ICET
Transcription
ICET
ICET Report – SG2 meeting Taipei, June 21-22, 2010 Jean-Pierre Barriot, Youri Verschelles, Lydie Sichoix and B. Ducarme (retired, but still very active !) Where is ICET ? University of French Polynesia Tahiti has become a fundamental geodetic reference since 1997 Tracking satellites with the SLR OGT GPS system Other system : DORIS The new OGT tide gauge station in Tubuai (Australs archipelago) With SHOM and Protection Civile Nuku-Hiva (Marquesas) Tide Gauge Station Tahiti Gphone #59 with Geoscope broadband seismometers The PET gravimeter is collocated with GEOSCOPE instruments in Tahiti mountains Sandwich Isl, 6.6 2009/04/16 14:57:05 -60.215 26.797 10.0 SOUTH SANDWICH ISLANDS REGION Gravi in muGal Gravity filtered between 20 et 100 seconds Summary of instruments in French Polynesia: -- SLR station (ILRS) at OGT -- 3 permanent GPS colocated with SLR at OGT -- 1 semi-permanent GPS at Arue -- 1 DORIS colocated with SLR at OGT -- 1 gPhone Earth Tides gravimeter at Pamatai -- 7 tide gauges+GPS stations (all actives 2010): (2 Tahiti, 1 Huahine (Society), 1 Nuku-Hiva (Marquesas), 1 Rangiroa (Tuamotu), 1 Tubuaï (Australs), 1 Mangareva (Gambiers) Planned: cryogenic gravimeter, VLBI, altimetry calibration, robotic telescope ICET activities • • • • • • • • • • International Centre for Earth Tides (ICET) http://www.upf.pf/ICET/ Director: Jean-Pierre Barriot (France, French Polynesia) Overview The period from mid-2007 to mid-2008 was essentially devoted to the translation of ICET from Brussels to Papeete. This includes three main points: web site, the “Bulletin des Marées Terrestres, BIM”, and GGP data stream validation. ICET activities: mid-2008/2010 • • • • • • • • • 1/ The web site of ICET has been completely migrated from the Royal Observatory of Belgium to the University of French Polynesia (www.upf.pf/ICET/). 2/ The new ICET database, presented at the ETS2008 meeting in Vienna, is now on line at http://maregraph-renater.upf.pf. The database currently hosts all the validated one-minute GGP data until December 2007 and is able to store any kind of data related to Earth Tides (e.g. tiltmeter or spring gravimeter data). 3/ A new validation software able to automatically validate GGP data has been developed. The purpose of this software is to identify and discard jumps and spikes in the raw data on an automated or nearly automated basis. Based on Wiener-Kolmogorov filtering techniques, it responds to the critics raised during the ETS2008 meeting in Iena, by re-adding the "noise" to the GGP filtered data. We are currently testing this software on several GGP raw files. We need beta-testers. 4/ A Python script able to write strictly normalized headers for GGP files is completed. This is another key to alleviate the burden of validating and storing GGP data. 5/ We developed a new XML format for storing GGP data (see the dedicated poster). 6/ The BIM 144 and 145 are on line on the ICET website. BIM 146 will be on line soon. All together, they will gather more than 50 papers presented at the ETS2008 meeting. 7/ The new gPhone gravimeter of the ICET center is now in operation in Tahiti-Pamatai. We routinely monitor all Earthquakes > 6.0 along the Pacific Rim. 8/ ICET is also participating in the deployment in Fench Polynesia of a network of Tide-Gauge / GPS stations (POGENET, POLynesian GEodetic NETwork), as a contribution to the Global Geodetic Observing System. Talk by Youri Querying the new ICET Earth Tides Database Schema of the New ICET Earth Tides Database Main_Information Series_index Release_number File_name Meaning Id_relation Main_relation Id_relation Id_unit Id_calibration Id_comment Id_time_sampling Id_status Id_operator Units Id_unit Latitude_unit Longitude_unit Altitude_unit Phase_lag_unit Time_lag_unit Pressure_unit Calibration_pressure_unit Calibration_measure_1_unit Calibration_measure_2_unit Calibration_measure_3_unit Measure_1_unit Measure_2_unit Measure_3_unit Comments Id_comment Comment Time_sampling id_time_sampling Time_sampling Status Id_status Status Measurements Series_index Release_number Time_of_measurement Julian_day Temperature Atmospheric_pressue Measure_1 Measure_2 Measure_3 Confidence_index_measurement_1 Confidence_index_measurement_2 Confidence_index_measurement_3 Calibrations Id_calibration Pressure_calibration Temperature_calibration Phase_lag Phase_lag_error Time_lag Time_lag_error Calibration_measure_1 Calibration_measure_2 Calibration_measure_3 Station_code Instrument_code Id_position Operator Id_operator Operator_information Stations Station_code Location Country_code Region_code Instruments Instrument_code Instrument_brand vectorial_type Id_instrument Instrument_position Id_position Latitude Latitude_error Longitude Longitude_error Altitude Altitude_error Altitude_type Countries Country_code Country_name Regions Region_code Region_name Instrument_type Id_instrument Instrument_name ICET activities: mid-2008/2010 • • • • • • • • • 1/ The web site of ICET has been completely migrated from the Royal Observatory of Belgium to the University of French Polynesia (www.upf.pf/ICET/). 