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

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.

[1]  Christian Schwatke,et al.  Treating the Hooking Effect in Satellite Altimetry Data: A Case Study along the Mekong River and Its Tributaries , 2016, Remote. Sens..

[2]  Christian Schwatke,et al.  DAHITI – an innovative approach for estimating water level time series over inland waters using multi-mission satellite altimetry , 2015 .

[3]  Jürgen Kusche,et al.  Waveform Retracking for Improving Level Estimations From TOPEX/Poseidon, Jason-1, and Jason-2 Altimetry Observations Over African Lakes , 2015, IEEE Transactions on Geoscience and Remote Sensing.

[4]  Lisa-Maria Rebelo,et al.  Development of a global inundation map at high spatial resolution from topographic downscaling of coarse-scale remote sensing data , 2015 .

[5]  P. D. Lele,et al.  Waveform Classification and Water-Land Transition over the Brahmaputra River using SARAL/AltiKa & Jason-2 Altimeter , 2015, Journal of the Indian Society of Remote Sensing.

[6]  Qinhuo Liu,et al.  Global Land Surface Backscatter at Ku-Band Using Merged Jason1, Envisat, and Jason2 Data Sets , 2015, IEEE Transactions on Geoscience and Remote Sensing.

[7]  Sergei Rudenko,et al.  Improved Sea Level record over the satellite altimetry era (1993-2010) from the Climate Change Initiative project , 2015 .

[8]  Frédérique Seyler,et al.  Water Level Fluctuations in the Congo Basin Derived from ENVISAT Satellite Altimetry , 2014, Remote. Sens..

[9]  Alexei V. Kouraev,et al.  Seasonal variability of the Western Siberia wetlands from satellite radar altimetry , 2014 .

[10]  Christian Schwatke,et al.  Multi-Mission Cross-Calibration of Satellite Altimeters: Constructing a Long-Term Data Record for Global and Regional Sea Level Change Studies , 2014, Remote. Sens..

[11]  Alireza A. Ardalan,et al.  Applying Satellite Altimetry to Wetland Water Levels Monitoring (Case Study: Louisiana Wetland) , 2014, IEEE Geoscience and Remote Sensing Letters.

[12]  Maycira Costa,et al.  Landcover classification of the Lower Nhecolândia subregion of the Brazilian Pantanal Wetlands using ALOS/PALSAR, RADARSAT-2 and ENVISAT/ASAR imagery , 2013 .

[13]  A. Cazenave,et al.  SOLS: A lake database to monitor in the Near Real Time water level and storage variations from remote sensing data , 2011 .

[14]  C. Padovani.  Dinâmica espaço-temporal das inundações do pantanal , 2010 .

[15]  S. Calmant,et al.  Water levels in the Amazon basin derived from the ERS 2 and ENVISAT radar altimetry missions , 2010 .

[16]  Remko Scharroo,et al.  A global positioning system–based climatology for the total electron content in the ionosphere , 2010 .

[17]  Xiaobin Cai,et al.  Wetland hydrologic application of satellite altimetry – A case study in the Poyang Lake watershed , 2009 .

[18]  Zhong Lu,et al.  Louisiana Wetland Water Level Monitoring Using Retracked TOPEX/POSEIDON Altimetry , 2009 .

[19]  Jean-François Crétaux,et al.  An absolute calibration site for radar altimeters in the continental domain: Lake Issykkul in Central Asia , 2009 .

[20]  H. Schuh,et al.  Forecast Vienna Mapping Functions 1 for real-time analysis of space geodetic observations , 2009 .

[21]  K. Verdin,et al.  New Global Hydrography Derived From Spaceborne Elevation Data , 2008 .

[22]  F. Aires,et al.  Global inundation dynamics inferred from multiple satellite observations, 1993–2000 , 2007 .

[23]  C. Prigent,et al.  Inundated wetland dynamics over boreal regions from remote sensing: the use of Topex‐Poseidon dual‐frequency radar altimeter observations , 2006 .

[24]  J. Crétaux,et al.  Lake studies from satellite radar altimetry , 2006 .

[25]  Jinyun Guo,et al.  Coastal Gravity Anomalies from Retracked Geosat/GM Altimetry: Improvement, Limitation and the Role of Airborne Gravity Data , 2006 .

[26]  A. Cazenave,et al.  Preliminary results of ENVISAT RA-2-derived water levels validation over the Amazon basin , 2006 .

[27]  A. Cazenave,et al.  Floodplain water storage in the Negro River basin estimated from microwave remote sensing of inundation area and water levels , 2005 .

[28]  P. Berry,et al.  Global inland water monitoring from multi‐mission altimetry , 2005 .

[29]  Curt H. Davis,et al.  Elevation change of the Antarctic ice sheet, 1995-2000, from ERS-2 satellite radar altimetry , 2004, IEEE Transactions on Geoscience and Remote Sensing.

[30]  M. Watkins,et al.  The gravity recovery and climate experiment: Mission overview and early results , 2004 .

[31]  Fabrice Papa,et al.  Use of the Topex-Poseidon dual-frequency radar altimeter over land surfaces , 2003 .

[32]  S. Hamilton,et al.  Comparison of inundation patterns among major South American floodplains , 2002 .

[33]  R. Coleman.  Satellite Altimetry and Earth Sciences: A Handbook of Techniques and Applications , 2001 .

[34]  Marcos Heil Costa,et al.  Surface water dynamics in the Amazon Basin: Application of satellite radar altimetry , 2001 .

[35]  Walter H. F. Smith,et al.  Free software helps map and display data , 1991 .

[36]  P. Woodworth,et al.  Changes in the mesoscale variability and in extreme sea levels over two decades as observed by satellite altimetry , 2015 .

[37]  K. Moffett,et al.  Remote Sens , 2015 .

[38]  G. Pereira,et al.  Evaluation of reduction of Pantanal wetlands in 2012 , 2013 .

[39]  Bradley Doorn,et al.  From Research to Operations: The USDA Global Reservoir and Lake Monitor , 2011 .

[40]  T. S. F. Silva,et al.  Using PALSAR and RADARSAT-2 to map land cover and inundation in the , 2010 .

[41]  S. Hamilton,et al.  Small-scale spatial variation of inundation dynamics in a floodplain of the Pantanal (Brazil) , 2009, Hydrobiologia.

[42]  S. Hamilton,et al.  Hydrological controls of ecological structure and function in the Pantanal wetland (Brazil). , 2002 .

[43]  A. Cazenave,et al.  Satellite altimetry and earth sciences : a handbook of techniques and applications , 2001 .

[44]  John M. Melack,et al.  Inundation patterns in the Pantanal wetland of South America determined from passive microwave remote sensing , 1996 .