study investigated the spatiotemporal patterns of snow cover using fine-resolution passive mi-crowave(PMW)snow depth(SD)data from 1987 to 2018,and revealed the potential influence of climate factors on SD variations.The results indicated that the interannual range of SD was between 2.90 cm and 9.60 cm during the snowy winter seasons and the annual mean SD showed a slightly increasing trend(P>0.05)at a rate of 0.009 cm/yr.In snowmelt periods,the snow cover contributed to an increase in volumetric soil water,and the change in SD was significantly affected by air temperature.The correlation between SD and air temperature was negative,while the correlation between SD and precipitation was positive during December and March.In March,the correlation coefficient exceeded 0.5 in Zhenlai,Da’an,Qianan,and Qianguo counties.However,the SD and precipitation were neg-atively correlated over western Jilin in October,and several subregions presented a negative correlation between SD and precipitation in November and April.展开更多
Surface roughness parameter is an important factor and obstacle for retrieving soil moisture in passive microwave remote sensing.Two statistical parameters,root mean square (RMS) height (s) and correlation length (l),...Surface roughness parameter is an important factor and obstacle for retrieving soil moisture in passive microwave remote sensing.Two statistical parameters,root mean square (RMS) height (s) and correlation length (l),are designed for describing the roughness of a randomly rough surface.The roughness parameter measured by traditional way is independence of frequency,soil moisture and soil heterogeneity and just the ″geometric″ roughness of random surface.This ″geometric″ roughness can not fully explain the scattered thermal radiation by the earth's surface.The relationship between ″geometric″ roughness and integrated roughness (contain both ″geometric″ roughness and ″dielectric″ roughness) is linked by empirical coefficient.In view of this problem,this paper presents a method for estimating integrated surface roughness from radiometer sampling data at different frequencies,which mainly based on the flourier relationship between power spectral density distribution and spatial autocorrelation function.We can obtain integrated surface roughness at different frequencies by this method.Besides "geometric" roughness,this integrated surface roughness not only contains "dielectric" roughness but also includes frequency dependence.Combined with Q/H model the polarization coupling coefficient can also be obtained for both H and V polarization.Meanwhile,the simulated numerical results show that radiometer with a sensitivity of 0.1 K can distinguish the different surface roughness and the change of roughness with frequency for the same rough surface.This confirms the feasibility of radiometer sampling method for estimating the surface roughness theoretically.This method overcomes the problem of ″dielectric″ roughness measurement to some extent and can achieve the integrated surface roughness within a microwave pixel which can serve soil moisture inversion better than the ″geometric″ roughness.展开更多
Spectral remote sensing technique is usually used to monitor flood and waterlogging disaster.Although spectral remote sensing data have many advantages for ground information observation,such as real time and high spa...Spectral remote sensing technique is usually used to monitor flood and waterlogging disaster.Although spectral remote sensing data have many advantages for ground information observation,such as real time and high spatial resolution,they are often interfered by clouds,haze and rain.As a result,it is very difficult to retrieve ground information from spectral remote sensing data under those conditions.Compared with spectral remote sensing tech-nique,passive microwave remote sensing technique has obvious superiority in most weather conditions.However,the main drawback of passive microwave remote sensing is the extreme low spatial resolution.Considering the wide ap-plication of the Advanced Microwave Scanning Radiometer-Earth Observing System(AMSR-E) data,an AMSR-E data unmixing method was proposed in this paper based on Bellerby's algorithm.By utilizing the surface type classifi-cation results with high spatial resolution,the proposed unmixing method can obtain the component brightness tem-perature and corresponding spatial position distribution,which effectively improve the spatial resolution of passive microwave remote sensing data.Through researching the AMSR-E unmixed data of Yongji County,Jilin Provinc,Northeast China after the worst flood and waterlogging disaster occurred on July 28,2010,the experimental results demonstrated that the AMSR-E unmixed data could effectively evaluate the flood and waterlogging disaster.展开更多