2/ The new ICET database, presented at the ETS2008 meeting in Vienna, is now on line at http://maregraph-renater.upf.pf. The database currently hosts all the validated one-minute GGP data until December 2007 and is able to store any kind of data related to Earth Tides (e.g. tiltmeter or spring gravimeter data). 3/ A new validation software able to automatically validate GGP data has been developed. The purpose of this software is to identify and discard jumps and spikes in the raw data on an automated or nearly automated basis. Based on Wiener-Kolmogorov filtering techniques, it responds to the critics raised during the ETS2008 meeting in Iena, by re-adding the "noise" to the GGP filtered data. We are currently testing this software on several GGP raw files. See dedicated presentation tomorrow 4/ A Python script able to write strictly normalized headers for GGP files is completed. This is another key to alleviate the burden of validating and storing GGP data. 5/ We developed a new XML format for storing GGP data (see the dedicated poster). 6/ The BIM 144 and 145 are on line on the ICET website. BIM 146 will be on line soon. All together, they will gather more than 50 papers presented at the ETS2008 meeting. 7/ The new gPhone gravimeter of the ICET center is now in operation in Tahiti-Pamatai. We routinely monitor all Earthquakes > 6.0 along the Pacific Rim. 8/ ICET is also participating in the deployment in Fench Polynesia of a network of Tide-Gauge / GPS stations (POGENET, POLynesian GEodetic NETwork), as a contribution to the Global Geodetic Observing System. Gravity Time Validation and correction of GGP data at ICET-Tahiti through a generalized collocation procedure (green: raw data, blue: corrected data) ICET activities: mid-2008/2010 • • • • • • • • • 1/ The web site of ICET has been completely migrated from the Royal Observatory of Belgium to the University of French Polynesia (www.upf.pf/ICET/). 2/ The new ICET database, presented at the ETS2008 meeting in Vienna, is now on line at http://maregraph-renater.upf.pf. The database currently hosts all the validated one-minute GGP data until December 2007 and is able to store any kind of data related to Earth Tides (e.g. tiltmeter or spring gravimeter data). 3/ A new validation software able to automatically validate GGP data has been developed. The purpose of this software is to identify and discard jumps and spikes in the raw data on an automated or nearly automated basis. Based on Wiener-Kolmogorov filtering techniques, it responds to the critics raised during the ETS2008 meeting in Iena, by re-adding the "noise" to the GGP filtered data. We are currently testing this software on several GGP raw files. See dedicated presentation tomorrow 4/ A Python script able to write strictly normalized headers for GGP files is completed. This is another key to alleviate the burden of validating and storing GGP data. 5/ We developed a new XML format for storing GGP data (see the dedicated poster). 6/ The BIM 144 and 145 are on line on the ICET website. BIM 146 will be on line soon. All together, they will gather more than 50 papers presented at the ETS2008 meeting. 7/ The new gPhone gravimeter of the ICET center is now in operation in Tahiti-Pamatai. We routinely monitor all Earthquakes > 6.0 along the Pacific Rim. 8/ ICET is also participating in the deployment in Fench Polynesia of a network of Tide-Gauge / GPS stations (POGENET, POLynesian GEodetic NETwork), as a contribution to the Global Geodetic Observing System. GGP header Generator (ask for a copy) ICET activities: mid-2008/2010 • • • • • • • • • 1/ The web site of ICET has been completely migrated from the Royal Observatory of Belgium to the University of French Polynesia (www.upf.pf/ICET/). 2/ The new ICET database, presented at the ETS2008 meeting in Vienna, is now on line at http://maregraph-renater.upf.pf. The database currently hosts all the validated one-minute GGP data until December 2007 and is able to store any kind of data related to Earth Tides (e.g. tiltmeter or spring gravimeter data). 3/ A new validation software able to automatically validate GGP data has been developed. The purpose of this software is to identify and discard jumps and spikes in the raw data on an automated or nearly automated basis. Based on Wiener-Kolmogorov filtering techniques, it responds to the critics raised during the ETS2008 meeting in Iena, by re-adding the "noise" to the GGP filtered data. We are currently testing this software on several GGP raw files. See dedicated presentation tomorrow 4/ A Python script able to write strictly normalized headers for GGP files is completed. This is another key to alleviate the burden of validating and storing GGP data. 5/ We developed a new XML format for storing GGP data (see the dedicated poster). 