Quantification of surface water volume changes in the Mackenzie Delta using satellite multi-mission data

Normandin, Cassandra; Frappart, Frédéric; Lubac, Bertrand; Bélanger, Simon; Marieu, Vincent; Blarel, Fabien; Robinet, Arthur; Guiastrennec-Faugas, Léa

doi:https://doi.org/10.5194/hess-22-1543-2018

Cassandra Normandin¹, Frédéric Frappart^2,3, Bertrand Lubac¹, Simon Bélanger⁴, Vincent Marieu¹, Fabien Blarel³, Arthur Robinet¹, and Léa Guiastrennec-Faugas¹ ¹EPOC, UMR 5805, Université de Bordeaux, Allée Geoffroy Saint-Hilaire, 33615 Pessac, France
²GET-GRGS, UMR 5563, CNRS/IRD/UPS, Observatoire Midi-Pyrénées, 31400 Toulouse, France
³LEGOS-GRGS, UMR 5566, CNRS/IRD/UPS, Observatoire Midi-Pyrénées, 31400 Toulouse, France
⁴Dép. Biologie, Chimie et Géographie, groupe BOREAS and Québec-Océan, Université du Québec à Rimouski, 300 allée des ursulines, Rimouski, Qc, G5L 3A1, Canada

Received: 22 Mar 2017 – Discussion started: 29 May 2017
Revised: 05 Dec 2017 – Accepted: 11 Jan 2018 – Published: 28 Feb 2018

Abstract. Quantification of surface water storage in extensive floodplains and their dynamics are crucial for a better understanding of global hydrological and biogeochemical cycles. In this study, we present estimates of both surface water extent and storage combining multi-mission remotely sensed observations and their temporal evolution over more than 15 years in the Mackenzie Delta. The Mackenzie Delta is located in the northwest of Canada and is the second largest delta in the Arctic Ocean. The delta is frozen from October to May and the recurrent ice break-up provokes an increase in the river's flows. Thus, this phenomenon causes intensive floods along the delta every year, with dramatic environmental impacts. In this study, the dynamics of surface water extent and volume are analysed from 2000 to 2015 by combining multi-satellite information from MODIS multispectral images at 500 m spatial resolution and river stages derived from ERS-2 (1995–2003), ENVISAT (2002–2010) and SARAL (since 2013) altimetry data. The surface water extent (permanent water and flooded area) peaked in June with an area of 9600 km² (±200 km²) on average, representing approximately 70 % of the delta's total surface. Altimetry-based water levels exhibit annual amplitudes ranging from 4 m in the downstream part to more than 10 m in the upstream part of the Mackenzie Delta. A high overall correlation between the satellite-derived and in situ water heights (R > 0.84) is found for the three altimetry missions. Finally, using altimetry-based water levels and MODIS-derived surface water extents, maps of interpolated water heights over the surface water extents are produced. Results indicate a high variability of the water height magnitude that can reach 10 m compared to the lowest water height in the upstream part of the delta during the flood peak in June. Furthermore, the total surface water volume is estimated and shows an annual variation of approximately 8.5 km³ during the whole study period, with a maximum of 14.4 km³ observed in 2006. The good agreement between the total surface water volume retrievals and in situ river discharges (R =  0.66) allows for validation of this innovative multi-mission approach and highlights the high potential to study the surface water extent dynamics.

Citation: Normandin, C., Frappart, F., Lubac, B., Bélanger, S., Marieu, V., Blarel, F., Robinet, A., and Guiastrennec-Faugas, L.: Quantification of surface water volume changes in the Mackenzie Delta using satellite multi-mission data, Hydrol. Earth Syst. Sci., 22, 1543-1561, https://doi.org/10.5194/hess-22-1543-2018, 2018.

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