Marine Data Literacy

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9.1 IDV Setup
9.2 GHRSST FTP
9.3 WW3 Waves
9.4 ColorWeb
9.5 GlobWaves
9.7 MET.NO Ice
9.8 AVISO SSH
9.10 HYCOM Direct
9.12 IDV->Google
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9.14 Cyclone Paths
9.16 AVISO Waves
9.17 ASCAT Winds
9.18 Optics/Pigments
9.19 NOGAPS Meteo
9.20 Coriolis Profiles
9.21 MODIS Images
9.22 Aquarius SSS
9.23 GDP Tracks
9.24 GlobColour
9.26 MIRAS Salinity
9.27 MODIS Optics
9.28 Marine Weather
9.29 Recent Precip
9.30 Cyclone Grids
9.31 RTOFS Model
9.32 JTWC Cyclones
9.33 NMOC Gallery
9.34 JPL/MUR SST
9.35 Tide Forecasts
9.36 OSCAR Currents
9.37 Global Stations
9.38 Trajectories
9.39 Mercator/PISCES
9.40 Time Series
9.41 RapidScat Winds
9.42 JPL/G1SST

Home > 9. Operational/Synoptic > 9.31 RTOFS Model

9.31 Visualizing Modeled Ocean Scalars & Vectors in IDV:  RTOFS

1.  Open the RTOFS homepage, and take some time to read about it.  Then click on DATA ACCESS.
2.  Here is the data access page.  We want to use OPeNDAP, but developmental servers can be trouble.  So click on the middle option, Number 2.
3.  The page that appears is a very large listing of datasets archived in NOAA's NOMADS service.  Many programs and projects deliver their data here for public access.

The author has greatly edited the page so you can see only the resource you need, RTOFS GLOBAL.  But take a few minutes to look over all the other available files.  About 40 lines of other resources are missing here, for clarity.

Click on the link RTOFS GLOBAL in the first column.

Data Set freq grib filter http gds-alt
Global Models

Links to 13 atmosphere/weather models and their products omitted here

Regional Models

Links to 30 atmosphere/weather models and their products omitted here

Ocean Models
RTOFS Global daily - http OpenDAP-alt

Links to 9 really interesting other ocean models (global or regional), including ice and wave products, omitted here

External Models

Links to 3 models of other agencies omitted here

4.  A page will open with this information.  Take a moment to read more about these data.
5.  Fortunately, there is usually a pathway to exact data location information when you're viewing an "OPENDAP" page.
6.  To the right of the RTOFS GLOBAL link above, you'll see an OpenDAP-alt  link.  Click it to see directories for the latest available data.

In the author's case, 20130924 is today, and 20130923 was yesterday.

We don't know what's in them, so we must explore.

7.  Here is the second link, the latest one, rtofs_global20130924/:dir where you'll see numerous typical OPeNDAP listings.  The INFO file for each listing is the URL we need in IDV.

But which one to use?  Here are our priorities:

  • We want forecasts, not just nowcasts
  • We want 3D grids, not just 2D; 3D lets us analyze throughout the water column, but 2D only provides the surface data
  • We want global data, not regional, for international training purposes

Look closely and you'll see that nothing here is suitable.  The model has not made enough products on 20130924 to satisfy our needs.  So we need to go back one day.

GrADS Data Server - directory for /rtofs/rtofs_global20130924 : 11 entries

 

1: rtofs_glo_2ds_nowcast_3hrly_diag: 2D Sfc 3 Hourly Diagnostic 00Z22sep2013: Nowcast, downloaded Sep 24 05:09 UTC   info  dds  das

2: rtofs_glo_2ds_nowcast_3hrly_prog: 2D Sfc 3 Hourly Prognostic 00Z22sep2013: Nowcast, downloaded Sep 24 05:07 UTC   info  dds  das

3: rtofs_glo_2ds_nowcast_daily_diag: 2D Sfc Daily Diagnostic 00Z22sep2013: Nowcast, downloaded Sep 24 04:11 UTC   info  dds  das

4: rtofs_glo_2ds_nowcast_daily_prog: 2D Sfc Daily Prognostic 00Z22sep2013 : Nowcast, downloaded Sep 24 04:11 UTC   info  dds  das

