During the summer, abundant sunshine during the long days heats up the ground near the surface. I’ve seen surface temperatures on dry ground up to 50°C in the south-central Great Plains of the United States. If you’ve dug a hole in the ground, have you noticed how cool the soil is? Last fall, when I was digging a hole for a dinosaur dig, I sat in the hole to cool off! (Figure 8).

Figure 8. Me enjoying the relatively cool temperatures in a hole. The shade helped, too! Photo by Lorrie McWhinny.

Figure 9 shows how the temperature varied beneath a winter wheat field in south-central Kansas during the late spring-early summer of 2002. The temperature 7.5 centimeters below the surface (blue curve) reaches a maximum in the early afternoon, with the peaks slightly later as you go to lower levels. Note that the daytime temperature at 7.5 centimeters below the surface is warmer than that at 15 centimeters, and so on, with the coolest temperatures at 80 centimeters below the surface.

Figure 9. Soil temperature as a function of day of year for a winter-wheat site in south-central Kansas. The distances in cm (centimeters) indicate how far below the ground surface the measurement is being taken. Day 138 is 18 May, Day 150 is 30 May, Day 180 is 29 June. All data for 2002. Date collected and processed by Professor Richard Cuenca, Oregon State University. The maxima in the blue curve occur in the early afternoon.

These data, which are fairly typical, are consistent with our impression that the soil is usually cooler than the surface for most of the day during summertime. (The cooler surface temperatures on some days appear to be related to rainfall.)

The surface temperature for the same site appears in figure 10. Notice how the surface temperature peaks during the day about five degrees higher than at 7.5 centimeters during the first part of the data record, and then 10-15 degrees higher than the temperature at 7.5 centimeters late in the record. The change is related to cooling of the winter wheat (the sensor is measuring the temperature of the winter wheat) due to evapotranspiration during the first part of the record. Once the winter wheat stops growing and becomes golden, transpiration is no longer happening and the dry wheat and then the wheat stubble and ground surface are strongly heated by the sun.

Figure 10. For same site as Figure 4, except for surface temperature. Note that the wheat becomes golden (senescent, stops growing, is almost ready to harvest) around Day 150 (30 May).

The same happens to the bare ground at other sites – the surface is much warmer than the temperature 7.5 cm below the surface.
Have you been in a cave in the summertime? Caves, being farther from the surface, are even cooler. At the Devil’s Icebox, a cave not far from where I am writing this blog in Columbia, Missouri, the temperature stays at about 56°F (13°C) all year, even though the average summertime high temperature in Columbia is in the upper eighties (around 30° Celsius) and the average wintertime low temperature here is in the mid-teens (around -8° C).

So in the summer, the ground gets cooler as you dig down, — at least through the upper few meters. In the winter, the ground gets warmer farther down. And in caves, the temperature doesn’t change much at all. In fact, I once read that a cave temperature is a good first guess of the average above-ground air temperature at the cave’s location.

Similarly, people in many countries take advantage of the cool below-ground temperatures too store food during the hot summer. Also, some people take advantage of the temperature several feet below the surface to heat their homes in the winter and cool their homes in the summer.

How do you compare two items? It’s easy if you have both of them to look at. If you have a series of tiles, like the one in the figure, you can see whether they are the same size by simply looking at them. They fit together, so they must be the same size. If the tiles are loose, you can find out whether they are the same size by placing them on top of each other.

Figure 1. Nine-inch (about 13 centimeters) wooden tiles

Now, suppose you need to go to the store to get more tiles, and don’t have any extra to take along. Of course, you would measure the sides of the tile. When you measure it, you would find that the tile was nine inches (or about 13 centimeters) on a side. In the United States, where tile size is still measured in the English system, either “about 13 centimeters” or “nine inches” would be sufficient information to get you the tile you wanted – provided of course you had the right color, etc.

Having agreed-upon standards for measurements of length and volume has always been important for trade. If you need a liter of milk, you can go to the store and know that you are getting a liter. Before people had standard measurements, lengths and volumes were only rough approximations. In the English system, a “yard” was related to the size of a king’s waist, or the distance from his nose to the thumb on his outstretched arm. The cubit, as used in Ancient Egypt, was the length of a man’s forearm, and also related to the width of the palm of the hand or the width of a thumb. The “royal cubit” was 52.4 cm long. Other ancient peoples also used the cubit, but the length varied. For example, the royal Persian Cubit was 64.2 cm long.

