Loading ...
Sorry, an error occurred while loading the content.

My report on earlier snowmelt runoff and increasing Feb dewpoints

Expand Messages
  • patneuman2000
    To view my report on earlier snowmelt runoff and increasing February dewpoints go to: http://www.mnforsustain.org/ near bottom of page, click on Climate
    Message 1 of 1 , Dec 12, 2004
    • 0 Attachment
      To view my report on earlier snowmelt runoff and
      increasing February dewpoints
      go to:

      http://www.mnforsustain.org/

      near bottom of page, click on "Climate Change"

      then click on my snowmelt report title.

      Pat N

      --- In Paleontology_and_Climate@yahoogroups.com, "patneuman2000"
      <npat1@j...> wrote:

      Sonya wrote:
      ...
      > Since water vapor is said to be a significant player
      > in the GH warming picture........why do we hear/see
      > so little about it...

      My report* shows winter February dewpoints for three stations in the
      Upper Midwest, 1948-2003. 1918-2003 annual dewpoint averages for
      Minneapolis, MN are in ClimateArchiveTwo.

      * Earlier in the Year Snowmelt Runoff and Increasing Dewpoints for
      Rivers in Minnesota, Wisconsin and North Dakota
      http://www.mnforsustain.org/climate_snowmelt_dewpoints_minnesota_neuma
      n.htm

