This 30 minute Sensible, Latent and Ground Heat Flux Composite is one of two surface-layer flux data sets provided in the Atmospheric Radiation Measurement(ARM)/Global Energy and Water Cycle Experiment (GEWEX) Continental-Scale International Project (GCIP) Near Surface Observation Data Set - 1997 (NESOB-97). This Sensible, Latent and Ground Heat Flux composite was formed from three data sources: the ARM Southern Great Plains (SGP) Clouds and Radiation Testbed (CART) Energy Balance/Bowen Ratio (EBBR) sites, the National Oceanic and Atmospheric Administration (NOAA)/Atmospheric Turbulence and Diffusion Division (ATDD) Little Washita Watershed site, and the ARM SGP Eddy Correlation (ECOR) sites. Data from 14 ARM/EBBR stations, 1 NOAA/ATDD station, and 8 ARM/ECOR stations were merged to form this composite. The University Corporation for Atmospheric Research/Joint Office for Science Support (UCAR/JOSS) did not do any quality control on the data set. Heat flux sensors consist of a differential temperature sensor which measures heat flow. Heat flux is a vector quantity of energy flowing through a 1 meter square surface in one second. Sensible heat flux is the transfer of sensible heat between the surface and the air, or vice versa. Latent heat flux is the transfer of latent heat (heat released or absorbed by water) between the surface and the air, or vice versa. Ground, or soil, heat flux is the transfer of sensible heat in the soil, either toward the surface or away from the surface. The Little Washita site records only 1 soil heat flux value. The EBBR sites record soil heat flux values from 5 different sensors. The ARM soil sensors are located in a half-circle approximately 2 meters in diameter under the net radiometer, which extends to the south about 1 meter from the EBBR frame. The soil conditions at the EBBR sites are varied from very sandy soil to very clay-laden soil. However, all of the sensors for one particular EBBR site are in the same soil type. Information on the soil characteristics at each of the ARM Soil Water and Temperature System (SWATS) sites (which are located nearby the ARM EBBR sites) is available as part of the ARM/GCIP NESOB-97. (These include the "Organic Carbon and Matter", "Soil Texture", "Parameters for Soil Water Retention Models", "Bulk Density", Particle Size", and "Soil Water Retention" data sets). The EBBR sites also record Bowen Ratio, home_15 and home_30 values, as well, whereas the Little Washita site does not. Since this is a composite data set, only the first 3 fields of data from the Little Washita site will have values, while the rest of the parameters on a line will always be missing. Missing values are -999.99999.
(NOAA)/Atmospheric Turbulence and Diffusion Division (ATDD) Little Washita, Oklahoma long term flux monitoring site. This composite was developed by the merging of the computed 30-minute averaged values of Net Radiation as derived by University Corporation for Atmospheric Research/Joint Office for Science Support (UCAR/JOSS) from the 20-second values provided by ARM for its SIROS and SIRS stations, and the 30-minute averaged values of Incoming/Outgoing PAR and Net Radiation as provided by NOAA/ATDD for its Little Washita station. UCAR/JOSS computed standard deviations for the averaged data when at least 15 observations were available within the 30-minute averaging interval. JOSS did not do any other quality control on the data set. The NESOB-97 Net Radiation and PAR Composite Dataset contains eight metadata parameters and nine data parameters and flags. The metadata parameters describe the date, time, network, station and location at which the data were collected. Data values are valid for the 30 minutes preceeding the time of observation. All times are UTC. The data parameters have an associated QC flag but UCAR/JOSS does not Quality Control the data at the present time. The Quality Control flag is set to "U" for "Unchecked", unless the datum is missing, in which case the flag is set to "M". Note that the SIROS stations were changed over to SIRS in August 1997.