ENVISAT likely dead in the sky

More bad satellite news: ENVISAT seems to have stopped phoning home. ENVISAT is a giant satellite managed by the European Space Agency, and has been collecting a ton of environmental data since 2002. It has 10 different instruments, and has been used extensively in climate research over the past decade.

Sometime on 8 April, ENVISAT stopped communicating with controllers at the ESA. There has been a concerted effort to determine the cause of the failure and re-establish communication of the satellite. This effort is impressive, with the French satellite Pleiades even being turned away from Earth to try to capture images of ENVISAT to determine the state of the solar panels. Other observations of the satellite are also being used to make sure that ENVISAT is -- and is staying -- in a stable orbit. There is some hope that a connection can be reestablished if ENVISAT has gone into -- or could be cajoled into switching to --  "safe mode." Otherwise, it is likely that there has been catastrophic failure of the main computer or power source on board, and there's no hope of recovery. 

ENVISAT's estimated lifetime was just 5 years, so again over-engineering paid off (like the Mars rovers, SeaWiFS, etc). Unfortunately, the Sentinel satellites that are planned to replace ENVISAT have not been put into orbit yet, so there is likely to be a gap in the data record for some of the quantities that ENVISAT monitors. These even include CO2; the launch failure of the Orbiting Carbon Observatory (NASA) in 2009 left just ENVISAT and a Japanese satellite with capabilities to monitor CO2 from space. Now there is just the Japanese satellite, the Greenhouse Gases Observing Satellite. Apparently there is a lot of controversy and arguing about how to pay for the Sentinels, making the ESA's commitment to climate monitoring just as shaky as NASA and NOAA's in the USA.

SOURCES:
Geoff Brumfiel, 

Nature

 

484,

 

423–424

 

(26 April 2012)

 

doi:10.1038/484423a

, 
ESA [link]

Glory Be.

Well, it might be, depends how the launch goes. Glory is the new NASA "A-Train" satellite that is supposed to be launched on 23 February [LINK]. The launch vehicle is a Taurus XL 3110; I know what you're thinking, but no this is not a Ford model. It is, however, a similar rocket to the one that delivered the Orbiting Carbon Observatory to the bottom of the ocean [LINK]. So let's hope for a little better luck with this one.

The satellite is really going to be doing two things once it is functional. First, it is going to measure the solar output. Put another way, it is going to measure how much sunshine reaches the top of the atmosphere. Second, it is going to use the Aerosol Polarimetry Sensor (APS) to measure properties of suspended particles in the atmosphere (aerosol). According the the overview, "this instrument will measure the size, quantity, refractive index, and shape of aerosols."[NASA]. This isn't the first time aerosol will be observed from space, but it is the first time that detailed properties will be retrieved (as opposed to bulk or geometric properties, as from CALIPSO).

If you are thinking, but isn't the A-Train lifetime actually nearly over? Well, yes, it sure is getting there. Because of the lack of funded missions on the horizon, I have heard our present period referred to as the golden age of satellite observations. The A-Train has been up for a while, except that everything has been delayed. Glory was scheduled to launch in 2008, and here we are years later. The OCO did launch, but crashed; there is an OCO2 planned, but it will be some time before they can build, test, and launch the replacement. The French companion to the A-Train, PARASOL, is heading toward end of life (probably this year), and has had to leave the train because it doesn't have enough fuel to maintain synchronous observations. I think it is safe to say that the original picture of the A-Train never came to fruition, but there has been a lot of overlap which is providing a better view from space than ever could have been achieved with a single satellite.

An interesting aspect of this mission is that the APS is measuring parameters that I don't think have ever been measured from space. It is a passive instrument, which just means that it looks at the light coming up from Earth, and then analyzes that light. Often satellites just measure the brightness (intensity) of the light, and might do that for several frequencies. Glory will measure the other "Stokes parameters" to get information about the polarization of the light, and will do it in 9 different spectral bands. It is quite an impressive piece of optical equipment, even more so when you think it is in a box 705 km above the earth traveling at 24,000 kph or so. Basically a small section of the Earth is seen by the satellite, and the light goes through a refractive telescope and then something called a Wollaston prism before reaching the detectors. The prism separates two orthogonal linearly polarized beams, each beam then impacts a detector. The instrument also contains a motor that rotates the mirrors and allows views of the scene at multiple angles. My knowledge of optics to too rusty to be able to say anything useful about this, but it amazes me that such a complex, delicate instrument can be put into orbit.

