Climate Charts Index > Pseudo-Blog

Climate Comments Pseudo-Blog

The main purpose of this pseudo-blog is to use current events to highlight what this website is all about - making climate data more accessible and more understandable. I’m a chartmaker, not a climatologist, so I will try to stick to talking about the data - what it is, where it comes from, and what it means.

I call this a pseudo-blog because it will be updated on a very irregular basis, and it does not have any comment capability, or any other blog-type functionality. It is blog-like though, in that is more informal than the rest of the site.

Please let me know if you have any problems, questions, or suggestions.

Prevailing Winds Maps

March 26, 2008

I have been looking for prevailing winds maps for more than a year. Well, actually, I gave up, but I still had a hole in the World Climate Maps page. Now site visitor Andrew Leventis has pointed me to NOAA Earth System Research Laboratory which produces maps on demand from its climate database.

So here is a Wind Vector map for January:
world wind vector map for January

And one for July:
world wind vector map for January

Note that both the direction, shown by the arrows, and the speed, shown by the background color, changes from January to July.

Climate Types in 10,000 BC

March 12, 2008

I saw the new movie 10,000 BC last weekend. I can’t recommend it unless you are a sucker for mammoths, sabertooth tigers, Atlantis, pyramids and the like. If you saw the trailer you know what I’m talking about.

But, I’ve had an eye out for good climate images to use in my upcoming Climate Type pages, and 10,000 BC covers the range pretty well. We’ve got tundra with a mammoth hunt
Mammoth hunt on tundra
jungle with a moa, (I think)
Moa and man in jungle
desert
Desert
and savanna with a sabertooth tiger.
Sabertooth on savanna
Sorry about the savanna image, the trailer didn’t spend much time on this part of the movie.

Our heroes travel across these regions in about about a day and a half, but we aren’t going to quibble. It’s all good fun, and I would actually say that, compared to a lot of Hollywood offerings, it’s relatively realistic.

All the images in this post are captured from trailers on the official 10000 BC website.

Climate Types

March 1, 2008

The study of climate - average weather - is by definition an attempt to ignore the details and focus on the underlying patterns. We can take this effort one step farther and look at climate types, to help us understand the similarities and differences between different places and different time periods.

This turns out to be tricky. It’s easy to set up some ranges of precipitation and temperature, and shoehorn every location into those ranges, thus classifying them. But this results in grouping together some places that otherwise seem quite different to us. Finding a set of grouping criteria that matches our sense of similarity in a reasonable number of groups is to some extent still an unsolved problem.

The Köppen system is widely used. It uses 5 major groups and many subgroups. Here’s a world map
World map of Koppen Climate Classification
(from
Wikipedia, Wikimedia Commons.)

There is a lot to see here. The groupings show us a lot, but also hide things. Notice, for example, how south Texas and Delaware are in the same group. This seems odd, but the differences between groups are even bigger that the differences between Texas and Delaware. We could subdivide the group, but where do you stop? This is what happens when we group things.

On the plus side, notice how the Texas-Delaware group also appears in parts of South America, China, Australia, etc. This grouping helps us quickly find somewhat similar areas around the world.

Likewise, notice that Australia, though mostly desert, has a wide range of climate types, as does the USA.

The Holdridge system has a cool diagram, but it doesn’t seem to have a lot of support in the climatological community.
Chart of Holdridge Climate Classification

I’ll be adding some instructive examples of Climate types to this site in the near future.

Trouble in Georgia - the Drought Continues

February 23, 2008

Georgia Drought has a lot of good information about the current problems there. To make a long story short, the situation is bad and likely to get worse over 2008. Especially see Drought and Water Outlooks for 2008, a PowerPoint presentation by David Emory Stooksbury, Ph.D. He is the State Climatologist and also an Associate Professor, Engineering and Atmospheric Sciences, at the University of Georgia. A man after my own heart, he uses lots of charts and maps to make the point that the drought is not over for Georgia and Alabama. Here’s a sample showing the lower soil moisture:

Soil Moisture Anomaly, Jan 28, 2008

In 2007, the Atlanta area, for example, got half or less of their average rainfall, bringing them to a point more like Abilene, Texas.

Monthly average
Precipitation
(inches)
Atlanta, GA
4.35″
precipitation for Atlanta, GA
Abilene, TX
1.98″
precipitation for Abilene, TX

Atlanta is the largest city hit by the drought, but most of northwest Georgia and northern Alabama, as well as the surrounding areas, are also feeling the pain.

Six Degrees in Nebraska

February 20, 2008

I just watched, or tried to watch, the new National Geographic Channel TV show Six Degrees Could Change the World. The NGC has moved in the direction of sensationalism lately, never missing an opportunity to use over-the-top images, animation, and verbiage (’cataclysmic’). It’s all too much for a data-driven guy like me to stomach. The problem is large, complex, and politically charged, I think it is important to try to use more light and less heat.

Anyway, I’m a chartmaker and not a TV critic, so lets look at some charts that address one of the show’s subtopics, how Nebraska will turn into a desert. Here we show precipitation for Hyannis in west-central Nebraska, Hutchinson in central Kansas, and Phoenix in south-central Arizona. The charts are from our USA climate pages, namely Hyannis, Hutchinson, and Phoenix.

Monthly average
Precipitation
(inches)
1.62 precipitation for Hyannis, NE
2.53 precipitation for Hutchinson, KS
0.69 precipitation for Phoenix, AZ

We see that Hyannis precipitation is about halfway between Hutchinson, which is pretty good farming country, and Phoenix, which is not.

So Hyannis is kind of marginal right now, and can not afford to get much dryer. Of course we are talking about ‘global warming’ and not ‘global drying’, but precipitation patterns will change along with temperature. Farmers in Nebraska had better be thinking hard about climate change.

The Drought of 2007, The Floods of 2007

February 16, 2008

Much of the southeast USA suffered through a severe drought in 2007, while Texas, Oklahoma, and the Midwest received much more rain than normal. Much of California and the Pacific Northwest was also much dryer than normal. This National Weather Service map shows the difference from normal in inches:
USA departure from normal precipitation 2007

This one also shows the difference from normal, this time as a percentage:
USA percentage of normal precipitation 2007

Here’s a Weather Department map showing what actually fell in 2007. Notice how ‘drought conditions’ depends on where you are. Central Alabama, in a severe drought, received about as much rain as western Texas, which experienced flooding. Farmers (and the ecosystem) in northern and central Alabama expect around 50-60 inches of rain a year, but they got about half that. Parts of Texas, on the other hand got 50%-100% more than normal.

See the Alabama, Texas, and all the USA charts on this site for much more detail.

USA observed precipitation 2007

Finally, compare the above maps to a long-term average ‘normal’ year:

USA normal precipitation 2007

The maps are from the National Weather Service Advanced Hydrologic Prediction Service. Use the ‘water’, ‘precipitation’, and ‘images’ tabs, then select the maps you want.

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