The National Aeronautics and Space Administration, NASA, is famous for studying stars and planets and galaxies in outer space.  But did you know it also has excellent programs that study planet Earth?  The GLOBE Program is one of these programs.  And over the past few years, I have been lucky enough to be a part of The Earth Observing System.  More specifically, I work on an experiment called HIRDLS, which stands for High Resolution Dynamics Limb Sounder.  HIRDLS was designed to measure the temperature and aerosols in Earth’s atmosphere.

HIRDLS Project Manager, Joann Loh, stands beside the HIRDLS Engineering Module.

HIRDLS is based on the idea of limb sounding, where you look horizontally through the limb of the atmosphere and take measurements.  When Earth is viewed from the side it looks like a flat circle and the atmosphere looks like a thin halo around it.  It is the edge of Earth’s atmosphere that is known as the limb.

This is a panoramic view of Earth’s atmospheric limb photographed by an Expedition 30 crew member aboard the International Space Station. Photo courtesy of NASA.

HIRDLS was launched on the Aura satellite on July 15, 2004.  Unfortunately, during the launch, we believe something went wrong.  It appeared that some of the insulating material inside the satellite fell on top of the HIRDLS instrument, which blocked it.  When the HIRDLS team started to receive data, we found that about 70% of HIRDLS was blocked.  This was not a good development.  But, never fear, the HIRDLS scientists persevered!  How?  We figured out what the systematic error was.

HIRDLS was launched on the Aura rocket, shown in the photograph above.

Usually, the word “error” is associated with negative connotations.  Most people think an error is a mistake.  But to scientists, “error” is a tool we can use to characterize data.  The goal is for the truth to be contained within the experimental uncertainty.  There are two general types of error that make up experimental uncertainty: random error and systematic error.  A random error has no pattern and can be attributed to chance.  A systematic error is a persistent error that often has a pattern and is not due to chance.  The insulation covering our machine caused a systematic error.  If we could understand and describe it, we could account for it and we could correct for it.  Thus, over the course of many months, we studied how the HIRDLS data differed from what we expected and eventually, we figured out what this systematic error was.  To get the good data, we subtracted off the systematic error from what we were receiving from the satellite.  With these adjustments, HIRDLS is able to provide important support toward reaching the goals of the Aura mission: monitoring the complex interactions that affect the globe.

Suggested activity: Have you ever seen a random error in one of your research projects?  What about a systematic error?  Let us know how you could design an experiment to study these types of errors by leaving a comment, sending us an email at science@globe.gov or telling us about it on our Facebook page.

Early sailors traveling the world’s oceans were all too familiar with an area of the tropical seas characterized by lack of winds and violent thunderstorms.  They called this zone “the doldrums” and dreaded being “stuck in the doldrums.” In his Rhyme of the Ancient Mariner, English poet Samuel Taylor Coleridge offered the following description of the Pacific doldrums:

All in a hot and copper sky,
The bloody Sun, at noon,
Right up above the mast did stand,
No bigger than the Moon.

Day after day, day after day,
We stuck, no breath no motion;
As idle as a painted ship
Upon a painted ocean.

Today, we have a better understanding of this phenomenon and now know this area as the Intertropical Convergence Zone, or ITCZ.  It shapes atmospheric circulation patterns throughout the world and is considered to be the most prominent rainfall feature on the planet; critical in determining who gets fresh water and who doesn’t in the world’s equatorial regions.  The ITCZ is defined by the coming together, or convergence, of the northern and southern hemisphere trade winds and a decrease in the pressure gradient.  Specifically, in the north, trade winds move in a southwesterward direction originating from the northeast, with somewhat of the opposite effect in the southern hemisphere (where trade winds blow from the southeast to the northwest).

A) Idealized winds generated by pressure gradient and Coriolis Force. B) Actual wind patterns owing to land mass distribution.
From: Figure 7.7 in The Atmosphere, 8th edition, Lutgens and Tarbuck, 8th edition, 2001.

The intense tropical sun pours heat into the atmosphere forcing the air to rise through convection and results in precipitation.  Rain clouds up to 9,144 m (30,000 ft) thick can produce up to 4 m (or 13ft) of rain per year in some places.  The ITCZ is not a stationary phenomenon nor are its movements symmetrical above and below the equator.  Many factors, including seasons and land masses, influence its overall movement.

Southern shift of ITCZ in January.
From Figure 7.9 in The Atmosphere, 8th edition, Lutgens and Tarbuck, 8th edition, 2001.

Northern shift of ITCZ in July.
From Figure 7.9 in The Atmosphere, 8th edition, Lutgens and Tarbuck, 8th edition, 2001.

With this knowledge in mind, we first encountered some of the effects of the ITCZ last year, as we approached the Caribbean coast of Panama aboard our sailing research vessel (RV) Llyr in July 2012. The map above shows the ITCZ located very near to Panama, the narrow strip of land that connects North, Central and South America.   At a latitude of about 9°North, we met up with the storms of the ITCZ during the night.  We could see the arrival of a band of storms on our ship’s radar and plotted a course to avoid them.  The storms had other plans, and we spent the night in their midst, at times feeling like they were chasing us as we tried to take evasive action while they kept building right overhead. Lightning lit the sea around us in an eerie glow and we could see, through the rain, bolts striking not far from the ship.  The next morning, tired but safe, we sailed into the harbor in Bocas del Toro, Panama, having had our introduction to the ITCZ.

