Radcomms 2012, Fingerprints of Nature, Dr Compton Tucker, NASA


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  • 5.3 C band, 13.6 K band, and 18, 21-22, & 37 GHz for corrections
  • Part one of this slide shows all the data collected by a series of satellites that look at the sun. Our knowledge of total solar irradiance can come only from satellites who observe the sun above the Earth’s atmosphere. Note that several satellites record different magnitudes of total solar irradiance when they observe the sun at the same time, with differences of a few Watts/sq. m at the top of the atmosphere. Part two of this slide shows how these data have been reconciled using the best calibrated of these data sources, the SORCE mission’s total irradiance monitor (TIM).
  • Part one of this slide shows all the data collected by a series of satellites that look at the sun. Our knowledge of total solar irradiance can come only from satellites who observe the sun above the Earth’s atmosphere. Note that several satellites record different magnitudes of total solar irradiance when they observe the sun at the same time, with differences of a few Watts/sq. m at the top of the atmosphere. Part two of this slide shows how these data have been reconciled using the best calibrated of these data sources, the SORCE mission’s total irradiance monitor (TIM).
  • To predict sea level rise in the future, one method is to extend simple linear trends through the available data. For example, in this plot, sea level rose about about 40 cm (1.5 ft) in 150 years, so extrapolating, sea level should rise about 25 cm (1 ft) by 2100. This method clearly uses solid, observed data, but it misses the observed increase in the rate of rise of the late 20 th century.
  • Sea level can change very dramatically. About 18,000 years ago, ice sheets over 3,000 m thick covered a large part of North America, Northern Europe and northern Eurasia. The growth in the ice sheets transferred about 3% of the ocean volume to the land, causing sea level to be about 120 m lower than present. The growth and decline of continental ice sheets is related to the amount of solar insolation received at 65 degrees N latitude. This varies with periods of 20,000, 41,000 and 100,000 years as a result of small changes in the Earth's orbit. Atmospheric CO2 concentrations during ice ages were about 230 ppm, and about 280 ppm during interglacial periods. The present CO2 concentration is about 392 ppm.
  • As the ice sheets melted, sea level rose very rapidly, as fast as 1-2 m per century 6000-8000 BC. In areas such as the Tigris-Euphrates plain, this would result in several km of inundation every generation. Sea level has been relatively stable since about 0 BC (2000 BP).
  • In some high latitude areas, relative, local sea level is falling. As world wide sea levels are rising, this record from Stockholm indicates that the land is rising, rebounding from the load of the ice sheet that covered it during the ice age. This illustrates that sea level effects can have local influences. For geodetic reasons, the effects of rising sea levels will not be the same in all locations. Some areas, such as the NE US, will see sea level rise greater than the World average.
  • In summary, sea level changes over many time scales. The principal factors that affect sea level are temperature, ice volume, and tectonic activity. Over short, decadal and centennial, time scales, sea level is most influenced by temperature and ice volumes. C band (5.3 GHz) & K band (13.6 GHz) This graphic illustrates global sea level change since 1993 as measured by satellite altimetry. The annual and interannual variation as a result of short-term temperature changes can be clearly seen, especially the high levels associated with the very warm 1997 El Nino year. However, the overall trend averaged over the period of record is a rise of about 4 cm since 1993.
  • The Gravity Recovery and Climate Experiment of GRACE, twin satellites launched in March 2002, are making detailed measurements of Earth's gravity field which will lead to discoveries about gravity and Earth's natural systems. These discoveries could have far-reaching benefits to society and the world's population. See http://www.csr.utexas.edu/grace/ for more information. GRACE is a joint undertaking of NASA and the German Aerospace Center (DLR). NASA and DLR have extended the Gravity Recovery and Climate Experiment (Grace) mission through the end of its on-orbit life, which is expected in 2015. NASA and DLR are working on a GRACE follow on mission, scheduled for launch in 2015 or 2016. GRACE has proven to be a tremendous success in studying ice sheets, aquifers, and many other phenomena that affect the Earth’s gravity field. The spatial resolution of GRACE is ~ 220 km. It is unusual for the climate change deniers to discuss the GRACE gravity data. Knowledge of the Earth’s gravity field has been studied extensively, as this is the basis for aiming intercontinental ballistic missiles.
  • Graduate students in action!
  • The basis of sea ice measurements is to use satellites that fly passive microwave radiometers operating at a wavelength 1.55 cm or 19 GHz frequency. At this wavelength/frequency there isa very sharp contrast between the spectral emissivity of sea water (0.44) and sea ice(~.80-.97). Also use 19 GHz & 22 GHz for atmospheric correction
  • Sea ice data are extremely robust and were the topic of a great deal of research during the Cold War. The Arctic sea ice “edge” is a very noisy place, hence a good place to “hide” submarines. It is impossible to attribute Arctic sea ice declines to anything but a warmer planet.
