scholarly journals Estimation of River Discharge Solely from Remote-Sensing Derived Data: An Initial Study Over the Yangtze River

2018 ◽  
Vol 10 (9) ◽  
pp. 1385 ◽  
Author(s):  
Arthur Sichangi ◽  
Lei Wang ◽  
Zhidan Hu
Keyword(s):  
River Discharge ◽  
Empirical Relationship ◽  
Time Lag ◽  
Initial Study ◽  
Roughness Coefficient ◽  
Novel Approach ◽  
Digital Elevation ◽  
Resultant Velocity ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Elevation Model

A novel approach has been developed to estimating river discharge solely using satellite-derived parameters. The temporal river width observations from Moderate Resolution Imaging Spectroradiometer (MODIS), made at two stream segments a distance apart, are plotted to identify the time lag. The river velocity estimate is then computed using the time lag and distance between the width measurement locations, producing a resultant velocity of 0.96 m/s. The estimated velocity is comparable to that computed from in situ gauge-observed data. An empirical relationship is then utilized to estimate river depth. In addition, the channel condition values published in tables are used to estimate the roughness coefficient. The channel slope is derived from the digital elevation model averaged over a river section approximately 516 km long. Finally, the temporal depth changes is captured by adjusting the estimated depth to the Envisat satellite altimetry -derived water level changes, and river width changes from Landsat ETM+. The newly developed procedure was applied to two river sites for validation. In both cases, the river discharges were estimated with reasonable accuracy (with Nash–Sutcliffe values >0.50). The performance evaluation of discharge estimation using satellite-derived parameters was also analyzed. Since the methodology for estimating discharge is solely dependent on global satellite datasets, it represents a promising technique for use on rivers worldwide.

Improving bioclimatic envelop modeling for Lichens through remote sensing based substratum correction: A study over Indian Himalaya

2016 ◽  
Vol 1 (2) ◽  
Author(s):  
C. P. Singh ◽  
R. Bajpai ◽  
R. P. Singh ◽  
D. K. Upreti
Keyword(s):  
Remote Sensing ◽  
Predictive Accuracy ◽  
Geographic Area ◽  
Jammu And Kashmir ◽  
Indian Himalaya ◽  
Novel Approach ◽  
Digital Elevation ◽  
Average Probability ◽  
Niche Area ◽  
Elevation Model

In alpine Himalaya, the niche map of lichens and its characteristics is a gap area. A novel approach of improving the bioclimatic envelop through use of remote sensing inputs was employed. The 19 bioclimatic indices and digital elevation model were used for training niche models through occurrence records of 33 lichen species across Indian Himalaya. Substratum correction was carried out using LU/LC data. About 45% of the total geographic area studied is found to be very conducive (with niche probability > 70%) for the growth of lichens with predictive accuracy of 91% ascertained through cross-validation. Jammu and Kashmir is having highest niche area (36.02%); however, average probability niche score is highest in Uttarakhand (81.08). Area between 27o - 28o N latitude is having highest area however average probability score is highest in 30o - 31o N. Overall maximum niche area (35.50 %) is found in the regions dominated by alpine meadow, alpine grasslands and parts of cold deserts. The potential use lies in reporting yet to be explored lichens in the Indian Himalaya.

scholarly journals Identification and mapping of soil erosion areas in the Blue Nile-Eastern Sudan using multispectral ASTER and MODIS satellite data and the SRTM elevation model

2010 ◽  
Vol 7 (1) ◽  
pp. 135-177
Author(s):  
M. El Haj Tahir ◽  
A. Kääb ◽  
C.-Y. Xu
Keyword(s):  
Soil Erosion ◽  
Thermal Emission ◽  
Land Use Changes ◽  
Shuttle Radar Topography Mission ◽  
Arid Ecosystems ◽  
Spatial And Temporal Variability ◽  
Blue Nile ◽  
Digital Elevation ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Elevation Model

Abstract. This paper is part of a set of studies to evaluate the spatial and temporal variability of soil water in terms of natural as well as land-use changes as fundamental factors for vegetation regeneration in arid ecosystems in the Blue Nile-Sudan. The specific aim is to indicate the spatial distribution of soil erosion caused by the rains of 2006. The current study is conducted to determine whether automatic classification of multispectral Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) imagery could accurately discriminate erosion gullies. Shuttle Radar Topography Mission (SRTM) is used to orthoproject ASTER data. A maximum likelihood classifier is trained with four classes, Gullies, Flat_Land, Mountains and Water and applied to images from March and December 2006. Validation is done with field data from December and January 2006/2007, and using drainage network analysis of SRTM digital elevation model. The results allow the identification of erosion gullies and subsequent estimation of eroded area. Consequently the results were up-scaled using Moderate Resolution Imaging Spectroradiometer (MODIS) images of the same dates. Because the selected study site is representative of the wider Blue Nile province, it is expected that the approach presented could be applied to larger areas.

