Assessing Disagreement and Tolerance of Misclassification of Satellite-derived Land Cover Products Used in WRF Model Applications   总被引：1，自引：0，他引：1  

GAO Hao  JIA Gensuo 《大气科学进展》2013,30(1):125-141

As more satellite-derived land cover products used in the study of global change,especially climate modeling,assessing their quality has become vitally important.In this study,we developed a distance metric based on the parameters used in weather research and forecasting(WRF) to characterize the degree of disagreement among land cover products and to identify the tolerance for misclassification within the International Geosphere Biosphere Programme(IGBP) classification scheme.We determined the spatial degree of disagreement and then created maps of misclassification of Moderate Resolution Imaging Spectoradiometer(MODIS) products,and we calculated overall and class-specific accuracy and fuzzy agreement in a WRF model.Our results show a high level of agreement and high tolerance of misclassification in the WRF model between large-scale homogeneous landscapes,while a low level of agreement and tolerance of misclassification appeared in heterogeneous landscapes.The degree of disagreement varied significantly among seven regions of China.The class-specific accuracy and fuzzy agreement in MODIS Collection 4 and 5 products varied significantly.High accuracy and fuzzy agreement occurred in the following classes:water,grassland,cropland,and barren or sparsely vegetated.Misclassification mainly occurred among specific classes with similar plant functional types and low discriminative spectro-temporal signals.Some classes need to be improved further;the quality of MODIS land cover products across China still does not meet the common requirements of climate modeling.Our findings may have important implications for improving land surface parameterization for simulating climate and for better understanding the influence of the land cover change on climate.  相似文献   

Study on Quantitative Identification Sand and Dust Storm Using MODIS Data          下载免费PDF全文

GUO Ni  LIANG Yun  WANG Xiaoping 《Acta Meteorologica Sinica》2006,20(5):76-82

In order to detect the scope and the intensity quanti cationally, the spectrum characteristic of sand and dust storm was analyzed in detail by using several MODIS data; bands that can distinguish sand and dust from cloud and surface were detected; two indices for determining the scope and intensity of sand and dust storm were found out, and were tested in several storms. Our study result shows: 1) The spectral characteristic of sand and dust in solar wavelengths is that the reflectance increases with the increasing of the wavelength. This is similar to the characteristic of the spectrum of soil. Also, the reflectance of large size dusts increases faster than small size dusts. 2) Small size dusts show typical characteristic of aerosol, being sensitive to blue band of 0.46 μm and insensitive to short wave infrared bands of 1.6 and 2.1 μm. 3) Large size dusts do not have aerosol characteristic, not sensitive to blue band but sensitive to short wave infrared bands. 4) Bands of 3.7 and 8.5 μm are sensitive to dusts. The difference of two bands can be used to identify sands and dusts and reflect the intensity to a certain extent. And 5) the two indices are very effective to monitor sands and dusts by testing a lot of sand and dust storm cases during the period of 2002-2005. Also, the method is simple and easy for operational use.  相似文献   

QUANTITATIVE MODELING OF SUSPENDED SEDIMENT IN MIDDLE CHANGJIANG RIVER FROM MODIS     

LIU Can-de HE Bao-yin LI Mao-tian REN Xian-you 《中国地理科学(英文版)》2006,16(1):79-82

1INTRODUCTIONThe quality of water is traditionally determined by col-lectingwatersamplesandanalyzingthesamplesin a lab-oratory. However, sampling is very much hard sledding,time-consuming, slow and expensive, and easily in thecontrol of weather conditions, and does not include allwater areas. Satellite estimates of water quality havefound widespread application. Remote sensing instru-ments have been applied in water quality monitoringwith varying success (DANA and RICHARD, 1999;RUDD…  相似文献   

应用MODIS影像监测海州湾无机氮浓度的研究   总被引：1，自引：0，他引：1  

许勇  张鹰  刘吉堂  张东 《海洋科学》2008,32(9):76-81

利用连云港海州湾2004年至2006年的水质监测资料，选取时间上完全同步的空间分辨率为500m的MODIS Terra 1B数据，对反射率的单波段因子和波段组合因子与可溶无机氮（DIN）质量浓度之间进行相关分析。从总体上看，单波段因子与DIN质量浓度的相关性较低，但在含氮基团倍频和合频吸收带附近的波段（波段2、7）反射率与DIN质量浓度呈负相关，显示了含氮基团对水体光谱特征的影响；在波段组合因子中，因子F11（3.4）和F13（3.4）与DIN质量浓度呈显著正相关，用这两个因子建立DIN质量浓度的回归模型，R^2都达到0．7以上，相对精度达70％左右，最终选择因子F11（3.4）的线性模型反演该海域的DIN质量浓度，其结果与实际情况非常吻合。  相似文献   

