The Blackboard

This emphasizes that an AGCM is a system whose mean behavior can reflect unanticipated and unphysical interactions between its component parameterizations.
Duh.
That unanticipated and unphysical interactions between component parameterizations may arise has been known in engineering cfd for ages. In the 80s and 90s, there were scads of (tediously boring ) papers in multiphase [...]

UAH temperature anomalies were officially posted yesterday. I thought you all might like to see a graph of temperature anomalies with uncertainty intervals. I included a trend of 2C/century for references:
As you can see:

The trends for both UAH and RSS are negative since 2001 with RSS having the larger negative trend.
If [...]

I mentioned we had a coolish April around here; the Scandinavians reported it’s warm over there. Interestingly, Chad had just finished downloading model data from HadCM3 and compared the local anomalies in HadCrut and HadCM3. The differences in anomalies for HadCRUT and HadCM3 relative to the period 1980-1999 are shown below:

You can see the [...]

Troposphere temps up or down? Yesterday, RSS said up; today, UAH says down. Here are the temperature anomalies since UAH began operation:

UAH for March was 0.208 C; April’s 0.091 anomaly is C . That’s quite a drop! (In contrast, RSS rose 0.04C.)
UAH for April 2008 was 0.015 C; April 2009 was 0.244C. [...]

RSS posted their anomaly: The Lower Troposphere warmed relative to the temperature in March 2009 and April 2008. I’ve created a very cluttered graph illustrating many things about RSS below:
As you can see:

The observed temperature from April, 2009, which is circled in red, and enclosed in a black triangle is up from March [...]

In comments, it appears Deep Climate wants us to compare the current trends to the stated trend in Table 10.5 in the AR4.
Slight correction to my previous comment: I was confusing the A2 and A1B scenario IPCC projections. The former is 0.66 C (0.21/decade) to 2030 and the latter is 0.69 C (0.22/decade). The [...]

From time to time, I like to think about how to show compare simulated and observed temperatures not in the way I think “best” but using methods “most similar” to figures contained in the AR4 itself. Today, I decided it would be useful to concoct a figure that compares the observed anomalies using a [...]

Friday’s post compared the multi-model mean trend based on simulations of AOGCM runs to the observed temperatures. In comments, I mentioned that I had also filtered based on models based on volcanic eruptions. The graph below shows that if we compare the multi-model mean trend based on models driven by the more realistic 20th [...]

HadCrut updated:

2009/01 0.375 C
2009/02 0.345 C

I need to take my mother-in-law shopping… so more later!

Way back in February, I promised I’d show how the observed trends through Jan 2009 compare to simulated trends based on the data I downloaded from The Climate Explorer. Then, I came down with a recurring sore throat, ended up on amoxicillin… and got distracted making mugs and slippers. But today I’m going to show [...]