scholarly journals Reliable Orientation Estimation of Vehicles in High-Resolution Radar Images

2016 ◽  
Vol 64 (9) ◽  
pp. 2986-2993 ◽  
Author(s):  
Fabian Roos ◽  
Dominik Kellner ◽  
Jurgen Dickmann ◽  
Christian Waldschmidt
2019 ◽  
Vol 11 (23) ◽  
pp. 2804 ◽  
Author(s):  
Diego Mejía-Veintimilla ◽  
Pablo Ochoa-Cueva ◽  
Natalia Samaniego-Rojas ◽  
Ricardo Félix ◽  
Juan Arteaga ◽  
...  

The prediction of river discharge using hydrological models (HMs) is of utmost importance, especially in basins that provide drinking water or serve as recreation areas, to mitigate damage to civil structures and to prevent the loss of human lives. Therefore, different HMs must be tested to determine their accuracy and usefulness as early warning tools, especially for extreme precipitation events. This study simulated the river discharge in an Andean watershed, for which the distributed HM Runoff Prediction Model (RPM) and the semi-distributed HM Hydrologic Modelling System (HEC-HMS) were applied. As precipitation input data for the RPM model, high-resolution radar observations were used, whereas the HEC-HMS model used the available meteorological station data. The obtained simulations were compared to measured discharges at the outlet of the watershed. The results highlighted the advantages of distributed HM (RPM) in combination with high-resolution radar images, which estimated accurately the discharges in magnitude and time. The statistical analysis showed good to very good accordance between observed and simulated discharge for the RPM model (R2: 0.85–0.92; NSE: 0.77–0.82), whereas for the HEC-HMS model accuracies were lower (R2: 0.68–0.86; NSE: 0.26–0.78). This was not only due to the application of means values for the watershed (HEC-HMS), but also to limited rain gauge information. Generally, station network density in tropical mountain regions is poor, for which reason the high spatiotemporal precipitation variability cannot be detected. For hydrological simulation and forecasting flash floods, as well as for environmental investigations and water resource management, meteorological radars are the better choice. The greater availability of cost-effective systems at the present time also reduces implementation and maintenance costs of dense meteorological station networks.


Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Terri Cook

High-resolution radar images from Switzerland’s experimental test site show that snow temperature is a key factor in classifying avalanche behavior.


Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1441
Author(s):  
Philippe Paillou ◽  
Sylvia Lopez ◽  
Eugene Marais ◽  
Klaus Scipal

The Kuiseb River is one of the major ephemeral rivers of Western Namibia, setting the northern limit of the Namib Sand Sea and outflowing in the Atlantic Ocean at Walvis Bay. Such ephemeral rivers are of the highest importance for the country since they are related both to recent past climatic conditions and to potential water resources. Using high-resolution radar images from the Japanese ALOS-2 satellite, we mapped for the first time the numerous channels hidden under the surface aeolian sediments: while the non-permanent tributaries of the Kuiseb River appear north of its present-day bed, a wide paleochannel system running westward, assumed by previous studies, could be clearly observed in the interdune valleys in the south. Radar-detected channels were studied during fieldwork in May 2019, which produced both subsurface ground-penetrating radar profiles and high-resolution drone-generated digital elevation models. It allowed us to confirm the existence of the “Paleo–Kuiseb” drainage system, a remnant of the Holocene history of the Kuiseb River, moving northward under the progression of the Namib Sand Sea. Our observations also contribute to the explanation of the young age of the linear dunes at the northern edge of the Namib Sand Sea, which are currently active and are pushing the Kuiseb River course toward the north.


Author(s):  
Fabian Roos ◽  
Dominik Kellner ◽  
Jens Klappstein ◽  
Juergen Dickmann ◽  
Klaus Dietmayer ◽  
...  

2010 ◽  
Vol 4 (3) ◽  
pp. 1607-1633 ◽  
Author(s):  
H. Rott ◽  
F. Müller ◽  
T. Nagler ◽  
D. Floricioiu

Abstract. The outlet glaciers to the embayment of the Larsen B Ice Shelf started to accelerate soon after the ice shelf disintegrated in March 2002. We analyse high resolution radar images of the TerraSAR-X satellite, launched in June 2007, to map the motion of outlet glaciers in detail. The frontal velocities are used to estimate the calving fluxes for 2008/2009. As reference for pre-collapse conditions, when the glaciers were in balanced state, the ice fluxes through the same gates are computed using ice motion maps derived from interferometric data of the ERS-1/ERS-2 satellites in 1995 and 1999. The difference between the pre- and post-collapse fluxes provides an estimate on the mass imbalance. For the Larsen-B embayment the 2008 mass deficit is estimated at 5.94 ± 1.55 Gt/yr, significantly lower than previously published values. The ice flow acceleration follows a similar pattern on the various glaciers, being initiated at the calving terminus. The acceleration extends far upstream, gradually decreasing in magnitude with distance from the front. This suggests stress perturbation at the glacier front being a main factor for acceleration. So far there are no signs of slow-down indicating that dynamic thinning and frontal retreat will go on.


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