Image of the RV Llyr. From Berkshire Sweet Gold

We came to Panama as part of a multi-year research expedition aboard RV Llyr, studying coral reefs, sustainable fisheries and changes taking place in the ocean.  As farmers, we have studied weather for many years, understanding oceans and atmospheric circulation as integrated systems that help produce weather at our forest farm in New England. As social scientists and human ecologists, our interest lies in researching the myriad links between biological and cultural diversity as key elements in sustainable development.  In the coming weeks, we will transit the famous Panama Canal aboard our 53′ steel ketch, and once again pass through “the doldrums” as we make passage for the Marquesas in French Polynesia.  During the 30+ day passage, we’ll be participating in global plankton studies and weather surveys. During our passages through the Pacific Islands, specifically French Polynesia, the Cook Islands, Tonga, and finally Fiji, we’ll perform reef surveys on scuba and hopefully meet with local schools to share the findings and experiences of our expedition.  We are a family of five, with three boys on board, and additional crew members and scientists joining us on expedition.  We look forward to sharing our journey.

Suggested activity: Do you live in a region affected by the ITCZ?  We’d love to hear about your experience as these storms pass through.  Send us a story or an image you have captured about the ITCZ either through a comment here, our website, or our Facebook page.  Be sure to collect temperature and precipitation data to document how your location is affected by the ITCZ, and think about what influence these two atmospheric variables may have on other GLOBE protocols.

Tree-of-heaven (Ailanthus altissima) is spreading widely throughout West Virginia and threatening the native forest ecosystems in Appalachia.  This invasive plant was introduced to the United States from China in the 1780s. The same exotic tree species was also introduced to Japan in 1860s but is not aggressive in this country. In Japan, particularly in the Kyushu Island, tree-of-heaven is rarely found in natural forest ecosystems but a few trees may be found growing in university campuses (i.e. Kyushu University), school premises and house backyards. Tree-of-heaven was initially introduced in the US and Japan as an ornamental plant cultivated in urban areas to combat air pollution. Similarities and differences in behavior and ecology of tree-of-heaven can be attributed to different climatic regions where they exist: cool temperate in West Virginia, USA and warm temperate in Fukuoka, Japan.

Maps showing the location of tree-of-heaven in Glenville, West Virginia and Fukuoka, Japan. The invasive plants in West Virginia are naturally growing in native forests (Photo A) while those in Fukuoka, tree-of-heaven were planted on campus of Kyushu University located in the center of Fukuoka city (Photo C) and others can be found on an experimental forest that was planted for demonstration purposes (Photo B). Although tree-of-heaven were artificially planted in Fukuoka, evidence of successful establishment with significant amount of natural regeneration (seedlings) indicates their potential to eventually encroach Japan’s native forests in the future.

Continuous encroachment of Ailanthus and its accompanied modification of the site conditions pose a great threat to the existence of native plants and to the overall productivity and stability of natural forests. The success of Ailanthus and the reduction in the occurrence of native species beneath them is most likely the result of its strong competitive abilities, particularly its allelopathy (the production of one or more biochemical that influence the growth, survival, and reproduction of other organisms), faster growth rate and abundant seed crops. It has been suggested that Ailanthus modify soil microbial communities and biogeochemical cycling in ways that can feedback to benefit them. Modification of soil chemical properties by Ailanthus trees and the release of toxins from stem, leaves, and roots are mechanisms by which they can maintain dominance in the stand. Success of Ailanthus in invading forest areas can be also attributed to its ability to exploit pulses of increased resource levels such as soil moisture and light. Low soil moisture and low light observed in pure stands of Ailanthus in Japan and West Virginia indicate its efficient light interception and water consumption capabilities. Hence, increased forest disturbances, accompanied by increased availability of sunlight, soil moisture, and nutrients could lead to more opportunities for Ailanthus to become established and invade natural forests.

Based on the preliminary analysis of our data, the leaf structure and physiological parameters measured in our study revealed unique differences in the key attributes of Ailanthus between West Virginia and Fukuoka, Japan that are associated with invasive success. Although leaf size was the same in both sites, specific leaf area, an indicator of photosynthetic capacity, was found larger in trees located in West Virginia compared to those in Fukuoka. Also, our analysis revealed that those trees in Fukuoka exhibited photoinhibition that can result to a decline in photosynthetic capacity due to high light intensity. Relative water content was lower in West Virginia than in Fukuoka that may indicate the ability of tree-of-heaven in West Virginia to sustain excessive water loss without desiccation. This translates to high photosynthesis that trees in West Virginia are able to sustain during the day. There were also leaf structural differences between the two sites with those in West Virginia exhibiting light-adapted leaf characteristics with shorter stomatal length and higher stomatal density than in Fukuoka. Stomata are microscopic pores on the leaf surface where carbon dioxide and water vapor exchange take place. The different physiological and morphological parameters indicate a more aggressive nature of tree-of-heaven in West Virginia compared to Fukuoka, Japan. Although Ailanthus spp. in Fukuoka may still be in its early stage of invasion, its successful establishment where it was originally planted and aggressive physiological characteristics showed its potential to continuously invade natural forest ecosystems of Japan. Ailanthus is rarely found in natural forest in Japan which could also be due to unique environmental factors in the warm temperate environment that control its spread such as presence of biological enemies and faster decomposition rate due to high moisture and temperature that may counteract the effect of its allelopathy.

Ailanthus seedlings planted on campus of Kyushu University, Japan

A mature Ailanthus tree and naturally growing seedlings on the campus of Kyushu University, Japan.

