Influence of recent climatic events on the surface water storage of the Tonle Sap Lake

Frappart, Frédéric; Biancamaria, Sylvain; Normandin, Cassandra; Blarel, Fabien; Bourrel, Luc; Aumont, M.; Azemar, P.; Vu, Phuong Lan; Toan, Thuy Le; Lubac, Bertrand; Darrozes, José

doi:10.1016/j.scitotenv.2018.04.326

Cited by 75 publications

(43 citation statements)

References 54 publications

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“…Using the approach summarized in Frappart et al [34], the cloud noise of the MODIS data were processed. First, pixels flagged with cloud cover or fill values were masked based on the data quality control information.…”

Section: Modis Productsmentioning

confidence: 99%

“…Tangdamrongsub et al used several satellite data products (included GRACE, MODIS, and TRMM) to estimate terrestrial water storage and quantify flood events over the Tonle Sap basin between 2002 and 2014 [33]. To determine the relationship between storage variations of Tonle Sap Lake and atmospheric forcing, Frappart et al extracted the flood extent from MOD09A1 products and used them to estimate lake storage variations [34].…”

Section: Introductionmentioning

confidence: 99%

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Changes in the Lake Area of Tonle Sap: Possible Linkage to Runoff Alterations in the Lancang River?

Luo

et al. 2018

Remote Sensing

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Tonle Sap Lake is the largest freshwater lake in Southeast Asia. Water development infrastructures are increasingly being constructed in the Lancang-Mekong River Basin, which is a major concern considering its potential impact on Tonle Sap Lake. This study aimed to investigate variations in the area of the lake and discuss their possible linkage to runoff alterations in the Lancang River (Upper Mekong) by comparing runoff at the Yunjinghong hydrological station before and after significant changes in runoff trends that occurred in 2008. First, four commonly used water body extraction methods (MNDWI, NDWI, NDVI, and EVI) were compared and MNDWI was found to provide a better and more stable performance. Based on MOD09A1 data, MNDWI was used to extract the water area of the lake from 2000 to 2014, and characteristics of variations in the area before and after 2008 were analyzed. The water area of Tonle Sap Lake displayed an overall decreasing trend, and specifically decreased by 8.3% during the flood season and by 1.5% on average during the dry season after 2008. Seasonal variations in the water area of Tonle Sap Lake were dominantly influenced by runoff from the Mekong River. Compared with the period 2000-2007, runoff at Yunjinghong station were increased during the dry season (20.74%) and decreased during the flood season (34.25%) between 2008 and 2014. Changes in upstream runoff contributed to runoff at the Stung Treng station in the lower Mekong River by 6.17% (dry season) and −2.41% (flood season). Evidently, the operation of dams in the Lancang River does not primarily account for the area decrease of Tonle Sap Lake during the flood season. In contrast, runoff increase during the dry season mitigates the area decrease of Tonle Sap Lake to a certain extent.

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Section: Modis Productsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Changes in the Lake Area of Tonle Sap: Possible Linkage to Runoff Alterations in the Lancang River?

Luo

et al. 2018

Remote Sensing

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“…If the Ocean retracker is likely to provide good estimates of the water level during ice-free periods because the waveform shape is close to the ocean-one, it is likely to provide results with lower accuracy for peaky waveforms (see, for instance, [11,29,30]). On the contrary, OCOG/Ice retracker was found to be very robust and is commonly used in the estimate of surface water over inland water bodies (i.e., lakes, rivers and wetlands) [11,26,29,[42][43][44][45][46][47]. Moreover, water strongly absorbs microwave radiation, thereby producing a substantial decrease in average brightness temperature under open water conditions.…”

Section: Discussionmentioning

confidence: 99%

Improving the Estimation of Water Level over Freshwater Ice Cover using Altimetry Satellite Active and Passive Observations

