Science Investigations: The Legacy of Explorer VII

1
Science Investigations The Legacy of Explorer
VII

• by
• Professor Tom Vonder Haar
• CIRA and Dept. of Atmospheric Science
• Colorado State University
• Program on 50 Years of Meteorological Satellite
  Observations
• University of Wisconsin, Madison
• November 2nd, 2009

2
Scope of this paper The Legacy of Explorer VII
for

• Global Satellite Observing Systems
• Global Synoptic Weather Analyses and Forecasting
• New Scientific Information and the Opening of New
  Lines of Science Study

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The Beginnings
(from Vaeth, J.G., 1965, Weather Eyes in the Sky,
Ronald Press, NY. 124 pages)
4
The thermal radiation experiment on board
Explorer 7 was proposed by Dr. Verner Suomi of
the University of Wisconsin and Dr. Harry Wexler
of the US Weather Bureau. The experiment was
designed to measure solar, reflected and
terrestrial radiation to gain a better
understanding of Earths Energy Budget.
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  The primary instrumentation for the thermal
radiation experiment consisted of bolometers in
the form of hollow silver Hemispheres.
Instruments included two black hemispheres that
responded to solar and terrestrial radiation, one
white hemisphere that was more sensitive to
terrestrial radiation and one gold hemisphere
designed to absorb short-wave radiation. Explorer
made 4000 radiation observations daily and 400 to
1000 readings were collected for analysis.
Observations were made every 30 seconds and
recorded at a low rate to a tape recorder. The
data was transmitted at a high rate to 1 of 21
ground stations.
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Explorer 7 loop
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Todays Global Satellite Observing Systems
Provide Much Greater Coverage
(Conway, 2008)
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New Satellite Systems Include Trains and
Constellations
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Global Synoptic Weather Analysis and Forecasting

• Weinstein and Suomi conclude their paper with a
  note that daily nephanalyses and improved
  synoptic charts might be possible with
  combination of the (nighttime) IR and the newly
  available (daytime) TIROS VIDICON images.
• Indeed, at the USAF Global Weather Central in
  Omaha, these operational analyses were done
  throughout the 1960s. They were used for ship
  routing, air traffic control including flight
  refueling over the Pacific, and synoptic scale
  weather forecasting including South East Asia.

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In the early 1960s Suomi-type radiometers were
onboard USAF sun-synchronous satellites providing
global Earth Radiation Budget measurements.
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Summary of satellite radiation data through 1965
(Vonder Haar, 1968)
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Mean annual values of longwave radiation from the
earth-atmosphere system (HL). Units 10-2 cal.
cm-2. min -1 and regions of HLgt0.35 are shaded.
1 cal. cm. -2 min. -1 698 watts.m-2 (Vonder
Haar, 1968)
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• We found that Earth was a Warmer and Darker
  Planet than previously believed - - especially
  in the Tropical Regions. We found that 40 More
  Energy must be transported poleward by the
  Atmosphere and Ocean Circulations!
• (Vonder Haar and Suomi, 1969, 1971)

Much more energy gain in the tropics
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Could these early results be true?

• If so, there were far-reaching implications to
  better understand and model Atmospheric and Ocean
  Circulations, Air-Sea Interactions, and both the
  Earths Energy and Water Cycles!
• The Scientific Method requires reproducibility of
  results.
• The Nimbus 2 3 MRIR experiments, the Nimbus 6
  7 ERB, and the ERBE Program were designed to
  check, verify, and expand the results from the
  1960s.