An Ailanthus tree that was artificially planted on a demonstration forest of Kyushu University. This experimental site is mowed on a regular basis as indicated by the absence of understory vegetation.

Natural regeneration of tree-of-heaven with plenty of light exposure on an experimental forest in Kyushu, Japan

Starting today, 1 August 2012, The GLOBE Program launches its Phenology and Climate Project!  How could you connect Budburst, Green Up and/or Green Down to an invasive plant species investigation?  We’d love to hear about it!  Leave a comment or send us an email at science@globe.gov.

http://earthquake.usgs.gov/earthquakes/eqinthenews/2010/us2010tfan/

Rather than be discouraged at the change in their project, the scientists realized what a unique opportunity they had to study the effects of an earthquake on the beaches of Chile. The scientists altered their study to instead look at the recovery of the marine plants and animals and the long-term effects of the earthquake on the beaches. It may not be obvious, but conducting scientific research requires you to be flexible. While you might have a well thought out theory or hypothesis, as you work through your investigation, new data or changes in the study environment will require you to go back and reassess your strategy. This is the scientific method in action and more often than not, leads to stronger research conclusions.

Before the earthquake, the scientists had learned that seawalls and other types of armoring actually lead to smaller beaches and less diversity of plants and animals living at the beaches. A seawall covers up parts of the beach habitat and over time, more and more sand is lost. Eventually, the beach will drown, or become nonexistent.

An example of a seawall at a beach in California (Photo Credit: David Hubbard)

After the earthquake, the scientists realized that some of the beaches that were drowning before the earthquake were now being restored.   Sometimes during earthquakes, there can be an uplift of material (like sand or rocks), which is what happened to some of the beaches in Chile.   They also found that many of the marine animals that were gone from the location for years before the earthquake were moving back into the newly restored beaches within a few weeks.

Uplifted rocks after the earthquake (Photo Credit: Mario Manzano)

This team of scientists embraced the unexpected and ended up finding some very important results!

Have you found something unexpected while doing GLOBE protocols? Or has something unexpected happened while you were doing an investigation? Send us an email at science@globe.gov or add a comment to let us know!

-Julie Malmberg

This year’s meeting was titled COP-17 (17th Conference of Parties).  The meeting is important because it includes things such as the adoption of the conference agenda, election of new officers, and reports from committees within the COP.  These meetings are held annually, because it is important to frequently assess progress in dealing with climate change.  After decisions are made at this meeting, a detailed set of rules are created for practical and effective implementation of the Convention.

As in 2009, a lot of the discussion centered around the Kyoto Protocol. The Kyoto Protocol is a binding agreement of 37 industrialized countries to reduce their greenhouse gas emissions.  This protocol was adopted in 1997 in Kyoto, Japan, and entered into force in February of 2005.  There is more information on this important international agreement on the United Nations Convention on Climate Change website.  This year’s conference officially ended on 9 December; however, the final package of agreements, now known as the Durban Platform, wasn’t finalized until the next morning.  This package is very important to the future of regulating climate change.  But what makes this package different than the Kyoto Protocol?

This new package of agreements is a legally-binding treaty of all 194 member governments of the United Nations Framework Convention on Climate Change by limiting greenhouse gas emissions. While this is an exciting advancement, there still are questions to be answered, such as how will this translate into actual reductions in greenhouse gases? When will this go into effect?  The hope is that all negotiations on how to reduce emissions will be decided by 2015 and enforced by 2020.

Another difference from the Kyoto protocol is that the United States, India, and China all agreed to be held accountable for their greenhouse gas emissions.  And while there are items in the agreement that countries don’t agree on, the overall package is important to keep the world focused on climate change mitigation.

So how does this apply to GLOBE schools?  For GLOBE schools looking at the aerosol protocol, it would be interesting to collect data over the next few years to see if there is any change in the optical thickness of the atmosphere (remember the optical thickness is how much of the sun’s light is absorbed or scattered by particles suspended in the atmosphere) and how it corresponds to the enforcement of these new agreements.

How do you think the Durban Platform will affect your location?   Have you been using the aerosol protocol to take measurements that could be used to monitor the changes that the Durban Platform may cause?  We’d love to hear from you!  Please leave us a comment or email us at science (at) globe (dot) gov.

-jm

The recent oil slick in the Gulf of Mexico is an example of a large environmental event that can have multiple ramifications. The oil slick resulted from an explosion that occurred on April 20, 2010, on the Deepwater Horizon rig, causing it to sink to the ocean floor and breaking a pipe, from which millions of gallons of oil have leaked.

This true color satellite image obtained from the NASA Earth Observatory website was acquired on April 29, 2010 by the Moderate-resolution Imaging Spectro-radiometer (MODIS) sensor aboard the NASA Terra satellite flying around the earth at a 705 km high orbit. The greenish and brownish land surfaces in the upper half of the image are contrasted with the darker ocean waters in the lower half. The whitish features of different shapes and sizes that look like paint over the land and ocean surfaces are clouds. The oil slick is shown enclosed in a rectangular white box near the center of this image. The scale at the lower right part of the image allows us to visualize how extensive the oil slick was on April 29; well over 100 km in diameter.

In fact, calculations of the approximate amount, area coverage, and thickness of the slick have been provided at the NASA Space Math website, click on Problem 339), which shows many excellent examples of useful mathematical applications in earth and space sciences for students. About 10 days after the incident, it was estimated that about 2 million gallons of oil had already leaked, and covered an area of over 6,000 km2 of the ocean surface.

