GRAS SAF System Products and Archive Frans Rubek

GRAS SAF System, Products, and Archive Frans Rubek & Martin Bjært Sørensen GRAS SAF Team Danmarks Meteorologiske Institut 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 1

$EPS/Metop Radio Occultation from GPS EPS/Metop Vertical profile of refractivity GPS 2 nd GRAS$

EPS/Metop Radio Occultation from GPS EPS/Metop Vertical profile of refractivity GPS 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 2

Typical 24 -hour EPS/Metop Radio Occultation Distribution 1 LEO with two occultation antennas 2 nd GRAS SAF User Workshop 24 GPS satellites June 11 - 13 2003 Helsingør Slide 3

Data Levels and Processing EPS/Metop Measurement GRAS SAF Level 1 b -> Level 2 Processing, Dissemination, Archiving, . . . Raw Data Downlink High-latitude Downlink Site Demultiplexing, Quality check Level 2 Data: Refractivity, pressure, temperature, and humidity profiles, Validation Data. . . Level 1 b Data: Bending Angles, Impact Parameters, Auxiliary Data, . . . Level 0 Data: Phase and Amplitude Data, Tracking and Ancillary Data, Ground Site Data, . . . 2 nd GRAS SAF User Workshop End Users Level 1 a Data: Phase Delays, Doppler Shifts, SNR, Earth Location Data, . . . EPS Core Ground Segment Level 0 -> Level 1 a Processing Level 1 a -> Level 1 b Processing June 11 - 13 2003 Helsingør Slide 4

GRAS SAF Data Flow Model Occultation measurements GPS Ground Station Networks EPS/Metop EUMETSAT Level 0 EPS / CGS EPS data downlink GPS POD data Level 0 Level 1 b EPS Primary NRT User Terminal Ancillary data Level 1 b Operational GRAS SAF Level 1 b NWP centers GRAS Ground Processor NWP users Development Processing Center NRT products (Level 2) RMDCN, GTS HTTP, FTP Archiving Center Offline Archive (Level 2) Software products Education / Help desk Public outreach DVD/CD- ROM per mail UMARF Client Server UMARF HTTP End users 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 5

Initial Joint Polar System (IJPS) (EPS + NPOESS Program) NOAA N, N’ (p. m. ), NPOESS METOP (a. m. ) Global data dump Blind orbits data dump Global data dump SAF NOAA global data METOP blind orbits NOAA EUMETSAT CNES IASI TEC SAF METOP global data NOAA blind orbits EUMETSAT POLAR SYSTEM (EPS) 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 6

GRAS SAF Products Time Requirements Near-Real Time Products: (NRT) To be delivered less than 3 hours after measurement, using RMDCN (Regional Meteorological Data Communication Network), GTS, a. o. Mainly for NWP use. Offline Products: Improved products re-processed using precise satellite orbits, additional NWP input, etc. To be delivered less than 30 days after measurement, using FTP, DVD/CD-ROM, WWW download, a. o. Mainly for climate research use. 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 7

NRT Data Flow as a Function of Time Recording Orbit N+1 Recording Orbit N+2 On board data acquisition Elementary unit Satellite dump to CDA to EPS/CGS transmission EPS/CGS Level 1 b processing NRT Level 1 b transmission to SAF GRAS SAF NRT Level 2 processing GRAS SAF NRT Level 2 dissemination Processing Orbit N 2 nd GRAS SAF User Workshop Processing Orbit N+1 June 11 - 13 2003 Helsingør TIME Slide 8

GRAS SAF Products Overview Data Product Characteristics Bending Angle Profile (Offline only) Bending angle as a function of impact parameter Refractivity Profile Neutral Refractivity as a function of height and location of the occultation Observation Characteristics Error profile and covariance matrices of the observables. Time information for the occultation data. Latitude, longitude and radial position of the occultation products in geodetic coordinates. Temperature Profile Temperature (dry/wet) and error estimate as a function of height and location of the occultation Specific Humidity Profile Specific humidity (water vapor) and error estimate as a function of height and location of the occultation Pressure Profile Dry pressure and error estimate as a function of height and location of the occultation, including surface pressure Surface Pressure (NRT only) Pressure estimate at surface level 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 9