      Pat N

      --- In Paleontology_and_Climate@yahoogroups.com, Sonya
      <msredsonya@e...> wrote:
      > Richard........
      >
      > your recent commentary (((Richard comments:This article underscores
      > one of the criticisms of current GCMs, i.e they underestimate
      > convective latent heat and water vapor transport generally and from
      > the tropics specifically about the ))))
      >
      > jolted something in my head earlier today...........
      >
      > Since water vapor is said to be a significant player in the GH
      warming
      > picture........why do we hear/see so little about it other than the
      > percentage of a significance that scientists or researchers feel it
      > will play--------everything is CO2...... So I wanted to know if
      water
      > vapor levels had been increasing, in a decadal pattern, or something
      > long term, or certain locales, or areas of the atmosphere...........
      >
      > http://www.tuc.nrao.edu/~mholdawa/warming/
      >
      > The water vapor levels have risen.......which stands to reason in
      the
      > context that increased temperatures translate into higher water
      vapor
      > levels, i.e. the warmer the temperature, the more water vapor that
      > will be present.
      >
      >
      > Rather oddly enough, there are a scarcity of studies upon it. I
      > finally found something comprehensive which is below (the SPARC
      study)
      >
      http://www.aero.jussieu.fr/~sparc/WAVASFINAL_000206/WWW_wavas/Cover.ht
      ml
      >
      > Of course, there is much argument about the role water vapor levels
      > will play positive or negative feedback, increased evaporation
      versus
      > decreased in relation to a rise in temperature.......polar opposite
      > camps in that aspect......
      >
      >
      > excerpts
      from........http://www.aero.jussieu.fr/~sparc/WAVASFINAL_000206/WWW_wa
      vas/Summary/Summary.html
      >
      > Key findings
      >
      > There has been a 2 ppmv increase of stratospheric water vapour since
      > the middle 1950s. This is substantial given typical current
      > stratospheric values of 4-6 ppmv. Photochemical oxidation of methane
      > in the stratosphere produces approximately two molecules of water
      > vapour per molecule of methane. The increase in the concentration of
      > tropospheric methane since the 1950s (0.55 ppmv) is responsible for
      at
      > most one half of the increase in stratospheric water vapour over
      this
      > time period. It is not clear what is responsible for the remainder
      of
      > the observed increase in stratospheric water vapour.
      >
      >
      > Long-term changes
      >
      > Stratosphere
      >
      > There is only one nearly continuous time series of stratospheric
      water
      > vapour with a duration of 20 years, made using a single instrument
      > type, and available for the determination of long-term change.
      > Although differences between instrument systems were largely
      > determined to fall within their stated uncertainty estimates, those
      > differences are still too large to combine various instrument
      records
      > to construct a longer time series. However, a number of data sets
      used
      > in the assessment sampled the atmosphere periodically over a long
      > period providing several time series of intermediate length (8-15
      > years). These were used in combination to estimate stratospheric
      > changes. The observations are consistent in suggesting that water
      > vapour has increased at a rate of about 1%/year over the past 45
      years
      > (Figure 5). The record also suggests that this increase has not been
      > uniform but has varied over this period
      >
      > Upper troposphere
      >
      > The longest data set of upper tropospheric humidity is one that is
      > derived from the HIRS instrumentation on different TOVS satellites.
      > The HIRS instruments cover a time period of nearly twenty years. A
      > linear fit of relative humidity from 1979 to present is shown in
      > Figure 6. The trends for different latitudinal bands, and especially
      > in the deep tropics, are slightly positive but insignificant at the
      > 99% confidence level.
      >
      > A shorter time series of UTH, 1992 to present, has been obtained
      using
      > the MLS instrument. Figure 7 shows the MLS humidity for centre
      > altitudes of 147 and 215 hPa over the latitude range 30°S-30°N.
      For
      > the overlapping time period both data sets show a minimum in
      relative
      > humidity that occurs in 1994 although the MLS minimum is shallower.
      >
      > When combined with satellite-derived upper tropospheric temperature
      > data which also show a small positive trend since 1979, the HIRS
      data
      > imply a larger positive specific humidity trend, but the combination
      > of uncertainties in these two types of measurements means that the
      > uncertainty in specific humidity is large enough to hide trends that
      > are significant to climate.
      >
      > The data sets used in this assessment are available for independent
      > verification of the results and conclusions of this Report at the