6/ The BIM 144 and 145 are on line on the ICET website. BIM 146 will be on line soon. All together, they will gather more than 50 papers presented at the ETS2008 meeting. 7/ The new gPhone gravimeter of the ICET center is now in operation in Tahiti-Pamatai. We routinely monitor all Earthquakes > 6.0 along the Pacific Rim. 8/ ICET is also participating in the deployment in Fench Polynesia of a network of Tide-Gauge / GPS stations (POGENET, POLynesian GEodetic NETwork), as a contribution to the Global Geodetic Observing System. New XML Proposed format For GGP data: header part <?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type="text/xsl" href="style.xsl"?> <data_file xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="schema.xsd"> <header> <comments>DATA CORRECTED AT ICET ([email protected]) </comments> <filename>H1010222_GGP.xml</filename> <station> <city>Bad Homburg</city> <country>Germany </country> </station> <instrument>GWR CD030_L</instrument> <phase_lag unit="sec"> <value>45.</value> </phase_lag> <latitude direction="N" unit="deg"> <value>50.2285</value> </latitude> <longitude direction="E" unit="deg"> <value>8.6113</value> </longitude> <elevation_msl unit="m" system="orthometric"> <value>190.0</value> </elevation_msl> <gravity_cal unit="nm..."> <value>-739.5</value> </gravity_cal> <pressure_cal unit="hPa/V"> <value>50.3</value> </pressure_cal> <author>P. Wolf ([email protected])</author> <header_column_data> <time_format>yyyymmdd hhmmss</time_format> <entitled_measure1 unit="V">gravity</entitled_measure1> <entitled_measure2 unit="V">pressure</entitled_measure2> </header_column_data> <data_border>c***********************************************</data_border> </header> <tides_data> New XML Proposed format For GGP data: data part <data_blocks> <eterna> <code>INSTR</code> <offset_measure1>1.0000</offset_measure1> <offset_measure2>1.0000</offset_measure2> <offset_measure3>0.000</offset_measure3> <offset_measure4>0</offset_measure4> </eterna> <start_and_drift> <start_record>77777777</start_record> <offset_measure1>.000</offset_measure1> <offset_measure2>.000</offset_measure2> </start_and_drift> <dp> <date> <y>2001</y> <m>02</m> <d>12</d> <hms>125500</hms> </date> <measure1>817.289</measure1> <measure2>1001.856</measure2> </dp> <dp> <date> <y>2001</y> <m>02</m> <d>12</d> <hms>125600</hms> </date> <measure1>814.103</measure1> <measure2>1001.826</measure2> </dp> . . . <dp> <date> <y>2001</y> <m>02</m> <d>28</d> <hms>235900</hms> </date> <measure1>1143.054</measure1> <measure2>972.058</measure2> </dp> <end_record>99999999</end_record> </data_blocks> </tides_data> </data_file> XML GGP data visualization Tool GGP Data Preprocessing and Analysis Status at ICET B. Ducarme and J.-P. Barriot GGP Data Preprocessing and Analysis Status at ICET B. Ducarme and J.-P. Barriot The last update of the GGP data had been made before the last Earth Tides symposium in 2008. The new revision gave the opportunity to process in most of the stations two years of additional data. We welcome the contribution of Hsinchu (HS) and Pecny (PE), who joined recently GGP. A total of 427 months (n in Table 1) from 14 stations have been processed since the beginning of 2010. These stations are marked in blue. Perhaps additional data have been uploaded since our processing as the data base is permanently in evolution. Stations marked in red are late in uploading their raw data. Four stations operated by the Japanese group (CB, ES, KA, NY) did not upload raw data since 2007. MA and TC stopped sending data after 2008/06. The instruments marked with a star are no more operated. The new data have been analyzed and the results carefully compared with the previous tidal analysis results when available. The responsibles of the 14 reprocessed stations received a report of our investigations. Global tidal analyses have been processed. In some stations the end of the data had to be rejected from the global analysis due to degraded signal to noise ratio (last column of Table 1).The number of days used for the global analysis N and the standard deviation STD computed with ETERNA (ANALYZE) are given in Table 1. As the stability of the sensitivity of the superconducting gravimeters is generally better than 0.1%, the STD is a measure of the signal to noise ratio in the station. For 9 stations among the 14 updated ones the STD is lower than 1nm/s2. Status of the processed stations BH: In Bad Homburg the new SG044 is operational for more than 900 days. The STD of this instrument is one of the lowest among all the GGP stations. The new SG C044 is perfectly fitting the results of the CD030-L. There is a slight calibration difference, close to 0.1%, between CD030-L and CD030-H.The phase differences of the different instruments agree within the associated RMS errors. CA: Cantley started in 1989. It is the longest series of observations. It suffered from technical problem and the STD was multiplied by a factor of two during several months in 2006/2007. This portion of the data was rejected from the global analysis. The