NOAA's PolarWatch


#1

Polarwatch (https://polarwatch.noaa.gov) is a NOAA effort to prove easy access to satellite data from both poles. The data being provided is based on a lot of input from people who work in both the Arctic and Antarctic regions. Besides the webpage above, there is a dedicated ERDDAP web data serve at https://polarwatch.noaa.gov/erddap. This provides for easy subsetting and download of the data in many formats, and can be used with rerddap in R and erddapy in Python. For some Python notebooks see https://polarwatch.noaa.gov/training, when I get a chance I will work up an R notebook. Feedback both welcomed and encouraged, particularly if there are other datasets that would be useful to researchers.


#2

Thanks @rmendels, very useful. I’ve added a mention of PolarWatch/rerddap to the task view (can be updated if I haven’t got the description quite right). I haven’t personally made much use of ERDDAP-served data, I generally prefer to get one step closer to the source and get raw files directly - I just find that’s easier in the long run. But I recognize that this isn’t necessarily true for anyone else!

So this might be a dumb question: I don’t quite get where PolarWatch fits in the NOAA scheme. The data sets on the PolarWatch ERDDAP server aren’t all polar-specific (many are global) - are these different to the ones I could get from the main NOAA ERDDAP server? Is the PolarWatch server a polar-friendly subset of the larger one, with some extra non-NOAA data (e.g. I see NSIDC sea ice) thrown in?

In terms of additional data sets, maybe the historic archive of sea ice concentration would be useful, to match the near-real-time data source that you already have?


#3

Hi Ben:

The data are a mix. some global datasets that people who work in the Polar region tell us would be useful to them, and since ERDDAP allows for easy subsetting, they can get the Polar data. And some are new ones that have been added through the PolarWatch effort. I believe, but don’t want to be quoted, that we are working on getting the historical ice data. People who could better answer this are copied on the memo. But even more, this is just the type of feedback we welcome. We can’t guarantee we can make things available, but getting feedback from people on what would be useful to them is very helpful.

One of the beauties of ERDDAP is the ability to be Federated, so yes these datasets are on other ERDDAPs. The advantage of a separate ERDDAP is in search and finding relevant datasets. View it as pre-sorting that we have been told are the most relevant data sets to simplify things for the user. We have been talking to quite a few groups that are doing research in both poles - I believe for the Southern Ocean mostly with folks from NMFS/SWFSC/Antarctic Research Division.

Also, you can store locally the parts of data that is relevant to the Southern Ocean rather than the entire huge dataset, nothing is preventing you from doing that, or, for files that we have locally, you can download the raw files using the “files” option if you prefer - though given things like the size of MUR files, you would do much better to store just the parts you need… The main thing is that everything in ERDDAP from search to graphics to subsetting is a very simple URL accessed by a HTTP GET, so anything that can send an URL and receive a file can be easily programmed to access the data if the already available packages like rerddap or erddapy don’t meet your needs. We have people use curl, wget, Python, Java, browsers, R, Matlab, among several other things to access the data. We also have programs that allow for extracts along tracks and in polygons, the former being the source of much of our usage - though this is pretty easy to write for an experienced programmer.

And, in fact, we have some one of some institution from Tasmania that comes in regularly every day to get data. :slight_smile:

Let me know if you have further questions or more suggestions.

-Roy M.