But don't forget that Glory is also measuring the Total Solar Irradiance. This is a critical parameter as it represents the energy source for the climate system. There have been continuous space-based measurements of the sunshine for about 30 years. The good news is that the measurements show the variability in solar output and are consistent with theory about what the solar constant should be. The bad news is that different instruments have shown slightly different values (ranging from 360-370 W/m2). That doesn't sound too bad, but 10W/m2 of incoming sunlight makes a substantial difference in the global energy budget. Glory will hopefully provide the accuracy and stability needed to better constrain the average solar output.

Details of Glory can be found in an overview paper from BAMS [LINK], but keep in mind that this was written by the scientists. Despite being for the general atmospheric science community, they don't do a great job of explaining things in simple non-jargony language.

Iceland Eruption and risk to airplanes

If you are looking for the best pictures of the ash plume flowing away from Iceland, then check out the NASA page [LINK].

Air traffic has been pretty badly impacted by the safety precautions, with a blanket ban on flights over much of northern Europe over the past five days. Things look to be getting back on track now, with the UK, France, and Germany opening their airspace starting today [LINK].

A troubling aspect of the ban on air traffic is a backlash against it [LINK]. Apparently there are a number of voices saying that grounding the flights is too cautions, including some airlines. These dissenters say that the precautions aren't based on this volcanic eruption, but on "theoretical" approach.

This line of thinking strikes a familiar chord, I think. It seems that there is a general pattern for science-based decisions, which tend toward being conservative, to be questioned by interested parties. Of course, in this case "interested parties" is a euphemism for people/corporations/industries/governments who have a financial or personal stake in the situation. The usual argument goes something like, these scientists are overly cautious (or alarmist) and the problem isn't that bad, and we should be making decisions based on what is really happening and not what some fancy computer model says.

Let us be quite honest in saying that the science-based findings will be conservative. Decision making based on science follows that. This is best summed up by the old phrase, "better safe than sorry." I think this is the right way to go. There are times when calculated risk is the right approach, but when the choice is between people perchance dying in plane crashes (and airlines making tons of money) or people NOT DYING but being stuck somewhere for a couple of days (and airlines losing some money), what is the right approach? Well, I am betting that there would certainly be some questions if planes started falling out of the sky. Better safe than sorry.

Another aspect of this story is that the decision-making process would certainly be better served with better real-time data. There's no doubt that if we had better in situ observations of the volcanic ash plume, then we would have a better idea of whether it would be safe for airplanes to fly. But guess what? There's really no money for these kinds of observations. Not in Europe and not in the USA. Sure, you can turn to the NASA satellites and get a lot of information. But the real-time information that can be gleaned from the satellites is limited, both because of the satellite coverage and technology, and also because of limited personnel who have the ability to analyze the data. I'm guessing a good amount of real science will come from this eruption, but it will take months (and years) to be done. Better observations could be collected by using balloons, mobile observing platforms, and aircraft. These all require the proverbial boots on the ground. There have to be scientists/technicians on the ready, with the equipment ready to go, a way to get to the site, and personnel to ingest the data and provide analysis to decision-makers. There's no doubt the capabilities exist, and there are scientists who would be willing to do the work (and excited to do it), but there aren't usually resources for that kind of science.

So for those who say that we shouldn't rely on models and statistics for decision-making, I think this is a false dichotomy. It is either that or nothing at this point, but the better way to go is to choose both models and statistics along with real-time observations. I'd also be willing to wager that many of those on that side of the debate would not want to put the money on the table for the kinds of observational networks and responses that they are calling for. In the end, isn't the existence of the risk enough to warrant a response? Isn't it better to be safe than sorry? Given the available resources and the collected knowledge about the risk, I can not see any other recourse.

Go read Eric Steig's & Kevin Wood's analysis at RC

A great comparison of raw weather station data with the CRU temperature reconstruction. Pretty much puts to bed any allegations that the CRU data is fraudulent.

LINK

Climate Index

I just saw this article about a new climate-change index [LINK]. I'm not sure whether I agree with how they are defining the index, but I do totally support the existence of these kinds of indices. If one (or a few) can gain popularity, I think they will be a great way to communicate the degree of climate change the Earth is experiencing. One pitfall of these indices is that you want to measure the climate change, and not things that are not part of the changing climate. For example, this index includes atmospheric CO2 concentration, but this is the forcing on the system, not the response of the system. So imagine we stop CO2 emissions, then the CO2 levels in the atmosphere will stay about the same or decrease, but that doesn't mean the climate won't be changing still (cf. Soloman et al. 2009). On the other hand, arctic sea-ice extent, which is also included in this new index, has potentially large natural variability. I think this comes out when we consider the rapid sea-ice melt season of 2007, which was largely due to a high pressure system sitting in one place for a while (e.g., Zhang et al. 2008). Depending on how they implement the index then, the arctic sea-ice term might be diminishing the overall climate change "factor" because the short-term trend is for sea-ice recovery, but the long-term trend remains and shows decreasing summer sea-ice extent. I'm sure they thought about these issues when designing the index, but I have a feeling we're going to see a bunch of these indices come and go over the next few years. Eventually a few will get picked up and become standard.