Since the oil spill occurred, different emergency response teams and other agencies have made intensive efforts to try to contain the oil leak as it has spread across both the surface and floor of the ocean. Such efforts are geared toward stopping the leak and limiting the spread of the oil. As we can imagine, if such measures are not taken urgently, the oil could have many unpleasant consequences for the affected ocean and land ecosystems (the physical and biological components of these environments) including the plants and animals that inhabit them, and the humans who depend on ocean and coastal ecosystems for food and water.

How do satellite sensors acquire information from space?

One may wonder, how it is possible for a satellite sensor to see the oil slick from as far away as 705 km above the earth’s surface, even though it may not be easy to see it with the human eyes from a few kilometers away. You may also wonder why the oil slick appears light colored on this image even though oil slicks are typically very dark in color. This demonstrates the power of ‘remote sensing’, which is the science of making measurements from far away, without physical contact with the object being measured. Satellite remote sensing is one of the most powerful and efficient ways of monitoring Earth in modern times and documenting different events. This is achieved by making instruments or sensors that measure the intensities of different types of electromagnetic radiation, which includes visible light, as well as other types of radiation that are invisible to the human eye, such as X-rays, ultraviolet (UV), and infrared (IR). These different electromagnetic waves travel with different wavelengths (which is the distance between the midlines of two consecutive crests or troughs of the wave). Detailed discussion of the electromagnetic radiation is beyond the scope of this blog. However, although the radiation measured in remote sensing can be from different sources, in the case of the above image, it is the reflection of sunlight from the various features and objects on the earth and ocean surfaces, as well as the molecules and particles in the atmosphere, such as air, aerosols (described in my previous blog), and clouds. The intensities of sunlight reflected at different wavelengths are measured by the satellite sensors, and transmitted to ground receiving stations, where they are recorded and forwarded to processing centers. By combining the measurements at different wavelengths on the computer according to logical scientific principles, a variety of images of the scene can be created. Depending on how the data are processed, different objects on the scene can be made to appear more prominently than some others. This is made possible because the surfaces and objects in the scene reflect and/or absorb the Sun’s radiation differently at different wavelengths. A more detailed discussion of how remote sensing works will be presented in a future blog.

Even with the capability to display satellite data as images, in such a way that certain objects and surfaces could appear more prominently, absolute confirmation of what an object really is can be achieved by matching the characteristics of these objects on the image with related observations made at close range on the ground. Such close range observations that are known with absolute certainty are referred to as “ground truth”. Whereas ground truth can only be obtained over limited areas, when combined with satellite observations, very large areas can be monitored considerably well. For instance, in the case of the satellite image shown above, it has been possible to visualize, practically in an instant, an area of ocean surface over 6,000 km2 covered by the oil slick, by linking the testimony of human observers, who have seen the oil in a small area on the ocean surface, to the satellite image. Without the knowledge from the ground that this is surely an oil slick, just by seeing it on the satellite image alone, it might have been mistaken for something else, such as ocean sediments or even clouds. On the other hand, without this satellite observation capability, such a large area over the ocean could have taken months to measure, even by the most advanced ship-based mapping technique. Now that the oil slick has been recognized and detected, it can be mapped accurately and its spread monitored from several satellites that pass over the area daily, until the slick breaks up so much so that it is no longer visible from satellite. For example, the image below was acquired on May 4, 2010 (one week after the previous image) by another MODIS sensor aboard a different NASA satellite called Aqua, and obtained from the MODIS Rapid Response website. This time, the image is displayed on an online mapping system called GoogleEarth, so that the oil slick’s location could be seen relative to accurate map features, such as the land/sea boundaries in yellow, and the position of the city of New Orleans. The oil slick is shown enclosed in a white box. I leave you to compare the position, shape, and size of the oil slick on the two images in this blog acquired one week apart. Bearing in mind that the oil is gradually breaking up and spreading: What are your observations or conclusions?

An important lesson to learn from this blog is that many environmental events and situations that can affect our lives and even our climate can be monitored from satellite, but observations and measurements on the ground are equally important for accurate identification of such events and situations. Students everywhere can help in acquiring the ground-truth information that can contribute toward solving important problems related to our environment and climate by active participation in various programs coordinated by GLOBE, which has very close relationships with agencies responsible for environmental and climate monitoring from satellites.

The recent volcanic eruption in Iceland marked by the spectacular “curtain-of-fire” and near-complete shut-down of air travel in Europe in mid-April will probably earn a place in the history books (see pictures of the Icelandic volcano at the Washington Post.)

The Icelandic Volcano. Credit: Washington Post

Two of the most commonly cited volcanic eruptions in the climate literature are Krakatua (1883; Indonesia) and Mt. Pinatubo (1991; Philippines). The most massive explosions of Krakatua took place in August, 1883, and rank among the most violent volcanic events in recorded history. In the year following the eruption, average global temperatures reportedly fell by as much as 1.2 °C (2.2 °F). Weather patterns continued to be chaotic for years, and temperatures did not return to normal until 1888. The eruption injected an unusually large amount of sulfur dioxide gas high into the stratosphere, which was subsequently transported by high-level winds all over the planet. This led to a global increase in sulfurous acid concentration in high-level cirrus clouds and the clouds became brighter. The increase in cloud reflectivity (or albedo) meant that more incoming light from the sun than usual was reflected back to space, and as a result, the entire planet became cooler, until the suspended sulfur fell to the ground as acid precipitation.

