Directory taodata/hourly This directory contains ascii files of hourly surface meteorological data, from the TAO array of ATLAS and Current Meter moorings maintained by NOAA's Pacific Marine Environmental Laboratory (*.met files). Also included are hourly subsurface temperatures from a few sites (*.tmp files). Time series of zonal wind (WND-U: west < 0, east > 0), meridional wind (WND-V: south < 0, north > 0), air temperature (AIRT), sea surface temperature (SST), and relative humidity (RH) are included. Several mooring sites were first occupied in 1979; however, data from the majority of the sites begin during the past five years. Relative humidity measurements were not available at any site until 1989. Details about the sampling regimes for the different time series are included below. Winds: Winds are measured 4m above the sea surface with a propeller-vane sensor. Winds are sampled at 2 Hz for 6 minutes centered on the hour (eg, 0057-0103) then vector averages of these 720 samples are computed which provides an hourly wind estimate. The time word for the hourly wind value is the centered in the middle of the averaging period (eg, 0100). The daily vector average is based upon these 24 hourly values. AIRT, SST, and RH: AIRT, SST, and RH are sampled every 10 minutes and then averaged at the end of the hour. Samples are taken at 0010, 0020, 0030, 0040, 0050, and 0100 (for example), averaged after the last sample and given the time word of the last sample (0100). The time word for temperatures and humidity is therefore the end of the averaging period. The daily averages of AIRT, SST, and RH are based on these 24 hourly averages. Subsurface Temperatures: The subsurface ocean temperatures were sampled in different ways over the years. Some are continuously sampled, and the value with time 0000 is from 0000 to 0059(:59). Others are spot samples ranging from 7.5 to 30 minutes apart. In these cases the time given is the time of the first sample. We have not attempted to indicate which sampling regime was in effect at any given time. As of August 1996, the only site with hourly subsurface temperatures is 0n110w. More sites will probably follow in the next 12 to 18 months. A typical line of data from an hourly data file is shown below 940522 1900 -1.1 -2.7 82.80 27.31 27.60 22222 These values are for May 22 1994 at 1900 hours GMT. The first two values are WND-U and WND-V, and the center of their averaging period is at 1900. The next three values are RH, AIRT, and SST, and the center of their averaging period is at 1835, which is just the average time of the samples used: 1810, 1820, 1830, 1840, 1850, and 1900. Also included at the right end of each line of data are are integer values which indicate the quality of the data at left. The column header for these quality values reads WDHAS which means W quality of wind speed D quality of wind direction H quality of relative humidity A quality of air temperature S quality of sea surface temperature The quality values may be interpreted using the following key: 0 = datum missing 1 = highest quality; pre/post-deployment calibrations agree 2 = standard quality; pre-deployment calibrations applied 3 = lower quality; pre/post calibrations differ 4 = questionable; doesn't agree with adjacent buoys, climatology, or other data sources 5 = sensor or tube failed The quality values at this time are all set to either 2, 0, or 5. As calibration comparisons progress, quality value indices will be updated as appropriate. The format of the subsurface temperature files is similar to the description above, but with obvious differences. The quality values are the same as for the *.met files. All of the data in this directory should be used with caution, since these data have not been part of our standard data sets. Revisions to this data set will be made from time to time. Please refer to the file taodata/tao_updates.doc for information about data revisions. Information about data revisions will be sent out on a monthly basis to all data users. The files in this directory are organized by site. For example, 0n110w_hr.met contains all the data from the site at the Equator and longitude 110W. At the top of each file you will find a two line header which gives the nominal location, the time range covered by the file, the total number of hours, the number of data blocks, the measured variables and their units, and the missing value. Gaps in time longer than 24 hours have been removed, and a three line header is inserted at the location of each gap. Blocks of data are separated by these headers which give, for their corresponding block, the time range, the time index range relative to the start of the file, and sensor heights or depths. (The time index range is used by programs that read the files; see below). For sensors above the ocean surface, depth values are negative. The file tao_highres.index details the number of hourly values at each site for Winds, RH, AIRT and SST. For the number of subsurface values at each site, see file tao_tmp.index. Moorings have on occasion broken free from their anchors and drifted from their deployed location while still returning data. These events can be found by inspection of the mooring location time series in the daily mean meteorological files in the directory taodata/surface. No corrections for drift velocity have been applied to hourly wind data for periods when a buoy is drifting. However, the daily mean data in taodata/surface have been corrected using drift velocities computed from location changes. Information on buoys that have been drifting during the program is listed in the file drifters.doc in this directory. Any of the *.met data files in this directory can be read using the example fortran program hr_met_read.f. You may copy this program, and adapt it to your needs. It uses the time index range mentioned above to create real arrays in program memory of winds, RH, AIRT, and SST, as well as integer arrays of data quality. All of these arrays are evenly spaced in time with gaps filled by missing data values. For the subsurface temperature files, use the program tmp_hr_read.f, which is very similar to hr_met_read.f. All of the hourly TAO data in this directory, as well as near-realtime and historical daily TAO data, are available in NetCDF (i.e. binary) format. These NetCDF files are provided for use with the TAO DISPLAY SOFTWARE package, which displays the data and many analyses in a point and click graphical user interface on color UNIX workstations. The software is available at no cost. For further information contact taogroup@pmel.noaa.gov. Also, see the web page http://www.pmel.noaa.gov/toga-tao/realtime.html DISK STORAGE REQUIREMENTS: As of September 1994, the files in this directory require about 50 Megabytes of disk space. If you GET any of these data, please notify "atlasrt@pmel.noaa.gov" so that we can inform you of any modifications to the data sets. Also, please provide a 1-2 line description of your intended use of the data, so that we can advise you of other TAO analysis projects underway on related topics. If you use TAO data in publications, please acknowledge the TAO Project Office, Dr. Michael J. McPhaden, Director. Also, we would appreciate receiving a preprint and/or reprint of those publications utilizing TAO data for inclusion in the TAO bibliography. These publications should be sent to: The TAO Project Office NOAA/Pacific Marine Environmental Laboratory 7600 Sand Point Way NE Seattle, WA 98115 Please send comments, questions, or problems to "atlasrt@pmel.noaa.gov".