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Frequently Asked Questions

The following frequently asked questions (FAQ) and answers are relevant to the NDBC TAO Array deployments. For additional information about the NDBC stations, the NDBC FAQ page may be helpful.
  1. What types of plots are available in TAO data display?
  2. What climatologies are used in TAO data display?
  3. How does NDBC produce anomaly plots in TAO data display?
  4. What gridding methods are used in TAO data display?
  5. What wind direction convention is used in TAO data display and data delivery?


What types of plots are available in TAO data display?
TAO Array Daily Status Graphics - The daily status graphics are automatically generated according to the data received in real-time and rendered on top of the web page in mornings.

Drill-down Navigation for Data Exploration - Users can explore a site by clicking on the array status graphic. The active primary deployment page will show deployment metadata, sensor status, and sensor data. This web page will also display links to historic deployments and active co-located deployments.

New Site Data Plots - On selected site, data plots are rendered for all configured sensors with a selectable time range. For each sensor, plots with different time ranges are available when the user mouses over the desired image icon. For data comparison purposes the user may select up to four different sites to plot each site's corresponding sensor data. The plots can be grouped by measurement types or by sites with desired time range.

Latitude vs. Longitude Plots - New Lat-Lon 5-day/Monthly plots are available with the same new look and feel as the site data plots.

Depth Section Plots - New Depth Section 5-day/Monthly plots are available with the same new look and feel as the site data plots.

Time Section Plots - New Time Section 5-day/Monthly plots are available with the same new look and feel as the site data plots.


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What climatologies are used in TAO data display?
The various Climatologies used by the TAO / TRITON Project to compute anomalies are briefly described below.

Reynolds and Smith AOI SST Climatology (1971 - 2000)
The AOI SST climatology is an optimum interpolation analysis of Sea Surface Temperature with an adjusted base period of 1971 to 2000, on a global 1 degree by 1 degree by 1 month grid. For further information, please see Reynolds, R. W. and T. M. Smith, 1995: "A high-resolution global sea surface temperature climatology". J. Climate, V8, N6 (JUN), p 1571-1583.

Kessler Objective Analysis of XBT and CTD Temperatures
The Kessler temperature climatology is a 4-D objective analysis of historical XBT and CTD temperatures, which uses best estimates of the correlation lengths in Longitude, Latitude, and Time to grid the data. Dr. Kessler is an Oceanographer here at PMEL/NOAA in Seattle.

The CTD data used in the analysis consist of all the available data from the earliest years these observations were taken through 1991. The XBT data range in time from 1970 to 1987.

For further information about the methods used to create the Kessler climatology, please refer to Kessler, W.S., 1990: "Observations of long Rossby waves in the northern tropical Pacific". J. Geophysical Research, 95(C4), 5183-5217, and Kessler, W.S. and J.P. McCreary, 1993: "The annual wind-driven Rossby wave in the subthermocline equatorial Pacific". J. Physical Oceanography, 23(6), 1192-1207.

This climatology is used for gridding the TAO / TRITON subsurface temperatures in Longitude-Depth and Latitude-Depth sections. For more information on how these TAO / TRITON data are gridded, see the zonal-depth gridding and meridional-depth gridding web pages.

COADS Winds (1946 - 1989)
The COADS climatologies of Zonal and Meridional Wind, Scalar Wind Speed, and Wind direction, are used for computing TAO / TRITON Wind anomalies, and for gridding Zonal and Meridional Winds and Scalar Wind Speed. For example plots of TAO / TRITON Winds and their anomalies see the TAO / TRITON Data Display web page. For information on the gridding methods mentioned above, see the TAO / TRITON gridding web pages.

COADS Relative Humidity (1946 - 1989)
The Relative Humidity (RH) climatology was derived from the COADS Specific Humidity (SH) climatology. The SH climatology was converted to RH using a routine written by Ms. Margie McCarty at NOAA/PMEL, which takes as input SH, pressure, and Air Temperature.

This climatology is used for computing TAO / TRITON RH anomalies, and for gridding RH in the Lat-Lon Maps and Latitude-Time and Time-Longtitude section plots. For example plots of RH see the Section Plots on the TAO / TRITON Data Display web page. For information on these gridding methods, see the TAO / TRITON gridding web pages.

20°C Isotherm depth
The 20 Degree C Isotherm Depth climatology was computed from the Kessler temperature climatology (see above), by linear interpolation of depth versus temperature.

This climatology is used for computing TAO / TRITON 20 degree C Isotherm depth anomalies, and for gridding 20 C depths in the Lat-Lon Maps and Latitude-Time section plots. For example plots of 20C Depth see the TAO / TRITON Data Display web page. For information on these gridding methods, see the TAO / TRITON gridding web pages.

Dynamic Height
The Dynamic Height climatology was computed from the Kessler temperature climatology (see above), by vertically integrating the specific volume anomaly using a set of long-term mean temperature-salinity relations, one for each grid location, derived from the World Ocean Atlas (See Conkright et al 2002: "World Ocean Atlas 2001: Objective Analyses, Data Statistics, and Figures, CD Rom Documentation").

This climatology is used to compute Dynamic Height anomalies, and for gridding Dynamic Heights in the Lat-Lon Maps and Latitude-Time section plots. For example plots of Dynamic Height see the TAO / TRITON Data Display web page. For information on these gridding methods, see the TAO / TRITON gridding web pages.


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How does NDBC produce anomaly plots in TAO data display?
The anomaly computations are the difference between the real time data and the operational climatology data base. The climatology NDBC uses was supplied by PMEL and is the basis for the anomaly computations. In its research role PMEL continues to refine the climatology data base and so, at times, NDBC and PMEL's means and climatology products might vary. However, once PMEL's research confirms a new data base to be ready for the operational site, it will be installed at NDBC. In this way there will always be an operational climatology and research version(s) but the process will continue to yield improved anomaly fields.


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What gridding methods are used in TAO data display?
A variety of gridding methods are used to create the 2-D fields that are displayed in the TAO / TRITON Data Display page. Below you will find a detailed explanation of the gridding methods used for each.

Some of the gridding methods utilize climatological averages in the gridding process. For plots and background info on these climatologies, see the TAO / TRITON Climatologies page. These gridded fields have been created as "quick look" fields for visual display. Users of these fields are cautioned that they may not be optimally contstructed for detailed scientific analyses. We encourage users of the TAO / TRITON data to do their own gridding for any serious scientific computations. Ungridded data are available by anonymous FTP (Host: tao.noaa.gov, Directory: taodata) and on the TAO / TRITON Data Display page.

Buoy gridding
Current meter gridding
Latitude - Longitude gridding
Zonal - time gridding
Meridional - time gridding
Zonal - depth gridding
Meridional - depth gridding


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What wind direction convention is used in TAO data display and data delivery?
The wind-to-direction is used throughout the NDBC TAO web site (except a non TAO station 41042).



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