In June 1991, the best-documented explosive volcanic event to date and the second largest volcanic eruption of the twentieth century took place on the island of Luzon in the Philippines, a mere 90 kilometers northwest of the capital city Manila. Up to 800 people were killed and 100,000 became homeless following the Mount Pinatubo eruption, which climaxed with nine hours of eruption on June 15, 1991. On June 15, millions of tons of sulfur dioxide were discharged into the atmosphere, resulting in a decrease in the temperature worldwide over the next few years.

Pinatubo eruption provided scientists with a basis for constructing or modeling the change in Earth’s radiation balance (scientists like to call this change “radiative forcing”) due to explosive volcanoes. It is now well established that volcanic eruptions cause the stratosphere to warm and the annual mean surface and tropospheric temperature decreases during a period of two to three years following a major volcanic eruption. If you are interested in more technical details on how volcanoes affect climate, you can read a very good paper written by Alan Robock. Given that the Icelandic eruption is along a Mid-Ocean ridge and volcanic Hot spot, do you think the gases and aerosols will be of different composition than the Krakatoa and Pinatubo eruptions, which are associated with plate subduction along convergent plate boundaries? If there is a difference, what effect might that have on weather and climate over the next few years?

So the disruption of the air travel by the Iceland’s Eyjafjallajökull Volcanic eruptions is just the beginning; other weather and climatic effects will follow.  In the days and months ahead, we are likely to experience darkened sky and spectacular sunsets in different parts of the world.

“Daddy, how long is a billion years?”

As soon as we got in the car this morning, and buckled up, I said “so Jordi, I need some help. I need more material for the blog.” “Daddy, what do you mean by ‘material’?”  “That’s what writers call the stuff they use to create stories”, said daddy.

Earth from MESSENGER spacecraft as it flew by Earth on August 2, 2005. MESSENGER goes into orbit around Mercury on March 18, 2011.

It was a beautiful, sunny morning, so he started talking about … the Sun. He had lots of questions—where did it come from, what’s burning on it to make it so bright, how old is it, what will happen to Earth when it stops burning? The last one was particularly cool. I asked him if he thought the question “what will happen to the Earth when the Sun dies?” is something lots of kids might ask. He said “yes!!” I asked him who he thought was the first person to actually figure it out. He didn’t know. I told him it was me.

When I was a grad student at Penn, one of the undergrads in the class I was teaching asked that question. I didn’t know the answer, so I told her I’d find out. I tried but I couldn’t. Nobody had done it before. So I decided to be the first. I didn’t know if I could, and I didn’t know what I’d find, but it was incredibly exciting—and that’s science. Here’s the result. (And it was far from the end of the story.)

Jordi said, “YOU DID?” I looked at his surprised face in the rearview mirror and said “yup, your daddy.” Then he said, “that’s sooo strange! That’s sooo cool! I asked a question that YOU figured out!!” He was very proud. I felt so connected to him. (We’ll see later if he told his friends.) And I promise that I’ll make this story into a blog post, because now YOU’RE waiting for the rest of the story.

By the time we arrived at the school 20 minutes later, I had a month’s worth of ‘material’ for Driving with Jordi (stay tuned). The conversation was incredible. At one point though, Jordi ran into a conceptual wall when I was talking about the Sun’s lifetime being 10 billion years, and that it’s now half way through its life. He said “Daddy, how long is a billion years?”—which is why I wrote this post.

It is actually such an important question, and I thought about it all the way home. It’s at the heart of a key recurring problem in science education in that the VAST majority of humans truly don’t understand lengths of time that are far longer than our lifetimes. No wonder that folks don’t understand global warming as due to human intervention, and think it reasonable to interpret the data as explained by natural variation in the environment over long timescales. No wonder that folks don’t understand the timescales for evolution of species.

So here now is a novel way to look at it. Thanks Jordi! I think this will help lots of folks understand something they’ve never understood before.

Humans and Time

We humans now live on average about 75 years (in the developed world; in Africa the life expectancy is frighteningly low at 32 to 55). I’ll assume that 75 years is the life expectancy of a human in the absence of devastating diseases like AIDS, and with availability to modern medicine.

We humans also like to perceive the passage of time in units of seconds, minutes, hours, days, weeks, months, and years. We’ve created these units because they are comfortable, connected to the rhythms in the sky and in our bodies, and each is used to make sense of events both short and long. Here’s the critical point for the rest of the story—

One of our average humans sees 75 years x 365.25 days/year =27,394 days in their life

That’s amazing. That’s 27,394 days of getting up in the morning, eating, working, playing, relaxing, and going to bed. Put this way, the length of a single day is absolutely inconsequential relative to a human lifetime. Agreed? Good.

A Really Cool Diary

So let’s say I had this really cool diary with one page for every day of our average human’s life. It’s a single book with 27,394 pages. I could give it to you at birth and ask you to record your life one page—one day—at a time (with some help from a friend in your early and possibly later years). Like I said, one cool diary.

A Day in the Life of the Earth

Let’s say planet Earth was this large cosmic creature. She’s got a life expectancy of about 10 billion years, from her birth with the Sun nearly 5 billion years ago, to her ultimate fate when the Sun is in its waning years some 5 billion years from now (nope not telling).

