Guest posts by Willis Eschenbach
Inspired by a comment on the model amount of rain by Dr Richard Betts on the Twitterverse, today I decided to look at how well climate models can impede historical rainfall amounts and patterns.
I’ve got satellite precipitation data from Mission to measure tropical rainfall. So I went to KNMI and got the Climate Inter-Model Comparison Project 6 (CMIP6) climate model precipitation results of 38 different models in their database.
Let me start looking at the TRMM satellite data. It lasts from 40°N to 40°S. The two charts below are the same, but the one on the left is the center of the Pacific Ocean and the one on the right is the center of the Atlantic.
Figure 1. Average annual TRMM rainfall over 18 years, December 1997 – March 2015
Of interest is the rainfall stream north of the Equator in both the Pacific and Atlantic oceans. This marks the mean position of the Intertropical Convergence Zone (ITCZ). It is a semi-permanent thunderstorm stream located where the northern and southern halves of the atmosphere meet. It forms the ascending part of the great Hadley cell circulation, rises north of the equator, moves polewards on both sides, descends over the desert belt 30° north latitude, and returns to the ITCZ north of the equator. This is a cross-section of the Hadley cell circulation.
Figure 2. Cross section of the ITCZ and the northern and southern Hadley cells.
With that in mind, consider the following Pacific-focused maps of some of the modeling results.
Figure 3. Results of precipitation model, CMIP6 . model
I’m sure you can see the problem. There are two ITCZs in the model output, one above and one below the Equator.
Now, this is not something only in modern models. That’s a problem since there are climate models. It even has its own name. Here’s a comment from 2013 in PNAS:
The problem of the Double Intertropical Convergence Zone (ITCZ), in which excessive rainfall is generated in the tropics of the Southern Hemisphere, is similar to the Southern Hemisphere’s counterbalance to the strong ITCZ in the Northern Hemisphere. perhaps the most significant and persistent deviation of global climate models.
That was ten years ago, the issue was old and recognized at the time, and they still has not been remedied.
And do we have to completely destroy our current energy source and power the world with unicorn methane based on these garbage Tinkertoy™ climate models? Actually? They can’t even hide the past!
Furthermore, they can’t replicate Hadley’s cells, a most fundamental feature of global circulation, but are they supposed to be able to predict the future in the next hundred years?
It’s funny, but also tragic, that governments are passing laws and persecuting the poor based on this nonsense.
The problems continued. Below are the monthly precipitation observations from the TRMM, along with the modeled monthly precipitation, for the 40°N to 40°S region.
Figure 4. TRMM (red) and modeled monthly precipitation values (color), 40°N/S, December 1997 – March 2015
Again, you may see problems. Not only is there no overlap between models and observations, but the models are far from unified.
Well, how about the trends? There is a slight uptrend in the TRMM data, but what about the patterns? Below is a “violin diagram” of the pattern trend each decade, along with the TRMM trend over the period.
Figure 5. Violin chart of the pattern trend in millimeters per decade, together with the yellow/black line representing the TRMM trend. The width of the purple area at any point represents the number of trending patterns of the displayed value on the vertical (Y) axis. For those familiar with “density plots,” a violin plot is just two of them turned against each other.
Again, the problem. The different modeling trends are not only quite different from each other, but also do not agree on the signing. 17% of them are less than 0. In addition, the TRMM trend is greater than all but two of the pattern’s trends.
Conclusion:
Anyone who seriously believes in a word that models say about precipitation is either a climate alarmist or a fool… but I repeat.
My best for all,
w.
As always: I asked that when you comment, you quote the exact words you’re mentioning so we can all be clear on your subject and who said it.
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