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Collection:
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NASA Planetary Photo Journal Collection
Collection
NASA Planetary Photo Journal Collection
Collection
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Title:
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NIMS Observes the Structure and Composition of Jupiter's Clouds
Title
NIMS Observes the Structure and Composition of Jupiter's Clouds
Title
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Original Caption Released with Image:
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With the NIMS instrument high quality observations are being obtained from all parts of Jupiter. The images in the upper panel are taken at a wavelength of 4.8 microns. At this wavelength thermal radiation from about 100 km deep below the visible cloud deck is escaping, allowing us to study the deep atmospheric region.
The overlying cloud deck absorbs a part of the radiation, but there are places where it is thin and more radiation can escape. These are called hot spot regions. Many hotspots regions occur in a zone between the equator and 15 degrees north latitude, the North Equatorial Belt (NEB), but thermal radiation is seen from much of the planet.
The uniqueness of NIMS is that it is capable of observing the same spatial region at a maximum of 408 different wavelengths between 0.7 and 5.2 micron simultaneously. Every picture element (pixel) contains a spectrum of up to 408 wavelengths. The gases that compose the atmosphere leave there traces in the spectra. In this particular case, 48 wavelengths were available between 4.6 and 5.2 micron, and we see spectral signatures of water, ammonia, and phosphine. Also, the total amount of radiation is determined by the amount of overlying cloud, characterized by the cloud opacity. By means of model calculations, we can determine the amount of water and the cloud opacity for each individual spectrum. The amount ammonia and phosphine is more difficult to obtain because its influence on the spectra is weaker.
The results of these calculations are shown in the form of maps in the next two panels. With NIMS, we can now have a detailed look at the spatial distribution of the water and ammonia amounts and the cloud opacity in the atmosphere. Not all the pixels from the observations have good spectra, so for some data points no reliable determination of the water and cloud opacity could be made.
We find that the atmosphere is extremely dry in, and close to, the hot spot, with relative humidities between 0.02 % and 10 %, with the dryest places being inside the hot spot. This corroborates the in-situ Galileo Entry Probe measurements. The Probe entered the atmosphere, on December 5 1995, in a hot spot region. Whereas the Probe obtained only a very localized snapshot, with NIMS we can do observations of larger areas and over longer periods. The spatial distribution of water is more complex than expected. More detailed investigations will be necessary to fully understand these results.
Future studies will also allow a better understanding of the dynamics of the Jovian atmosphere, since the spatial distribution of water is thought to be a tracer for atmospheric motions under the cloud deck.
NIMS will continue to provide excellent and unique data during the Galileo Europa Mission, planned to last until December 1999.
The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.
The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's
Original_Caption_Rel eased_with_Image
With the NIMS instrument high quality observations are being obtained from all parts of Jupiter. The images in the upper panel are taken at a wavelength of 4.8 microns. At this wavelength thermal radiation from about 100 km deep below the visible cloud deck is escaping, allowing us to study the deep atmospheric region.
The overlying cloud deck absorbs a part of the radiation, but there are places where it is thin and more radiation can escape. These are called hot spot regions. Many hotspots regions occur in a zone between the equator and 15 degrees north latitude, the North Equatorial Belt (NEB), but thermal radiation is seen from much of the planet.
The uniqueness of NIMS is that it is capable of observing the same spatial region at a maximum of 408 different wavelengths between 0.7 and 5.2 micron simultaneously. Every picture element (pixel) contains a spectrum of up to 408 wavelengths. The gases that compose the atmosphere leave there traces in the spectra. In this particular case, 48 wavelengths were available between 4.6 and 5.2 micron, and we see spectral signatures of water, ammonia, and phosphine. Also, the total amount of radiation is determined by the amount of overlying cloud, characterized by the cloud opacity. By means of model calculations, we can determine the amount of water and the cloud opacity for each individual spectrum. The amount ammonia and phosphine is more difficult to obtain because its influence on the spectra is weaker.
