2021-10-26 13:37:14.0 [sritz] update Definition (The OCO spectrometers measure sunlight reflected off the Earth's surface. The rays of sunlight that enter the spectrometers pass through the atmosphere twice, once as they travel from the Sun to the Earth, and then again as they travel from the Earth's surface to the OCO instrument. Carbon dioxide and molecular oxygen molecules in the atmosphere absorb light energy at very specific colors or wavelengths. Grating Spectrum Thus, the light that reaches the OCO instrument will display diminished amounts of energy at those characteristic wavelengths. The OCO instrument employs a diffraction grating to separate the inbound light energy into a spectrum of multiple component colors. The reflection gratings used in the OCO spectrometers consist of a very regularly spaced series of grooves that lie on a very flat surface. The back of a compact disc is an everyday example of a diffraction grating. The characteristic spectral pattern for CO2 can alternate from transparent to opaque over very small variations in wavelength. The OCO instrument must be able to detect these dramatic changes, and specify the wavelengths where these variations take place. Thus, the grooves in the instrument diffraction grating are very finely tuned to spread the light spectrum into a large number of very narrow wavelength bands or colors. Indeed, the OCO instrument design incorporates 17,500 different colors to cover the entire wavelength range that can be seen by the human eye. A digital camera covers the same wavelength range using just three colors. Group: Instrument_Details Entry_ID: OCO SPECTROMETERS Group: Instrument_Identification Instrument_Category: Earth Remote Sensing Instruments Instrument_Class: Passive Remote Sensing Instrument_Type: Spectrometers/Radiometers Instrument_Subtype: Spectrometers Short_Name: OCO SPECTROMETERS Long_Name: Orbiting Carbon Observatory Spectrometers End_Group Group: Associated_Platforms Short_Name: OCO-2 Short_Name: OCO End_Group Group: Spectral_Frequency_Information Wavelength_Keyword: Near Infrared Spectral_Frequency_Coverage_Range: 0.76, 1.58, 2.06 μm End_Group Online_Resource: https://ocov2.jpl.nasa.gov/observatory/instrument/ Creation_Date: 2008-12-16 Group: Instrument_Logistics Instrument_Owner: NASA End_Group End_Group); update Definition (Source: NASA/OCO home page, https://ocov2.jpl.nasa.gov/observatory/instrument/);
Spectrometers
OCO SPECTROMETERS
The OCO spectrometers measure sunlight reflected off the Earth's surface. The rays of sunlight that enter the spectrometers pass through the atmosphere twice, once as they travel from the Sun to the Earth, and then again as they travel from the Earth's surface to the OCO instrument. Carbon dioxide and molecular oxygen molecules in the atmosphere absorb light energy at very specific colors or wavelengths. Grating Spectrum Thus, the light that reaches the OCO instrument will display diminished amounts of energy at those characteristic wavelengths. The OCO instrument employs a diffraction grating to separate the inbound light energy into a spectrum of multiple component colors. The reflection gratings used in the OCO spectrometers consist of a very regularly spaced series of grooves that lie on a very flat surface. The back of a compact disc is an everyday example of a diffraction grating. The characteristic spectral pattern for CO2 can alternate from transparent to opaque over very small variations in wavelength. The OCO instrument must be able to detect these dramatic changes, and specify the wavelengths where these variations take place. Thus, the grooves in the instrument diffraction grating are very finely tuned to spread the light spectrum into a large number of very narrow wavelength bands or colors. Indeed, the OCO instrument design incorporates 17,500 different colors to cover the entire wavelength range that can be seen by the human eye. A digital camera covers the same wavelength range using just three colors. Group: Instrument_Details Entry_ID: OCO SPECTROMETERS Group: Instrument_Identification Instrument_Category: Earth Remote Sensing Instruments Instrument_Class: Passive Remote Sensing Instrument_Type: Spectrometers/Radiometers Instrument_Subtype: Spectrometers Short_Name: OCO SPECTROMETERS Long_Name: Orbiting Carbon Observatory Spectrometers End_Group Group: Associated_Platforms Short_Name: OCO-2 Short_Name: OCO End_Group Group: Spectral_Frequency_Information Wavelength_Keyword: Near Infrared Spectral_Frequency_Coverage_Range: 0.76, 1.58, 2.06 μm End_Group Online_Resource: https://ocov2.jpl.nasa.gov/observatory/instrument/ Creation_Date: 2008-12-16 Group: Instrument_Logistics Instrument_Owner: NASA End_Group End_Group