The tropical ocean: more than just hurricanes

The Climate Prediction Center recently released a new El Nino Advisor [link]. The advisory says essentially that all indicators suggest that the current El Nino is still strengthening, and is expected to last through the winter and maybe into spring. It's likely, based on past El Nino events, that the largest anomalies of the tropical sea-surface temperature will happen some time in the next couple of months.

Recall that we knew this El Nino was forming last spring and summer, and that's why the Atlantic hurricane season was forecast to be relatively inactive. As we've seen, that forecast was pretty successful; we've only gotten up to "Ida" in the tropical storm names. The presence of El Nino conditions in the tropical Pacific ocean has effects that reach beyond hurricanes though, as this paragraph from the advisory lists:

Expected El Niño impacts during November 2009-January 2010 include enhanced precipitation over the central tropical Pacific Ocean and a continuation of drier-than-average conditions over Indonesia. For the contiguous United States, potential impacts include above-average precipitation for Florida, central and eastern Texas, and California, with below-average precipitation for parts of the Pacific Northwest. Above-average temperatures and below-average snowfall is most likely for the Northern Rockies, Northern Plains, and Upper Midwest, while below-average temperatures are expected for the southeastern states.

So those of you up north and in Seattle can probably expect relatively mild winters, which might not be bad news! Meanwhile, California is expected to have a wetter than normal year, which so far looks to be true. Some of these correlations aren't very robust, so you can't really count on them, but so far they seem to be holding.

It is also worth noting that the effects of the tropical oceans are not limited to this kind of El Nino action. There's a flip-side to the story, too, which has come to be called La Nina. This is the cold phase of the oscillation, when the eastern tropical pacific is a bit cooler than normal. An interesting side effect of La Nina conditions in the tropical Pacific ocean is that precipitation tends to decrease over the central part of the USA, especially Texas, but extending north into the upper midwest and also west through the southwest and California. The Pacific Northwest and much of the southeast experience extra precipitation. The crazy thing is that it isn't just a seasonal effect, but can be clearly seen at longer time scales. A new paper by McCrary and Randall (2009, link) examines this relationship in observations and climate models, confirming what I've just said on timescales of 6 years and longer. Much of the paper deals with comparing three leading climate models with the observed 20th Century droughts in the USA. While they find that the models do capture some aspects/statistics of long-term drought in the central USA, none of the models seems to convincingly capture the relationships between tropical ocean variability and precipitation seen in the observations.

Of course, the fact that the models struggle to establish these connections between the tropics and the extratropics does not come as a great surprise. A key challenge for these comprehensive climate models is to produce realistic patterns and cycles of El Nino and La Nina. One of the models in McCrary & Randall (2009) is the Community Climate System Model (v3.0), which is known to have an overly regular cycle of El Ninos, with a period of about 2 years. Along with this regular cycle, the observed connections with remote regions is underrepresented. (link) So when looking for longer-term variations, it's unlikely for CCSM to have realistic patterns. In this case, the CCSM's long-term droughts don't seem to be very connected to the tropical oceans at all. The other models have different problems, but do notably better at establishing at least some relationship between cool tropical Pacific surface temperatures and increased likelihood of drought conditions in the central USA.

A key point to emerge from this analysis is that the climate models only marginally represent long-term droughts, and without very convincing physical processes compared to the observations. This means that these models are not necessarily proper tools for studying the frequency of droughts in the future. This hasn't stopped people from doing just that, as the authors note. So if you come across stories about changes in drought, pay close attention to the methods used, and keep a skeptical view of the findings. In the meantime, climate models are now being developed that have much improved representations of El Nino and La Nina (see link above, e.g.), so the next generation of climate models may have more credible (and interesting) droughts. And if you're an optimist, they might even teach us something about how the future of the USA's grain belt will look, and if you are very optimistic, maybe they won't point toward perpetual Dust Bowl conditions in the future.

Melting glaciers, changing rivers

Well, in another blatant theft from DeSmogBlog, I bring you Jeanne Roberts' article about glaciers in the Swiss-Italian Alps melting. The interesting part of this article is not just that the glaciers in Europe are melting, this is really old news by now, but actually that the Swiss and Italian governments are implicitly acknowledging -- and I dare say adapting to? -- climate change by renegotiating their border. Yeah, two countries are talking about how to redefine their border without bothering to send a bunch of kids to their horrible dismemberment and death. 

