||Altimeter Applet Usage|
Position the mouse over each component on the image below to learn
more about it.
This interface displays near-real time sea height anomalies (SHA)
derived from JASON-1, TOPEX, ERS-2, ENVISAT and GFO altimeters, processed by the NRL site at the Stennis Space Center, and
GTS data provided by NOAA/NOS. The maps are generated by interpolating SHA data
corresponding to a 10-day period up to the selected date. The SHA is the
default parameter displayed, with contour values drawn every 10 cm. The dynamic
height maps are displayed by activating the field labelled 'currents', with
contour values drawn every 50 cm of dynamic height. The data spatial
distribution can be observed by
overlaying the data points used to generate the SHA map. To identify
the data source, the ground-track for each sensor is displayed with different
colors: blue-JASON-1,black-TOPEX, red-ERS-2, brown-ENVISAT, pink-GFO.
Three different Mean Surface Heights are available:
- OCCAM_MODEL. This field is derived from a 3-year OCCAM run driven
with realistic (ECMWF) winds. The OCCAM mssh errors in boundary current
separation regions are removed by using climatological dynamic heights based
on Levitus (Kuroshio) and Lozier (Gulf Stream) climatologies. Spatial
Resolution: 0.25 degree. Additional Information: Alan Fox,
Keith Haines, Beverley De Cuevas and David Webb. Altimeter Assimilation in
the OCCAM Global Model, Part II: TOPEX/POSEIDON and ERS1 Data. Journal
of Marine Systems, 26, 323-347, 2000.
- OCCAM_XBT. This field is derived from a 4-year 1992-96 OCCAM run
driven by ECMWF winds and assimilated with XBT subsurface temperature data.
This assimilation of hydrographic data helps control the biases in the OCCAM
mean ssh. The mean represents years 1993-95.
Spatial Resolution: 0.25 degree. Data Source: Alan Fox, Haines and the OCCAM
- LEVITUS1000m. Mean Dynamic Topography relative to 1000m depth. Spatial
Resolution: 1 degree.
The GTS controls are located in the
applet's upper area. Four types of GTS headers are routinely processed and
ingested into the database:
- BUOY - Reports from buoy observations
- TRACKOB - Reports of marine surface observations along ship's tracks
- BATHY - Reports of bathythermal observations
- TESAC - Temperature, salinity and current reports from sea stations
Using the 'Days' scrollbar, you can select the number of days prior
to the chosen ending date as the temporal range to extract the GTS data. The oldest
measurement for each WMO code is displayed as a
square. The output type is selected by using a drop-down list which comes with
the 'Graphics' default.
You can click and drag the mouse on either of the displayed maps to select
the area of interest. The button labelled
'Go!' launches the CGI routine that generates the results.
Thanks to Alan Fox
for providing the OCCAM mean surfaces.
This applet is based on
the TMAPapplet developed by Jonathan Callahan at NOAA/PMEL.
Please, address your questions or comments to Joaquin A. Trinanes