$GRAS SAF Assimilation S/W Products Statistically optimal 1 D-Var refractivity retrieval code Forward models$

GRAS SAF Assimilation S/W Products Statistically optimal 1 D-Var refractivity retrieval code Forward models for 4 D-Var: - Direct assimilation of refractivity profiles into an NWP model - Plane-averaged refractivity forward model for assimilation into an NWP model - Direct assimilation of bending angle as a function of impact parameter into an NWP model 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 10

User Requirements for NWP 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 11

User Requirements for Climate Research 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 12

GRAS SAF Prototype Temperature Profile from CHAMP Data 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 13

GRAS SAF Prototype Temperature Statistics using CHAMP Data 1630 profiles January 6 – 23 2002 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 14

NRT & Offline Processing Flowchart 1 a NOISE REDUCTION (LP FILTERING), QUALITY CHECK, COORDINATE TRANSFORMATION, BACK PROPAGATION/CANONICAL TRANSFORM ROUTINE (below 17 km), BENDING ANGLE ROUTINE (above 17 km) PHASE AND AMPLITUDE MEASUREMENTS + ORBIT INFORMATION (OFFLINE) BENDING ANGLES (NRT) 1 b 1 b BENDING ANGLE PROFILE IONOSPHERE CORRECTION, STATISTICAL OPTIMIZATION (NRT ONLY) ABEL TRANSFORM ROUTINE BACKGROUND TEMPERATURE, HUMIDITY, and SURFACE PRESSURE REFRACTIVITY PROFILE 1 D-VAR RETRIEVAL (NRT ONLY), ITERATIVE ALGORITHM (OFFLINE ONLY) WET TEMPERATURE, SPECIFIC HUMIDITY, SURFACE PRESSURE (NRT ONLY) 2 nd GRAS SAF User Workshop 2 2 HYDROSTATIC EQUILIBRIUM, IDEAL GAS EQUATION 2 DRY PRESSURE, DRY TEMPERATURE June 11 - 13 2003 Helsingør Slide 15

GRAS SAF Processing Chain Near real time retrieval: from bending angle to level 2 Off-line retrieval: from observed phase to level 2 Processing steps: • Excess phase (offline only) • Bending angle (offline only) • Refractivity • “Dry” temperature, pressure and density • “Wet” temperature, pressure and density • Surface pressure (NRT only) 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 16

Software & Platforms § Distributed scaleable system using CORBA § Based on Sun workstations and Linux PC’s § § Python Omni. ORB UNIX shell FORTRAN 77/90 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 17

Interfaces 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 18

GRAS SAF Processing System Request Manager Task. Manager Monitor Client GTS End. User Report. Ge System nerator Send. D Report. Gen FTP ata erator store/retrieve Archive Manager Task. Man ager store/retrieve UMARF store/retrieve Archive Proxy Task. Manager Client store/retrieve Product Generator Task. Manager Archive Client Proxy do_job process Processor store/retrieve Data Retriever registrer Job. Manager EPS NRT 2 nd GRAS SAF User Workshop EPS FTP IGS ECMWF June 11 - 13 2003 Helsingør Slide 19

Hardware Components Internet Router RMDCN Router Firewall GTS Interface FTP Server Data switch Firewall Level 1 B downlink NRT Terminal UMARF Client Data Reciever Task Managment NRT Processor OFF-Line Processor Archive & User facilities External lines Deployment Site Ethernet GRAS SAF Private Ethernet 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 20

Data Distribution Near Real Time products: • RMDCN ( BUFR only) • GRAS SAF ftp server Off-line enhanced products: • User Requests at EUMETSAT’s UMARF V 2 User services • - and delivery at the GRAS SAF ftp server • - or via DVD/CD-ROM 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 21

NRT Dissemination Regional Meteorological Data Communication Network for ECMWF and WMO Region VI 2 nd GRAS SAF User Workshop June 11 - 13 2003 Helsingør Slide 22