Near real-time weather data and volcanic ash dispersal in the North Atlantic

Andrew Zolnai

Cambridge UK

blog.zolnai.ca

Abstract

Newly available internet technologies allow freely available government data mash-ups help track

weather patterns in real time. This allows for example to ascertain the weather risk across the north

Atlantic, and help track weather and flight disruptions associated with ongoing Icelandic volcanic

eruptions. Such developments will encourage citizen geographers to monitor their environment.

Introduction

The Eyjafjallajokull volcano is situated on the south coast of Iceland astride the mid-Atlantic oceanic

ridge. Its eruption has been spewing ash into the atmosphere more or less continuously since late

April 2010. It had a major impact on air traffic in the north Atlantic, affecting flights from North

America as well as those across northern Europe. The only respite is provided when the wind bears

ash away from the continent towards the uninhabited Arctic region.

It is therefore critical to be able to follow the dispersal of ash in near-real time, in order to try and

anticipate it impact in the near future. Whilst government meteorological offices have been

providing advisories and the news media followed its consequences, new tools allow the public to

follow this themselves. Here are simple tools available for free on the internet, as well as freely

accessible government data sources in order to do this.

Data Sources

US National Oceanic and Atmospheric Administration (NOAA) Goddard Space Flight Center (GSFC)

hosts web mapping services (WMS) of near-real time cloud cover data worldwide. They also carry

sulphur dioxide (SO2) and carbon monoxide (CO) readings, as reflective of ash dispersal hard to see

in the visible spectrum. These can be displayed for the current and up to six previous day in near real

time using WMS on a mapping system described in the next paragraph.

The US Geological Survey (USGS) also produced an Open File Report (OFR) that describe the plate

tectonic boundaries and the volcanoes along them. These are available in Keyhole Mark-up

Language (KML) and have been exported to a spreadsheet for correction (global data often posted

as east E and W longitude are more often read as positive and negative, respectively, and data

across the antemeridian or date line are often repeated or misread by software and data systems).

Tools

These data can be posted individually straight from source, either as NOAA WMS in any browser or

USGS KML in Google Earth. A web GIS service is used here to spatially register and correctly stack the

data together into what is called a mash-up. It is the combination of several datasets that provides

the power to link, track and even predict complex weather phenomena.

Vector web service

The service used is a free Geographic Information System (GIS) on the web called GIS Cloud posted

on www.giscloud.com. Data can be freely viewed anonymously, a free login can be created, and data

can be freely posted with certain terms and conditions (please review the website for details). The

mash-up can be found under Google Fusion > NOAA Cloud or directly under http://bit.ly/ansAbe.

Near-real time weather data are posted together with their origin, and freely usable under the

NOAA and USGS terms & conditions. Note that data posted here are original vectors and images.

Raster web service

The same data can be posted on ESRI’s free GIS viewer ArcGIS Explorer (AGX). The data file has been

posted on the new Arcgis.com repository http://bit.ly/bkdntd - double-clicking the icon will

download the NMF file and launch it in ArcMap or AGX desktop , whichever you have. Note that at

time of posting, ArcGIS Explorer online http://explorer.arcgis.com/ could not access this type of file.

Usage

The original screenshot of the ash cloud over England is posted on my blog http://bit.ly/ajU8IR

giscloud.com ArcGIS Explorer

SO2 readings clearly indicate where the as plume went early May 2010. The blog also show a video

created from snapshots of the cloud cover in the visible light spectrum, taken late May after the

second air traffic disruption – it is also posted on YouTube http://bit.ly/b4Iz85.

Conclusion

This shows how easy it can be to post weather and geographic data freely available from

government websites, by using free GIS software on the internet: Can’t you thus view, analyse and

post near-real time data relevant to your specific geography and to your particular sphere of

interest? We hope this will inspire you to become citizen geographers surveying your environment!

References

NOAA WMS, current: Goddard Earth Sciences Data and Information Services Center, Atmospheric

Infrared Sounder (AIRS) Near-Real-Time, http://disc.sci.gsfc.nasa.gov/services/ogc_wms

USGS, 2009: Open File Report 2009-1133, Preliminary Spreadsheet of Eruption Source Parameters

for Volcanoes of the World, http://pubs.usgs.gov/of/2009/1133/of2009-1133_text.pdf