CIMO ET on Upgrading the Global Radiosonde Network
• CIMO ET on Upgrading the Global Radiosonde Network – Geneva 3 -7 November 2003 Upper Air Network UK National Report. Tim Oakley & John Nash Met Office, Exeter, UK 00/XXXX 1
00/XXXX n Network early 2001 n 8 ‘Core’ stations, manned 24/7 n Defence and Boundary layer sites, when available 2
Current Upper-Air Network 2003 2 Manned Radiosonde Sites 4 Autosonde Sites Supplementary Radiosonde sites, ascents as required 5 Wind-Profiler Sites 00/XXXX 3
Upper-Air Network (Met Office) n n n n Lerwick Camborne Castor Bay Albemarle Watnall Herstmonceux Larkhill(defence) Aberporth(defence) W. Freugh(defence) S. Uist(defence) Supplementary(8) Manned Autosonde Manned Manned Digi. Cora III MW 15 Digi. Cora III PC-Cora RS 80 H Loran RS 80 H Loran RS 80 H Loran 00 , 12 00 , 12 IRREG IRREG Gibraltar Falklands St Helena Manned Digi. Cora III RS 80 H GPS 00 , 12 12 Additional radiosonde ascents at the request the National Met Centre. 00/XXXX 4 of
Digi. CORA III - Ground System n Operational from June 01 n Able to interface with the continuing evolution of operational radiosondes & different wind finding. COTS Processor using Windows NT Remote or local interrogation Service Level Agreement with manufacturer n n n 00/XXXX 5
Autosonde at 4 UK Sites • Autosonde trialled for operationally feasible • Radiosondes Tested • Proved successful for operations at inland sites. • From 2002 - operational at 4 Met. Office sites, UK • Plans to upgrade Autosondes to Digi. CORA III during 03/04 00/XXXX 6
UK Radiosonde Trials 2002 n Jan 2002 - Radar v Graw v Sippican v Vaisala RS 90 Test of GPS systems for both wind measurements & GPS heights as possible reference system to replace COSSOR radar. n Feb 2002 – Vaisala RS 90 v RS 80 Comparison of alternative RS 90 humidity measurements (i. e. cap/no cap) n May 2002 – Vaisala RS 90 v RS 80 v Snow-whites Continuing evaluation of the RS 90 humidity measurements + comparison with Microwave Radiometer measurements. n August 2002 – Radar v Graw v Sippican v Vaisala RS 90 Final test for systems to replace the COSSOR radar. n October 2002 – Vaisala RS 92 (High Power) v RS 80 First trials on Digi. CORA III, comparisons with the operational ascent. 00/XXXX 7
UK Radiosonde Trials 2003 n May 2003 - Vaisala RS 92 (Low Power) v RS 80 First trials on Digi. CORA III of the low power radiosonde + necessary hardware upgrades. Comparisons with the operational ascent. n July 2003 – Meteorlabor SPC/Snow-whites v RS 80/RS 92 Trial of complete Meteolabor system with Snow-whites as possible reference radiosonde system for 2004+. n October 2003 – Vaisala RS 92 v RS 80 Acceptance test for Pristina airport installation. Further evaluation of the RS 92 GPS measurements. n December 2003 – Vaisala RS 80 v RS 92 (L&H) v S/Whites Pre-acceptance test for the RS 92 radiosonde. 00/XXXX 8
Next Generation Radiosonde n RS 80 radiosonde is considered obsolete by Vaisala, and production will gradually be reduced over 4 to 5 years. n The radiofrequency transmitter is out of date and needs to be improved to meet requirements for reduced spectrum occupation and hence spectrum charges. 00/XXXX n The RS 90 radiosonde had improved sensors, but the transmitter and internal electronics were not optimised. n The RS 90 relative humidity sensor package failed the Met Office acceptance test [ Sensor calibration errors, sensor instability and inadequate protection in cloud] 9
Future RS 92 work 00/XXXX n Vaisala are proposing that the Met Office use the newly developed RS 92 radiosonde , built using dedicated ASIC’s not only for GPS winds but also for processing PTU information during flight and for digital data transmissions to the ground n The mechanical design of the RS 92 has been changed to make the deployment of the temperature and relative humidity sensor exposure more reproducible, as suggested by Met Office. 10
Future work [2] n RS 92 Acceptance testing 2003/04 Sensor performance ( i. e. humidity – pulse heating) Digital transmitter/receiver (low & high power) Complete ‘system’ acceptance test – Spring 04 00/XXXX n Handover of RS 92 to operations n Implementation of BUFR coding n Implementation of one software suite for Autosondes + Digi. Cora III 11
BUFR Code n DC III system has the capability to produce BUFR. n Test and evaluate the BUFR. (Content, communications, storage) n Implement operationally. Benefits 00/XXXX n Transmission of complete Radiosonde archive n No need for manual editing of selected points n Inline with CBS recommendations to change to BUFR n Archive of high resolution data for verification/research 12
BUFR findings to date. 00/XXXX n BUFR encoding on Digi. CORA III has been tested to Met Office satisfaction. (Decoded successfully by operational database. ) n Some inconsistencies between the encoded and decode data. n Questions about the necessary level of data QC flagging. n Concerns over the size of the BUFR message and the ability of the operational databases to archive/access the data. n Project in Met Office tasked with delivering BUFR messages for the future. 13
Quality monitoring of RH sensor performance. 00/XXXX n 12 year archive of ‘high resolution’ radiosonde measurements from 4 UK sites. n Using surface observation to identify ascents that have passed through cloud. n Monthly/annual statistics used to monitor the performance of the RH sensor. n Information/results feedback to manufacturer. n Used to detect changes from A & H Humicap , also batch performances and manufacture & calibration problems. 14
Wind Profiler Network 00/XXXX n 4 systems are operational components of the UK network. n Wind data from these systems being assimilated into the UK NWP models. n New 64 MHz system under final acceptance and hand-over to operations. n Collaboration with WINPROF (European network) 15
GPS Water Vapour Network 00/XXXX 16
Network Configuration 00/XXXX 17
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GPS Water Vapour Network 00/XXXX n Project has demonstrated the feasibility and usefulness of a ‘real-time’ GPS IWV network. n Working with Nottingham University to develop a Met Office system to provide real-time IWV in < 2 hours from observation. n Planned x 10 increase in UK network by collaborations with other services. n Aim to deliver an operational network of IWV measurements by 2005. 19
Upper Air Networks – The Future. 00/XXXX n Further Automation. n Integration. n Increased use of high temporal & high resolution data. n Use of other measurements ( i. e. Signal to Noise) 20
Summary 00/XXXX n Integrated wind data already being used operationally and changing observing networks in the UK. n Usefulness and potential benefits of IWV networks accepted by users and will be introduced into operations in next 2 -3 years. n Significant progress in exploiting the high resolution capabilities of remote sensing systems. n Progress in the techniques necessary to integrate different remote sensing system for temperature and humidity profiling. 21
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