scholarly journals Air Temperature Modelling Depended on Remote Sensing Techniques

2020 ◽  
Vol 38 (3A) ◽  
pp. 352-360
Author(s):  
Zainab T. Mohammed ◽  
Riyad H. Al-Anbari ◽  
Oday Z. Jasim
Keyword(s):  
Air Temperature ◽  
Land Surface ◽  
Accuracy Assessment ◽  
Day Length ◽  
Temperature Estimation ◽  
Digital Elevation ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Remote Sensing Techniques ◽  
Elevation Model

Air temperature (T air) near the land surface is a fundamental descriptor of physical environmental conditions and one of the most widely used climatic variables in global change studies. In this study, the researcher trying to suggest a model for estimating air temperature in summer season for any region through integrating of Iraqi Agrometeorological network daily (T air) with the moderate resolution imaging spectroradiometer (MODIS) land surface temperature (LST), Duration Day Length (DDL) and Digital Elevation Model (DEM). In this model, using satellite images for the study area and data of air temperature for four weather stations located in Babylon governorate from 1- June to 30- September on year 2017 for modeling and accuracy assessment air temperature estimation. The standard error of this model is 1.72887° C, and the correlation equal to 0.69698.

scholarly journals Assessment of possible uncertainties arising during the hydromorphological monitoring of a Sand-Bedded Large River

2017 ◽  
Vol 10 (3-4) ◽  
pp. 27-33
Author(s):  
Tamás Právetz ◽  
György Sipos ◽  
Zsuzsanna Ladányi
Keyword(s):  
Morphological Changes ◽  
Time Lag ◽  
Large River ◽  
Bedload Transport ◽  
Repeated Measurements ◽  
Anthropogenic Factors ◽  
Variable Environment ◽  
Digital Elevation ◽  
Adcp Measurements ◽  
Elevation Model

Abstract The riverbed morphology of sand-bedded rivers is dynamically changing as a consequence of quasi continuous bedload transport. In the meantime, the dimension, size and dynamics of developing bedforms is highly depending on the regime of the river and sediment availability, both affected by natural and anthropogenic factors. Consequently, the assessment of morphological changes as well as the monitoring of riverbed balance is challenging in such a variable environment. In relation with a general research on the longer term sediment regime of River Maros, a fairly large alluvial river in the Carpathian Basin, the primary aim of the present investigation was to assess uncertainties related to morphological monitoring, i.e. testing the reproducibility of hydromorphological surveys and digital elevation model generation by performing repeated measurements among low water conditions on selected representative sites. Surveys were conducted with the combination of an ADCP sonar, GPS and total station. The most appropriate way of digital elevation modelling (DEM) was tested and 30-point Kriging was identified to be optimal for comparative analysis. Based on the results, several uncertainties may affect the reproducibility of measurements and the volumetric deviation of DEM pairs generated. The mean horizontal difference of survey tracks was 3-4 m in case of each site, however this could not explain all the DEM deviation. Significant riverbed change between measurements could also be excluded as the main factor. Finally, it was found that results might be affected greatly by systematic errors arising during motor boat ADCP measurements. Nevertheless, the observed, normalised and aggregated DEM uncertainty (600-360 m3/rkm) is significantly lower than the changes experienced between surveys with a month or longer time lag. Consequently, the developed measurement strategy is adequate to monitor long term morphological and sediment balance change on sand bedded large river.

scholarly journals Pannonian plain as a morphostructural unit of Serbia

2012 ◽  
Vol 92 (1) ◽  
pp. 47-70 ◽  
Author(s):  
Jelena Calic ◽  
Marko Milosevic ◽  
Tivadar Gaudenji ◽  
Dragoljub Strbac ◽  
Milovan Milivojevic
Keyword(s):  
Pannonian Basin ◽  
Geological Structure ◽  
Roughness Coefficient ◽  
Digital Elevation ◽  
Pannonian Plain ◽  
The Status ◽  
The Republic ◽  
Elevation Model ◽  
Definition Of ◽  
Basin System