5: rtofs_glo_3dz_nowcast_6hrly_reg1: 3D Volume 6hrly Region 1 00Z22sep2013: Nowcast, downloaded Sep 24 05:10 UTC   info  dds  das

6: rtofs_glo_3dz_nowcast_6hrly_reg2: 3D Volume 6hrly Region 2 00Z22sep2013: Nowcast, downloaded Sep 24 05:09 UTC   info  dds  das

7: rtofs_glo_3dz_nowcast_6hrly_reg3: 3D Volume 6hrly Region 3 00Z22sep2013: Nowcast, downloaded Sep 24 05:08 UTC   info  dds  das

8: rtofs_glo_3dz_nowcast_daily_salt: 3D Volume Daily Salinity 00Z22sep2013: Nowcast, downloaded Sep 24 05:09 UTC   info  dds  das

9: rtofs_glo_3dz_nowcast_daily_temp: 3D Volume Daily Temperature 00Z22sep2013: Nowcast, downloaded Sep 24 05:08 UTC   info  dds  das

10: rtofs_glo_3dz_nowcast_daily_uvel: 3D Volume Daily U Component 00Z22sep2013: Nowcast, downloaded Sep 24 05:09 UTC   info  dds  das

11: rtofs_glo_3dz_nowcast_daily_vvel: 3D Volume Daily V Component 00Z22sep2013: Nowcast, downloaded Sep 24 05:09 UTC   info  dds 
das

8.  Here is the first link, the earliest one, rtofs_global20130923/:dir where you see many more listings.  This is because 20130923 is finished, and all its products can be listed.

If you look closely (please do so; don't take my word for it), only the products marked in yellow are acceptable (by our criteria, above).  They are salinity, temperature, U and V forecast, 3D data grids for the globe.

GrADS Data Server - directory for /rtofs/rtofs_global20130923 : 22 entries


1: rtofs_glo_2ds_forecast_3hrly_diag: 2D Sfc 3 Hourly Diagnostic 00Z23sep2013: Forecast, downloaded Sep 23 16:23 UTC   info  dds  das

2: rtofs_glo_2ds_forecast_3hrly_prog: 2D Sfc 3 Hourly Prognostic 00Z23sep2013: Forecast, downloaded Sep 23 16:18 UTC   info  dds  das

3: rtofs_glo_2ds_forecast_daily_diag: 2D Sfc Daily Diagnostic 00Z23sep2013: Forecast, downloaded Sep 23 15:15 UTC   info  dds  das

4: rtofs_glo_2ds_forecast_daily_prog: 2D Sfc Daily Prognostic 00Z23sep2013: Forecast, downloaded Sep 23 15:15 UTC   info  dds  das

5: rtofs_glo_2ds_nowcast_3hrly_diag: 2D Sfc 3 Hourly Diagnostic 00Z21sep2013: Nowcast, downloaded Sep 23 05:07 UTC   info  dds  das

6: rtofs_glo_2ds_nowcast_3hrly_prog: 2D Sfc 3 Hourly Prognostic 00Z21sep2013: Nowcast, downloaded Sep 23 05:07 UTC   info  dds  das

7: rtofs_glo_2ds_nowcast_daily_diag: 2D Sfc Daily Diagnostic 00Z21sep2013: Nowcast, downloaded Sep 23 04:13 UTC   info  dds  das

8: rtofs_glo_2ds_nowcast_daily_prog: 2D Sfc Daily Prognostic 00Z21sep2013 : Nowcast, downloaded Sep 23 04:13 UTC   info  dds  das

9: rtofs_glo_3dz_forecast_6hrly_reg1: 3D Volume 6hrly Region 1 00Z23sep2013: Forecast, downloaded Sep 23 16:27 UTC   info  dds  das

10: rtofs_glo_3dz_forecast_6hrly_reg2: 3D Volume 6hrly Region 2 00Z23sep2013: Forecast, downloaded Sep 23 16:19 UTC   info  dds  das

11: rtofs_glo_3dz_forecast_6hrly_reg3: 3D Volume 6hrly Region 3 00Z23sep2013: Forecast, downloaded Sep 23 16:20 UTC   info  dds  das

