Towards IASI-New Generation (IASI-NG): impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables

Besides their strong contribution to weather forecast improvement through data assimilation, thermal infrared sounders onboard polar-orbiting platforms are now playing a key role for monitoring atmospheric composition changes. The Infrared Atmospheric Sounding Interferometer (IASI) instrument developed by the French space agency (CNES) and launched by Eumetsat onboard the Metop satellite series is providing essential inputs for weather forecasting and pollution/climate monitoring owing to its smart combination of large horizontal swath, good spectral resolution and high radiometric performance. EUMETSAT is currently preparing the next polar-orbiting program (EPS-SG) with the Metop-SG satellite series that should be launched around 2020. In this framework, CNES is studying the concept of a new instrument, the IASI-New Generation (IASI-NG), characterized by an improvement of both spectral and radiometric characteristics as compared to IASI, with three objectives: (i) continuity of the IASI/Metop series; (ii) improvement of vertical resolution; (iii) improvement of the accuracy and detection threshold for atmospheric and surface components. In this paper, we show that an improvement of spectral resolution and radiometric noise fulfill these objectives by leading to (i) a better vertical coverage in the lower part of the troposphere, thanks to the increase in spectral resolution; (ii) an increase in the accuracy of the retrieval of several thermodynamic, climate and chemistry variables, thanks to the improved signal-to-noise ratio as well as less interferences between the signatures of the absorbing species in the measured radiances. The detection limit of several atmospheric species is also improved. We conclude that IASI-NG has the potential for strongly benefiting the numerical weather prediction, chemistry and climate communities now connected through the European GMES/Copernicus initiative

Le sondage satellitaire et son évolution

De nos jours, le sondage par satellite est couramment utilisé par la météorologie opérationnelle et pour l'étude de l'atmosphère et du climat, grâce aux progrès réalisés depuis une vingtaineNowadays, satellite sounding is currently used for operational meteorology and for studies of the atmosphere and climate thanks to the methods for data inversion and assimilation that have been developed over the last twenty years. Instrumental techniques are also quickly evolving and will soon allow much improved sounders, like the IASI interferometer. We are waiting for sounders to be put aboard geostationary satellites and for active sounders in the next decade

The IASI mission after 2020: what to expect for atmospheric composition monitoring

In terms of Earth observing capability, the horizon is shrinking as only a few new satellite missions have been approved and will be financed in the coming years. This is particularly true for polar-orbiting nadir viewing instruments using the thermal radiation emitted by the Earth's surface to probe the troposphere. After 2020 there should be an unprecedented combination of more frequent observation from the geostationary orbit (Meteosat Third Generation (MTG)/Sentinel 4 program) with more precise measurements from the polar orbit (MetOp- Second Generation satellites as part of the EPS-Second Generation/Sentinel 5 program). Along with several other instruments, the latter should embark the IASI-New Generation (IASI-NG) mission. The IASI-NG mission is a versatile mission that builds on the legacy of IASI and fulfills the needs of three different communities: numerical weather forecast, climate research and atmospheric composition monitoring. The instrument is currently designed by CNES and both the spectral resolution and the signal/noise ratio should be improved by at least a factor of two. In order to converge on the design of such an instrument all three communities had to make "reasonable accommodations". The presentation will describe what to expect in terms of products, accuracy and vertical resolution

IRSUTE : A minisatellite project for land surface heat flux estimation, from field to regional scale

International audienc

Towards IASI-New Generation (IASI-NG): impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables

Besides their strong contribution to weather forecast improvement through data assimilation, thermal infrared sounders onboard polar-orbiting platforms are now playing a key role for monitoring atmospheric composition changes. The Infrared Atmospheric Sounding Interferometer (IASI) instrument developed by the French space agency (CNES) and launched by Eumetsat onboard the Metop satellite series is providing essential inputs for weather forecasting and pollution/climate monitoring owing to its smart combination of large horizontal swath, good spectral resolution and high radiometric performance. EUMETSAT is currently preparing the next polar-orbiting program (EPS-SG) with the Metop-SG satellite series that should be launched around 2020. In this framework, CNES is studying the concept of a new instrument, the IASI-New Generation (IASI-NG), characterized by an improvement of both spectral and radiometric characteristics as compared to IASI, with three objectives: (i) continuity of the IASI/Metop series; (ii) improvement of vertical resolution; (iii) improvement of the accuracy and detection threshold for atmospheric and surface components. In this paper, we show that an improvement of spectral resolution and radiometric noise fulfill these objectives by leading to (i) a better vertical coverage in the lower part of the troposphere, thanks to the increase in spectral resolution; (ii) an increase in the accuracy of the retrieval of several thermodynamic, climate and chemistry variables, thanks to the improved signal-to-noise ratio as well as less interferences between the signatures of the absorbing species in the measured radiances. The detection limit of several atmospheric species is also improved. We conclude that IASI-NG has the potential for strongly benefiting the numerical weather prediction, chemistry and climate communities now connected through the European GMES/Copernicus initiative

