MSU

Surface air temperature is monitored using thermometers. Temperature above the surface can also be measured with thermometers using radiosondes, radio transmitters which relay weather information to the ground from instruments usually attached to balloons and allowed to rise through the atmosphere. However, there are some distinct problems with balloon-borne radiosonde data: there’s poor coverage, especially over the oceans, and both instruments and procedures have changed over the years, making it difficult to determine long-term trends with accuracy. But since late 1978, temperature in various layers of the atmosphere has been measured by satellites carrying a microwave sounding unit (MSU), or its more advanced cousin the advanced microwave sounding unit (AMSU). The satellite missions were intended to aid weather studies rather than climate studies, but the data they have returned has been examined for its implications relating to climatic change in earth’s atmosphere.

Happy Holidays

To all readers: for the next 8 days I’ll be visiting relatives for the holiday season. I’m not sure how much internet access I’ll have, so there may be delays in moderating comments. Stay tuned, there’s more to come … and thanks to all for readership.

Happy Holidays!

Wiggles

I started working on a post about feedbacks, an interesting and important topic recently raised in reader comments. But I’ve been sidetracked by the revival of one of the favorite false claims of denialists, one of those pieces of garbage that never dies. Occasionally I look at the stats provided by wordpress, and I noticed I was getting a lot of hits from the science blog Deltoid. That’s because Deltoid commented on an open letter in the National Post signed by a collection of scientists which includes many, if not most, of the usual list of denialists. The open letter has some rather outrageous claims; possibly the most egregious (and most easily proved false) is this:

Denial?

Let’s take a look at this report posted three days ago on “Joe’s blog” on “icecap.us”. The report is titled “Southern Hemisphere Ice Cover Remains Well Above Normal.” There’s also an addendum stating that “In the Northern Hemisphere, the ice and snow cover have recovered to within 1% (one snowstorm) of normal with the official start of winter still more than 12 days away.” The intent is clear and undeniable: to give you the impression that the cryosphere (the frozen part of our planet) does not show shrinkage from global warming, let alone any profound effect. Instead it shows signs of being perfectly normal, unaffected by global warming — or maybe even a little bigger than normal.

Bush censors climate science

The House Oversight and Government Reform Committee has concluded an investigation into George W. Bush’s attempts to interfere with climate science. Their conclusion:

The evidence before the Committee leads to one inescapable conclusion: the Bush Administration has engaged in a systematic effort to manipulate climate change science and mislead policymakers and the public about the dangers of global warming.

Read the report.

U.S. Obstruction

Representatives from nations around the world are meeting is Bali for the United Nations Climate Change Conference. Executive Secretary Yvo de Boer said the first meeting this afternoon of the contact group, an initiative of Conference President Rachmat Witoelar, will discuss ways of reaching a future climate change agreement and how this agreeement should be structured.

Wobbles, part 2

In a previous post, we looked at the effect of changing eccentricity on the total amount of solar energy intercepted by earth throughout a year. Now I’d like to take a look at how precession and obliquity (the tilt of the earth’s axis) affect the distribution of incoming sunlight. Neither of these factors affects the total energy intercepted by the entire planet earth throughout the year. But they have a profound effect on how that energy is geographically distributed.

This post has a lot of equations; if that makes your eyes glaze over you can skip past them and look directly at the graphs (and read some of the discussion) below.