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1.
The purpose of this study is to estimate long-term SMC and find its relation with soil moisture (SM) of climate station in different depths and NDVI for the growing season. The study area is located in agricultural regions in the North of Mongolia. The Pearson’s correlation methodology was used in this study. We used MODIS and SPOT satellite data and 14 years data for precipitation, temperature and SMC of 38 climate stations. The estimated SMC from this methodology were compared with SM from climate data and NDVI. The estimated SMC was compared with SM of climate stations at a 10-cm depth (r2 = 0.58) and at a 50-cm depth (r2 = 0.38), respectively. From the analysis, it can be seen that the previous month’s SMC affects vegetation growth of the following month, especially from May to August. The methodology can be an advantageous indicator for taking further environmental analysis in the region. 相似文献
2.
This letter shows how conventional methods for satellite image classification can be improved by applying some filtering algorithms as a pre-classifying step. We will introduce a filtering scheme based on convolution equations of fractional type. The use of this kind of filter as a pre-classification step will be illustrated by classifying MODerate-resolution Imaging Spectroradiometer (MODIS) data to map burned areas in Mediterranean countries. The methodology we propose improved the estimations obtained by merely classifying the post-fire images (i.e. without filtering) in the study areas considered. 相似文献
3.
合成孔径雷达反演裸露地表土壤水分的新方法 总被引：4，自引：0，他引：4
提出了一种新的合成孔径雷达(SAR)反演裸露地表土壤水分的经验模型,该模型同时考虑了均方根高度S和相关长度L的影响,并将两个粗糙度参数合二为一,然后利用VV和VH极化的后向散射系数即可反演得到土壤水分。通过实测数据对模型进行了验证,发现在θ020°时,模型反演值与模拟值有着良好的相关关系(R2=0.71)。该模型在不需要测量地面粗糙度的情况下可以反演得到比较好的土壤水分精度,尤其适用于地表情况复杂、难以精确测量的地区。 相似文献
4.
S. Srinivasa Rao S. Dinesh kumar S. N. Das M. S. S. Nagaraju M. V. Venugopal Prashant Rajankar Pankaj Laghate M. Sivaprasad Reddy A. K. Joshi J. R. Sharma 《Journal of the Indian Society of Remote Sensing》2013,41(4):865-872
This paper discusses a new methodology to estimate soil moisture in agriculture region using SAR data with the use of HH and HV polarization. In this study the semi empirical model derived by Dubois et al. (IEEE Transactions on Geoscience and Remote Sensing, 33(4), 915–926, 1995) was modified to work using σ HH instead of two like polarization equations σHH, σVV so that soil moisture can be obtained for the larger area frequently. The field derived roughness correlated with the cross polarization ratio (HV/HH) to replace the one unknown parameter ‘s’ in the Dubois model and hence the dielectric constant was derived by inverting the Dubois model equation (HH). The Topp et al. (Water Resources Research, 16(3), 574–582, 1980) model was used to retrieve soil moisture using the dielectric constant. The mid incidence angle was used to overcome the incident angle effect and it worked successfully to the larger extent. The result is realistic overall, especially where surface has less variation in the roughness and vegetation since the penetration capability of C-band is limited when plant grows hence model valid in the initial period of cultivation. The derived model is having good scope for soil moisture monitoring with the present availability of Indian RISAT data. 相似文献
5.
双极化SAR数据反演裸露地表土壤水分 总被引：1，自引：0，他引：1
为了较高精度地获取大范围地表土壤水分,提出一种基于双极化合成孔径雷达数据的裸露地表土壤水分反演模型即非线性方程组,通过改进的粒子群算法求解非线性方程组从而得到土壤水分。首先通过AIEM模型数值模拟和回归分析,得到一种新的组合粗糙度,然后模拟分析得到土壤水分与雷达后向散射系数的关系,从而建立雷达后向散射系数与组合粗糙度、土壤水分的经验关系。利用ASAR C波段双极化雷达数据,基于经验关系和改进的粒子群算法即可实现土壤水分的反演。经过黑河流域实测土壤水分数据对模型进行验证,反演结果与实测数据具备良好的相关性(R~2=0.778 6)。与以往同一区域研究成果比较,文中的方法反演精度有所提高,更适用于裸露地表土壤水分反演。 相似文献
6.
