earth

a visualization of global weather conditions
forecast by supercomputers
updated every three hours

ocean surface current estimates
updated every five days

ocean surface temperatures and
anomaly from daily average (1981-2011)
updated daily

ocean waves
updated every three hours

atmospheric pressure corresponds roughly to altitude
several pressure layers are meteorologically interesting
they show data assuming the earth is completely smooth
note: 1 hectopascal (hPa) = 1 millibar (mb)

the "Surface" layer represents conditions at ground or water level
this layer follows the contours of mountains, valleys, etc.

overlays show another dimension of data using color
some overlays are valid at a specific height
while others are valid for the entire thickness of the atmosphere

about ocean waves

Significant Wave Height is the average height of the highest 1/3 of waves at a particular point in the ocean. There's a great writeup here describing what this means.

Peak Wave Period is the (inverse) frequency of the most energetic waves passing through a particular point, whether wind generated or swells. Certainly, there are many more groups of waves moving through an area, each in different directions, but trying to show them all rapidly becomes complex. Instead, we show the one wave group contributing the most energy. This has the effect, though, of creating "boundaries" between regions of ocean where the #1 wave group suddenly switches to second place. Often these boundaries represent swell fronts, but other times they are just artifacts of the ranking mechanism.

about CO₂ concentrations

While implementing the visualization of CO₂ surface concentration, I noticed the NASA GEOS-5 model reports a global mean concentration that differs significantly from widely reported numbers. For example, from the run at 2015-11-23 00:00 UTC, the global mean is only 368 ppmv whereas CO₂ observatories report concentrations closer to 400 ppmv. GEOS-5 was constructed in the 2000s, so perhaps the model does not account for accumulation of atmospheric CO₂ over time? This is simply speculation. I am just not certain.

To bring the GEOS-5 results closer to contemporary numbers, I have added a uniform offset of +32 ppmv, increasing the global mean to 400 ppmv. This is not scientifically valid, but it does allow the visualization to become illustrative of the discussion occurring today around atmospheric CO₂. Without question, I would welcome a more rigorous approach or an explanation why the GEOS-5 model produces the data that it does.

disclaimer

GEOS-5 data (covering all Chem and Particulates layers) comes with the following disclaimer: Forecasts using the GEOS system are experimental and are produced for research purposes only. Use of these forecasts for purposes other than research is not recommended.

about aerosols and extinction

An aerosol is air containing particles. Common particles are dust, smoke, soot, and water droplets (clouds). These particles affect sunlight primarily through absorption and scattering, which combine to reduce the amount of light reaching the ground. This loss of light as it passes through the atmosphere is called extinction.

One common measure of extinction is aerosol optical thickness (AOT), which is (the log of) the ratio between the power of incoming light and the power of transmitted light. This helps us understand how "thick" the air is with particulates.

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The GEOS-5 data used on this site have been provided by the Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center through the online data portal in the NASA Center for Climate Simulation