The important effects of snow cover to ground thermal decades. In the most of previous research, the effects were usually regime has received much attention of scholars during the past few evaluated through the numeri...The important effects of snow cover to ground thermal decades. In the most of previous research, the effects were usually regime has received much attention of scholars during the past few evaluated through the numerical models and many important results are found. However, less examples and insufficient data based on field measurements are available to show natural cases. In the present work, a typical case study in Mohe and Beijicun meteorological stations, which both are located in the most northern tip of China, is given to show the effects of snow cover on the ground thermal regime. The spatial （the ground profile） and time series analysis in the extremely snowy winter of 2012-2013 in Heilongjiang Province are also performed by contrast with those in the winter of 2011-2012 based on the measured data collected by 63 meteorological stations, Our results illustrate the positive （warmer） effect of snow cover on the ground temperature （GT） on the daily basis, the highest difference between GT and daily mean air temperature （DGAT） is as high as 32.35℃. Moreover, by the lag time analysis method it is found that the response time of GT from 0 cm to 20 cm ground depth to the alternate change of snow depth has 10 days lag, while at 40 cm depth the response of DGAT is not significant. This result is different from the previous research by modeling, in which the resnonse denth of ground to the alteration of snow depth is far more than 40 cm.展开更多
目的:分析经尿道输尿管镜碎石术(URL)、微创经皮肾镜取石术(MPCNL)、腹膜后腹腔镜输尿管切开取石术(RLU)三种微创术式治疗对嵌顿性输尿管上段结石患者肾功能、氧化应激、炎症因子水平的影响。方法:选取2014年3月-2017年3月收治的嵌顿性...目的:分析经尿道输尿管镜碎石术(URL)、微创经皮肾镜取石术(MPCNL)、腹膜后腹腔镜输尿管切开取石术(RLU)三种微创术式治疗对嵌顿性输尿管上段结石患者肾功能、氧化应激、炎症因子水平的影响。方法:选取2014年3月-2017年3月收治的嵌顿性输尿管上段结石患者120例,依据手术方法将其分为URL组(50例)、MPCNL组(40例)、RLU组(30例),比较三组结石清除率、手术一般情况及手术前后肾功能[血尿素氮(BUN)、血肌酐(SCr)、明胶酶相关脂质运载蛋白(NGAL)]、氧化应激[过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)、活性氧(ROS)]与炎症因子[肿瘤坏死因子-α(TNF-α)、C反应蛋白(CRP)]水平、并发症发生情况。结果:URL组结石清除率、手术时间、住院时间低/短于MPCNL组、RLU组,MPCNL组手术时间短于RLU组,住院时间长于RLU组(P<0.05);URL组术后3 d NGAL高于MPCNL组、RLU组(P<0.05),三组BUN、SCr比较差异无统计学意义(P>0.05);术后24 h三组CAT、GSH-Px均下降,而MDA、ROS、TNF-α、CRP水平均增加,且URL组术后GSH-Px高于MPCNL组、RLU组,而MDA、CRP低于MPCNL组、RLU组(P<0.05);Pearson相关性分析发现,三组术后CAT、GSH-Px与TNF-α、CRP均呈负相关,而MDA、ROS与TNF-α、CRP均呈正相关(P<0.05);三组术后并发症发生率比较差异无统计学意义(P>0.05)。结论:URL、MPCNL、RLU三种微创术式治疗嵌顿性输尿管上段结石疗效均可靠,各有优势,临床应根据患者情况进行选择。展开更多
基金Under the auspices of the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA28110502)Science and Technology Development Plan Project of Jilin Province(No.20220202035NC)+1 种基金National Natural Science Foundation of China(No.41871248)Changchun Science and Technology Development Plan Project(No.21ZY12)。
文摘Seasonal snow cover is a key global climate and hydrological system component drawing considerable attention due to glob-al warming conditions.However,the spatiotemporal snow cover patterns are challenging in western Jilin,China due to natural condi-tions and sparse observation.Hence,this study investigated the spatiotemporal patterns of snow cover using fine-resolution passive mi-crowave(PMW)snow depth(SD)data from 1987 to 2018,and revealed the potential influence of climate factors on SD variations.The results indicated that the interannual range of SD was between 2.90 cm and 9.60 cm during the snowy winter seasons and the annual mean SD showed a slightly increasing trend(P>0.05)at a rate of 0.009 cm/yr.In snowmelt periods,the snow cover contributed to an increase in volumetric soil water,and the change in SD was significantly affected by air temperature.The correlation between SD and air temperature was negative,while the correlation between SD and precipitation was positive during December and March.In March,the correlation coefficient exceeded 0.5 in Zhenlai,Da’an,Qianan,and Qianguo counties.However,the SD and precipitation were neg-atively correlated over western Jilin in October,and several subregions presented a negative correlation between SD and precipitation in November and April.
基金Under the auspices of the Key Direction in Knowledge Innovation Programs of Chinese Academy of Sciences (No. KZCX2-YW-340)
文摘Surface roughness parameter is an important factor and obstacle for retrieving soil moisture in passive microwave remote sensing.Two statistical parameters,root mean square (RMS) height (s) and correlation length (l),are designed for describing the roughness of a randomly rough surface.The roughness parameter measured by traditional way is independence of frequency,soil moisture and soil heterogeneity and just the ″geometric″ roughness of random surface.This ″geometric″ roughness can not fully explain the scattered thermal radiation by the earth's surface.The relationship between ″geometric″ roughness and integrated roughness (contain both ″geometric″ roughness and ″dielectric″ roughness) is linked by empirical coefficient.In view of this problem,this paper presents a method for estimating integrated surface roughness from radiometer sampling data at different frequencies,which mainly based on the flourier relationship between power spectral density distribution and spatial autocorrelation function.We can obtain integrated surface roughness at different frequencies by this method.Besides "geometric" roughness,this integrated surface roughness not only contains "dielectric" roughness but also includes frequency dependence.Combined with Q/H model the polarization coupling coefficient can also be obtained for both H and V polarization.Meanwhile,the simulated numerical results show that radiometer with a sensitivity of 0.1 K can distinguish the different surface roughness and the change of roughness with frequency for the same rough surface.This confirms the feasibility of radiometer sampling method for estimating the surface roughness theoretically.This method overcomes the problem of ″dielectric″ roughness measurement to some extent and can achieve the integrated surface roughness within a microwave pixel which can serve soil moisture inversion better than the ″geometric″ roughness.