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Warmer
Darker
S
Annual zonal averages of albedo (percent) and
outgoing long wave radiation obtained from Nimbus
3 (dashed line) and from earlier satellites
(solid line Vonder Haar and Suomi, 1971) and
from calculations with climatological data (black
dots London, 1957)
So, Nimbus 3 supports earlier satellite results!
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A 3rd Mission, ERBE, to decrease uncertainty
began with the launch of the Earth Radiation
Budget Satellite from the Shuttle Challenger on
Oct. 4, 1984. We included WFOD cavity
radiometers with the Suomi concept of calibration
by direct solar irradiance (Vonder Haar, 2009).
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ERBE fits Nimbus and thus the early ERB results
from the 1960s have been confirmed and greatly
expanded during the 1970s and 1980s
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• Therefore, by 1985, the early Earth Radiation
  Budget results from the Suomi Experiments were
  replicated twice by Nimbus and ERBE
• This knowledge of the fundamental global Earth
  Radiation Budget provides an important point of
  closure for understanding Earths Climate System

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Opening Lines of New Science Inquiry

• Observed variations of Earth Radiation Budget are
  due to changing Earth temperature, clouds, water
  vapor, carbon dioxide, etc.
• Therefore, many new science observations were
  stimulated as part of the legacy from Explorer 7.

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2008 annual cloud cover anomaly () for the
period 1982-2008, PATMOS-x dataset.
2008 annual total column water vapor anomaly (mm)
for the period 1997-2008, SSM/I/GPS dataset.
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NVAP Daily Total Precipitable Water
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The newest Global Science Challenge CO2 Sources,
Sinks and Transport (modeling simulation by
Parazoo and Denning, 2008)
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Summary

• With concepts and science objectives developed
  for the International Geophysical Year in the
  late 1950's, Vern Suomi's Explorer-VII experiment
  launched the era of Earth Observing Systems. 
  With his students and colleagues in the new space
  programs of NASA, the US Weather Bureau, the US
  Air Force and aerospace industries, new lines of
  science inquiry and global observations were
  embarked.
• The early Earth Radiation Budget measurements
  from the first three decades following
  Explorer-VII had great scientific impact.  The
  science legacy of Explorer-VII continues in
  successive, larger space observing programs
  related to Earth's Energy, Water and Carbon
  Cycles.
• Today, it is the knowledge of intersections among
  these three cycles and budgets which provides us
  so much promise for new scientific understanding.

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Verner E. Suomi
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BACK UP SLIDES
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  The radius of coverage for each observed data
point covered about 23 o of equatorial latitude
(2500 km) at perigee and 31.5 degrees (3500 km)
at apogee. Half the radiation was received from
an area below the satellite with a radius of 5.3
degrees (545 km) at perigee and 9 degrees (1015
km) at apogee.
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Col. Ralph Steele
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Inverse Modeling of CO2
Air Parcel
transport
transport
Air Parcel
Air Parcel
concentration
transport
sources and sinks
(model)
(observe)
(solve for)
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Studies of Earths Radiation Budget

• Dines (1915)
• Simpson, G.C. (1929), Mem. Roy. Soc.
• Baur and Philips (1935), Gerlands Beitr. Geophys.
• Lettan, H. (1954), Arkiv. Meteor., Geophys. und
  Bioklima
• London, J. et al., Report, NYU
• --------------------------------------------------
  ------
• Age of Artificial Earth Satellites 1957
• -Vonder Haar, T. and V. Suomi (1969), Science
• -Vonder Haar, T. and V. Suomi (1971), J. Atmos.
  Sci.
• More

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Launched by a Juno rocket fired from Cape
Canaveral Air Force station on October 13, 1959,
Explorer 7 achieved an orbit with initial apogee
of 1090 km, a perigee of 555 km, inclination of
50 degrees and a period of 101 min. The satellite
is still in orbit today.
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Wielicki et al., Science, 2005
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Comparison of Nimbus-7 and the new ERBE results
in 1985 (after Kyle et al, 1990)
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Total Solar Irradiance at Earth
Recent Measurements
0.5
(Courtesy Gary Rottman, CU)
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Suomi, V.E., K.J. Hanson and T. H. Vonder Haar,
1967  The Theoretical Basis for Low-Resolution
Radiometer Measurements from a Satellite, Annual
Report on Weather Bureau Grant ( WBG-27 ),
Department of Meteorology, The University of
Wisconsin, Madison, p 79-100.