The Satellite Methane Tracker Blog

Near Real-Time Sea Ice Concentration Data Layer

Posted on 7/6/2013 by Omar Cabrera in Sea Ice Concentration Data Layer NSDIC Sea Ice
image

Please read this. It is VERY important you understand how our sea ice concentration maps are created and how the data is generated and where is the data coming from, as they are NOT provided by the NSDIC.

What is it? 

The Near Real-Time Sea Ice Concentration data layer is somewhat similar to the NSDIC Sea Ice Concentration maps, as the data is coming from the same instrument and same satellite (SSMIS, on board the Defense Meteorological Satellite Program (DMSP) F17 satellite). This data layer is built through an internally proprietary software written by us at MethaneTracker.org, based on the parsing of experimental data originally processed and generated by the University of Bremen in Germany

Our Near Real-Time Sea Ice Concentration data layer it's currently providing sea ice concentration percentage ranges from 10% to 100% ice, and with data ranging from 01/01/13 until yesterday.

Our software currently:

1. Downloads from the University of Bremen every day a GeoTIFF with their false color maps for the Arctic and Antarctic Regions for the previous day.

2. Reprocesses all colors to be as close as possible to the NSDIC Sea Ice Concentration map color tables (white for solid color, and shades of blue for less percentages).

3. Adds geocode information to the new color processed transparent images.

4. Translates them and warps them using GDAL, and then adds them daily to the data layer "Near Real-Time Sea Ice Concentration".

The operation occurs automatically at 2pm every day, at the same time that we processed the data from IASI.

We start with the daily false color SSMIS-derived GeoTIFF Sea Ice Maps from the University of Bremen,  for the Arctic and Antarctic regions. This service is part of the GMES project Polar View and of the Arctic Regional Ocean Observing System (Arctic ROOS).

Originally, both the instrument AMSR-E and its successor AMSR2, worked on the 89GHz frequency and that data was processed using the ARTIST sea ice algorithm. The University of Bremen applies the same algorithm to the SSMIS 91 GHz (read more here: http://www.iup.uni-bremen.de:8084/ssmis/). The AMSR2 data was originally coming from the satellite しずく "Shizuku" (GCOM-W1)

Please note, this visualization of the SSMIS data is experimental and do use this data layer carefully for this reason. Until the ARTIST sea ice algorithm running on SSMIS 91 GHz is validated or its data supported by peer reviewed publications, my suggestion would be to use the interactivity provided with this data layer just for quickly testing of hypothesis, and then use the NSDIC Sea Ice Concentration maps available at http://nsidc.org/ for further validation. 


Why & When should you use it?

If you understand sea ice and methane, this will be the first data layer you'll use. With this data layer we're able to clearly see a methane venting episode and the ice concentration (or lack thereof) underneath. Does sea ice melting release methane per se? Do ice-free shallow arctic seas actually release methane to the atmosphere? When? How much methane is being and can be absorbed? Having the full picture of the interaction between methane and sea ice could answer those questions.

Using methanetracker.org you can view the seafloor depth at the exact same geographical point of the release (just check the "Status Bar" and hover with your mouse over the methane, it will show you how deep the seafloor is); or you can even view specific methane venting episodes coming from specific thermokarst lakes.

As with other data layers, our Near Real-Time Sea Ice Concentration data layer can provide you with a quick way to test your hypotheses and, hopefully, to narrow down methane field research to the most useful spots. 

Other than that, it's just way cool to not only see the sea ice cycles around the world like viewing daily coverage maps from NSDIC, but being able to animate it and control it with a slider. Any sea ice follower can play all day with that slider and not get tired.

Post your comments