20-FEB-2002 SHOWEX LongEZ along-track averaged radar and laser data sets Doug Vandemark NASA/GSFC, Laboratory for Hydrospheric Processes douglas.vandemark@nasa.gov (603) 862-0195; FAX (603) 862-0243 The files *.5000m.v57.bin represent first-version processing of the radar and laser ocean surface data collected with the NOAA/FRD-LongEZ during SHOWEX. See the following sites for background detail: http://rows.wff.nasa.gov/dls.html and http://www.mmm.ucar.edu/science/abl/showex/showex.html. The data sets covered under this processing include those of Nov. 1997, Nov. 1998, March 1999 and Nov. 1999, all collected off Duck NC. Latest version LongEZ NCP data sets used as input except for the 1997 set where a specialized *.rad data product was used. DATA LOCATION: /gen/rows/IDLPRO/dls/data PRODUCTS: The processed output includes averaged radar cross section, laser-derived elevation and slope, and electromagnetic bias data. These are accompanied with ancillary words containing related quality control variables and the number of samples used in the respective statistic \373 after conservative within-leg filtering. A subset of environmental and book keeping words are also included. These are averaged over the same segment and time and position information are given at the segment midpoint. Some references on the products included here can be found in the following: Vandemark, D., P. D. Mourad, T. L. Crawford, C. A. Vogel, J. Sun, S. A. Bailey and B. Chapron, Measured changes in ocean surface roughness due to atmospheric boundary layer rolls, J. Geophys. Res., 106(C3), 4639-4654, 2001. Sun J. , D. Vandemark , L. Mahrt, D. Vickers, T. L. Crawford and C. A. Vogel, Momentum transfer over the coastal zone, J. Geophys. Res., in press. Vandemark, D. , T. Crawford, R. Dobosy, T. Elfouhaily and B. Chapron, 'Sea surface slope statistics from a low-altitude aircraft', Proceedings of IGARSS'99, 381-383, 1999. AVERAGING LENGTH: The file format includes a word indicating the approximate spatial length of the averaging segment used. For example *.5000m. indicates that a 5000 sample segment average was used. At the nominal 50 m/s LongEZ ground speed this translates to that distance. DATA AVAILABLILITY: These data are available to any SHOWEX investigator upon request. Because of the newness of the techniques and products I request that I be consulted before any publication is submitted. Dissemination to outside parties is welcome but needs approval of the SHOWEX team. DATA FORMAT: The data are presently in SUN floating point binary, each record containing 57 words. The data can be converted to ascii or other format upon special request. The format follows: ; Environmental data Word_0 ; u* computed here Word_1 ; U_z Word_2 ; SST degC Word_3 ; AirT degC ; Radar data Word_4 ; Ka-band NRCS data (dB) Word_5 ; NRCS std. dev. (dB) Word_6 ; Ka-band rcv. power level (dBm) Word_7 ; #samples in NRCS estimate (and in EMB_r) Word_8 ; Ratio(lin.) of rad_hi to lo voltage@lo=160 ; Laser data Word_9 ; Avg # Laser retns per N xmitted Word_10 ; # of samples in elev & 1Dalong slp stats Word_11 ; Laser-derived sig. wave height Word_12-15 ; Avg. of the 3 elev. moment arrays Word_16-19 ; Along-trk 1Dslp, avg of 3 mom. Word_20 ; # of samples in 2D slp stats Word_21-24 ;2d moment(tan(2dang)) ;2Dslp moments ; [Note:mss_l2D = mom_0^2. + mom_1 = mean(tan(th)^2.)] Word_25-28 ; 0.93 m cross-track slp moments Word_29-32 ; 0.46 m cross-track slp moments Word_33-36 ; 10 m 2D slope moments ; EM bias data Word_37 ; EM bias Ka-band radar Word_38 ; EMB 2D slope, 1m Word_39 ; EMB 2D slope, 10m Word_40 ; EMB 1D cross-track Word_41 ; EMB 1D along-track ; Book keeping Word_42 ; Date (yymmdd) Word_43 ; SecsOfDay Word_44 ; GPS Lat. Word_45 ; GPS Lon. Word_46 ; Wind Dir (deg. wrt N) Word_47 ; AC heading (deg. wrt N) Word_48 ; Mean altitude above MSL Word_49 ; RMS of GPS.alt Word_50 ; RMS of AC roll Word_51 ; water depth (m) Word_52 ; distance from beach Word_53 ; absolute stress angle in radians, atan(vw/uw),needs conv to N head. Word_54 ; P_z (in mB) Word_55 ; dewPt (deg C) (faulty!!!) Word_56 ; radar and 2Dslope cross correlation within segment