et al. 2020

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Owing to its temporal resolution of 10-day and its polar orbit allowing several crossings over large lakes, the US National Aeronautics and Space Administration (NASA) and the French Centre National d’Etudes Spatiales (CNES) missions including Topex/Poseidon, Jason-1/2/3 demonstrated strong capabilities for the continuous and long-term monitoring (starting in 1992) of large and medium-sized water bodies. However, the presence of heterogeneous targets in the altimeter footprint, such as ice cover in boreal areas, remains a major issue to obtain estimates of water level over subarctic lakes of similar accuracy as over other inland water bodies using satellite altimetry (i.e., R ≥ 0.9 and RMSE ≤ 10 to 20 cm when compared to in-situ water stages). In this study, we aim to automatically identify the Jason-2 altimetry measurements corresponding to open water, ice and transition (water-ice) to improve the estimations of water level during freeze and thaw periods using only the point measurements of open water. Four Canadian lakes were selected to analyze active (waveform parameters) and passive (brightness temperature) microwave data acquired by the Jason-2 radar altimetry mission: Great Slave Lake, Lake Athabasca, Lake Winnipeg, and Lake of the Woods. To determine lake surface states, backscattering coefficient and peakiness at Ku-band derived from the radar altimeter waveform and brightness temperature at 18.7 and 37 GHz measured by the microwave radiometer contained in the geophysical data records (GDR) of Jason-2 were used in two different unsupervised classification techniques to define the thresholds of discrimination between open water and ice measurements. K-means technique provided better results than hierarchical clustering based upon silhouette criteria and the Calinski-Harabz index. Thresholds of discrimination between ice and water were validated with the Normalized Difference Snow Index (NDSI) snow cover products of the MODIS satellite. The use of open water threshold resulted in improved water level estimation compared to in situ water stages, especially in the presence of ice. For the four lakes, the Pearson coefficient (r) increased on average from about 0.8 without the use of the thresholds to more than 0.90. The unbiased RMSE were generally lower than 20 cm when the threshold of open water was used and more than 22 cm over smaller lakes, without using the thresholds.

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“…The MRD is a transition zone that is seasonally affected by both water discharge of the MRB, and ocean tidal processes propagated landward [57] via the Bassac River and Mekong River branches [77,78]. In addition, the regulation effect of Cambodia's Tonle Sap Lake on the total discharge of the MRB is substantial (e.g., [79][80][81]) before discharging into the northern part of Sunda Shelf.…”

Section: Geographic Environment Of the Mekong River Basin And Mekong mentioning

confidence: 99%

Upstream GPS Vertical Displacement and its Standardization for Mekong River Basin Surface Runoff Reconstruction and Estimation

et al. 2019

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Surface runoff (R), which is another expression for river water discharge of a river basin, is a critical measurement for regional water cycles. Over the past two decades, river water discharge has been widely investigated, which is based on remotely sensed hydraulic and hydrological variables as well as indices. This study aims to demonstrate the potential of upstream global positioning system (GPS) vertical displacement (VD) and its standardization to statistically derive R time series, which has not been reported in recent literature. The correlation between the in situ R at estuaries and averaged GPS-VD and its standardization in the river basin upstream on a monthly temporal scale of the Mekong River Basin (MRB) is examined. It was found that the reconstructed R time series from the latter agrees with and yields a similar performance to that from the terrestrial water storage based on gravimetric satellite (i.e., Gravity Recovery and Climate Experiment (GRACE)) and traditional remote sensing data. The reconstructed R time series from the standardized GPS-VD was found to have a 2-7% accuracy increase against those without standardization. On the other hand, it is comparable to data that are obtained by the Palmer drought severity index (PDSI). Similar accuracies are exhibited by the estimated R when externally validated through another station location with in situ time series. The comparison of the estimated R at the entrance of river delta against that at the estuaries indicates a 1-3% relative error induced by the residual ocean tidal effect at the estuary. The reconstructed R from the standardized GPS-VD yields the lowest total relative error of less than 9% when accounting for the main upstream area of the MRB. The remaining errors may be the result of the combined effect of the proposed methodology, remaining environmental signals in the data time series, and potential time lag (less than a month) between the upstream MRB and estuary.environments. There is no global coverage of gauging network, however, that monitors the RWDs [7]. Apart from this, the frequency of discharge data acquisition has continuously declined since the late 1970s [8] because of insufficient funds for facility maintenance and upgrade [9]. As a result, indirect methods for the RWD monitoring, such as remote sensing (RS), have recently gained increasing interest.Traditional RS, such as Landsat Thematic Mapper (TM) and its Enhanced TM Plus (ETM+) images, as well as moderate resolution imaging spectrometer (MODIS), have passively recorded instantaneous surface parameters since the 1990s (e.g., [7]). The surface parameters obtained from RS [10][11][12][13], such as flood area inundation, land surface temperature (LST), normalized difference vegetation index (NDVI), and RS-derived geometric variables (e.g., river width), allow the direct correlation with water level or RWD. Except for the RS-derived geometric variables, the foregoing localized RS data yield indirect relationships to the RWD. Although RS-derived geometric variables can a...

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Influence of recent climatic events on the surface water storage of the Tonle Sap Lake

Cited by 75 publications

References 54 publications

Changes in the Lake Area of Tonle Sap: Possible Linkage to Runoff Alterations in the Lancang River?

Changes in the Lake Area of Tonle Sap: Possible Linkage to Runoff Alterations in the Lancang River?

Improving the Estimation of Water Level over Freshwater Ice Cover using Altimetry Satellite Active and Passive Observations

Upstream GPS Vertical Displacement and its Standardization for Mekong River Basin Surface Runoff Reconstruction and Estimation

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