基于MODIS数据的植被指数分析     

向天梁  张志艺 《地理空间信息》2009,7(6):62-64

针对宏观土地覆盖遥感分类的现状,充分利用MODIS相对于AVHRR数据具有的多光谱和分辨率优势,提出了利用MODIS数据进行分类特征选择与提取并结合多时相特征进行宏观土地覆盖分类的分类方法,并进行了分类试验。  相似文献   

MODIS多光谱信息在海上溢油检测中的应用   总被引：1，自引：0，他引：1  

陈辉  赵朝方 《海洋湖沼通报》2009,(3)

利用搭载在EOS-Aqua/Terra卫星上的MODIS数据,对长江口溢油、委内瑞拉的马拉开波湖溢油等4次事故进行光谱分析和研究.在对出事海域的卫星数据进行图像处理的基础上,利用MODIS数据的多光谱信息,分析溢油在各个波段的特征,并确定油膜特征比较明显的波段范围,为可见光/近红外卫星监测溢油提供参考.  相似文献   

气象服务产业化、商品化趋势及其对策     

黄宗捷  蔡久忠 《成都信息工程学院学报》1992,(3)

20世纪50年代以来,大气科学的发展和新科技在气象实践中的运用,不同程度地提高着气象成果的多样性、专业性、应用性和有效性,从而创造了气象成果产业化、商品化的物质技术条件;社会生产和居民生活对气象成果更为多样的、专一的需要,形成了气象成果产业化、商品化的市场条件。我国气象服务有偿化的发展已成为趋势;但从社会需求与气象服务自身现状考察,认真转变观念、积极调整结构、大力拓展市场、深化基础研究乃是加速气象成果产业化、商品化趋势的基本对策。  相似文献   

Volatile Organic Compounds in the Po Basin. Part B: Biogenic VOCs     

M.?Steinbacher  J.?Dommen  C.?Ordonez  S.?Reimann  F.?C.?Grüebler  J.?Staehelin  S.?Andreani-Aksoyoglu  A.?S.?H.?PrevotEmail author 《Journal of Atmospheric Chemistry》2005,51(3):293-315

Measurements of volatile organic compounds (VOCs) were performed in the Po Basin, northern Italy in early summer 1998, summer 2002, and autumn 2003. During the three campaigns, trace gases and meteorological parameters were measured at a semi-rural station, around 35 km north of the city center of Milan. Bimodal diurnal cycles of isoprene with highest concentrations in the morning and evening were found and could be explained by the interaction of emissions, chemical reactions, and vertical mixing. The diurnal cycle could be qualitatively reproduced by a three-dimensional Eulerian model. The nighttime decay of isoprene could be attributed mostly to reactions with NO₃, while the decay of the isoprene oxidation products could not be explained with the considered chemical reactions. Methanol reached very high mixing ratios, up to 150 ppb. High concentrations with considerable variability occurred during nights with high relative humidities and low wind speeds. The origin of these nighttime methanol concentrations is most likely local and biogenic but the specific source could not be identified.  相似文献   

The amino acid composition of estuarine colloidal material     

A.C. Sigleo  P.E. Hare  G.R. Helz 《Estuarine, Coastal and Shelf Science》1983,17(1):87-96

Amino acids were determined in estuarine colloidal and particulate material from near surface waters ranging from fresh to brackish water (12 g kg^?1 salinity). The hydrolizable amino acids and associated ammonia account for an average of 80% of the nitrogen present in colloidal samples, and approximately 75% of the nitrogen from particulate fractions of the same samples. The relative proportions of these amino acids are similar to those of a cultured estuarine diatom. There are no significant amounts of D amino acids, or non-protein amino acids characteristic of bacteria in sediments and soil. A single deep-water sample (25 m) shows some evidence of bottom mud resuspension by the presence of a possible aspartic acid-hydroxyproline dimer.  相似文献   

甘肃省森林、草原火灾定量判识方法研究   总被引：5，自引：0，他引：5  

梁芸 《干旱气象》2004,22(4):60-63

利用EOS/MODIS资料分析了2002年12月到2003年5月发生在甘肃省的6次草原、森林火灾的火区、火灾影响区及环境的亮温关系,结果表明:火区、火灾影响区及正常环境区在20通道与31通道的亮温存在近似的临界值,即(T20-T31)/T20<0.08的区域为正常环境区;0.08<(T20-T31)/T20<0.093的区域为火灾影响区;(T20-T31)/T20>0.093的区域为火区。同时此方法对"4.15"迭部森林火灾进行定量分析表明:此方法对火灾不同区域的判识及火灾面积的估算有很好的效果,为火灾监测及火灾面积的估算提供了一定的参考依据。  相似文献