Differentiation between the terms ?Pannonian Basin? and ?Pannonian Plain? is not clear enough in geographical literature. The paper discusses the usage of the term ?plain? in geomorphology, as well as the usage of a quantitative method for plain delineation, through calculation of relief roughness coefficient (using a digital elevation model). Qualitative analysis, which includes the definition of dominant geomorphological processes and the distribution of Quaternary sediments, is an addition to the quantitative analysis. In the Republic of Serbia, the area of the Pannonian plain defined in this way is 24,448 km2, which is 27.5% of the total territory of the country. The paper gives the overview of the geotectonic structure and evolution of the Pannonian Basin System, with special stress on the territory of Serbia, as well as the chronology of the Pannonian sedimentation area in Serbia from the Lower Miocene till present. In order to explain the status of the Pannonian plain as one of the morphostructural units of Serbia, the theoretical basics of morphostructures are discussed, as well as the principles of their spatial definition and the relation to the notion of a geological structure.

STUDY OF THE LANDSLIDE MORPHOLOGY BASED ON GNSS DATA AND AIRBORNE SOUNDING (ON THE EXAMPLE OF A SECTION OF THE PROTVA RIVER VALLEY)

2018 ◽  
Vol 12 (5-6) ◽  
pp. 50-57 ◽  
Author(s):  
I. S. Voskresensky ◽  
A. A. Suchilin ◽  
L. A. Ushakova ◽  
V. M. Shaforostov ◽  
A. L. Entin ◽  
...  
Keyword(s):  
Digital Elevation Model ◽  
Geodetic Network ◽  
Aerial Survey ◽  
River Valley ◽  
Ease Of Use ◽  
Digital Elevation ◽  
Loose Deposits ◽  
Positioning Method ◽  
Landslide Body ◽  
Elevation Model

To use unmanned aerial vehicles (UAVs) for obtaining digital elevation models (DEM) and digital terrain models (DTM) is currently actively practiced in scientific and practical purposes. This technology has many advantages: efficiency, ease of use, and the possibility of application on relatively small area. This allows us to perform qualitative and quantitative studies of the progress of dangerous relief-forming processes and to assess their consequences quickly. In this paper, we describe the process of obtaining a digital elevation model (DEM) of the relief of the slope located on the bank of the Protva River (Satino training site of the Faculty of Geography, Lomonosov Moscow State University). To obtain the digital elevation model, we created a temporary geodetic network. The coordinates of the points were measured by the satellite positioning method using a highprecision mobile complex. The aerial survey was carried out using an unmanned aerial vehicle from a low altitude (about 40–45 m). The processing of survey materials was performed via automatic photogrammetry (Structure-from-Motion method), and the digital elevation model of the landslide surface on the Protva River valley section was created. Remote sensing was supplemented by studying archival materials of aerial photography, as well as field survey conducted immediately after the landslide. The total amount of research results made it possible to establish the causes and character of the landslide process on the study site. According to the geomorphological conditions of formation, the landslide refers to a variety of landslideslides, which are formed when water is saturated with loose deposits. The landslide body was formed with the "collapse" of the blocks of turf and deluvial loams and their "destruction" as they shifted and accumulated at the foot of the slope.

Urban Flood Mapping

2017 ◽  
Author(s):  
Indra Riyanto ◽  
Lestari Margatama
Keyword(s):  
Natural Disasters ◽  
Satisfying Condition ◽  
Three Dimensions ◽  
Urban Flood ◽  
Digital Elevation ◽  
Elevation Data ◽  
Recent Occurrence ◽  
Elevation Model ◽  
Digital Elevation Model Data ◽  
Potential Area

The recent degradation of environment quality becomes the prime cause of the recent occurrence of natural disasters. It also contributes in the increase of the area that is prone to natural disasters. Flood history data in Jakarta shows that flood occurred mainly during rainy season around January – February each year, but the flood area varies each year. This research is intended to map the flood potential area in DKI Jakarta by segmenting the Digital Elevation Model data. The data used in this research is contour data obtained from DPP–DKI with the resolution of 1 m. The data processing involved in this research is extracting the surface elevation data from the DEM, overlaying the river map of Jakarta with the elevation data. Subsequently, the data is then segmented using watershed segmentation method. The concept of watersheds is based on visualizing an image in three dimensions: two spatial coordinates versus gray levels, in which there are two specific points; that are points belonging to a regional minimum and points at which a drop of water, if placed at the location of any of those points, would fall with certainty to a single minimum. For a particular regional minimum, the set of points satisfying the latter condition is called the catchments basin or watershed of that minimum, while the points satisfying condition form more than one minima are termed divide lines or watershed lines. The objective of this segmentation is to find the watershed lines of the DEM image. The expected result of the research is the flood potential area information, especially along the Ciliwung river in DKI Jakarta.

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