12: rtofs_glo_3dz_forecast_daily_salt: 3D Volume Daily Salinity 00Z23sep2013: Forecast, downloaded Sep 23 16:18 UTC   info  dds  das

13: rtofs_glo_3dz_forecast_daily_temp: 3D Volume Daily Temperature 00Z23sep2013: Forecast, downloaded Sep 23 16:18 UTC   info  dds  das

14: rtofs_glo_3dz_forecast_daily_uvel: 3D Volume Daily U Component 00Z23sep2013: Forecast, downloaded Sep 23 16:18 UTC   info  dds  das

15: rtofs_glo_3dz_forecast_daily_vvel: 3D Volume Daily V Component 00Z23sep2013: Forecast, downloaded Sep 23 16:14 UTC   info  dds  das


16: rtofs_glo_3dz_nowcast_6hrly_reg1: 3D Volume 6hrly Region 1 00Z21sep2013: Nowcast, downloaded Sep 23 05:08 UTC   info  dds  das

17: rtofs_glo_3dz_nowcast_6hrly_reg2: 3D Volume 6hrly Region 2 00Z21sep2013: Nowcast, downloaded Sep 23 05:10 UTC   info  dds  das

18: rtofs_glo_3dz_nowcast_6hrly_reg3: 3D Volume 6hrly Region 3 00Z21sep2013: Nowcast, downloaded Sep 23 05:10 UTC   info  dds  das

19: rtofs_glo_3dz_nowcast_daily_salt: 3D Volume Daily Salinity 00Z21sep2013: Nowcast, downloaded Sep 23 05:09 UTC   info  dds  das

20: rtofs_glo_3dz_nowcast_daily_temp: 3D Volume Daily Temperature 00Z21sep2013: Nowcast, downloaded Sep 23 05:09 UTC   info  dds  das

21: rtofs_glo_3dz_nowcast_daily_uvel: 3D Volume Daily U Component 00Z21sep2013: Nowcast, downloaded Sep 23 05:09 UTC   info  dds  das

22: rtofs_glo_3dz_nowcast_daily_vvel: 3D Volume Daily V Component 00Z21sep2013: Nowcast, downloaded Sep 23 05:09 UTC   info  dds 
das

9.  Now we need the actual working URL for the first scalar of interest, salinity.  Find the global, 3D forecast for salinity, and click on the INFO link on the right side (beside DDS and DAS).
10.  This page will open, describing the salinity data.  Notice that there is an OPeNDAP DATA URL.  Block it and copy it for use in IDV.
11.  You can also block and copy all 4 URL's into a "collection" in an easily accessible location, as you see here.
  • http://nomads.ncep.noaa.gov:9090/dods/rtofs/rtofs_global20130923/rtofs_glo_3dz_forecast_daily_salt

  • http://nomads.ncep.noaa.gov:9090/dods/rtofs/rtofs_global20130923/rtofs_glo_3dz_forecast_daily_temp

  • http://nomads.ncep.noaa.gov:9090/dods/rtofs/rtofs_global20130923/rtofs_glo_3dz_forecast_daily_uvel

  • http://nomads.ncep.noaa.gov:9090/dods/rtofs/rtofs_global20130923/rtofs_glo_3dz_forecast_daily_vvel

12.  Now we can display the data.  Run IDV.
13.  If IDV doesn't look like this now, then you can use 9.1 Integrated Data Viewer (IDV) Preliminary Setup to fix it.

14.  In IDV, use the dashboard to select GENERAL > URLs > GRID FILE.  Then enter the URL for SALINITY data, and click ADD SOURCE.

15.  After a short wait (be patient) you'll see these items on the dashboard.  The dataset is listed on the left, and salinity is listed in the middle.
16.  To select times, locations, etc., right-click on the name of the dataset, and select PROPERTIES.

 

17.  Here is the PROPERTIES setup.  You can make some of the same choices in the lower-right corner.  But SPATIAL SUBSET must always be made in the upper-left corner.
18.  Select SPATIAL SUBSET.  Then use your cursor to draw a small rectangle anywhere on the map, but close to Liberia.
19.  Now you can enter the exact coordinates for our Liberia area of interest.