      > SPARC Data Center (http://www.sparc.sunysb.edu) where they will also
      > be preserved for future studies.
      > ====================================================
      > excerpted..................
      > Proceedings of the XX Quadrenial Ozone Symposium, 1-8 June 2004,
      Kos,
      > Greece; pp 953-954 The Distribution of Stratospheric Water Vapour
      > Observed by an
      > Airborne Microwave Radiometer Vladimir Vasic1, Dietrich G. Feist,
      > Stefan Muller and Niklaus Kampfer Institute of Applied Physics,
      > University of Bern, Switzerland
      >
      > The Institute of Applied Physics (IAP) has measured stratospheric
      > water vapour at 183 GHz using an airborne millimeter wave
      > radiometer since 1994.
      >
      > 1. Introduction
      > The stratospheric waver vapour plays a major role in the ozone
      > catalytic cycle in the middle atmosphere. As a source of a very
      reactive
      > OH radical and being an important factor for building PSCs,
      > stratospheric water vapour contributes directly to the ozone
      depletion.
      > On the other hand, stratospheric water vapour is a key greenhouse
      > gas and a reliable dynamical tracer due to its long lifetime.
      > Despite the obvious importance of stratospheric H2O, the
      measurements
      > have been relatively sparse. The available ones from
      > the ground at 22 GHz Nedoluha et al. [1998] and from balloon
      > Oltmans et al. [2000] show an increase of the stratospheric water
      > vapour amount over the last decade. However, the ground based
      > and balloon-borne measurements have limited spatial resolution.
      > The airborne 183 GHz radiometer offers ideal means to look at the
      > changes in the stratospheric water vapour over a large geographic
      > area and in a period of several years Peter [1998].
      >
      > 5. Conclusions
      > Since 1988, the Institute of Applied Physics has measured the
      > stratospheric water vapour on a yearly basis. The measurements
      > show a very stable situation in summer and strong dynamical
      processes
      > in winter. The ve-year data record allows us to look into
      > water vapour trends. Our results conrm an increase in water
      > vapour which has also been reported by other authors. However,
      > the increase is not uniform and is highest in tropics and artic,
      with
      > almost no increase in mid-latitudes. On the other hand, the origin
      > of the water vapour increase in the stratosphere remains unknown.
      > Therefore we are going to continue the measurements and to
      coordinate
      > them with the activities of other groups, like in the LAUTLOS
      > water vapour validation campaign in February 2004.
      >
      > Acknowledgments.
      > This work has been supported through the Swiss National Science
      foundation
      > under grant 2000-063793.00 and under grant 2000-063897.00. We
      > would like to thank Swiss Air Force and especially their pilots for
      the support
      > during this project. Thanks are due to the British Atmospheric Data
      > Centre for providing access to the Met Ofce Stratospheric
      Assimilated
      > Data that we used in the retrieval.
      >
      > http://www.iapmw.unibe.ch/publications/pdffiles/851.pdf
      > ======================================
      > The major GHGs are water vapor (H2O), carbon dioxide (CO2), methane
      > (CH4), nitrous oxide (N2O), fluorocarbons [30], and ozone (O3). Of
      > these, carbon dioxide is the most commonly discussed. However, water
      > vapor is the most important GHG due to its abundance (it represents
      > about 3 percent of the gases in the Earth's atmosphere). Carbon
      > dioxide and water vapor are the two major products of all
      hydrocarbon
      > fuel combustion
      >
      > Water vapor is the predominant absorber of incoming solar radiation
      > and a major contributor to the natural greenhouse effect. Scientists
      > at the National Oceanic and Atmospheric Administration have reported
      > that the atmospheric water vapor content in the stratosphere at
      > mid-latitudes in the northern hemisphere has been increasing over
      the
      > last 14 years [31]. Water vapor in the stratosphere can harm the
      ozone
      > layer by stimulating the formation of polar clouds, which help
      > pollutants such as oxides of nitrogen and halocarbons destroy ozone.
      > At the tropopause, a rather distinct boundary between the
      troposphere
      > and the stratosphere located at an altitude fluctuating around 15
      > kilometers, there is a sharp change in the concentration of water
      > vapor (that is, the variation in concentration within the
      stratosphere
      > is minimal) (Table 3). Lindzen and others [32] argue that water
      vapor
      > between 2 kilometers (800 millibars) and 16 kilometers from Earth's
      > surface (the tropopause) is the primary determinant of the
      greenhouse
      > effect. However, Shine and others [33] argue that water vapor
      > concentration in the lower troposphere is an equally important
      > contributor to the greenhouse effect. Currently, it is believed that
      > the impact of anthropogenic water vapor from the surface sources
      such
      > as fuel combustion is minimal on the atmospheric water vapor