The importance of the melting glaciers is clear for countries like Switzerland, which are landlocked and use mountain runoff for freshwater. The melting glaciers provide a lot of fresh water to streams and rivers, that is then used for the human population of those countries. In a glacier-free Europe, that source of water is gone, and countries will have to rely solely on seasonal snowpack melting. This isn't a great strategy, though, since the melt season is getting longer and longer, and seasonal snowpack is quite variable. Essentially the absence of the glaciers will add a level of instability to the water resources of interior Europe.

It is also worth noting that this story comes on the heels of a scientific paper about changing streamflow made waves two weeks ago. The paper is by Dai et al., and is in the upcoming issue of Journal of Climate. Some of the news coverage of the paper was a bit out of control. The paper is a compilation of data sets from around the world, measuring streamflow in large rivers. The main point of the paper is to show the basic results of the combined data set, and to provide a climatology to other researchers who want to know how much freshwater is going from the land into the oceans. You wouldn't have gotten that from the media coverage, much of which seemed to focus on the Colorado river, which isn't even mentioned in the paper by name. The headline grabbing aspect of the paper is a cursory examination of the trends in the data. Freshwater input into all the ocean basins except the Arctic show a decrease in overall streamflow, while the Arctic has an increase. It is not clear from my reading of the paper that these trends are (1) statistically significant or (2) attributable to climate change. The first point will be cleared up over the next couple of years as more people look at the statistics of this and other data sets. The second point will hopefully be better accounted for in future studies by trying to explicitly incorporate human-made changes in streamflow (for agriculture and including building dams and resevoirs). In the meantime, it is an interesting data set, and could have important implications for budgets of freshwater flux to the oceans. Whether the rivers are drying up remains an open question, and one that a lot of us are very interested in. 

Conflicting reports about Colorado snow pack?

Just last week I posted a link to an article saying the northern Colorado snow pack was slightly above the 30-year average, even though much of the state remains in drought conditions. Saturday, the same news source posted an article saying the state's snow pack is slightly below the 30-year average. 

So, what's the story? 

As of 1 March, the state-wide snow pack was above average for all the major basins. February was, however, quite dry, and lead to decreases in the percent of normal across all basins. [source: US Dept of Agriculture, Nat'l Resources Conservation Service] It is also notable that the dry conditions in early 2009 have made the snowpack much less than in 2008. The story from Friday, supposedly from GreeleyTribune.com (I can not find the article) specifically is about the 1 April report, though. 

Although the report from the USDA NRCS for 1 April does not appear to be available, the data is. Looking at the Basin reports, it is clear that the FortCollinsNow.com article from 1 April is misleading. Here are the relevant numbers:

CACHE LA POUDRE BASIN
BENNETT CREEK         83 64
BIG SOUTH             50 79
CAMERON PASS         105 108
CHAMBERS LAKE         74 72
DEADMAN HILL SNOTEL   92 99
HOURGLASS LAKE        69 64
JOE WRIGHT SNOTEL    100 110
LONG DRAW RESERVOIR   97 ****
RED FEATHER           91 94
Basin Totals          93% 95%
Number Courses         9  8
                   (LSWE = 108.5) (SWE = 93.3)
                   (LAST = 117.0) (AVG = 97.7)

Cameron pass is 108% of average, and 105% of last year (these numbers are as of today), just as the article reported. However, Joe Write Resevoir is just 110% of average, not the 112% reported. More importantly though, note that every other station in the Cache La Poudre Basin is below normal, some amazingly below normal. The basin as a whole is at 95% of normal, which is clearly below 100%. 

The Colorado state-wide snowpack stands at 96% of normal as of 1 April. This is the value given in the FortCollinsNow.com article from yesterday.

So to summarize, I think we've learned a couple of things. First, Colorado is, on average, below the 30-year mean snowpack. Second, there is large regional variability, and very large station-to-station variability. Third, we are reminded that news sources are not as reliable as they should be; the numbers in the article I linked to on Friday are a clear cherry-pick. Two spot measurements clearly do not reflect the overall situation in either the Cache La Poudre basin or state-wide. 