  • See: http://data.giss.nasa.gov/gistemp/ for NASA’s Goddard Institute for Space Studies surface temperature data; see: http://www.ncdc.noaa.gov/cmb-faq/anomalies.html for NOAA’s National Climatic Data Center’s surface temperature data; and see: http://www.cru.uea.ac.uk/cru/data/temperature/ for the Climate Research Unit of the Univ. of East Anglia surface temperature data. See http://www.skepticalscience.com/print.php?n=287 for a discussion about these data. Note that all three data sets have at their core the monthly temperature data from the Global Historical Climatology Network (GHCN) , and all three produce both a land-stations-only reconstruction and a combined land/ocean reconstruction that includes sea surface temperature measurements. Source code and data to recreate GISTEMP and CRUTEM are available from NASA and CRU websites.  (The data set provided by CRU excludes a fraction of the data that were obtained from third parties, but the results are not substantially affected by this). The temperature increase is not an artifact of the GHCN adjustment process. The temperature increase is not an artifact of declining numbers of stations While it is true that the number of stations in GHCN has decreased since the early 1990s, that has no real effect on the results of spatially weighted global temperature reconstructions.  How do we know this? * Comparisons of trends for stations that dropped out versus stations that persisted post-1990 show no difference in the two populations prior to the dropouts (see, e.g., here and here and here ). The temperature increase is not an artifact of stations being located at airports This might seem like an odd statement, but some people have suggested that the tendency for weather stations to be located at airports has artificially inflated the temperature trend.  Fortunately, there is not much difference in the temperature trend between airport and non-airport stations . Conclusions (from http://www.skepticalscience.com/print.php?n=287) The well-known and widely-cited reconstructions of global temperature, produced by NASA GISS, UEA CRU, and NOAA NCDC, are replicable .  Independent studies using different software, different methods, and different data sets yield very similar results .   The increase in temperatures since 1975 is a consistent feature of all reconstructions.  This increase cannot be explained as an artifact of the adjustment process, the decrease in station numbers, or other non-climatological factors.  In contrast to normal practice here at Skeptical Science, for this post we have emphasized the "near-real-time" results of studies undertaken by individuals (in some cases non-specialists and highly talented amateurs) as published on blogs, rather than the work of professional scientists published in the peer reviewed literature. Since many of the "controversies" about the reliability of surface temperature trends first arose in the blogosphere, it is perhaps appropriate that those controversies are now being carefully and thoughtfully resolved in the same environment.
  • Data from NOAA’s Earth System Research Laboratory ( http://www.esrl.noaa.gov/gmd/ccgg/trends/). The inset pictures are Charles David Keeling, as he looked when he started his measurements (left) and as he looked in 2000 (right). Keeling started measuring atmospheric CO2 on top of the Mauna Loa volcano in Hawaii in 1958. During the planning phase for the International Geophysical Year, Scripps was designated as a participant, and then later as the principal center, in the Atmospheric Carbon Dioxide Program. In July 1956, Charles David Keeling joined the Scripps staff as a postdoctoral fellow under Roger Revelle to head the program and began measurements of atmospheric carbon dioxide at Mauna Loa, Hawaii, and Antarctica.
  • It is important to point out that (according to Solomon PNAS 2009) the climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop. Just because CO2 declines does not mean that the climate cools at the same rate and in fact it cools much more slowly.
  • Mauna Loa atmospheric CO2 from published data (interpolated values) (HOTS Aloha) Aloha seawater pCO2 calculated with co2sys from discrete samples using temperature, salinity, Talk, and TCO2 Aloha seawater pH calculated with co2sys. Climate change deniers seldom discuss ocean acidification. From Richard A. Feely NOAA/Pacific Marine Environmental Laboratory and used with permission.
  • NASA and NOAA have a series of satellites that look down at Earth and provide daily observations of atmospheric, ocean, and land temperatures; measure the extent of sea ice; measure the mass of ice sheets; measure sea level; measure land use change and map forest extent; and measure many other aspects of the coupled land-ocean-atmosphere system. These are quantitative data that are acquired day after day, week after week, month after month, and year after you. These satellite data have revolutionized earth science and provide an excellent view of climate the past 30-35 years. These data are available to anyone who wants them free of charge.