The IASI-NG mission onboard METOP-SG: Scientific objectives and expected results

Thermal infrared sounders onboard polar-orbiting platforms are now playing a key role for monitoring the atmospheric composition change. Thanks to its smart combination of large horizontal swath, good spectral resolution and high radiometric performance, the IASI instrument developed by CNES and launched by Eumetsat onboard the MetOp satellite series is providing essential inputs for weather forecasting, for the monitoring of several essential climate variables, and for the study of atmospheric composition and pollution. IASI thus strongly benefits the NWP, chemistry and climate communities now connected through the GMES initiative (Sentinel 5, MACC project). In the framework of the EPS-SG program of EUMETSAT, CNES is currently preparing the IASI-NG (IASI-New Generation) mission that will fly on the ESA MetOp-SG satellite series. The mission is now moving to Phase-B and specifications have been narrowed to an improvement of the spectral resolution (factor of 2 as compared to IASI) and the radiometric noise (factor of 2 in the longwave, better in the shortwave and in some spectral regions particularly important for atmospheric composition). In this talk, we will discuss the science plan of IASI-NG that involves the NWP, climate and atmospheric composition communities and is structured around three main objectives: (i) continuity of the MetOp series; (ii) improvement of vertical coverage, especially in the lower troposphere; (iii) improvement of the precision and detection threshold of atmospheric and surface components

Evaporation over land-surfaces: First results from HAPEX-MOBILHY special observing period

International audiencePreliminary results are presented from the May 7-July 15, 1986 Special Observing Period (SOP) of the HAPEX-MOBILHY program, which examines the hydrological budget and evaporation flux at the scale of a 10,000 sq km GCM grid square to determine soil moisture, surface-energy budgets, and surface hydrology. The SOP used two highly instrumented remote sensing aircraft to obtain detailed measurements of atmospheric fluxes and surface properties. It is noted that the measurements are reliable at spatially local and short time scales, as well as on the monthly time scale. The data base obtained may be used in parametrization schemes against which land-surface water budgets can be tested

Hyperspectral Earth observation from IASI: Five years of accomplishments

The Infrared Atmospheric Sounding Interferometer (IASI) forms the main infrared sounding component of the European Organisation for the Exploitation of Meteorological Satellites's (EUMETSAT's) Meteorological Operation (MetOp)-A satellite (Klaes et al. 2007), which was launched in October 2006. This article presents the results of the first 4 yr of the operational IASI mission. The performance of the instrument is shown to be exceptional in terms of calibration and stability. The quality of the data has allowed the rapid use of the observations in operational numerical weather prediction (NWP) and the development of new products for atmospheric chemistry and climate studies, some of which were unexpected before launch. The assimilation of IASI observations in NWP models provides a significant forecast impact; in most cases the impact has been shown to be at least as large as for any previous instrument. In atmospheric chemistry, global distributions of gases, such as ozone and carbon monoxide, can be produced in near–real time, and short-lived species, such as ammonia or methanol, can be mapped, allowing the identification of new sources. The data have also shown the ability to track the location and chemistry of gaseous plumes and particles associated with volcanic eruptions and fires, providing valuable data for air quality monitoring and aircraft safety. IASI also contributes to the establishment of robust long-term data records of several essential climate variables. The suite of products being developed from IASI continues to expand as the data are investigated, and further impacts are expected from increased use of the data in NWP and climate studies in the coming years. The instrument has set a high standard for future operational hyperspectral infrared sounders and has demonstrated that such instruments have a vital role in the global observing system