Baleares 2013 Calibration Campaign for Jason-2 and Saral/AltiKa
Martínez Benjamín, Juan José,Biancale, Richard,Martín Dávila, José,Gárate Pasquín, Jorge,Pérez Gómez, Begoña,Gili Ripoll, José Antonio,López Bravo, Rogelio,Tapia Gómez, Ana M.,Gracia Gómez, Carlos,Frappart, Frédéric,Roussel, Nicolas
- Published
- 2013
- Language
- en
Abstract
A Baleares calibration campaign in Spanish-French cooperation is being prepared for mid September 2013 for the altimeters of Jason-2 and Saral/AltiKa in the Ibiza island area. A similar Spanish/French experience with Jason-1 was made in June 2003 in this geographical area under IBIZA 2003 campaign. In this local/regional campaign focusing in bias, we foresee to calibrate the altimeter of Jason-2 and Saral satellites by means of GPS buoys. 4 buoys will be used near a node from Jason-2 (September 15 about 9:38 in ascending track) and Saral (September 15 about 7:30 in ascending track) satellites to get the slope of the sea in along track and cross track directions, what is necessary to interpolate the exact nadir point of the satellite. It will be used Argos floating transmitters from CLS to be tied to the buoys with a long rope. We have thought over different configurations. The crossover point between Jason-2 and Saral North of Ibiza (around 40 nm) and West of Mallorca island seems to be optimal in order to have a comparable layout of buoys at the same place for both satellites, of couse at one day interval. This would allow moreover cross calibration between Jason2 and Saral. The GPS receivers will be at 1Hz. It will be used the CGPS at Ibiza harbour from Puertos del Estado. A description of the actual geodetic infrastructure of Ibiza site will be presented. This campaign Baleares 2013 is founded from the Ministerio de Ciencia e Innovacion of Spain under National Project I+D+i ref:CGL2009-13435/CLI.
Full text
The 2013 Ibiza calibration campaign of Jason2 and Saral altimeters J.J. Benjamin (1), R. Biancale (3), J.M. Davila (2), J. Garate (2), C. Gracia (1), R. Lopez (1), A. Tapia (1), F. Frappart (3), N. Roussel (3), I.Valles, J. Gili (1) OSTST 2013, Boulder (Colorado) project in cooperation 1) UPC , 2) ROA , 3) GRGS Processing 1) pre-campaign Jason2 and Saral orbit prediction with the GINS/GRGS software fitting SLR data from previous days 2) post-campaign GPS buoy processing with the GINS/GRGS software both in IPPP mode and in semidynamical mode 3) Jason2 and Saral orbit processing with the GINS/GRGS software in semi-dynamical mode fitting GPS/DORIS/SLR tracking data Expected results 1) calibration of the 5 buoy antennas with respect to the sea level from GPS and tide gauge data 2) computation and smoothing of the buoy position from GPS data at the Jason2-Saral mixed crossover calibration site (by interpolation) and at the Jason2-Saral pass times exactly (to be achieved yet) 3) comparison with the Jason2/Saral altimeter data (to be achieved yet) The goal is to achieve an optimal calibration of Jason2 and Saral altimeters in deep sea. Results will be published and presented next year as well as provided to the Jason2 and Saral project managers Aim precise calibration of Jason2 and Saral altimeters with the help of 5 GPS buoys Experiment coordinator J.J. Benjamin Martinez / Universitat Politècnica de Catalunya (UPC) Participating teams •UPC: C. Gracia, R. Lopez, A. Tapia, I. Valles, J. Gili • ROA: J.M. Davila, J. Garate • GRGS/CNES/OMP: R. Biancale, F. Frappart, N. Roussel •Puertos del Estado: B. Perez (Ibiza tide gauge & GPS) Ship Patrol ship Toralla of the Spanish Navy Calibration location Jason2-Saral crossover point North of Ibiza (Spain) Latitude : 39deg. 35.74’ Longitude : 1deg. 42.69’ Jason2 crossing time : 7h 37mn 45s UTC Saral crossing time : 5h 28mn 49s UTC Buoys deployment 4 buoys displayed along track and cross track at 1 nautical mile interval around the crossover point + one buoy at that point in order to get position and sea slope Experiment duration 4 hrs at each deployment site over 3 days Experiment phases 14 September, 11am-4pm : pre-calibration of the 5 buoys with the Ibiza tide gauge to reference the GPS antennas to the sea level 15 September, 6am-10am : GPS buoy positioning at the crossover point 16 September, 5am-9am : GPS buoy positioning at the crossover point 4pm-8pm : post-calibration of UPC buoys with the Ibiza tide gauge Oceanic current forecasting daily current maps from Mercator Ocean The 2013 Ibiza calibration campaign of Jason2 and Saral altimeters was initiated at Prof. J.J. Benjamin’s instigation (UPC) with the fruitful participation of the “Real Observatorio de la Armada” (ROA) of the Spanish Navy who places a 28m long military ship at disposal: the patrol vessel Toralla. This research has been funded under the Spanish National R+D+i (ref: CGL2009-13435/CLI). Particular thanks are addressed to LEGOS and IPGP for having made GPS buoys available, to the CLS company for having lent localization instruments (Argos buoys and goniometer) as well as to Mercator Ocean for the diurnal delivery of current maps. Jason2 Saral The buoys were located on the track and crosswise at 1 nautical mile distance (1.852 km) ARGOS/CLS buoys were tied up to each GPS buoy. CLS sent positions each 15mn through the Iridium satellite service to allow to recover the buoys easily Example of current map from Mercator Ocean used to anticipate the buoy drift during 4hrs (around 1 km) Patrol vessel Toralla Organizing Committee with the Toralla's captain Buoy recovery after 4hrs in water The GPS buoy antennas were first referenced to the sea level at the Ibiza tide gauge Maps of buoy displacement during 4 hrs GRGS LEGOS/INSU IPGP UPC UPC CLS Different types of GPS buoys used Jason2 and Saral altimeters were cross calibrated at the mixed crossover point North of Ibiza at their ascending passes, respectively on 15 and 16 September 2013 Longitude + 1°40'E Buoy tracks on 15 Sept. in civil time (UTC+2hr) Latitude + 39°35'N Jason2 xover calibration point +1'40" +1'30" +1'20" +1'10" +1' 50" 40" 30" 20" 10" 0' 1'15" 1'40" 2'05" 2'30" 2'55" 3'20" 3'45" Buoy tracks on 16 Sept. in civil time (UTC+2hr) Latitude + 39°35'N +4' +3' +2' +1' 0' 0 1' 2' 3' 4' 5' 6' Longitude + 1°40'E Saral xover calibration point