Earth obviously has a lot to say, and SHE’s been keeping a diary since she was born. But she’s got it in far too many volumes, since each didn’t come with many pages, and they’re all old and worn out. Hey, I think a new diary is a perfect gift for her! I’ll give her one of my really cool diaries with 27,394 pages. I’ll help her move all her old diary entries into the new one so it will truly record her 10 billion year life. Why don’t we call each page a GEOLOGIC DAY (a Dr. Jeff made-up term.) And every Geologic Day is absolutely inconsequential relative to Earth’s lifetime. After all, Earth has 27,394 of them.

Every Geologic Day, Earth will write in her diary the comings and goings for that day. Here’s the next important point—

Every one of the 27,394 pages in Earth’s diary—each Geologic Day—is 365,000 years long.enough time for 14,600 human generations

How come? Easy: 10 billion years divided by 27,394.

Take a minute to process that.

I hope this gives you a new perspective for spans of time for Earth—called geologic time—relative to the time span for our fleeting lives.

So I give my friend the Earth one of my cool diaries. She likes it—her life all in one book. I also happen to be very close with Earth, and she’s letting me look at her diary. So here we are in the middle of her life and she just now finished her entry for day 13,697. She’s already written the first 13,696 pages (I helped her transfer the entries from her old diary with Apple Time Capsule.) Here now is her page 13,697—

Dear diary-

Today, as always, I’m going to keep a watchful eye across my surface. It’s an important responsibility being an oasis of life in a vast space. I’m very aware that all the countless forms of life living on me depend on a very delicate balance of surface conditions. Every Geologic Day, I hope I can avoid asteroids, comets, and super volcanoes, all examples of catastrophic events that have wreaked havoc with my sphere of life—my biosphere—in the past.

Today started out as pretty routine with lots of new things to see. I’m still watching those bipedal creatures that first appeared about 6 Geologic Days ago. Over the last few days, it looked like there were a few different species of them. But by late today I’m pretty sure there was only one dominant species left. I’m fascinated with them. They’re intelligent. They make tools.

Well, time to stop writing it’s just about the next Geologic Day. There’s only 35 Geologic Seconds left in this one (150 years to us humans). Wait … did you see that?! Carbon dioxide levels in my atmosphere just spiked! This just can’t be right! All of a sudden carbon dioxide is at the highest level it’s been in at least 2 Geologic Days (800,000 years) … maybe even 50 Geologic Days (20 million years)!

This is serious. Carbon dioxide might seem innocent enough—my diversity of life creates and uses it. But my neighbor Venus has an atmosphere that is 96% carbon dioxide, and while her surface should be about 125°F (50°C) at her distance from the Sun, the actual temperature is 880 °F (470 °C)—hot enough to melt lead. Carbon dioxide is a gas that induces a greenhouse effect on a planet, causing elevated surface temperatures, and in the case of Venus the effect is absolutely extreme. In my case, my biosphere is in a delicate balance, and even though carbon dioxide is a trace gas, a substantial percentage increase can cause dramatic changes in the environment.

IN AN ALMOST IMPERCEPTIBLY SMALL AMOUNT OF TIME—carbon dioxide in my atmosphere has skyrocketed by 60% over typical levels. Its increase is nothing short of—stunning. This is not due to natural cycles. No natural variation would happen this fast. This is the signature of a CATASTROPHIC EVENT. Some global scale, very short event that should be OBVIOUS. But I see no obvious crater, no super volcano … let me keep looking.

Wait. What’s happening now?! The temperature just spiked! Global temperature variation over the recent past shows “little ice ages” and warming trends, but what I’m seeing now is a SPIKE—a very quick change— that looks very different than those natural temperature variations. The global temperature is now CLEARLY INCREASING, and higher than it’s been recently (us humans currently have the ability to gauge it over the last 2,000 years), and it spiked at the same time as did the carbon dioxide.

This is very bad. Warnings are now coming in from everywhere—rapidly decreasing sea ice, rapid glacial melt. There has to be a cause. Something’s happened. Something’s different. This looks like the start of an irreversible change in the global environment. I’ve got to find out what’s happening before it’s too late for countless species on my surface. Let me keep looking and see if I can find something big that’s happened in this INSTANT in time … a trigger … something OBVIOUS.

Wait …. it’s … it’s the bipeds! OH NO … they’re everywhere! Their technology is EVERYWHERE—just in the last 35 Geologic Seconds! It’s an infestation!

They have got to be stopped. They’re supposed to be intelligent … maybe not. But I’ve got to try reasoning with them.

HEY YOU!! Look at the data!! Look at the data!! Quick! Quick!

What are you doing! Stop! Are you crazy?! Do you think you can load my atmosphere with those levels of emissions from your technology—in a blinding instant of time—and not impact me? Do you think my systems are capable of scrubbing the atmosphere that fast?  MY SYSTEMS DON’T WORK ON TIMESCALES OF 35 GEOLOGIC SECONDS!!

…not enough of them are listening

They’re too busy, too pre-occupied … with themselves.

They don’t seem to care if they are committing suicide. Their choice. But … they don’t have the right to take countless other life forms with them. I’ve got to put in an emergency call to Interplanetary Pest Control, or … tomorrow will be a very bad day.

(Note to reader: spread the word on climate change. I’d argue you have a duty to spread the word. You should Tweet this one up planet-wide. And be moved to leave a comment.)

To Teachers:

You can really make this a powerful visual demonstration in class. The life of Earth recorded on 27,394 sheets of paper is a challenge to demonstrate. But if you can borrow some cartons of xerox paper, with each carton containing typically 10 reams, then here is what I’d do. Each ream contains 500 sheets. So you need 5 full cartons (that’s 50 reams = 25,000 sheets) + 4 reams (another 2,000 sheets) + 394 sheets.