NOTE:  If you have changed the map size and the little boxes are too small to write in, then you must close this dataset (right-click then REMOVE) and open it again.  This is a bug in IDV.

20.  In the DISPLAYS panel, you can make choices of how the data are displayed.
  • Explore the other possibilities on your own, but select COLOR-SHADED PLAN VIEW for now
  • For most data sources, you can also select the TIMES here.  The DEFAULT would be all days, but with USE SELECTED you can pick any days of interest. 
  • There is a problem with the use of these RTOFS analyses.  They are being served by a GRADS Data Server (GDS), which unfortunately cannot deliver the first item in an ordered list.  The first day is empty...just a black map. The author has selected TIMES > USE SELECTED and picked all days after the empty first day
21.  The LEVEL or LEVELS can only be picked in the DISPLAYS control.  There are 2 small issues here:
  • The standard depths are by "millibars", but this should be decibars for ocean models.  This is another GDS issue.
  • The "0 millibar" level is empty...just a black map.  This is also a GDS issue.

When you've made these choices, then click CREATE DISPLAY.

22.  Wait a short time while IDV fetches the necessary data for this area.  You'll see the status message READING DATA in the lower right corner.

And here is the SALINITY map, using the default colors.  It's really quite understandable, with lower values moving away from the coast toward the west.  The southern arm of the Canary Current is possibly in the NW corner.

You can select specific days from the timer control along the upper-left corner of the map (the blue and green rectangles).  Or you can start an animation by clicking the RUN icon (right-facing triangle).

23.  And you can capture the animation as by selecting VIEW > CAPTURE > MOVIE.
24.  The author has not investigated most of these options, but gets good results with the defaults.  Just click on TIME ANIMATION, and IDV does all the work.

You can play with the settings later, on your own time, and probably make much better animations.

25.  When asked where to save the result, just navigate to PRODUCTS > IDV > IMAGES and use the filename salinity_animation_10m_liberia_20130924_20131001_rtofs.mov.  You can actually click this link to see the author's attempt with the same data.

26.  Now, let's move on to see the current vectors we can make from the U and V velocity components:

  • Go back to the collection of URLs, and add the U current component to IDV, exactly as you did above.  Make the same time and spatial subset choices.

  • Go back to the collection of URLs, and add the V current component to IDV, exactly as you did above.  Make the same time and spatial subset choices.

27.  Now we don't want to view these grids as scalars, but combined as vectors.  To do this, click on DATA SOURCES > FORMULAS in the upper left corner of IDV to reveal a whole tree of formula items.
  • Of special interest is GRIDS > ENSEMBLE.  Open it and select MAKE FLOW VECTORS FROM U AND V DATA.
  • Also, select DISPLAYS > FLOW DISPLAYS > VECTOR PLAN VIEW as the format of the product

Then click CREATE DISPLAY.

34.  This special panel opens for you to specify how the ensemble formula will work.  It's asking you which variables to use for the U and which to use for the V.  If they are not already correctly identified, then make the correct choices as you see here.

But don't click OK yet.

35.  You can also set the depth(s) with the LEVEL tab, as a single value or a range.  Make your choices and click OK to make the map. 
36.  Here is your first view of the map, using default display values.  It has 3 problems:
  • Vector arrows are too small
  • Vector arrows are packed too closely
  • The red color probably isn't good on a black background

We need to fix these issues.

37.  Open the a dashboard's DISPLAY tab, and examine these possible settings.  The author has made some changes that seem to work (see below), but you should just play with it to make it look how you want.
  • SIZE - Refers to the size of the arrows and must be changed with the little "slider" control
  • SKIP - Is a control that lets you display only every second, or third arrow, or even fewer.  Must be changed with the slider
  • COLOR - Obvious
  • STREAMLINES - For a big surprise, try this one and you'll see a completely different display.
38.  And here's the map after the author's changes.
31.  If you want to get back to the temperature image, then make sure to save it now with an appropriate filename in PRODUCTS > IDV
The exercises, notes and graphics in this website are copyrighted, and may not be copied or abstracted in any way, without my explicit permission (in writing).  Making one copy for your personal use is allowed.   Please report any copyright infringement to me. Murray Brown m.brown.nsb <at> gmail.com