      > concentrations.
      >
      >
      >
      > Methane (CH4) is a product of organic decay. The largest natural
      > source of methane is the world's wetlands, although it is also the
      > major constituent of natural gas and a potent GHG. Although methane
      > occurs in the atmosphere in one two-hundredth of the quantity of
      > carbon dioxide, it has 5-10 times the heat-trapping potential per
      > molecule [34] [35]. Methane is increasing in the atmosphere at an
      > annual rate of 1 percent, double the rate of increase for carbon
      > dioxide. Activities that release methane are rice-paddy agriculture,
      > waste treatment, biomass burning, livestock production, and venting
      > during natural gas and coal exploration and production activities.
      > Methane is also released during the transport of natural gas.
      >
      >
      > Approximately 90 percent of atmospheric methane is chemically
      > destroyed in the troposphere. Chemical destruction of methane
      through
      > oxidation occurs by hydroxyl radicals. Although the concentration of
      > hydroxyl radicals is very small (0.04 parts per trillion by volume)
      > [36], they are the main oxidants of atmospheric methane, carbon
      > monoxide [37], oxides of nitrogen, and non-methane hydrocarbons.
      > Atmospheric hydroxyl radicals are produced by dissociation of water
      > vapor and reaction between water vapor and other trace gases in the
      > atmosphere. These reactions are controlled by pressure, temperature,
      > atmospheric pH, altitude, and reactants concentration
      > ==================
      > Nitrous oxide (N2O) is also a powerful GHG. It stays in the
      atmosphere
      > for 150-180 years, eventually floating up into the stratosphere
      where
      > it helps destroy the ozone layer. Its concentration is increasing by
      > 0.2 percent to 0.3 percent per year. Its main source is the tropics,
      > but roughly 20 percent of nitrous oxide emissions result from
      > manufacturing and using chemical fertilizers and from burning fossil
      > fuels. The increased use of emission control devices like catalytic
      > converters in internal combustion engines contributes further to
      these
      > emissions. The use of fertilizers in growing corn for ethanol is the
      > major component of the ethanol fuel cycle's high nitrous oxide
      > emission.
      >
      > Page last modified on Fri Sep 6 08:42:14 EDT 2002.
      > URL: http://www.eia.doe.gov/cneaf/pubs_html/attf94_v2/chap2.html
      > ==================
      > This particular article deals with the water vapor and the
      > troposphere, specifically and there are contradictory points within
      > it...........
      >
      > "Water vapor is the most important greenhouse gas in the
      atmosphere,"
      > says Steven Sherwood, a professor in the Department of Geology and
      > Geophysics at Yale University. As anyone who lives in a humid
      climate
      > can attest, water traps heat being radiated from the Earth.
      > http://eobglossary.gsfc.nasa.gov/Study/WaterVapor/water_vapor2.html
      > ===================================
      > It's not the Heat, it's the Humidity
      >
      > The abundance of water vapor in the atmosphere is usually expressed
      > as "relative humidity": the percent of water in the air relative to
      > the amount of water the air can hold. Just as an 8-ounce cup
      holding 4
      > ounces of water is 50 percent full, air that contains half the water
      > it can hold is said to be at 50 percent relative humidity. But if
      you
      > pour the 4 ounces of water into a 16-ounce cup, the cup is only 25
      > percent full, even though you still have the same amount of water.
      The
      > same principle applies to the percentage of water in the atmosphere.
      > As temperatures increase, the air becomes capable of holding more
      > water, and the percent of water in the air drops unless more water
      is
      > added.
      >
      > In climate modeling, scientists have assumed that the relative
      > humidity of the atmosphere will stay the same regardless of how the
      > climate changes. In other words, they assume that even though air
      will
      > be able to hold more moisture as the temperature goes up,
      > proportionally more water vapor will be evaporated from the ocean
      > surface and carried through the atmosphere so that the percentage of
      > water in the air remains constant. Climate models that assume that
      > future relative humidity will remain constant predict greater
      > increases in the Earth's temperature in response to increased carbon
      > dioxide than models that allow relative humidity to change. The
      > constant-relative-humidity assumption places extra water in the
      > equation, which increases the heating.
      >
      > Many have questioned whether this prediction of a wetter future
      > atmosphere is right, including Dessler and Minschwaner. "There's no
      > theoretical, simple line of reasoning that should say that it
      > [relative humidity] should be constant," says Ian Folkins, an
      > associate professor of atmospheric sciences at Dalhousie University
      in
      > Halifax, Nova Scotia, Canada. Critics of the