OCO crashes and burns

Well, about 6 hours ago (as of writing time), a Taurus XL rocket built by Orbital Sciences Corporation of Virginia ignited and launched from Vandenberg Air Force Base. It was carrying the Orbiting Carbon Observatory on board, which was a new NASA satellite designed to very accurately (and sensitively) detect carbon dioxide. The goal was to better describe the sources and sinks of atmospheric carbon dioxide. However, that mission will now fall more heavily on the similar Japanese satellite called Ibuki than planned because a few minutes after launching, the Taurus XL's second stage didn't fully complete, leaving a part of the rocket attached to the 3rd and 4th stages, weight that could not be accommodated. The rocket crashed into the Southern Ocean, currently a large sink for atmospheric carbon dioxide A few more details at NYTimes.com [LINK]

Newsflash? No.

Well, according to NOAA's National Climatic Data Center, 2006 was even warmer than 2005. That means, if you haven't been keeping score, that 2006 was the warmest year on record (for the USA). I didn't find an actual ranking for the global mean temperature, but I think we can safely assume 2006 was in the top 5 (if not the top 2). The press release blames (rightly, for a change) ENSO (which is El Nino) for the getting 2006 into the top seat. It turns out December was really hot, mostly because there weren't very many storms crossing the country. My suspicion is that this El Nino will continue to make this winter much warmer than average, and 2007 will beat 1998 and 2006 as the warmest year in the past 1000+ years.

LINK TO NCDC

The Ozone Hole is confusing

I've been seeing small news items over the past week or two saying that this year's Antarctic ozone hole has matched the previous record, and that the amount of ozone is the lowest ever [e.g., LINK]. While this is interesting and important news, I'm wondering if it might confuse people. Afterall, a lot, way more than you think, of people think there is a direct link between anthropogenic global warming and the ozone hole. Not just laypeople on the street either, smart and usually-informed people think this. Climate scientists everywhere are constantly being forced to correct people at cocktail parties and other social events. "No, the ozone hole is due to chemicals called CFCs in the upper atmosphere; global warming has to do with burning fossil fuels."

After the gigantic ozone hole of 2000, the size has actually decreased, leading most to believe that the Montreal Protocol of 1987 was a smashing success, and that the hole would disappear in 50 years or so. Actually, that is still what most people in the know are thinking.

So what's with the new big ozone hole? Well, it may have something to do with global warming. Sigh.

Basically, every winter (in Antarctica the winter is during June-July-August) it gets really, really, really cold around and over Antarctica. Because of the geography of the southern hemisphere, there are incredibly strong winds that essentially circle around the continent of Antarctica. Cold air basically gets trapped inside this huge votex, and has nothing better to do than get even colder, all winter. During this deep freeze, polar stratospheric clouds (PSCs) can form, in which molecular chlorine can form (Cl2), and the stronger the vortex, the larger the PSCs and the more Cl2 can form.

When the spring comes, sunlight is added to the equation. Sunlight easily breaks the molecular chlorine into atmoic chlorine. The atomic chlorine (Cl) quickly reacts in a chain of events that destroys ozone; it's a catalytic reaction; a single chlorine atom can tear apart many ozone molecules. This is why the ozone hole appears suddenly in September, when the sun finally shines on the pole.

How is this related to global warming? Well, the same course of events happens year in and year out, but there is variability, of course. Because of the international agreement to eliminate the use of CFCs, every year the amount of CFCs decreases. As a side note, CFCs get absorbed by the upper ocean, and are used as a great passive tracer to study ocean motion. Even with the decrease, the coldness of the winter is still quite variable. The colder the winter, the stronger the polar vortex, the more PSCs can form and condition the stratosphere for ozone depletion. It is possible that the large-scale circulation pattern of the southern hemisphere could adjust to make the polar night colder even as the global surface temperature rises. A paper from 2000 explores some of these issues of synergy between stratospheric ozone depletion and greenhouse gas warming (Hartmann et al, 2000, PNAS). This is ongoing research, as the question of how the circulation will adjust to a warmer world is hard to answer, but my feeling is that more and more people seem to think that the change might favor these extremely cold winters with a strong polar vortex and favorable conditions for ozone depletion.

By the way, Cambridge has a nice ozone hole web site: LINK

Deniers try to misrepresent science.

A nice blog entry has been posted over on Deltoid, of ScienceBlogs [LINK]. It shows Hansen's 1988 climate model predictions of global warming along with observed global temperature. Despite how crude climate models were in 1988, Hansen's predictions are pretty much spot on. It is especially interesting to look at 1993, where the observations take a nosedive because of Mt. Pinatubo. They "recover" in about 2 years. Note that the credit on the figure is to the GISS page [LINK], but neither the blue line nor the extension of the red line (both observations) from 1998 to 2005 is on that page, and I don't know where that data come from. I tend to believe it though. If I find a better reference, I'll post it.

UPDATE: The red line (observations) actually isn't extended. Instead another dataset (blue) is just overlaid.