Frequently Asked Questions

General questions

Characteristics of the Argovis dataset

Argovis display

Using Argovis

Argovis API

* Is there a quick start guide to Argovis?
Yes, see the Argovis User Guide page for more information on Argovis' features and how to use it.

* How do I cite the Argovis web application and the Argovis database?
Tucker, T., D. Giglio, M. Scanderbeg, and S.S. Shen, 2020: Argovis: A Web Application for Fast Delivery, Visualization, and Analysis of Argo Data. J. Atmos. Oceanic Technol., 37 (3), 401-416, https://doi.org/10.1175/JTECH-D-19-0041.1

If using data from Argovis in publicaitons, please cite both the above Argovis web application paper and the original data source references below in your paper.

Argo data reference:
" These data were collected and made freely available by the International Argo Program and the national programs that contribute to it. (https://argovis.colorado.edu/docs, http://argo.jcommops.org). The Argo Program is part of the Global Ocean Observing System. "
Argo (2000). Argo float data and metadata from Global Data Assembly Centre (Argo GDAC). SEANOE. http://doi.org/10.17882/42182

Gridded Argo data reference

Roemmich, D. and J. Gilson, 2009: The 2004-2008 mean and annual cycle of temperature, salinity, and steric height in the global ocean from the Argo Program. Progress in Oceanography, 82, 81-100, http://dx.doi.org/10.1016/j.pocean.2009.03.004

Atmospheric River data reference
Guan, B., and  Waliser, D. E. (2015),  Detection of atmospheric rivers: Evaluation and application of an algorithm for global studies, J. Geophys. Res. Atmos.,  120, 12514– 12535, doi:10.1002/2015JD024257.

SOSE & B-SOSE
M. Mazloff, P. Heimbach, and C. Wunsch, 2010: An Eddy-Permitting Southern Ocean State Estimate. J. Phys. Oceanogr., 40, 880-899. doi: 10.1175/2009JPO4236.1

A. Verdy and M. Mazloff, 2017: A data assimilating model for estimating Southern Ocean biogeochemistry. J. Geophys. Res. Oceans., 122, doi:10.1002/2016JC012650

Tropical Cyclones

Priestley, M. D. K., Ackerley, D., Catto, J. L., Hodges, K. I., McDonald, R. E., & Lee, R. W. (2020). An Overview of the Extratropical Storm Tracks in CMIP6 Historical Simulations, Journal of Climate, 33(15), 6315-6343. Retrieved May 1, 2021, from https://doi.org/10.1175/JCLI-D-19-0928.1

https://www.nhc.noaa.gov/data/

https://www.metoc.navy.mil/jtwc/jtwc.html?best-tracks

Other relevant references:
Pierret, J., 2018: Climate Data Computing: Optimal Interpolation, Averaging, Visualization and Delivery. PhD Thesis in Computational Science, San Diego State University and Claremont Graduate University, 123pp.

Pierret, J., and S.S.P. Shen, 2017: 4D visual delivery of big climate data: A fast web database application system. Advances in Data Science and Adaptive Analysis, 9, DOI: 10.1142/S2424922X17500061.

Tucker, T., 2018: Mathematics and Big Data Technology Development to Visualize, Deliver and, Analyze IMS and ARGO data. MS Thesis in Applied Mathematics, San Diego State University, 123pp.

* What Argo data are in Argovis?
The Argovis database is a curated set of Argo profiles available from the Argo GDACs. Entire profiles are excluded if their position or time is bad (e.g., POSITION_QC = '3' or '4', JULD_QC = '3' or '4') or if the entire profile data is bad (e.g., all parameters have a QC value not equal to '1'). Profiles without a position are kept in the database and will not be visible on the home web interface, but will be displayed when looking at the platform plots and downloaded via the API. Profiles with an estimated position are in Argovis.