      > constant-relative-humidity assumption have said that compensating
      > effects will prevent large quantities of extra water from entering
      the
      > atmosphere, explains Dessler. "The atmosphere is very efficient at
      > generating dry air. Increases in these processes could balance
      > increased evaporation in a warmer climate, leading to little change
      in
      > the humidity in the atmosphere." Like air running over the cooling
      > coils in an air conditioner, he adds, air that rises to high
      altitudes
      > cools off and water condenses out, leaving the air drier.
      >
      > Water Woes: Predicting the Humidity of the Future
      > To start to pin down the relationship between humidity and
      > temperature, Minschwaner and Dessler modeled how water in the
      > atmosphere around 11 to 14 kilometers from the surface of the Earth
      > reacts to changes in temperature. They chose to focus their study on
      > the upper troposphere over the tropics because it is a physically
      > simple system compared to other sections of the atmosphere. For
      > example, "things like evaporation of rain don't have much of an
      > effect," Dessler says. While there is very little water in this
      > section of the upper atmosphere, the climate is quite sensitive to
      the
      > amount of water that is there because, closer to the cold of space,
      > water cools off and becomes far more reluctant to let go of any heat
      > it absorbs. The higher the altitude, the more efficiently water
      vapor
      > traps heat.
      >
      > Minschwaner and Dessler's model describes how the humidity of the
      > upper troposphere changes as the surface warms. As the Earth warms,
      > more water is expected to evaporate from the surface. At the same
      > time, thunder storms are expected to become more severe and extend
      to
      > higher altitudes in the atmosphere. Since temperature decreases with
      > altitude, warm, humid air rising to higher altitudes in such storms
      > will encounter colder temperatures, and therefore more water is
      > 'freeze dried' out." These two factors oppose each other, and the
      > overall change in water vapor in the upper troposphere is a
      > combination of these opposing forces. In order to predict changes in
      > humidity, you have to predict both increased evaporation from warmer
      > temperatures and increased freeze-drying from convection to higher
      > altitudes. Minschwaner and Dessler's model shows that these two
      > factors are closely coupled, and in fact, the two can not vary
      > independently.
      >
      > Within these constraints, the model does predict that there will be
      a
      > net increase in the water content of the upper troposphere as the
      > Earth's surface temperature rises, but not so much that the relative
      > humidity remains constant. That means that water vapor will cause
      the
      > Earth to warm, because the feedback is positive, but it won't warm
      as
      > much as it would if constant relative humidity were maintainedâ€"a
      > result that contradicts the assumptions put into big global climate
      > models. "I don't think too many people would have expected a simple
      > model like this to give a result other than the one that people have
      > been assuming will happen," Sherwood notes.
      >
      > http://eobglossary.gsfc.nasa.gov/Study/WaterVapor/water_vapor3.html
      > ===================
      > Water in a Changing Climate
      >
      > Support from the Skies
      >
      > Unexpected though the results may be, they are supported by
      satellite
      > data. By choosing to model the upper troposphere, Dessler and
      > Minshwaner were able to test their model against the data collected
      by
      > two instruments on the Upper Atmosphere Research Satellite. The
      > Microwave Limb Sounder (MLS) and the Halogen Occultation Experiment
      > (HALOE) have been taking regular measurements of water vapor in the
      > upper troposphere since late 1991, giving the scientific community
      its
      > first look at what was actually going on over time in the upper
      > troposphere. HALOE observes the way that sunlight passes through the
      > atmosphere at sunrise and sunset. As the Sun rises, its light slices
      > horizontally across the atmosphere. Stationed opposite the Sun,
      HALOE
      > measures how the light changes as it passes through the atmosphere.
      > This gives a vertical profile of the make-up of the atmosphere,
      > including water vapor concentrations. The Microwave Limb Sounder
      > measures naturally occurring microwave thermal emissions from the
      limb
      > of Earth's atmosphere to make a similar vertical profile of the
      > atmosphere. Minschwaner and Dessler correlated these profiles of the
      > upper troposphere with surface temperatures to determine the effect
      of
      > temperature on relative humidity. "We are the first to use direct
      > observations of water vapor in this region," says Dessler.
      >
      >
      > They found that the water vapor content of the upper troposphere
      > measured during the 1990s climbed as the Earth's surface temperature
