Applying Satellite Altimetry to Wetland Water Levels Monitoring (Case Study: Louisiana Wetland)

Khajeh, Saman; Jazireeyan, Iraj; Ardalan, Alireza A.

doi:10.1109/lgrs.2013.2295831

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…The three common re-tracking methods, namely OCOG, -Parameter, and Threshold are implemented. These corrections should be applied on satellite range for each repeat cycle to create the time series of sea height [Khajeh et al, 2014;Khaki et al, 2014]. Thus, corrected SSHs are derived from the following equations.…”

Section: Re-tracking Of Sa Observationsmentioning

confidence: 99%

Point wise Determination of Vertical Deformation at southern Coastal Areas of Caspian Sea by Combination of Satellite Altimetry and Tide Gauge Observations

Pirooznia

Naeeni

Yousefzadeh

2020

Annals of Geophysics

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In this paper, a combination of satellite altimetry (SA) and tide-gauge (TG) observations is used to determine the pattern of vertical deformation at southern coasts of Caspian Sea. Satellite altimetry measures the variations of sea water surface with a respect to a reference ellipsoid, while tide gauge data gives the sea level relative to a particular ground station; consequently, the difference between these two observations will give the vertical motion at the ground station. However, altimeter satellites still have problems at shallow waters or coastal areas which leads to inaccurate and corrupted sea surface height at tide gauge stations. To minimize this imprecision, two strategies are applied for the selection of the suitable SA points near the TG stations. The First one is to choose those close passes to the TG stations, provided that the SA data is not corrupted (range observation is available). The second strategy is to extrapolate the SA points at TG stations using Spatio- Temporal Kriging method. In both point of views, use is made of re-tracking methods to improve the ranges of SA observations near the coast. Amplitudes of tidal components are removed from both SA and TG observations to derive the residual tide free signals. Afterward, a linear trend is fitted to the residual signals in the sense of least square; the difference between these two, supplies the vertical deformation of the ground station. The results illustrate that the average vertical crustal motion at Anzali, Noshahr and Neka are -1.387, -1.903 and -3.14 mm/year, respectively.

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Section: Re-tracking Of Sa Observationsmentioning

confidence: 99%

Point wise Determination of Vertical Deformation at southern Coastal Areas of Caspian Sea by Combination of Satellite Altimetry and Tide Gauge Observations

Pirooznia

Naeeni

Yousefzadeh

2020

Annals of Geophysics

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“…With the rise of satellite geodesy, satellite radar altimetry techniques upgraded the global knowledge about the oceans. However, this technique suffers from the low quality observations at the coastal lines (Khajeh, Jazireeyan et al 2014, Wickert, Cardellach et al 2016). The potential of water level altimetry by using GNSS signals that are reflected off the water surface was first proposed by (Martin-Neira 1993) and introduced as a new bi-static technique that is called GNSS Reflectometry (GNSS-R).…”

Section: Introductionmentioning

confidence: 99%

Interferometric Path Models for GNSS Ground-Based Phase Altimetry

Khajeh

Ardalan

Schuh

2019

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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Abstract. Altimetry by using GNSS (Global Navigation Satellite Systems) reflectometry is regarded as a new promising technique. One important step to utilize this technique is modeling the interferometric path (the difference between the direct and the reflected signal paths). This paper evaluates three models: the planar model, the planar model with tropospheric correction and a model based on ray-tracing. If decimeter level accuracy for water surface fluctuation is required, the planar model cannot be used when a receiver is at an altitude of a few hundred meters and observations are taken at low elevation angles. On the other hand, depending on the mapping function and zenith total delay in the tropospheric correction, the planar model with tropospheric correction can provide decimeter level accuracy for low altitude stations. If simulated observations with a 1 cm accuracy have been employed to estimate Sea Surface Height (SSH) by the model based on ray-tracing the numerical results present 1 cm as RMSE for phase retrieval and 5 cm for Doppler retrieval. The planar model with tropospheric correction does not yield RMSE better than some decimeters for the same condition.

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“…Their results are promising but a comprehensive validation of the results is missing. Moreover, some dedicated studies exist for the Louisiana wetlands (e.g., Lee et al [20] and Khajeh et al [21]) and Poyang Lake watershed [22]. Most of these studies do not provide satisfying results or lack comprehensive validations.…”

Section: Introductionmentioning

confidence: 99%

Potential of ENVISAT Radar Altimetry for Water Level Monitoring in the Pantanal Wetland

Dettmering¹,

Schwatke²,

Boergens³

et al. 2016

Remote Sensing

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Wetlands are important ecosystems playing an essential role for continental water regulation and the hydrologic cycle. Moreover, they are sensitive to climate changes as well as anthropogenic influences, such as land-use or dams. However, the monitoring of these regions is challenging as they are normally located in remote areas without in situ measurement stations. Radar altimetry provides important measurements for monitoring and analyzing water level variations in wetlands and flooded areas. Using the example of the Pantanal region in South America, this study demonstrates the capability and limitations of ENVISAT radar altimeter for monitoring water levels in inundation areas. By applying an innovative processing method consisting of a rigorous data screening by means of radar echo classification as well as an optimized waveform retracking, water level time series with respect to a global reference and with a temporal resolution of about one month are derived. A comparison between altimetry-derived height variations and six in situ time series reveals accuracies of 30 to 50 cm RMS. The derived water level time series document seasonal height variations of up to 1.5 m amplitude with maximum water levels between January and June. Large scale geographical pattern of water heights are visible within the wetland. However, some regions of the Pantanal show water level variations less than a few decimeter, which is below the accuracies of the method. These areas cannot be reliably monitored by ENVISAT.

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Applying Satellite Altimetry to Wetland Water Levels Monitoring (Case Study: Louisiana Wetland)

Cited by 4 publications

References 9 publications

Point wise Determination of Vertical Deformation at southern Coastal Areas of Caspian Sea by Combination of Satellite Altimetry and Tide Gauge Observations

Point wise Determination of Vertical Deformation at southern Coastal Areas of Caspian Sea by Combination of Satellite Altimetry and Tide Gauge Observations

Interferometric Path Models for GNSS Ground-Based Phase Altimetry

Potential of ENVISAT Radar Altimetry for Water Level Monitoring in the Pantanal Wetland

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