Otherwise, all temperature, pressure and salinity data are included in Argovis if their QC flag is equal to '1'. BioGeoChemical data are included no matter the QC flag and Deep data under 2000 db is included if the QC flag is '2' for pressure and temperature and '3' for salinity. If adjusted data is available for a parameter, that is used. Otherwise, the raw data is used.

*  Why does some of the data look wrong? Are quality control flags being used?
In the Argovis database, only measurements with a good quality control (QC) flag of '1' are included. However, Argo data have two different stages of quality control. Files with a data mode of 'R' or 'A' contain data that have only passed automated simple QC tests in real time and so may contain temperature, pressure and/or salinity errors. Most of these errors are the result of sensor drifts. Files with a data mode of 'D' have passed expert QC inspection and have had sensor drifts removed.

*  How accurate is the Argo data?
The temperatures in the Argo profiles are accurate to ± 0.002°C and pressures are accurate to ± 2.4dbar. For salinity,there are two answers. The data delivered in real time are sometimes affected by sensor drift. For many floats this drift is small, and the uncorrected salinities are accurate to ± .01 psu. At a later stage, salinities are corrected by expert examination, comparing older floats with newly deployed instruments and with ship-based data. Corrections are made both for identified sensor drift and for a thermal lag error, which can result when the float ascends through a region of strong temperature gradients. Following this delayed-mode correction, salinity errors are usually reduced further and in most cases the data become good enough to detect subtle ocean change.

*  Are Deep Argo data in Argovis?
Yes, Deep Argo data are in Argovis. Their profiles appear as dark blue circles on the map. The data above 2000db has QC flags of 1. The data below 2000db have different QC flags per Argo's current practice. Currently, all data below 2000db is flagged with a lower quality QC flag because the accuracy of the sensors is not yet well understood. QC flags of '2' are used for pressure and temperature and '3' for salinity.

*  Are BioGeoChemical Argo data in Argovis?
Yes, BioGeoChemical Argo (BGC Argo) data are in Argovis. Their profiles appear as green circles on the map. All BGC data, no matter the QC flags, are currently in Argovis. The QC flags appear when hovering over points on the plots and are included in the JSON data available for download. Additionally, for BGC floats, even core Argo variables with QC flags other than '1' are available. This is by request from the BGC Argo community. The bad core Argo variables do not appear on the 'core' Argo pages for BGC floats, but do appear on the BGC pages.

* How many profiles are in Argovis? How many are BGC? How many are Deep?
Click on the upside down triangle shape under the 'Choose Projection' menu on the left sidebar. A window should pop up at the bottom of the page listing when the database was last updated, the total number of profiles in Argovis, the number of Deep and BGC profiles and the DACs in Argovis.

*  Two-way communication and the Argo dataset
The majority of floats deployed in 2017 use the two-way communication system Iridium. With two-way communication, floats will be on the surface for a much shorter amount of time (~30 minutes to 2 hours instead of 8 to 24 hours) and their position will usually be fixed by GPS. Sometimes GPS fixes are not available and other, lower quality fixes can sometimes be used.

Additionally,there is the possibility for the floats to send back a much larger volume of data. Therefore, profiles from Argo floats using two-way communications will likely include many more CTD measurements; the frequency of measurements might increase to every couple of decibars in some areas and parts of the profile.

* Why does it take so long to load the pages?
When a selection is made, Argovis needs to access its database to get the profiles that match the query and then send that data to Plotly to create the plots. The first thing to appear on selection and platform pages is the table with a row for each profile. After that, it may take some time for the plots to appear. The larger your selection region in time and space, the longer it will take. Please be patient. If it is taking too long, you might want to consider using the API feature to download the data and make the plots yourself.

* Why are there different colored dots?
Yellow dots are core Argo profiles - pressure, temperature and salinity.
Green dots are BioGeoChemical Argo profiles.
Dark blue dots are Deep Argo profiles - deeper than 2000db.

* Why is the menu disappearing in Chrome?
There seems to be a bug right now with Argovis and the Chrome browser where the left side menu sometimes disappears. We are working on fixing this. In the meantime, if you hit the 'reset' button or re-load the page, it seems to temporarily fix the problem.