change of electronics on January 22 2008 did not affect the calibration. The amplitude factors agree perfectly. The new time lag of 16.3s applied since that epoch provides phases which seem a bit too large compared to previous results. If a precise determination of the true time lag is obtained it will be possible to normalize the data prior to 2008/01/22 to get homogeneous results. HS: Hsinchu is a new station which has a large STD. The modelling of the tidal factors using recent ocean tides models is questionable as it provides ratios obs /mod close to 1.01 in the diurnal band and close to 0.995 in the semi-diurnal band. The misfit is thus not related to calibration. Status of the processed stations MA: Matsushiro remained a good station and the two last years of data are in perfect agreement with previous data. MB: Membach continued to run very well as usual. From It is interesting to note a more or less continuous drift of sensitivity of the order of 0.03% to 0.04% between 1998 and 2009. This variation could probably not be detected by calibration. It confirms that the stability of the superconducting gravimeters is better than 0.1%. MC : The end of Medicina is a bit noisier than usual. After the change of electronics on 2007/06/12 the calibration factor was modified as well as the time lag. The new time lag of 11.1s is good as the phase lag on M2 is not modified. However a large jump of the amplitude factors of the order of 0.4% is appearing, while the ratio of the new and old calibrations is 1.0043. It is clear that the sensitivity of the voltage output has not been modified. It is the new calibration value which seems questionable as the results obtained with the previous calibration were fitting very well the other GGP stations in Europe as shown in Ducarme et al., 2009. Status of the processed stations ME: Metsahovi is also a station which started well before 1997. A comparison of 5 successive analyses covering each 2 years between 2000 and 2009 has shown no shift of sensitivity at the level of 0.05%. The registration prior to the GGP period is in agreement with the GGP data within 0.1%. An adjustment factor of 0.9996 could be introduced for a better fit. MO: Moxa is an excellent station with very low STD. PE: Pecny is a new station with exceptionally low STD.. The 900 registration days provide the same tidal factors as the 6 years of excellent rsults with the modified ASK228 but the RMS errors on the tidal factors are already lower. ST: Strasbourg remains an excellent station even if January and December 2009 are perturbed. SU: In Sutherland the dual sphere instrument was replaced by SG052 after July 2008. The RMS error on the unit weight of the new SG C052 is better than the RMS error of the CD instrument. There was no difference in the tidal factors between CD037-L and CD037-H. The provisional calibration of the new SG C052 seems to be very slightly too large compared to both components of CD037, but the series of the new instrument is still too short to draw firm conclusions. TC: Only 7 additional months have been processed in Tigo and there is no special remark. Status of the processed stations WE: The dual sphere instrument of Wettzell is excellent. After the change of electronics on April 17, 2007 new calibration values and new time lags have been determined. The amplitude factors and the phase differences of the L and H sensors are now in perfect agreement. In the previous series there was a difference in the values between L and H sensors at the level of 0°05%, while the phase differences were in agreement within the associated RMS errors.. It should be noticed that the amplitude factors are now increased by more than 0.1% with respect to the previous values. It confirms the conclusions of Ducarme et al., 2009 based on the previous results. The authors showed that, after tidal loading corrections, the c values for O1 and M2 at Wettzell were 0.1% lower than the mean of 15 European stations. To get homogeneous results it should be necessary to apply a normalisation factor 1.0017 on the previous series of channel L and 1.0012 on channel H. WU: Wuhan station remains in good shape since its repair at the beginning of 2005. Due to the failure two years of data have been eliminated from the global analysis i.e. 2003-2004. The STD is well below 1nm/s2. Future plans for the Tahiti Observatory (> 2011): • • • • Cryogenic gravimeter (2012 ?) New laser station (2014 +) VLBI station (2014 +) All these three colocated at Taravao (TahitiEast) • + Robotic telescope at Maiao (2011 ?) • + Altimetry calibration line (2012 ?) Seismic japanese BBOBS (Jamstec) (Mirai oceanographic vessel, recovery end2010) Etablissement d’une miniantenne VLBI à Tahiti-Iti Observatoire TIGO (Conception, Chile) A superconducting gravimeter in Tahiti ? Gravimètre à supraconductivité de la nouvelle génération Observation of gravity effects by Prof. Verreault of the University of Quebec, using a Paraconic pendulum, hosted at OGT