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OBS 3 Radiative transfer for thermal radiation. Instruments Bruno Carli. Table of Contents. Space instruments Recent and future instruments (IMG, ILAS, AIRS, MIPAS, TES, HIRDLS, ACE, IASI, CrIS, GIFTS, GGOS, REFIR) General considerations. Space Instruments. IMG overview.
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OBS 3 Radiative transfer for thermal radiation. Instruments Bruno Carli COST 723 Training School - Cargese 4 - 14 October 2005
Table of Contents • Space instruments • Recent and future instruments (IMG, ILAS, AIRS, MIPAS, TES, HIRDLS, ACE, IASI, CrIS, GIFTS, GGOS, REFIR) • General considerations COST 723 Training School - Cargese 4 - 14 October 2005
Space Instruments COST 723 Training School - Cargese 4 - 14 October 2005
IMG overview IMG: Interferometric Monitor for Greenhouse Gases Agency: NASDA Satellite: ADEOS I Launched on 17th August 1996. Stopped on 30th June 1997. COST 723 Training School - Cargese 4 - 14 October 2005
IMG IMG is a nadir-looking Fourier transform infrared spectrometer (FTIR) operating in the spectral range from 3300 - 714 cm-1 (3.3 - 14.7 µm), with a spectral resolution of 0.1 cm-1 (apodized). IFOV=10 mrad (8x8 km2 footprint) COST 723 Training School - Cargese 4 - 14 October 2005
ILAS I and II overview • ILAS I and II: Improved Limb Atmospheric Spectrometer • Agency: NASDA / JAXA • Satellites: ADEOS I and II • ADEOS-I launched on 17th August 1996. Stopped on 30th June 1997. • ADEOS-II launched on 10th April 2003. Stopped on 24th October 2003. COST 723 Training School - Cargese 4 - 14 October 2005
ILAS I e II ILAS is a solar occultation grating spectrometer with two gratings, one measuring in the thermal IR with 44 channels in the range from 6.21-11.77 µm (850-1610 cm-1), the other measuring in the VIS and IR with 1024 channels in the range of 0.753 - 0.784 µm. IFOV (at tangent height) 2 km (vertical) x 13 km (horizontal). COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS overview MIPAS: Michelson Interferomer for Passive Atmospheric Sounding Agency: ESA Satellite: Envisat Launched on 1st march 2002. Operating. COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS MIPAS is a Fourier Transform (FT) Spectrometer that measures the middle infrared (MIR) emission of the atmosphere at the limb. COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS MIPAS is a Fourier Transform (FT) Spectrometer that measures the middle infrared (MIR) emission of the atmosphere at the limb. FT COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS MIPAS is a Fourier Transform (FT) Spectrometer that measures the middle infrared (MIR) emission of the atmosphere at the limb. • Spectral range: 685 - 2410 cm-1, • = 14.6 – 4.15 m • Spectral resolution 0,025 cm-1 unapodized • Spectral resolution FWHM 0.035 cm-1 • Vibrational spectra of molecules COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS MIPAS is a Fourier Transform (FT) Spectrometer that measures the middle infrared (MIR) emission of the atmosphere at the limb. • Spontaneous thermal emission (blackbody) of the atmosphere • Continuous (day and night) measurements are possible COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS MIPAS is a Fourier Transform (FT) Spectrometer that measures the middle infrared (MIR) emission of the atmosphere at the limb. In a limb view the line of sight (LOS) penetrate the atmosphere down to a minimum altitude (tangent altitude) and exits again to space. A typical limb sequence is made of a set of measurements made with different tangent altitudes (typically 3 km increments). COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS Functional Description COST 723 Training School - Cargese 4 - 14 October 2005
Telescope Elevation Scan Unit Azimuth Scan Unit Baseplate Front End Optics (FEO) COST 723 Training School - Cargese 4 - 14 October 2005
Beamsplitter Corner Cube Interferometer COST 723 Training School - Cargese 4 - 14 October 2005
Interferometer characteristics • Cooled instrument • Optical compensation of alignment errors • Double sided interferograms • Double input and double output COST 723 Training School - Cargese 4 - 14 October 2005