  • Radcomms 2012, Fingerprints of Nature, Dr Compton Tucker, NASA

    1. 1. Observing Climate with Satellites: Are We on Thin Ice? Compton Tucker NASA/Goddard Space Flight Center Greenbelt, Maryland USA
    2. 2. Why NASA?NASA uses space for exploration & scientific discovery 2
    3. 3. HubbleImages 3
    4. 4. Looking down Bahamas
    5. 5. Earth Sensing Requires Using Unique Frequencies• Atmospheric temperature soundings: 23.8, 31.4, 50.0-58.0, 89.0, 150.0, & 183.0 GHz• Sea ice detection: 22.0, 19.0, & 37 GHz• Sea level radar altimetry: 5.3, 13.6, 18.0, 21-22, & 37 GHz• Ocean Salinity: 1.26, 1.413, 23.8, & 36.5 GHz
    6. 6. Summary of Talk• Observations not beliefs• Satellites & spectrum allocation v. important• Sun constant since late 1970s• Earth is warming• Greenhouse gases/human activities are responsible, ice sheets are melting...• Residence time of CO2 is LONG...
    7. 7. DefinitionsWithout proper definitions, logical discourse is impossible.Without logical discourse, nothing can be accomplished. Confucius 7
    8. 8. Is the Earth Warming?• Surface thermometers increasing• Atmospheric temp. increasing• Glaciers melting• Sea Ice• Ocean temperatures increasing• Sea level rising• Sun no change 8
    9. 9. Total Solar Irradiance Record TIM -4.5 W m-2 Fundamental discovery that the TSI is ~1361 W m-2, not 1366 W m-29
    10. 10. Total Solar Irradiance Record • In the satellite record, total solar irradiance varied by ~one part in 500 • ∆ T ~ 0.1˚C, nearly all associated with the ~11-year solar cycle10
    11. 11. Global Warming—Keep it Simple • The Earth warms, sea level rises • The Earth cools, sea level falls ~60% thermal expansion ~40 glacial melt11
    12. 12. Tide Gauge Measurements About +1.5 ft in 150 years
    13. 13. At the maximumextent of the last ice age,sea level wasover 400 feet lower.Florida wasabout twice its current size
    14. 14. Last Glacial Maximum Sahulland
    15. 15. When the ice melted, sea level rose 1.7 m/100 yr
    16. 16. Scandinavian Post-Glacial Rebound Stockholm, Sweden
    17. 17. Sea level can be very accurately measured by satellites rise = 1.5’/150 yr C band (5.3 GHz) & Ku band (13.6 GHz), + 18, 21, & 37 GHz for water vapor correction
    18. 18. Gravity Recovery & Climate Experiment500 km orbit220 km separationDistance accuracy ± 0.001 mm Fg = G( m1*m2)/r2 18
    19. 19. Greenland Ice Mass Flux from GRACE mascon solutionNASA GSFC mascon solution (update to Luthcke et al. Science(update to Luthcke et al. Science 2006)2006) 1 Giga-ton = 1 Billion metric tons 1,200 Giga-ton ~ 1,300 km3 of ice or 310 mi3 of ice 3.4 mm of global sea level rise. 19 Photo Credit: Roger Braithwaite
    20. 20. Antarctic Ice Sheet Mass Variation from GRACE Antarctica & Alaska GRACE
    21. 21. NASA GSFC Global Mascon Solution (Luthcke et al. 2012)V12 (mascons iterated, corrected for geocenter, ICE5G and LIA/GIA correction for GOA)
    22. 22. Gravity: Fg = G( m1*m2)/r2Static gravity field
    23. 23. Arctic & Antarctic Sea IceNASA 24 Photo by K. Steffen, U. of Colorado
    24. 24. Satellite Detection of Sea Ice Higher rate of microwave emission from sea ice than from open water. Emissivity indicated is for wavelength of 1.55 cm/19 GHz. 22 GHz & 37 GHz used for water vapor corrections.25
    25. 25. Arctic Sea Ice studied since the 1950s… 26
    26. 26. Arctic Sea Ice Minima Update 19 GHz, 22 GHz, & 37 GHz
    27. 27. Antarctic Sea Ice Minimum Update 19 GHz, 22 GHz, & 37 GHz
    28. 28. Antarctica is a continent surrounded byocean – the Arctic Ocean the opposite
    29. 29. Measured Surface Temperature the past 150 years 12 warmest years are still: 1998 & 2001-2011 A UC Berkeley reanalysis effort funded in part by the Koch brothers . 30
    30. 30. Global Atmospheric & Surface TemperaturesPassive microwave sensing at 22.8, 31.4, 50-58, 89-90, 150, & 183 GHz
    31. 31. Dave Keeling 32
    32. 32. Historical data: Now = 200810,000 5,000 0 33 Time
    33. 33. The fraction of CO2 remaining in the air, after emission by fossil fuelburning, declines rapidly at first, but 1/3 remains in the air after a centuryand 1/5 after a millennium (Atmos. Chem. Phys. 7, 2287-2312, 2007).