Average variograms to guide soil sampling 总被引：4，自引：0，他引：4
R. Kerry M.A. Oliver 《International Journal of Applied Earth Observation and Geoinformation》2004,5(4):307-325
To manage land in a site-specific way for agriculture requires detailed maps of the variation in the soil properties of interest. To predict accurately for mapping, the interval at which the soil is sampled should relate to the scale of spatial variation. A variogram can be used to guide sampling in two ways. A sampling interval of less than half the range of spatial dependence can be used, or the variogram can be used with the kriging equations to determine an optimal sampling interval to achieve a given tolerable error. A variogram might not be available for the site, but if the variograms of several soil properties were available on a similar parent material and or particular topographic positions an average variogram could be calculated from these. Averages of the variogram ranges and standardized average variograms from four different parent materials in southern England were used to suggest suitable sampling intervals for future surveys in similar pedological settings based on half the variogram range. The standardized average variograms were also used to determine optimal sampling intervals using the kriging equations. Similar sampling intervals were suggested by each method and the maps of predictions based on data at different grid spacings were evaluated for the different parent materials. Variograms of loss on ignition (LOI) taken from the literature for other sites in southern England with similar parent materials had ranges close to the average for a given parent material showing the possible wider application of such averages to guide sampling. 相似文献
7.
8.
玉米地组分亮度温度分类变化研究 总被引：2，自引：4，他引：2
以玉米整个生长期野外热红外辐射观测数据为基础,对两种组分亮温分类方法作了比较,并对玉米地组分亮温的变化特征展开了分析。结果表明,农田亮温组分的数目和数值随测量时间和日期改变。在整个测量期间,在当地时间中午前后,农田呈现出3个亮温组分植被、被阳光照到的亮土和植被阴影下的暗土。观测早期,植被亮温分布相对集中;随着农田植被覆盖率的增高,植被亮温分布逐步分散,组分间温差缩小,部分亮温值相互重叠。产生这些现象的原因将在以后的研究中加以探讨。 相似文献
9.
This paper presents a new strategy for GPS carrier phase data processing. The classic approach generally consists of three steps: a float solution, a search for integer ambiguities, and a fixed solution. The new approach is based on certain properties of ambiguity function method and ensures the condition of integer ambiguities without the necessity of the additional step of the integer search. The ambiguities are not computed explicitly, although the condition of “integerness” of the ambiguities is ensured in the results through the least squares adjustment with condition equations in the functional model. An appropriate function for the condition equations is proposed and presented. The presented methodology, modified ambiguity function approach, currently uses a cascade adjustment with successive linear combinations of L1 and L2 carrier phase observations to ensure a correct solution. This paper presents the new methodology and compares it to the three-stage classic approach which includes ambiguity search. A numerical example is provided for 25 km baseline surveyed with dual-frequency receivers. All tests were performed using an in-house developed GINPOS software and it has been shown that the positioning results from both approaches are equivalent. It has also been proved that the new approach is robust to adverse effects of cycle slips. In our opinion, the proposed approach may be successfully used for carrier phase GPS data processing in geodetic applications. 相似文献
10.
Assessment of deforestation in near real time over the Brazilian Amazon using multitemporal fraction images derived from Terra MODIS 总被引：1，自引：0，他引：1
《Geoscience and Remote Sensing Letters, IEEE》2005,2(3):315-318
We present a methodology for rapidly assessing deforestation over the Amazon region needed for policy intervention. We use soil fraction images generated from Moderate Resolution Imaging Spectroradiometer (MODIS) data at 250-m spatial resolution. Results showed reasonable agreement with higher resolution Landsat data (r/sup 2/=0.73) for our study area. MODIS data are promising for near real-time deforestation monitoring, previously not practical with Landsat data. 相似文献
11.