Without telling the class anything about what you are doing, have them take the reams out of the boxes (without opening them) and lay them out on the floor. Have them open one ream to see how many sheets are in it. In fact, have them count the sheets in the ream and take out the 394 sheets you need. Then:

• walk them through the concept of a single diary for an average human lifetime: they should calculate how many diary pages they would need if there is one page per day; then have them calculate how many sheets are on the floor—”oh, the number of days in a human lifetime!  WOW!!  That’s a lot of days for a human!”

• let them in on the idea of giving this diary to Earth, and assuming a lifetime of 10 billion years, have them calculate how many years of history are on EACH sheet—”365.000 years! No way!!” Then have them calculate the equivalent number of human generations on one sheet assuming 25 years per generation (a reasonable time from parent birth to child of parent birth)—”Can that be right? 14,600 generations!?”

• re-arrange the paper with half of it on one side of the floor to represent Earth’s history that is already recorded,and the other half on the other side of the floor representing Earth’s future history.

• then pick the single sheet of paper that represents the last 365,000 years of history, so that on this sheet, the final diary entry is the present. Lay it between the two groups of paper representing the past and future history of Earth.

Ask the class to think about this sheet of paper as a 24-hour clock. So at time 0:00:00, you’re at the beginning of the sheet, 365,000 years ago. At time 12:00:00 you’re in the middle of the sheet 182,500 years ago. At time 24:00:00 you’re in the present moment, where you all happen to be sitting in class.

Ask them to calculate the time on the clock when human civilization began (10,000 years ago, answer: at time 23:20:19); when the industrial age began (the age of fossil fuels; 150 years ago, answer: at time 23:59:25).

Have them look at world population growth noting what’s happened during the age of fossil fuels, the carbon dioxide level over the last 650,000 years, and the world temperature over the last 2,000 years. What is the data telling you?

• have them figure out how many sheets ago the dinosaur extinction took place.

• have them research Earth’s geological history, and figure out which sheets contain other milestones or important intervals in Earth’s history.

This should be MIND BLOWING! It is an experience your students will likely remember for a lifetime.

* * *

Image courtesy NASA, Johns Hopkins University Applied Physics Laboratory, and Carnegie Institution of Washington.

From Dr. James Hansen, Director of the NASA Goddard Institute for Space Studies, concerning this post—Public understanding of climate change depends on an understanding of time scales. Goldstein [Dr. Jeff] does a brilliant job of making clear the rapidity of the human-made intervention in the climate system, and the correlation of global warming with the appearance of technology powered by fossil fuels.

Image courtesy NASA, Johns Hopkins University Applied Physics Laboratory, and Carnegie Institution of Washington.

In December 2009, I attended the Fall Meeting of the American Geophysical Union, a huge annual meeting of scientists that Dr. Gatebe wrote about earlier in this space.  I have been attending parts of this meeting most years since I began working in atmospheric science in the mid 1990s.  This year I attended the meeting for the entire week, because I had a pre-meeting event to attend on Sunday before the conference began, and my own presentation was scheduled on Friday.

Since I had to be there all week, I deliberately decided to approach the meeting a little differently this time.  I made a point of attending sessions outside of my own area of expertise.  AGU includes 27 separate discipline sections, ranging from Atmospheric Science through Volcanology, so there was a lot of room for being exposed to new areas.  There is also a Union section that covers timely topics from the perspective of multiple disciplines.

So I attended some sessions in Atmospheric Sciences, and Education and Human Resources, my usual haunts.  But I also visited several Union sessions, Paleoceanography and Paleoclimatology sessions – the study of oceans and climate in pre-historical times, Global Environmental Change sessions, and Public Affairs sessions.  In the process I was exposed to a huge amount of new vocabulary, including several words I still don’t understand; but which clearly had a precise meaning to the scientists in those sessions (see my prior blog on the vocabulary of science.  I also got a glimpse into the many deep studies that scientists are carrying out in interesting places around the globe:  ancient lakes in Europe and South America, ocean bottom sediments, caves, glaciers, etc.  I also learned about some of the cutting edge new ideas that are being explored to better monitor our Earth today.

The paleo sessions were the most eye-opening experience to me, since my only exposure before this was the same as most people:  reading short articles in the newspaper.  It is quite a different thing to hear about this first-hand from the scientists carrying out the work.  It is clear that most have a deep understanding of the kind of system they are studying; they know about related research in similar systems (for example, lakes on different continents), and they have developed an extensive framework within which to interpret the local measurements.  This framework identifies and assigns dates to major events that can be seen in many locations, and allows local work to gain meaning from a wider context while avoiding the trap of drawing broad conclusions about something that may be only a local event.  The old saying about “standing on the shoulders of giants” seems a propos here.  Knowledge in these fields has been built step by step over many years, based on the work of many scientists.

I also attended a special lecture, the Bjerknes lecture, named after a famous meteorologist from Norway who developed much of our early understanding of weather systems.  The lecturer this year was Dr. Richard Alley, a Geoscience professor from Pennsylvania State University and a well-known ice core researcher.  His talk drew thousands of scientists, and was also webcast.  The recording is still available if you want to get a glimpse (http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml).  Again it was fascinating to hear how knowledge has evolved over time, with new discoveries continuing to explain things that were previously puzzles, gradually building a solid framework of understanding.

