• Tabibi, Sajad
• Geremia-Nievinski, Felipe
• Park, Jihye Jihye
• Antonoglou, Nikolaos
• Purnell, Dave
• Williams, Simon D. P.
• Wickert, Jens

Abstract

<!--!introduction!--><b></b><p>The use of reflected radio signals at L-band broadcasted by GNSS for coastal sea level studies has gained popularity in recent years. The geodetic GNSS-R working group 4.3.7 of the IAG, with 21 members, aims to further establish the value of GNSS-R for various scientific communities, including geodesy, oceanography, cryosphere, and hydrology. As part of this effort, the first inter-comparison campaign on SNR-based GNSS-R for sea level monitoring was conducted between 2015 and 2019 by the JWG 4.3.9, using the Onsala GNSS-R tide gauge station. A second campaign, involving eight research groups, was launched in July 2020 to examine the effects of large tidal range and multi-GNSS revisit time on GNSS-R sea level retrievals. Data from two GNSS stations in the Netherlands and France (VLIS and ROTG) with varying tidal ranges and mean reflector heights were provided to all participating groups. Five groups submitted their solutions for a 1-year period at ROTG in 2015 and the first 274 days of 2020 at VLIS. Here, the solutions are compared to tide gauge records, which are located 2 meters from the GNSS antennas.&nbsp;The processing settings of the comparison are presented in Table 1.<br><br></p><p>Table 1. Second inter-comparison processing&nbsp;settings</p><table><colgroup><col><col><col></colgroup><thead><tr><th>&nbsp; </th><th>VLIS </th><th>ROTG </th></tr></thead><tbody><tr><td><strong>Lat., Long. (deg)</strong> </td><td>51.44286, 3.59734</td><td>48.71844, -3.966566</td></tr><tr><td><strong>Receiver</strong> </td><td>LEICA GR50</td><td>TPS GB-1000</td></tr><tr><td><strong>Antenna</strong> </td><td>LEIAR25.R4 </td><td>TPSPG_A1+GP </td></tr><tr><td><strong>Mean RH(m)</strong> </td><td>10 </td><td>8.5 </td></tr><tr><td><strong>Tidal&nbsp;range (m)</strong> </td><td>5 </td><td>9 </td></tr><tr><td><strong>Azimuth interval (deg.)</strong> </td><td>60-180 </td><td>90-270 </td></tr><tr><td><strong>Elevation interval (deg.)</strong> </td><td>2.5-30 </td><td>5-30 </td></tr><tr><td><strong>Sampling rate (Hz)</strong> </td><td>1 </td><td>1 </td></tr><tr><td><strong>Tropospheric correction</strong> </td><td>optional </td><td>optional </td></tr><tr><td><strong>Distance to TG (m)</strong> </td><td>2 </td><td>2 </td></tr></tbody></table><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p>

Topics

• thermogravimetry
• reflectometry