R. S. Reddy D. Goosen G. W. W. Elbersen 《Journal of the Indian Society of Remote Sensing》1985,13(2):1-11
A methodology for the preparation of semi detailed soil maps using medium scale aerial photographs for an area of about 3600 ha in Merida area, Spain is presented. The new concepts such as ‘Basic Land Units’, ‘Soil Consociation’ and ‘Soil Set’ developed by Elbersen (1976) were adopted for this study to see their utility for the preparation of semidetailed soil maps which can be used for land evaluation, land classification and also for making prodictions about the feasibility of a particular project for rural development plannning purposes. Basic land units and their subdivisions like major and minor compo-nents were used for the delineation of interpretation units. Mapping units, viz, Soil Consoication, Soil Complex and miscellaneous land type were used for mapping soils. Soils were classified upto family level and shown as subgroups in the 1:50,000 scale soil map. Soils were mapped as soil sets per basic land unit per subgroup. A model legend for use in the preparation of seimdetailed physiographic cum soil maps is given which is in terms of physiography and Soil Taxonomy qualified by soil sets. 相似文献
12.
Knowledge of dielectric permittivity of the soil provides direct measure of soil moisture content. A methodology to determine soil moisture based on the reflection coefficient measurement by a pseudo vector method using a horn antenna has been presented. To verify the efficacy of the method, measurements have been carried out at S, C & X band frequencies at two moisture levels and the corresponding emissivity parameters computed. Results so obtained are in good agreement with the already reported data and the direct moisture measurements. This method is expected to be of interest to agricultural scientists and to those involved in the application of remote sensing in crop studies. 相似文献
13.
The purpose of this paper is to develop a canonical formulation of the rotational motion for an elastic Earth model. We have
obtained the canonical equations for the precession and nutation motion in an inertial frame, and from this we have deduced
the equations in an Earth-fixed frame. The linearized equations deduced for polar motion are equivalent to those obtained
using Liouville's equations. 相似文献
14.
对于由 m个相依线性回归方程组成的线性回归系统 ,本文作者基于岭回归估计和预检验估计 ,提出了回归参数的一种新型估计 ,即预检验岭回归估计。并讨论了它的统计性质。 相似文献
15.
Prem Chhetri Robert Stimson Jim Cooper Jonathan Corcoran Martin Bell David Pullar 《Transactions in GIS》2007,11(4):597-619
This article presents a GIS‐based methodology to integrate a measure of geographic attractiveness of localities in the process of allocating potential dwellings in the context of a large urban region. The methodology was developed for a study area in Brisbane‐South East Queensland (SEQ), known as the Sunbelt Region, a rapidly growing region and a popular tourist destination in Australia. In this article, we have used a multivariate technique to develop a set of parameterised linear equations to define underlying dimensions that drive residential location decision choices. Aesthetic and accessibility factors were identified in the factor analysis from data collected via a survey of Quality of Life. Spatial measures were based on a combination of network distance and kernel density estimation to calculate ‘aesthetic’ and ‘accessibility’ scenarios, which were then overlaid and multiplied by their subjective weights to create an ‘overall attractiveness scenario’. These development scenarios were integrated as a set of criteria to control the allocation of potential dwelling capacity over the next 25 years at a grid cell level. 相似文献
16.
In this paper, the registration of decimeter-resolution airborne multi-aspect SAR (MASAR) data of inner city areas by application of the radargrammetric range-Doppler equations is investigated. The geometrical model is adapted to linear flight trajectories and zero-Doppler processed SAR data, whereas the observed trajectory parameters are adjusted using a strict Gauss–Helmert model and known ground control points. The significance of the estimated corrections is examined and the most suitable set of free parameters is determined. Finally, the methodology is applied to real test data of an airborne campaign over the city of Munich, Germany, and the feasability of the proposed radargrammetric registration method is shown. 相似文献
17.
Enkhjargal Natsagdorj Martin Kappas Batchuluun Tseveen Chimgee Dari Oyunbileg Tsend 《地球空间信息科学学报》2017,20(1):46-55
Soil moisture (SM) content is one of the most important environmental variables in relation to land surface climatology, hydrology, and ecology. Long-term SM data-sets on a regional scale provide reasonable information about climate change and global warming specific regions. The aim of this research work is to develop an integrated methodology for SM of kastanozems soils using multispectral satellite data. The study area is Tuv (48°40′30″N and 106°15′55″E) province in the forest steppe zones in Mongolia. In addition to this, land surface temperature (LST) and normalized difference vegetation index (NDVI) from Landsat satellite images were integrated for the assessment. Furthermore, we used a digital elevation model (DEM) from ASTER satellite image with 30-m resolution. Aspect and slope maps were derived from this DEM. The soil moisture index (SMI) was obtained using spectral information from Landsat satellite data. We used regression analysis to develop the model. The model shows how SMI from satellite depends on LST, NDVI, DEM, Slope, and Aspect in the agricultural area. The results of the model were correlated with the ground SM data in Tuv province. The results indicate that there is a good agreement between output SM and SM of ground truth for agricultural area. Further research is focused on moisture mapping for different natural zones in Mongolia. The innovative part of this research is to estimate SM using drivers which are vegetation, land surface temperature, elevation, aspect, and slope in the forested steppe area. This integrative methodology can be applied for different regions with forest and desert steppe zones. 相似文献
18.
