Missions

Data Access: /data/omps

The Ozone Mapping and Profiler Suite (OMPS) is the next generation of back-scattered UltraViolet (BUV) radiation sensors. The first OMPS is currently flying onboard the Suomi NPP spacecraft and has a dual mission to provide NOAA with critical operational ozone measurements while continuing the nearly 40 year NASA records of total column and profile ozone created by previous BUV sensors.

OMPS is composed of three different sensors, two nadir-looking and one looking at the limb.

For the nadir sensors, NASA's science team has the responsibility to evaluate the performance of the sensors and, since NOAA is already operationally processing OMPS nadir, to evaluate the performance of the operational algorithm and products to determine if they are suitable for continuing the long-term climate records. If not, the science team is to suggest improvements and alternatives in both calibration and processing. In order to do it's work, the nadir science team is generating research products utilizing the latest version of NASA's BUV retrieval algorithms. Comparisons between the research and operational products provide insight into the performance of the operational system.

Data Access: /data/omps

The Ozone Mapping and Profiler Suite (OMPS) is the next generation of back-scattered UltraViolet (BUV) radiation sensors. The first OMPS is currently flying onboard the Suomi NPP spacecraft and has a dual mission to provide NOAA with critical operational ozone measurements while continuing the nearly 40 year NASA records of total column and profile ozone created by previous BUV sensors.

OMPS is composed of three different sensors, two nadir-looking and one looking at the limb.

For the limb sensor, NASA's science team has the responsibility of evaluating the performance of the sensor, developing the retrieval algorithm, generating a product, and evaluating the performance of both the algorithm and product. Once the product has been validated, operational processing of OMPS limb data will transition to NOAA.

Data Access: /data/omps

The Ozone Mapping and Profiler Suite (OMPS) is the next generation of back-scattered UltraViolet (BUV) radiation sensors. The first OMPS is currently flying onboard the Suomi NPP spacecraft and has a dual mission to provide NOAA with critical operational ozone measurements while continuing the nearly 40 year NASA records of total column and profile ozone created by previous BUV sensors.

OMPS is composed of three different sensors, two nadir-looking and one looking at the limb.

For the nadir sensors, NASA's science team has the responsibility to evaluate the performance of the sensors and, since NOAA is already operationally processing OMPS nadir, to evaluate the performance of the operational algorithm and products to determine if they are suitable for continuing the long-term climate records. If not, the science team is to suggest improvements and alternatives in both calibration and processing. In order to do it's work, the nadir science team is generating research products utilizing the latest version of NASA's BUV retrieval algorithms. Comparisons between the research and operational products provide insight into the performance of the operational system.

Data Access: /data/omps

The Ozone Mapping and Profiler Suite (OMPS) is the next generation of back-scattered UltraViolet (BUV) radiation sensors. The first OMPS is currently flying onboard the Suomi NPP spacecraft and has a dual mission to provide NOAA with critical operational ozone measurements while continuing the nearly 40 year NASA records of total column and profile ozone created by previous BUV sensors.

OMPS is composed of three different sensors, two nadir-looking and one looking at the limb.

For the nadir sensors, NASA's science team has the responsibility to evaluate the performance of the sensors and, since NOAA is already operationally processing OMPS nadir, to evaluate the performance of the operational algorithm and products to determine if they are suitable for continuing the long-term climate records. If not, the science team is to suggest improvements and alternatives in both calibration and processing. In order to do it's work, the nadir science team is generating research products utilizing the latest version of NASA's BUV retrieval algorithms. Comparisons between the research and operational products provide insight into the performance of the operational system.

Data Access: /data/omi

OMI is a contribution of the Netherlands's Agency for Aerospace Programs (NIVR) in collaboration with the Finnish Meteorological Institute (FMI) to the EOS Aura mission. It will continue the TOMS record for total ozone and other atmospheric parameters related to ozone chemistry and climate. OMI measurements will be highly synergistic with the other instruments on the EOS Aura platform. The OMI instrument employs hyperspectral imaging in a push-broom mode to observe solar backscatter radiation in the visible and ultraviolet. The Earth will be viewed in 740 wavelength bands along the satellite track with a swath large enough to provide global coverage in 14 orbits (1 day). The nominal 13 x 24 km spatial resolution can be zoomed to 13 x 13 km for detecting and tracking urban-scale pollution sources. The hyperspectral capabilities will improve the accuracy and precision of the total ozone amounts. The hyperspectral capabilities will also allow for accurate radiometric and wavelength self calibration over the long term. The expanded wavelength characteristics will provide the following features.

  • Continue global total ozone trends from satellite measurements beginning in 1970 with BUV on Nimbus-4.
  • Map ozone profiles at 36 x 48 km, a spatial resolution never achieved before.
  • Measure key air quality components such as NO2, SO2, BrO, OClO, and aerosol characteristics.
  • Distinguish between aerosol types, such as smoke, dust, and sulfates. Measure cloud pressure and coverage, * which provide data to derive tropospheric ozone.
  • Map global distribution and trends in UV-B radiation.
  • A combination of algorithms including TOMS version 7, Differential Optical Absorption Spectroscopy (DOAS), Hyperspectral BUV Retrievals and forward modeling will be used together to extract the various OMI data products.
  • Near Real Time (NRT) production of ozone and other trace gases.

Data Access: /data/toms

Originally, the data obtained from Earth Probe (EP) TOMS were intended to complement data obtained from ADEOS TOMS, which gave complete equatorial coverage due to its higher orbit. EP-TOMS was launched into a 500 kilometer orbit rather than the originally planned 950 kilometer orbit. The lower orbit decreased the size of the "footprint" of each measurement, which increased the resolution and also increased the ability to make measurements over cloudless scenes. This orbit was chosen to improve the ability of the TOMS instrument to make measurements of UV-absorbing aerosols in the troposphere. Tropospheric aerosols play a major role in the Earth's climate and the capability to measure them from a TOMS instrument has recently been developed using data from Nimbus-7.

