date 20-04-00 All files in this directory consist of one ten day back trajectory for a single flight level conducted during INDOEX. The file alldata_traj.txt contains the input data for the trajectory calculations and the filename of the output file (filename, date, time, alt, press, lat, lon). The data for a trajectory consist of a header and a body. Example of a header for backward trajectories : WTK 6 96021512 96021422 96021822 1 97 59 518 400 06 1.0 1.0 0.0000 mTK lp yymmddh1 yymmddh2 yymmddh3 ts npt LON LAT PRES DT DX DY frac m : mode : available now : 0: vertical profile W: using 3D wind field X: using 3D wind field :given PV E: explicit scheme using 3D wind field L: using 3D wind field linear time interpolation R: isopicnic, using T P: isobaric I: isentropic : using T Y: isentropic : given PV T: isentropic : given teta Q: moist isentropic : given P K: moist isentropic : given teteq B: rising balloon S: single level mode 9: internal fields test mode Remark : the isentropic modes en the 3D mode are tested well with ECMWF wind fields TK : Updated KNMI trajectorie model TRAJKS lp: number of calculation timesteps within one hour. yymmddh1: last analyses time used Last analyses means the newest analyses time as found in the input data. Remark: each parameter at a time is calculated from 3 times, because of the time interpolation. Remark: if first guess is used, this gives an extra shift in the last analysis time compared to the hour. If e.g the calculaton starts at 18 GMT, using 6 hourly FG data. Last analysis will then be 18 -6 -6 = 06 GMT. yymmddh2: start time of trajectory calculation yymmddh3: end time of trajectory calculation ts : timestep in hours (usually 1 or -1) npt: number of points = the number of lines in the body LON, LAT, PRES = coordinates of begin point trajectory LON and LAT are in 0.1 degrees , press in hPa DT : data timestep in input (i.q. ECMWF) data (usually 06) DX : grid longitude distance in degrees DY : grid latitude distance in degrees frac : time correction of start time : fraction of an hour. Remark : the exact verification time is calculated from yymmddh2 + TTTT Remark : if frac is not 0.000, then all the output coordinates are shifted in time compared to the hour. The format of the header is: I1,A2,I3,1X,I8,1X,I8,1X,I8,I3,I4,3I5,I4.2,2f5.1,f9.4 Example of a header for backward trajectories : WTK 6 99021606 99021607 99020607 -1 241 747 51 410 06 1.0 1.0 0.2667 The body consists of lines describing each one trajectory position: TTTT PRES0 LON LAT PRES U V W T q PV dPV errflg The format of a line is: 4X,I7,I6,2I5,I6,7I7,I4,I5,I7 Here follows an example of the first five lines (traj. positions): 0 10115 759 8 9941 -46 -27 -25 2997 16429 -3 -3 0 14 9 -63 59 0 -1 10117 761 9 9950 -49 -23 -24 2997 16464 -3 -3 0 8 4 -206 53 0 -2 10119 762 9 9958 -51 -20 -19 2997 16451 0 -2 0 9 4 -199 65 0 -3 10118 764 10 9964 -50 -19 -13 2997 16434 2 0 0 11 15 -182 77 0 -4 10115 765 10 9967 -48 -20 -6 2997 16448 4 0 0 14 15 -164 80 0 TTTT PRES0 LON LAT PRES U V W T q PV dPV CF CP CPc STD STN errflg TTTT : time in minutes relative to start time yymmddhh2 PRES0: pressure at bottom of model LON, LAT: horizontal trajectory position (in 0.1 degrees) PRES : vertical trajectory position (0.1 hPa) U, V : horizontal winds in EW resp. NS direction at trajectory position in 0.1 m/s) W : vertical wind at trajectory position (in mPa/s) T : temperature in 0.1 K q : moisure mixing ratio in mg / kg PV : Potential vorticity in 0.001 PV units (1 PV unit = 10**-6 K m**2 / kg / s ) dPV/dp : Potential vorticity gtradient in uPV/Pa CF : cloud fraction in grid cell in % CP : Convective precipitation on surface interpolated in .1 mm CPc: Convective precipitation on surface in the nearest grid cel in .1 mm STD : dry stability in - d(theta)/dp lapse rate of the potential temperature STN : wet stability in - d(theta-e)/dp lapse rate of equivalent-potential temperature (a positive value means stable, negative unstable) errflg : error flag. This error flag is an integer. If 0, anything is OK. It is composed as 10000*nit + 100*ntf + cDT + sh. sh : surface hit. Or top layer hit. sh =1: trajectory below lowest model level. sh =3: trajectory below surface pressure : correction has been made. sh =2: trajectory above highist model level. sh =4: trajectory above highist layer: P < 0. In all four cases, the trajectory goes on, using the uppermost resp. lowermost level data. cDT : 0(no) or 70(jump): data timestep jump from 6 to 12 hours ( implemented for X,J W forward runs only) nit: number of times that the iteration -sceme failed (none-convergent) within an hour. Remember that the iteration procedure is repeated for every calculation time-step. ntf: number of times that no unique theta-level, or theta-E-level was found. Remember that the search procedure is executed before time interpolation. For format reasons nit and ntf are never allowed to be more than 99. The sign that the model ran out of area, is 99990 for the pressure. For PV and dPV it is 9999 PVU. Good luck. Rinus Scheele