* How many profiles are displayed on the map?
The homepage map shows the most recent position of all active Argo floats within a three day window. The default end date is the previous day, but can be changed by clicking on the calendar icon next to the date or by entering a new date.

* How many profiles are displayed on selection page?
If you export the table and open it up in excel or your favorite application, it should give you a count of the number of rows in the table which is equal to the number of profiles displayed.

* Are there other map projections? How I see the Southern Ocean?
Yes, Argovis has three map projections to choose from in a drop-down menu on the left side bar. Click on 'Choose Projection' and the three options appear:
  • Web mercator
  • Southern stereo projection
  • Northern stereo projection

* How do I use the pressure slider to modify the pressure range?
You must FIRST change the pressure bar to the desired range and THEN draw your selection region. If not, all profiles disappear.

* How do I use the realtime, BGC and Deep Argo toggles?
You must FIRST set the toggles to the appropriate setting and THEN draw your selection region. The 'Include realtime' toggle lets you choose whether you want to see only delayed mode data ('Include realtime' toggle is OFF) or real time and delayed mode data ('Include realtime' toggle is ON). The 'Show only BGC' toggle lets you choose whether to look only at BGC Argo data (toggle is ON) or all Argo data (toggle is OFF). The 'Show only Deep' toggle lets you choose whether to look at only Deep Argo data (toggle is ON) or all Argo data (toggle is OFF).

* Why do the profiles that appear after making a selection look outside of my selected region?
This is because the Earth is a sphere and when it is stretched out to look flat like on the homepage, distances are distorted. Argovis queries the MongoDB database with a set of coordinates that correspond to the corners of the shape you created. The database then calculates the spherical area and looks for latitudes and longitudes of profiles within that area on the sphere. Therefore, when transformed back into distance coordinates, the profiles may look outside of the drawn shape. If you want to reduce this problem, use the polygon tool and make very short distances between points.

* Can I make a selection that is wider than 180° longitude?
Not with the rectangle tool. The shortest distance is calculated between the different drawn vertices and if the vertices are more than 180° apart, the distance will be calcuted for the shortest distance which will be the other way around the globe. Instead, if you use the polygon tool and make several dots that are closer together, you can end up drawing a shape that is wider than 180° that way. Alternately, you could draw multiple rectangles.

* How do I use the 'Platform number box'?
Enter a WMO number into the Platform number box and all the profiles should appear on the map in orange. To find the WMO number, it is the 5 or 6 digit number at the start of the profile file name.

* Can I modify or download plots?
Yes, it is possible to use the Plotly tools on the webpage itself to zoom in and out and download the plot as a png file. After playing around with the plot, you can also hit the home button to return it to the ones that appeared when the page first loaded. You can also go directly to Plotly to modify the plot which allows for more customization of the plot. Just click on the 'edit in chart studio' button.

* Can I download the data? What format will it be in?
You can download the data from the Argovis database in JSON format by clicking on the 'Download as JSON' button. If you prefer to have the data directly from the Argo Program data servers in NetCDF format, click on the link in the tables.

* Can the API be used to display database metrics?
Yes, through API. See the metadataExamples Gallery in the API section.

* Is there a Argovis API tutorial? In what language?
Yes, there are Argovis API calls written in Matlab and Python. All of the example coding is available via GitHub in the Argovis repository, with the latest example codes described at the bottom of the README.md file. There is also an Argovis Swagger webpage that provides documentation on how the API URL calls are constructed and lets you test them out. Finally, there is an Argovis blog with several posts on how to access the Argovis database via API in Python and one in R.

* Can you access only BGC data via the Argovis API?
Yes, there is a new region and platform API call in the Argovis repository to retrieve only BGC data or both BGC and core/deep Argo data. You can also access BGC data by platform. Because there can be large amounts of data on a BGC platform, the data are returned by parameter. This allows you to retrieve all BGC data or simply the BGC parameter(s) you are looking for.