| Publisher | MDPI |
| Source |
N/A
|
| Volume / Issue | 10/2 |
| Pages |
N/A
|
| Total Pages | 18 pages |
| Article Link |
N/A
|
| PDF Link | https://www.mdpi.com/2072-4292/10/2/350 |
| ISBN |
N/A
|
| DOI | doi.org/10.3390/rs10020350 |
| Editor(s) |
N/A
|
| Conference / Book Title |
N/A
|
| Flag |
N/A
|
| Tags | altimetry; water level; discharge |
| Other |
N/A
|
| Conference Title |
N/A
|
| Conference Date |
N/A
|
| Publication Date | February 24, 2018 |
| Article Date |
N/A
|
| GS Citation |
N/A
|
| Abstract | Radar altimetry is now commonly used for the monitoring of water levels in large river basins. In this study, an altimetry-based network of virtual stations was defined in the quasi ungauged Ogooué river basin, located in Gabon, Central Africa, using data from seven altimetry missions (Jason-2 and 3, ERS-2, ENVISAT, Cryosat-2, SARAL, Sentinel-3A) from 1995 to 2017. The performance of the five latter altimetry missions to retrieve water stages and discharges was assessed through comparisons against gauge station records. All missions exhibited a good agreement with gauge records, but the most recent missions showed an increase of data availability (only 6 virtual stations (VS) with ERS-2 compared to 16 VS for ENVISAT and SARAL) and accuracy (RMSE lower than 1.05, 0.48 and 0.33 and R² higher than 0.55, 0.83 and 0.91 for ERS-2, ENVISAT and SARAL respectively). The concept of VS is extended to the case of drifting orbits using the data from Cryosat-2 in several close locations. Good agreement was also found with the gauge station in Lambaréné (RMSE = 0.25 m and R2 = 0.96). Very good results were obtained using only one year and a half of Sentinel-3 data (RMSE < 0.41 m and R2 > 0.89). The combination of data from all the radar altimetry missions near Lamabréné resulted in a long-term (May 1995 to August 2017) and significantly improved water-level time series (R² = 0.96 and RMSE = 0.38 m). The increase in data sampling in the river basin leads to a better water level peak to peak characterization and hence to a more accurate annual discharge over the common observation period with only a 1.4 m3·s−1 difference (i.e., 0.03%) between the altimetry-based and the in situ mean annual discharge. |
Created: 12/21/2018 2:01 PM (ET)
Modified: 12/21/2018 2:01 PM (ET)