The increased probability of making measurements over cloud-free areas enhanced the capability of converting the TOMS aerosol measurements into geophysical quantities such as optical depth. Although the lower orbit precluded full global coverage in the equatorial region, the scanning range of the TOMS instrument still provided full coverage over the poles. EP-TOMS would have still been able to completely track and map the development of the Antarctic ozone hole and the springtime decrease of ozone in the northern hemisphere.

However, ADEOS failed in June 1997. The orbit of EP has been boosted to 740 km and circularized to provide coverage that is as complete as possible. As with the pre-boosted measurements, the EP-TOMS data still has missing elements at the equator, but these do not present a significant problem in analysis.

Current TOMS and OMI data were processed with the Version 8 algorithm that has been developed by NASA Goddard's Ozone Processing Team to address errors associated with extreme viewing conditions. The basic algorithm used just 2 wavelengths (317.5 and 331.2 nm under most conditions, and 331.2 and 360 nm for high ozone and high solar zenith angle conditions). The longer of the two wavelengths is used to derive the surface reflectivity (or cloud fraction). Once the surface reflectivity has been established, the shorter wavelength, which is heavily absorbed by ozone, may be used to derive total ozone. The algorithm also calculates the "aerosol index" (AI) from the difference in surface reflectivity derived from the 331.2 and 360 nm measurements. The AI primarily provides a measure of absorption of UV radiation by smoke and desert dust. This algorithm is described in detail in the TOMS algorithm theoretical basis document (ATBD). Interested viewers may also wish to read about the Version 8 algorithm.


Orbital characteristics (after 12/13/97):

  • Altitude: 740km
  • Inclination: 98.385 degrees
  • FOV at nadir: 39km lat x 39km lon

Original orbital characteristics (before 12/5/97):

  • Apogee altitude: 515.2km
  • Perigee altitude: 490.5km
  • Inclination: 97.432 degrees
  • Period: 94.6 min
  • FOV at nadir: 26km lat x 26km lon

There are no EP TOMS data in the periods Dec 5, 1997 - Dec 10 1997 and Dec 13, 1998 and Jan 2, 1999.

Data Access: /data/toms

As a team of NASA/Goddard scientists and engineers watched, a Soviet-built Cyclone booster carried the second TOMS into orbit and history. In the last days of the Cold War, Meteor-3 TOMS became the first and the last American-built instrument to fly on a Soviet spacecraft. Within weeks, Meteor-3 TOMS would become the first American instrument aboard a Russian spacecraft. Launched from the Plesetsk facility near the White Sea, Meteor-3 TOMS had a unique orbit that presented special problems for processing data.

Meteor-3 TOMS began returning data in August 1991 and stopped in December 1994. The Meteor-3 TOMS was launched from Plesetsk, Russia on a Cyclone booster.

Current TOMS and OMI data were processed with the Version 8 algorithm that has been developed by NASA Goddard's Ozone Processing Team to address errors associated with extreme viewing conditions. The basic algorithm used just 2 wavelengths (317.5 and 331.2 nm under most conditions, and 331.2 and 360 nm for high ozone and high solar zenith angle conditions). The longer of the two wavelengths is used to derive the surface reflectivity (or cloud fraction). Once the surface reflectivity has been established, the shorter wavelength, which is heavily absorbed by ozone, may be used to derive total ozone. The algorithm also calculates the "aerosol index" (AI) from the difference in surface reflectivity derived from the 331.2 and 360 nm measurements. The AI primarily provides a measure of absorption of UV radiation by smoke and desert dust. This algorithm is described in detail in the TOMS algorithm theoretical basis document (ATBD). Interested viewers may also wish to read about the Version 8 algorithm.

Data Access: /data/toms

The TOMS program began with the launch of TOMS Flight Model #1 on the Nimbus-7 spacecraft on October 24, 1978. Valid measurements started in November of that same year and the instrument continued to return data long after all other on-board experiments had failed. The TOMS instrument fell silent in May 1993. The software to derive useful information from the data returned by Nimbus 7 TOMS is the basis for the algorithm used to analyze all TOMS data and has gone through a lengthly evolutionary process bring it to the current version.

Current TOMS and OMI data were processed with the Version 8 algorithm that has been developed by NASA Goddard's Ozone Processing Team to address errors associated with extreme viewing conditions. The basic algorithm used just 2 wavelengths (317.5 and 331.2 nm under most conditions, and 331.2 and 360 nm for high ozone and high solar zenith angle conditions). The longer of the two wavelengths is used to derive the surface reflectivity (or cloud fraction). Once the surface reflectivity has been established, the shorter wavelength, which is heavily absorbed by ozone, may be used to derive total ozone. The algorithm also calculates the "aerosol index" (AI) from the difference in surface reflectivity derived from the 331.2 and 360 nm measurements. The AI primarily provides a measure of absorption of UV radiation by smoke and desert dust. This algorithm is described in detail in the TOMS algorithm theoretical basis document (ATBD). Interested viewers may also wish to read about the Version 8 algorithm.

Algorithmic improvements include:

  • use of wavelength "triplets" that correct for errors linear in wavelength
  • improved ISCCP cloud height climatology, higher resolution terrain height maps
  • use of improved profile shape selection to improve total ozone at very large solar zenith angles
  • use of a more accurate model for partially-clouded scenes
  • improved radiative transfer calculations for table generation

More Nimbus-7 TOMS information