For weights, early peoples would put stones on one side of a hand-held balance scale to measure the weight of whatever was being sold. Different sets of stones would be used for different items.

With such imprecise measurements, it was fairly easy for dishonest merchants to cheat their customers.

Even today, some measurements are surprisingly imprecise. The most extreme example I’ve come across is the size of women’s clothes in the United States. I have noticed for a number of years that my clothes size was getting smaller even though my actual size wasn’t.

I illustrate this with a story. About three years ago, when my husband and I went to see our daughter’s graduation from college, we stayed near the home of home one of America’s most famous woolen mills. In 1974, I had purchased a pair of their wool pants, which I loved. Since the cuffs were getting a bit frayed, I decided to take advantage of being near the mill to get another pair, as close to the first one as I could find. And I succeeded. They were exactly the same size except for a couple of details – the newer pants were slightly longer and the legs were narrower at the bottom.

Figure 2. Wool pants purchased in 2004 (left) and 1974 (right). The tiles are nine inches (about 13 centimeters) on a side.

However, the new pants (left in the figure) are Size 6 and the old pants (right) are Size 12. I also purchased a jacket to go with the pants on both occasions. The new jacket is a Size 8; the old jacket is Size 14. And my weight hasn’t changed with time. I still wear both pairs of pants, and both jackets, and they all fit.

I have noticed this with clothing from other manufacturers, but only the recent experience allowed me to buy the same items of clothing from the same manufacturer. So it should not be a surprise that I never buy clothing without out first trying it on.

Can you speculate as to why these clothing measurements have changed? Could it be that the average weight of Americans continues to rise, so that what was once considered a medium size is now considered small?

So, you can see that the measurements of women’s clothing sizes in the United States can cause confusion. They are not “standardized” measurements. Today, there are standardized definitions of what a liter, meter, or temperature is. When you buy a liter or milk, or a meter of cloth, you know exactly how much you are getting. Measurements are really useful only when they mean the same thing to everyone.

Below you will find Dr. Kevin Czajkowski’s summary of the participation in his surface temperature field campaign. We at GLOBE join Kevin is his sincere thanks for your help!

8 January 2008

Thank you for your participation in the 2007 GLOBE Surface Temperature Field Campaign.

The surface temperature field campaign is completely over. I think that every student and teacher who was going to enter observations has done so. We had over 1100 total observations. That is wonderful. As you know, each complete observation represents 9 surface temperature observations, 9 snow depth, cloud cover and cloud type, condensation trail cover and type, surface wetness, and cover type for a total of 24 observations per complete surface temperature observation. That means that there were over 26,000 individual student observations for the campaign. That is impressive!

A total of 40 schools participated from the United States, Estonia, Thailand, Poland and from the following states in the United States Ohio, Pennsylvania, West Virginia, Michigan, Iowa, Alaska, Illinois, Kansas and Colorado. The school with the largest number of observations was Roswell Kent Middle School in Akron, Ohio with 75 observations. A close second was Kilingi-Nomme Gymnasium in Parnumaa, Estonia (72 observations), Gimnazium in Toszek, Toszek, Poland (69 observations), Waynesboro Senior High School, Waynesboro, Pennsylvania (69 observations), Dalton High School, Dalton, Ohio (67 observations) and Rockhill Elementary School, Alliance, Ohio with 61 observations. Even if your school only entered one observation, every observation is important and your contribution to the project is greatly appreciated.

Figure 1. Map of schools participating in the surface temperature field campaign.

I wanted to give you a little update on how things were going around my house. In late December, my frost tube showed that the ground was frozen to about 10 cm in depth. But, then, on New Year’s Eve, temperatures warmed up and melted the frost. I was actually with my family about two hours drive north in Michigan visiting family when it snowed 38 cm (15 inches) New Year’s Eve and New Year’s Day morning. I tried to drive my van out of the side road to a main road. Unfortunately, the snow was too deep and the van got stuck several times. I used a shovel to dig the van out and finally gave up and parked in a neighbor’s driveway. This was the first time in my life I had been stuck in the snow. Having grown up near Buffalo, NY where there is lots of snow in the winter, I prided myself on being a good winter driver. Of course, it wasn’t poor driving skills that got us stuck. It was the fact that the snow was so deep. We finally made it out and got to our house near Toledo, Ohio later that night.