      > rose, but not enough to maintain constant relative humidity, just as
      > their model predicted. These observations give Dessler and
      > Minshwaner's results far more weight than they might otherwise have
      > had. Richard Lindzen, the Alfred P. Sloan Professor of Meteorology
      at
      > the Massachusetts Institute of Technology (Cambridge, Massachusetts)
      > and a pioneer in the study of the water vapor feedback,
      acknowledges,
      > "Regardless of the model [which he calls 'not very conclusive'], the
      > observations do make a case that the water vapor feedback above 200
      > millibars [12 kilometers] is likely to be somewhat positive."
      >
      > But what do these results mean for the larger picture of climate
      > change? "The climate implications are very limited," Lindzen says.
      One
      > of his main criticisms is that the upper troposphere doesn't have
      much
      > influence over the water vapor feedback of the entire atmosphere.
      The
      > region between three and ten kilometersâ€"where weather
      occursâ€"has a far
      > greater impact on the Earth's climate. "At the levels Dessler [and
      > Minschwaner] are concerned with, there simply is not much water
      > vapor," says Lindzen. In response, Dessler argues that their
      > conclusions almost certainly apply at 10 kilometers, where water
      does
      > have a significant climate impact (although they only can only
      confirm
      > the model's behavior at 12 kilometers altitude).
      >
      > Still, Sherwood agrees with Lindzen. "The levels where they found
      > something unexpected are making a relatively small contribution, so
      we
      > might be talking about something like a ten percent weaker feedback
      > effect than we thought." But, when other influences on the climate
      are
      > factored in, "that could still make a difference," he adds.
      >
      > Folkins believes that Minschwaner and Dessler's results might be
      used
      > to refine the scientific understanding of water vapor feedback and
      the
      > models that predict climate change. "It is important to understand
      > water vapor both using simple process approaches and data, plus
      global
      > climate models." Unlike big climate models, Minschwaner and
      Dessler's
      > model can be tested and confirmed with satellite data, Folkins
      points
      > out, and that makes it valuable to the scientific community. "I
      think
      > it's a pretty provocative and good paper because it should get
      people
      > thinking more seriously about their assumptions on how water vapor
      > will change in the upper troposphere."
      >
      > "There is a certain sense of complacency that water vapor feedback
      is
      > understood. And that comes from the fact that a lot of these global
      > climate models agree with each other," Folkins observes. "But just
      > because they agree, doesn't mean they are all right."
      >
      > http://eobglossary.gsfc.nasa.gov/Study/WaterVapor/water_vapor4.html
      > ========================
      > excerpted .......
      > New Haven, Conn. - The doubling of the moisture content in the
      > stratosphere over the last 50 years was caused, at least in part, by
      > tropical biomass burning, a Yale researcher has concluded from
      > examining satellite weather data.
      >
      > "In the stratosphere, there has been a cooling trend that is now
      > believed to be contributing to milder winters in parts of the
      northern
      > hemisphere; the cooling is caused as much by the increased humidity
      as
      > by carbon dioxide," said Steven Sherwood, assistant professor of
      > geology and geophysics whose article appears in this month's issue
      of
      > the journal, Science. "Higher humidity also helps catalyze the
      > destruction of the ozone layer."
      >
      > Cooling in the stratosphere causes changes to the jet stream that
      > produce milder winters in North America and Europe. By contrast,
      > harsher winters result in the Arctic.
      >
      > Sherwood said that about half of the increased humidity in the
      > stratosphere has been attributed to methane oxidation. It was not
      > known, however, what caused the remaining added moisture.
      >
      > http://www.sciencedaily.com/releases/2002/02/020221073102.htm
      > ===============
      > Most-Serious Greenhouse Gas Is Increasing, International Study Finds
      > April 24, 2001 -- Scientists know that atmospheric concentrations of
      > greenhouse gases such as carbon dioxide have risen sharply in recent
      > years, but a study released today in Paris reports a surprising and
      > dramatic increase in the most important greenhouse gas â€" water
      vapor â€"
      > during the last half-century.
      >
      > http://www.sciencedaily.com/releases/2001/04/010427071254.htm
      >
      >
      >
      > --
      > Sonya PLoS Medicine
      > The open-access general medical journal from the Public Library of
      Science
      > Inaugural issue: Autumn 2004 Share your discoveries with the world.
      > http://www.plosmedicine.org
      --- End forwarded message ---
    Your message has been successfully submitted and would be delivered to recipients shortly.