The results of these calculations are shown in the form of maps in the next two panels. With NIMS, we can now have a detailed look at the spatial distribution of the water and ammonia amounts and the cloud opacity in the atmosphere. Not all the pixels from the observations have good spectra, so for some data points no reliable determination of the water and cloud opacity could be made.
We find that the atmosphere is extremely dry in, and close to, the hot spot, with relative humidities between 0.02 % and 10 %, with the dryest places being inside the hot spot. This corroborates the in-situ Galileo Entry Probe measurements. The Probe entered the atmosphere, on December 5 1995, in a hot spot region. Whereas the Probe obtained only a very localized snapshot, with NIMS we can do observations of larger areas and over longer periods. The spatial distribution of water is more complex than expected. More detailed investigations will be necessary to fully understand these results.
Future studies will also allow a better understanding of the dynamics of the Jovian atmosphere, since the spatial distribution of water is thought to be a tracer for atmospheric motions under the cloud deck.
NIMS will continue to provide excellent and unique data during the Galileo Europa Mission, planned to last until December 1999.
The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.
The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's
Original Caption Released with Image
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Original Caption Released with Image:
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Office of Space Science, Washington, DC.
This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.n asa.gov.
Original_Caption_Rel eased_with_Image
Office of Space Science, Washington, DC.
This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.n asa.gov.
Original Caption Released with Image
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Addition Date:
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1998-03-26
Addition_Date
1998-03-26
Addition Date
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Produced By:
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JPL
Produced_By
JPL
Produced By
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Mission:
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Galileo
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Spacecraft:
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Galileo Orbiter
Spacecraft
Galileo Orbiter
Spacecraft
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Target Name:
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Jupiter
Target_Name
Jupiter
Target Name
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Is a satellite of:
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Sol (our sun)
Is_a_satellite_of
Sol (our sun)
Is a satellite of
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Instrument:
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Near Infrared Mapping Spectrometer
Instrument
Near Infrared Mapping Spectrometer
Instrument
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Product Size:
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712 samples x 725 lines
Product_Size
712 samples x 725 lines
Product Size
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Primary Data Set:
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Galileo EDRs
Primary_Data_Set
Galileo EDRs
Primary Data Set
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Producer ID:
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P49330A
MRPS85067
Producer_ID
P49330A
MRPS85067
Producer ID
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facet_what:
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Sun
facet_what
Sun
facet_what
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facet_what:
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Jupiter
facet_what
Jupiter
facet_what
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facet_what:
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Galileo
facet_what
Galileo
facet_what
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facet_what:
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Galileo Orbiter
facet_what
Galileo Orbiter
facet_what
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facet_what:
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Spectrometer
facet_what
Spectrometer
facet_what
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facet_what:
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Europa
facet_what
Europa
facet_what
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facet_what:
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Snapshot
facet_what
Snapshot
facet_what
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facet_what:
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Near Infrared Mapping Spectrometer (NIMS)
facet_what
Near Infrared Mapping Spectrometer (NIMS)
facet_what
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facet_where:
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Jet Propulsion Laboratory
facet_where
Jet Propulsion Laboratory
facet_where
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facet_where:
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Jupiter
facet_where
Jupiter
facet_where
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facet_where:
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Europa
facet_where
Europa
facet_where
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facet_where:
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Washington
facet_where
Washington
facet_where
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facet_where:
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Jet Propulsion Laboratory (JPL)
facet_where
Jet Propulsion Laboratory (JPL)
facet_where
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facet_where:
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Washington, D.C.
facet_where
Washington, D.C.
facet_where
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facet_when:
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December 5 1995
facet_when
December 5 1995
facet_when
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facet_when:
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December 1999
facet_when
December 1999
facet_when
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facet_when_year:
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1999
facet_when_year
1999
facet_when_year
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facet_when_year:
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1995
facet_when_year
1995
facet_when_year
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Image #:
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PIA01224
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UID:
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SPD-PHOTJ-PIA01224
UID
SPD-PHOTJ-PIA01224
UID
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orignial url:
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orignial_url
orignial url
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