    34. 34. Ocean Acidification from Increasing Atmospheric CO2 – Global Warming’s Evil Twin CO2 Time Series in the North Pacific 400 8.38 Mauna Loa atmospheric CO2 (ppmv) CO2 = (1.738 ± 0.0293)x – 3105.9 Aloha seawater pCO2 (µatm) r2 = 0.94 8.33 375 Aloha seawater pH 8.28CO2 350 8.23 pHconc. 8.18 325(ppm) pCO2 = (1.855 ± 0.224)x – 3364 8.13 r2 = 0.310 300 8.08 pH = (-0.0019 ± 0.00025)x + 11.82 r2 = 0.265 275 8.03 1950 1960 1970 1980 1990 2000 2010 2020 Year From Richard A. Feely NOAA/Pacific Marine Environmental Laboratory Used with permission 35
    35. 35. Arctic Tundra Photosynthesis: Who?GIMMS 3g NDVI setand global NDVI trends
    36. 36. Temperature increases at higher northern latitudes:Tundra photosynthesis, Sea ice, and Greenland surface melt
    37. 37. Arctic Tundra Biomass Work: How?
    38. 38. Arctic Tundra Biomass Work: Where? Raynolds et al.
    39. 39. Change in zonalArctic phytomass
    40. 40. Arctic AVHRR-MODIS Comparison
    41. 41. Unequivocal Signs of Global Warming• Night-time temperatures increasing more than day-time temperatures• Winter temperatures increasing more than summer temperatures• Upper atmosphere cooling & lower atmosphere warming• Poles warming faster than equator• More extreme weather, more active hydrological cycle
    42. 42. Climate & the Global Energy Balance Through cosmic good fortune Earth has retained water in the liquid phase for billions of years. Climate sensitivity: very stable, slight initial forcing + feedback = glacial, inter-43 glacial cycles.
    43. 43. Business-as-Usual (2% annual growth until 50% depletion, then 2% annual decline) 600 560 (deforestation) Biosphere(ppmv) 520 Coal 480 2Atmospheric CO 440 400 360 Gas 320 Oil 280 1900 1950 2000 2050 2100 2150 45
    44. 44. Alternative Case: Coal Phaseout (+2%/yr to 2012; +1%/yr to 2022; linear shutdown between 2025-2050) 600 560(ppmv) 520 480 2 Biosphere (deforestation) 440Atmospheric CO Coal 400 360 Gas 320 Oil 280 1900 1950 2000 2050 2100 2150 46
    45. 45. ClimateChange?
    46. 46. Extra Material
    47. 47. Tropical Glaciers
    48. 48. Nature’s best thermometer, perhaps its most sensitive and unambiguous indicator of climate change, is ice. “Ice asks no questions, presents no arguments, reads no newspapers listens to no debates. It is not burdened by ideology and carries no political baggage as it changes from solid to liquid. It just melts.” From A World Without Ice by Henry Pollack, 2009
    49. 49. Areas Studied 52
    50. 50. Cordillera Blanca Peru 2006 from ISS
    51. 51. 54
    52. 52. New World Tropical Glacier area by elevation 55
    53. 53. Formerly the World’s highest ski areaChacaltaya, Bolivia 5,300 m/17,500’ 56
    54. 54. Unequivocal Signs of Global Warming
    55. 55. Unequivocal Signs of Global Warming
    56. 56. Unequivocal Signs of Global Warming
    57. 57. Unequivocal Signs of Global Warming
    58. 58. Unequivocal Signs of Global Warming
    59. 59. Unequivocal Signs of Global Warming
    60. 60. June, July, & August 2011 were OFF THE CHARTS in Texas Climate change?
    61. 61. Climategate: The Lion That Squeaked
    62. 62. Pounds CO2 per 1,000,000 BTUs Natural Gas 115 Petroleum 150 Coal 220 Tar Sands 250-290 Oil Shale 300+2 phase changes takes a lot of energy!Tar Sands—Dirty fuel, cook with CH4, requiresdouble refining, uses huge quantities of water
    63. 63. Where does the heat go?• oceans: 18.2 x 1022 J – warms the oceans• cryosphere: 1.1 x x 1022 J – melts ice  water• atmosphere: 0.6 x 1022 J – warms the air
    64. 64. Sea Level & CO2/Temp from Ice Cores
    65. 65. NASA’s Earth- viewing satellites Not pictured: SeaWiFS,Landsat-5, andNOAA’s GOES &POES satellitesWhat’s crucial? Free & open data policy! 70