That storm produced only rain in Toledo, Ohio. Then, 7 cm (3 inches) of snow fell on New Year’s Day at our house near Toledo. After that, temperatures dropped to –13º C (8º F) two nights in a row. Interestingly, due to the 7 cm of snow on the ground, the frost tube showed no ice below the ground surface. The snow had insulated the ground from the cold.

Then, there were extremely warm temperatures January 6-9, 2008 in Toledo, Ohio and much of the eastern United States. On Monday, Toledo reached a record high of 19º C (66º F). The old record temperature was 16º C (61º F) that was set in 1907. All of the snow and ice has melted around here. But, the weather forecast models show that temperatures are going to drop again below freezing.

Schools involved in the surface temperature field campaign to date:

Dr. C

Last week, my husband and I went hiking in Montana, looking for marine shelled fossils and birds along the way. We were in much the same place where we saw all the forest fires last year (see blog on Forest Fires).

This year, we found almost no fossils for several days. Yet, I took careful notes. Why?

• We thought there should be fossils there (our hypothesis).
• We didn’t find any (disproving our hypothesis).

So we learned something from the experience. From geologic maps, we can identify the type of rock (Bearpaw Shale). We knew that fossils form the nucleus of rocks called “concretions” in the Pierre Shale. There was Bearpaw Shale. There were concretions. But the concretions had no visible fossils.

From a personal point of view, this tells us not to expect to find too many fossils in this area.

From a geologic point of view, this poses the question – why are there so few? This fascinating question probably has a two-part answer. The first part involves where the creatures lived (Was the water too deep?). The second part involves whether the creatures were fossilized (Did the shells dissolve? Did they get crushed? Were the animals eaten?).

Null – or zero – results were also important in GLOBE’s past Contrail Count-a-Thons. If you see a contrail, and report it as “non-persistent”, “persistent,” or “persistent spreading,” that is valuable information. It tells us that there was enough water vapor for the contrail to exist. Indeed, the findings of former GLOBE PI Lin Chambers show – not surprisingly – that more humid air at jet altitude means longer contrails that can spread horizontally.

But a report of no contrails is interesting because it indicates very dry air – assuming that the observer is below where jets are known to be flying.

Another example of important “zero” observations is for precipitation. According to Nolan Doeskin of the Community Collaborative Rain, Hail, and Snow network, an observation of “no precipitation” is very important. “No rain” for a long period of time – or drought is significant information if you need water, which we all do.

Of course a “zero” observation doesn’t always mean that there is nothing there. As someone once said…

“The presence of absence doesn’t necessarily mean the absence of presence.”

One of the best examples of this involves life on other planets.

If I go to Mars and find no life, life could still exist there. Why? Because:

• I could have been in the wrong place (as in the fossil example).
• Or I could have not realized what kind of life I should be looking for.
• Or I could have been looking for it the wrong way. (maybe I needed a microscope, or some chemical test).

So if you are recording weather data for GLOBE, for CoCoRaHS, for some other organization, or for yourself – don’t forget to record the “boring” weather as well as the interesting weather.

During the last several blogs, I’ve written about how humans affect climate locally. Today, I am writing about young people noticing things locally, but many of these changes are related to global changes.

I was privileged to be the moderator for the International Polar Year Pole-to-Pole Videoconference, which was coordinated by GLOBE for the Seasons and Biomes Project. For a transcript of the event, see the transcript page. The Seasons and Biomes Project, which is based in the University of Alaska at Fairbanks, is teaching students how to notice changes in seasons in their biomes –- and how the seasonal markers are changing; e.g. budburst, green-up, green-down, freeze-up and break-up. The videoconference brought together scientists studying both the Arctic and the Antarctic, with students from both the Arctic and Antarctic.

Where? The Antarctic scientists and students were in Ushuaia, Tierra del Fuego, Argentina, on the extreme southern tip of South America. The Arctic scientists and students were from Fairbanks, in the middle of Alaska, and Healy, about 200 kilometers southwest of Fairbanks. Fairbanks is at 64.84°N, and Healy is at 63.97°N, and close to Denali National Park, which is named after the highest mountain in North America. Ushuaia at 54.8°S, is the southernmost city on Earth, only 1000 km from Antarctica, and it has a ski area with such good snow that many Olympic teams go to practice there.