基金Under the auspices of National Natural Science Foundation of China (No. 40971189)Knowledge Innovation Programs of Chinese Academy of Sciences (No. KZCX2-YW-340)China Postdoctoral Science Foundation (No. 20100471276)
文摘Spectral remote sensing technique is usually used to monitor flood and waterlogging disaster.Although spectral remote sensing data have many advantages for ground information observation,such as real time and high spatial resolution,they are often interfered by clouds,haze and rain.As a result,it is very difficult to retrieve ground information from spectral remote sensing data under those conditions.Compared with spectral remote sensing tech-nique,passive microwave remote sensing technique has obvious superiority in most weather conditions.However,the main drawback of passive microwave remote sensing is the extreme low spatial resolution.Considering the wide ap-plication of the Advanced Microwave Scanning Radiometer-Earth Observing System(AMSR-E) data,an AMSR-E data unmixing method was proposed in this paper based on Bellerby's algorithm.By utilizing the surface type classifi-cation results with high spatial resolution,the proposed unmixing method can obtain the component brightness tem-perature and corresponding spatial position distribution,which effectively improve the spatial resolution of passive microwave remote sensing data.Through researching the AMSR-E unmixed data of Yongji County,Jilin Provinc,Northeast China after the worst flood and waterlogging disaster occurred on July 28,2010,the experimental results demonstrated that the AMSR-E unmixed data could effectively evaluate the flood and waterlogging disaster.
基金Under the auspices of National Natural Science Foundation of China(No.41471289,41301368)Natural Science Foundation of Jilin Province(No.20140101158JC)Foundation of State Key Laboratory of Remote Sensing Science(No.OFSLRSS201517)
文摘The important effects of snow cover to ground thermal decades. In the most of previous research, the effects were usually regime has received much attention of scholars during the past few evaluated through the numerical models and many important results are found. However, less examples and insufficient data based on field measurements are available to show natural cases. In the present work, a typical case study in Mohe and Beijicun meteorological stations, which both are located in the most northern tip of China, is given to show the effects of snow cover on the ground thermal regime. The spatial （the ground profile） and time series analysis in the extremely snowy winter of 2012-2013 in Heilongjiang Province are also performed by contrast with those in the winter of 2011-2012 based on the measured data collected by 63 meteorological stations, Our results illustrate the positive （warmer） effect of snow cover on the ground temperature （GT） on the daily basis, the highest difference between GT and daily mean air temperature （DGAT） is as high as 32.35℃. Moreover, by the lag time analysis method it is found that the response time of GT from 0 cm to 20 cm ground depth to the alternate change of snow depth has 10 days lag, while at 40 cm depth the response of DGAT is not significant. This result is different from the previous research by modeling, in which the resnonse denth of ground to the alteration of snow depth is far more than 40 cm.
文摘目的:分析经尿道输尿管镜碎石术(URL)、微创经皮肾镜取石术(MPCNL)、腹膜后腹腔镜输尿管切开取石术(RLU)三种微创术式治疗对嵌顿性输尿管上段结石患者肾功能、氧化应激、炎症因子水平的影响。方法:选取2014年3月-2017年3月收治的嵌顿性输尿管上段结石患者120例,依据手术方法将其分为URL组(50例)、MPCNL组(40例)、RLU组(30例),比较三组结石清除率、手术一般情况及手术前后肾功能[血尿素氮(BUN)、血肌酐(SCr)、明胶酶相关脂质运载蛋白(NGAL)]、氧化应激[过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)、活性氧(ROS)]与炎症因子[肿瘤坏死因子-α(TNF-α)、C反应蛋白(CRP)]水平、并发症发生情况。结果:URL组结石清除率、手术时间、住院时间低/短于MPCNL组、RLU组,MPCNL组手术时间短于RLU组,住院时间长于RLU组(P<0.05);URL组术后3 d NGAL高于MPCNL组、RLU组(P<0.05),三组BUN、SCr比较差异无统计学意义(P>0.05);术后24 h三组CAT、GSH-Px均下降,而MDA、ROS、TNF-α、CRP水平均增加,且URL组术后GSH-Px高于MPCNL组、RLU组,而MDA、CRP低于MPCNL组、RLU组(P<0.05);Pearson相关性分析发现,三组术后CAT、GSH-Px与TNF-α、CRP均呈负相关,而MDA、ROS与TNF-α、CRP均呈正相关(P<0.05);三组术后并发症发生率比较差异无统计学意义(P>0.05)。结论:URL、MPCNL、RLU三种微创术式治疗嵌顿性输尿管上段结石疗效均可靠,各有优势,临床应根据患者情况进行选择。