Maarit Middleton Paavo Nrhi Raimo Sutinen 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(3):287-297
In a humid northern boreal climate, the success rate of artificial regeneration to Scots pine (Pinus sylvestris L.) can be improved by including a soil water content (SWC) based assessment of site suitability in the reforestation planning process. This paper introduces an application of airborne visible-near-infrared imaging spectroscopic data to identify suitable subregions of forest compartments for the low SWC-tolerant Scots pine. The spatial patterns of understorey plant species communities, recorded by the AISA (Airborne Imaging Spectrometer for Applications) sensor, were demonstrated to be dependant on the underlying SWC. According to the nonmetric multidimensional scaling and correlation results twelve understorey species were found to be most abundant on sites with high soil SWCs. The abundance of bare soil, rocks and abundance of more than ten species indicated low soil SWCs. The spatial patterns of understorey are attributed to time-stability of the underlying SWC patterns. A supervised artificial neural network (radial basis functional link network, probabilistic neural network) approach was taken to classify AISA imaging spectrometer data with dielectric (as a measure volumetric SWC) ground referencing into regimes suitable and unsuitable for Scots pine. The accuracy assessment with receiver operating characteristics curves demonstrated a maximum of 74.1% area under the curve values which indicated moderate success of the NN modelling. The results signified the importance of the training set’s quality, adequate quantity (>2.43 points/ha) and NN algorithm selection over the NN algorithm training parameter optimization to perfection. This methodology for the analysis of site suitability of Scots pine can be recommended, especially when artificial regeneration of former mixed wood Norway spruce (Picea abies L. Karst) - downy birch (Betula pubenscens Ehrh.) stands is being considered, so that artificially regenerated areas to Scots pine can be optimized for forestry purposes. 相似文献
19.
《Geoscience and Remote Sensing Letters, IEEE》2009,6(4):623-624
The 52 papers in this special issue make use of airborne and/or ground data to deal with questions such as: 1) the estimation of effective soil temperature and vegetation water content from remote sensing data; 2) the impact of physical parameters such as soil texture, topography, vegetation type. and surface roughness on surface soil moisture retrieval; 3) the transferability of current retrieval equations across scales ranging from tens of kilometers; and 4) issues related to downscaling of low-resolution passive-microwave observations of surface soil moisture. 相似文献
20.
Frequency-dependent data weighting in global gravity field modeling from satellite data contaminated by non-stationary noise 总被引：1，自引：0，他引：1
Satellite data that are used to model the global gravity field of the Earth are typically corrupted by correlated noise, which
can be related to a frequency dependence of the data accuracy. We show an opportunity to take such noise into account by using
a proper noise covariance matrix in the estimation procedure. If the dependence of noise on frequency is not known a priori,
it can be estimated on the basis of a posteriori residuals. The methodology can be applied to data with gaps. Non-stationarity
of noise can also be dealt with, provided that the necessary a priori information exists. The proposed methodology is illustrated
with CHAllenging Mini-satellite Payload (CHAMP) data processing. It is shown, in particular, that the usage of a proper noise
model can make the measurements of non-gravitational satellite accelerations unnecessarily. This opens the door for high-quality
modeling of the Earth’s gravity field on the basis of observed orbits of non-dedicated satellites (i.e., satellites without
an on-board accelerometer). Furthermore, the processing of data from dedicated satellite missions – GRACE (Gravity Recovery
and Climate Experiment) and GOCE (Gravity field and steady-state Ocean Circulation Explorer) – may also benefit from the proposed
methodology. 相似文献