++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Meteorological Analysis and Forecast during the Pacific Exploratory Mission- Tropics B(March-April 1999) Analysis Period: February 20, 1999-April 19, 1999 By: Prof. T. N. Krishnamurti Florida State University August 30, 1999 This readme file briefly describes the analysis of the meteorological fields during the PEM-Tropics B mission and the archival files documenting that analysis. There are four sets of files: (1) velocity fields(uvw): 59 files of 113.2 mbytes each (2) precipitation(rain): 59 files of 4.7 mbytes each (3) trajectory forecast(trajfor): 59 files of 0.2 mbytes each (4) images: 590 .gif files of about 15 kbytes each Each file date is identified as follows: YYYY=year MM=month DD=day HH=time (UTC) All files are a product of the Florida State University Global Spectral Model(FSUGSM). Reanalysis of the data in this study is based on physical analysis procedures developed at the Florida State University. The inital data sources are ECMWF, NCEP analysis and The Air Force Global Weather Service Real-Time Nephanalysis. Trajectories are calculated using a three dimensional, semi-lagrangian, advective algorithm which makes use of the analyzed and predicted winds at 6 hourly intervals. ===================== DATA ===================== 1) uvw.YYYYMMDDHH: The daily uvw.YYYYMMDDHH files are the gridded multi-level data sets at T170 resolution (512 x 256 lat,lon) in GrADS format. Each file contains u zonal velocity(m/s), v meridional velocity(m/s) and w vertical velocity(mbars/s-positive up), respectively, for anaylsis (present) time and 48 hours forecast with 6 hours time interval. Each file contains 9 records. Format is given as: UNDEFINED -9.99e33 X-DIREC. 512 linear grids starting at 0.0deg with dx=.70312deg Y-DIREC. 256 linear grids starting at -89.29961deg with dy=.70039deg Z_DIREC. 8 levels, 1000 850 700 500 400 300 200 100mb, upward. To read one of these files rewrite or modify the FORTRAN code given in file uvw.f. 2) rain.YYYYMMDDHH: The precip files (rain.YYYYMMDDHH) are also gridded T170 Lat,Lon 512 x 256 records, 9 total, representing the analysis time and 48 hours forecast with 6 hours time interval. It is given as accumulated rainfall totals (units are mm/s). To read one of these files rewrite or modify the FORTRAN code given in file rain.f. EXAMPLE: Take the April 5, 1999 file. Then, YYYYMMDDHH=1999040512 contains; analysis time: 1999040512, (analysis) remaining 8 records: 1999040518, (forecast) 1999040600, (forecast) 1999040606, (forecast) 1999040612, (forecast) 1999040618, (forecast) 1999040700, (forecast) 1999040706, (forecast) 1999040712, (forecast) This is true for both rain and uvw data. 3) trajfor.YYYYMMDDHH: Backward trajectory files are formatted (ASCII) files called trajfor.YYYYMMDDHH containing the locations of the parcels at hourly interval. Each file has 40 trajectories which show the motions of 40 different parcels for the 6 day period ending at YYYYMMDDHH. To read the files rewrite or modify the FORTRAN code given in file traj.f. ================== IMAGES ================== 1) Streamlines Surface superimposed on rainfall (mm/day), YYYYMMDDHH.surf.gif 500mb, YYYYMMDDHH.500mb.gif 300mb, YYYYMMDDHH.300mb.gif 2) Cloud cover (%) High clouds, YYYYMMDDHH.hcloud.gif Mid. clouds, YYYYMMDDHH.mcloud.gif Low clouds, YYYYMMDDHH.lcloud.gif 3) Backward Trajectories 925mb, YYYYMMDDHH.traj925.gif 850mb, YYYYMMDDHH.traj850.gif 500mb, YYYYMMDDHH.traj500.gif 300mb, YYYYMMDDHH.traj300.gif The date is also labeled on each image as YYYY:MM:DD:HH. Trajectory images show the motions of 10 different parcels for the 6 day period ending at YYYYMMDDHH. The arrows at one side of the trajectories show where the parcels are at the present time. The labels on trajectories are the pressure levels in millibars (only first two digids are shown, i.e, 94 means 940mb, etc.). The rainfall is the accumulated amount and is in units of millimeters/day. The domain for all figures is 60S-50N and 140E-40W, covering almost the entire Pacific. The polygon on each image is a representation of the flight tracks. All figures are created using the data sets described above. Images for the following dates are available as files, but do not show the cloud cover: 1999022012 1999030212 1999031212 1999031512 1999040912 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Because of the size of the files, they have been placed online through the NASA LaRC DAAC at: http://eosweb.larc.nasa.gov/DATDOCS/web_order.html When this URL is opened, select GTE select download data login(makeup password) select submit select GTE PEM Tropics B modeling precip., traj., or velocity choose date of data required receive zip file For large downloads, contact User Services for possible alternative media. If you need assistance in accessing or downloading any of these files, please contact: User Services at 757-864-8656 and larc@eos.nasa.gov +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Three small FORTRAN files have been provided for reading the data. They are: uvw.f for velocity fields rain.f for precipitation traj.f for trajectory forecast Plans are underway in providing C Code version of these files. When available they will be described here and made available with the files written in FORTRAN. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ If there are any questions regarding the analysis or how to use the data, please contact: PI: T.N. Krishnamurti e-mail: tnk@io.met.fsu.edu Tel: (850) 644 2210 Assistant: N. Cubukcu e-mail: nihat@io.met.fsu.edu Tel: (850) 644 2732 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++