Why now? The videoconference honors the beginning of the International Polar Year (IPY, http://www.ipy.org), which runs from 1 March 2007 to March 2009. IPY is dedicated to science related to the Earth’s Polar Regions. There have been three earlier International Polar Years, with the last one in 1957-1958. But scientists see this International Polar Year as especially urgent, because there are big changes at the poles. The average temperature at the Earth’s surface has been rising over the last century. And, while not all parts of Earth have been warming (some parts are actually cooler!), the poles are warming more than anywhere else on Earth. This warming has meant big changes in polar regions -– the permafrost is thawing out, damaging houses and roads due to erosion, the ice sheets are becoming smaller and thinner, threatening the polar bear’s habitat, and affecting the lives of many people. Melting of ice on land has increased sea level, which is starting to affect people in coastal areas around the world. And, the changes in the ice and the land surface can affect both ocean currents and weather and climate patterns.

During the web chat, we heard from four scientists in Alaska (Dr. Elena Sparrow, Dr. Dave Verbyla, Dr. Javier Fochesatto, and Dr. Derek Mueller), two scientists from Ushuaia (Dr. Gustavo Lovrich and Sr. Daniel Leguizamon), one scientist from the U.S. National Science Foundation (Dr. Martin Jeffries), and one scientist from the U.S. National Snow and Ice Data Center (Dr. Walt Maier). These scientists answered questions from the students, who were from three schools in Fairbanks (Pearl Creek, Moosewood Farm, and Effie Kokrine), the Healy school, and the school in Ushuaia. Then, the students asked each other questions about the weather and climate in their areas, whether the climate seemed to be changing, and things that students were doing to reduce their impact on climate change.

Some questions were simple but fundamentally important -– “What is it like in the Antarctic in December?” It’s easy to read in a book that the Southern Hemisphere has summer while the Northern Hemisphere has winter, but it’s a fact many forget when thinking about what causes seasons -– especially those of us who haven’t had the chance to feel winter while talking to someone on the opposite side of the Earth feeling summer!

Many questions were about how the environment was changing -– we heard about the number of polar bears declining, but that coyotes and magpies (a bird) were coming farther north than in the past. At the same time, krill and the animals that eat krill, like the whales, are declining in numbers around the Antarctic. One student pointed out that the ice hockey field in Healy was thawing out in February, when the temperature reached 55°F (13°C, unusually warm for that time of year in Healy).

Are all these changes related to warming in the Polar Regions? This question wasn’t answered for everything, but the decline in whales around Antarctica seems related to warming. Dr. Lovrich, who studies a 5 cm long shrimp-like animal called krill, described a strong link to warming. During the winter, when the sun is low in the sky and the days are short, krill feed on algae that grow underneath the sea ice. There is less sea ice compared to previous years, hence less algae available during winter for krill. This translates to less food for animals that eat krill e.g. penguins, seals, and whales. Populations of these animals would be adversely affected.

And, students talked about other causes of changes near the poles -– such as what high values of ultraviolet radiation, resulting from the ozone hole over Antarctica, might do. (The Alaska scientists noted ozone was affected in the high northern latitudes, but much less.) Also, the students in Ushuaia noticed changes in where beaver and foxes live, but this could be related to more houses where forest used to be.

There was much talk about the relationship between ocean currents and climate. Both salt content and cooler temperature make water denser. The ocean current associated with the Gulf Stream (east of the US) sinks at high latitudes as it cools. If the water doesn’t sink; the current cannot continue, and the water “backs up” and goes nowhere, just like water in a sink with a clogged drain. No northward current and the areas whose climate is warmed by the Gulf Stream cool off -– especially Western Europe.

An additional surprising effect: The oceans take up carbon dioxide, meaning lower amounts in the air to warm our climate. When you have ocean currents sinking downward; the carbon dioxide is carried down with them. And somewhere else, water rises that is low in carbon dioxide, since it hasn’t been at the surface for a long time, so more carbon dioxide can be absorbed. If there is no more fresh water arriving at the surface to absorb carbon dioxide, the ocean absorbs less carbon dioxide. That is -– stopping the Gulf Stream means a faster rise in carbon dioxide in the air.

In the Antarctic, a big cooling in temperature happened 13 million years ago. This is the same time the Antarctic Continent broke off from South America. This enabled ocean currents –- and air currents -– that isolated the continent and made it the coldest place on earth.

Finally, students talked of things they could do to slow the increase of carbon dioxide that is warming our planet. They noted simple things that we can do every day, like recycling, walking places, and carpooling.

How do seasons affect the environment where you live? Have you noticed how seasons change from year to year? Have you talked to your parents about how things change? Think about those changes and what might be causing them. Keeping track of such changes is one of the main goals of GLOBE.