One challenge that I carried away from my small sampling of the thousands of talks presented at this meeting was the problem of how to integrate all this deep knowledge.  If one person could have all of this information together … I think they would need extra brains to hold it together!  But in this information age, finding a way to integrate all this knowledge to inform decisions about resource use and the future state of our planet is becoming more and more important.  I suspect – I hope! – that one day some of you may be involved in developing solutions to that challenge.

The 2009 Fall American Geophysical Union (AGU) meeting being held in San Francisco, California, USA, from 12 December to 18 December is billed as one of the biggest gathering of scientists in the world. This year more than 16,000 scientists are expected from 78 countries around the world with their latest research in Earth and space sciences. The meeting helps to disseminate quality scientific research findings to a wider audience, enhance learning, and encourage international collaboration among scientists. The meeting also attracts teachers and students who come to learn about the latest research in Earth and space sciences.

I am writing this blog at the AGU meeting and it’s hard to decide which sessions to attend and which one to miss given my wide interest in many subjects.  However, I realize that I can’t cover all the sessions, and since my research work involves measurements of reflection properties of opaque surfaces (e.g. land, ocean, cloud, snow, ice, etc) and studying how surface properties affect remote sensing of aerosols, I am mainly attending and presenting my work at the Atmospheric Sciences sessions. Let me try to explain the structure of the AGU meetings and why it is hard for me to decide where to go.

By any measure, a crowd of 16,000 is not small and can fill up to 20 schools, each with 800 students. So having a crowd of this size in one place, in this case, the Moscone Convention Center (pronounced “moss-coney center”) in San Francisco turns the whole place into a very busy market place of ideas. In fact, there are more ideas than can be gleaned from the 500 page document containing 15,788 abstracts that are expected to be presented at the 2009 Fall meeting. But still, the number of participants is smaller than half the total number of the AGU membership, currently standing at over 57,000 from 115 countries.

Because of the sheer size of the meeting, it is organized into many parallel sessions, each day starting 0800h until 1800h, five days in a row. There are also side events and small group meetings that are held either before 0800h or after 1800h sometime ending late in the evening. These sessions and events are listed in the AGU program guide, which is a 224-page document. Scientists either present their work in oral sessions, where each speaker is allowed a total of 15 minutes, or in poster sessions, where presenters have to stand by their posters, at least for two hours (see the picture showing AGU Posters this year).

It should be pointed out that the general format of the poster sessions is no different from that of science fairs in schools.  However, the oral sessions are a little bit more complex. The first morning set of oral sessions start at 0800h and last for two hours, after which there is a 20-minute break, followed by the second set of morning sessions from 1020h-1220h. Then, there is a lunch break of 1hr, 20 minutes. The first afternoon sessions run from 1340h-1540h, followed by 20 minutes break, then the second afternoon sessions run from 1600h-1800h. This contrasts with the poster sessions which are presented either in the morning between 0800h and 1220h or afternoon between 1340h and 1800h. Posters are displayed for a whole day or in very rare cases, several days, after which they have to be removed to create room for the following day’s posters. That is pretty much how a day at the AGU is partitioned, time-wise, starting at 0800h and ending at 1800h. But of course, if there are special events or special group meetings, which is often the case for some scientists, then the day is stretched accordingly.

Lets now examine how research topics are grouped or organized at the AGU meetings. Everything revolves around sessions.  The sessions are arranged by broad categories or disciplines such as Atmospheric Sciences, Hydrology, Ocean Sciences, Planetary Sciences, Cryosphere, Natural Hazards, Education and Human Resources, Solar and Heliospheric Physics, Public Affairs, and many other categories. Currently, AGU has 27 categories. Disciplines with a large number of scientists such as Atmospheric Sciences or Hydrology can hold more than 10 parallel sessions (both oral and poster presentations) during any 2-hr time period, morning or afternoon, while smaller-sized disciplines such as Cryosphere have one session during any 2-hr time period, morning or afternoon. If one was to organize a school day in the AGU style, visualize a discipline as a subject (e.g. Math or English or Science), a session as a topic and a lesson as an individual presentation or poster. Following the AGU format, if you pick say, Math, then in each 2-hr time period (e.g. 0800h-1000h) there has to be subject math, then under each time period several math topics would be taking place at the same time in several classes and in each class, there would be several lessons, 15 minutes per lesson (or 30 minutes if a double lesson). So for just one subject, there are multiple topics going on at the same time in different classes, sometime in different building. At the Fall AGU meeting, the Convention Center has three large buildings, Moscone South, Moscone North and Moscone West, all located in the same general area across the street from each other. Therefore, there can be a lot of walking to do especially if your sessions are held in different buildings. A good pair of walking shoes comes in hardy. So, choosing which subject, which topic, and which lesson to take is not as easy as A-B-C, especially if you have a wide range of interests like me. This gives you a flavor of how complex and busy a day can become at the AGU meeting.

Therefore, if you were to attend the Fall AGU meeting or any other large scientific meeting like it, you would have to decide in advance which subject, topic and lessons you want to attend, then mark the day, time, building and room number. It is important to select carefully to make sure that the sessions you are interested in are not taking place at the same time, and that you have enough time to change rooms or buildings if that becomes necessary. Given the breadth of this meeting, there is only so much you can cover each day, and it is so easy to get lost.

I will end with a quotation from Andrew Alden, a science writer, who is also blogging from the 2009 Fall AGU meeting. In one of his old blogs he stated that “there are three major arenas in the scientific life—the lab (or the field), the library, and the meeting room. School teaches you about the first two, but meetings can only be experienced.”