O MIPAS on ENVISAT COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS Observation Principle COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS measurement scenario Characteristics: • sweep duration: 4.45 s (full resolution) • sweeps per limb seq.: 17 (68km, 60km, 52km, 47km, (42 – 6) km in 3 km steps • # limb seq. per orbit: ~ 75 (deep space cal. every 5 sequences) • azimuth scan range: ~ +/-150 • rearward geometries: global coverage, poles visible COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS coverage in one orbit COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS coverage in one day COST 723 Training School - Cargese 4 - 14 October 2005
MIPAS coverage in three days COST 723 Training School - Cargese 4 - 14 October 2005
Ozone vertical distribution as a function of latitude and longitude 10 5 0 ppm 12 h measurements -110° long 66° long -85° long 91° long -60° long 116° long 166° long 141° long -9° long 16° long -160° long 41° long -135° long -35° long COST 723 Training School - Cargese 4 - 14 October 2005
3D global ozone distribution 10 32 km 8 km 11 km 14 km 17 km 20 km 23 km 29 km 26 km 35 km 41 km 44 km 47 km 50 km 53 km 8 - 53 km 38 km 5 0 ppm COST 723 Training School - Cargese 4 - 14 October 2005
AIRS overview AIRS: Atmospheric InfraRed Sounder Agency: NASA Satellite: AQUA Launched on the 4th of May 2002. Operating COST 723 Training School - Cargese 4 - 14 October 2005
AIRS AIRS is a grating nadir-looking instruments. 3 IR wavebands (from 3.74 µm to 15.4µm) with a total of 2378 channels at spectral resolution < 1cm -1. 4 Vis/NIR channels (from 0.4 µm to 1.1 µm). IFOV 13.5km at nadir COST 723 Training School - Cargese 4 - 14 October 2005
ACE overview • ACE: Atmospheric Chemistry Experiment • Agency: Canadian Space Agency • Satellite: SCISAT-1 • Launched on 12th August 2003. Operating. COST 723 Training School - Cargese 4 - 14 October 2005
ACE ACE is a high spectral resolution (0.02 cm-1) occultation FT spectrometer operating from 750–4400 cm-1 (about from 2.2 to 13.3 µm) with a spectral resolution of 0.02 cm-1. COST 723 Training School - Cargese 4 - 14 October 2005
TES overview TES: Tropospheric Emission Spectrometer Agency: NASA Satellite: AURA Launched on 15th July 2004. Operating. COST 723 Training School - Cargese 4 - 14 October 2005
TES TES is an infrared-imaging Fourier transform spectrometer operating in a combination of limb and nadir modes. COST 723 Training School - Cargese 4 - 14 October 2005
TES • TES is an infrared-imaging Fourier transform spectrometer operating in a combination of limb and nadir modes. • Spectral range 650 – 3050 cm-1 (about 3.3 – 15.4 mm). • Spectral resolution 0.02 cm-1 COST 723 Training School - Cargese 4 - 14 October 2005
TES • TES is an infrared-imaging Fourier transform spectrometer operating in a combination of limb and nadir modes. 1x16 element focal plane arrays COST 723 Training School - Cargese 4 - 14 October 2005
HIRDLS overview HIRDLS: High Resolution Dynamics Limb Sounder Agency: NASA-UK Satellite: AURA Launched on 15th July 2004. Operating. COST 723 Training School - Cargese 4 - 14 October 2005
HIRDLS HIRDLS is a multi-channel limb-viewing infrared (IR) radiometer operating in the spectral range from 6 to 18 m COST 723 Training School - Cargese 4 - 14 October 2005
IASI overview • IASI: Infrared Atmospheric Sounding Interferometer • Agency: CNES • Satellite: Metop 1, 2 and 3 by EUMETSAT • Launch scheduled for 2006, 2010 and 2015. COST 723 Training School - Cargese 4 - 14 October 2005
IASI IASI is a nadir-sounding imaging FT spectrometer operating in the spectral range 645 to 2760 cm-1 (15.5 to 3.62 µm) with a spectral resolution of 0.25 cm-1. IFOV=10 mrad (8x8 km2 footprint). A 2 x 2 array in each of its three bands. COST 723 Training School - Cargese 4 - 14 October 2005
CrIS overview • CrIS: Cross-track Infrared Sounder • Agency: NOAA • Satellite: NPOESS (National Polar-orbiting Operational Environmental Satellite System) • Launch scheduled for 2008. COST 723 Training School - Cargese 4 - 14 October 2005
CrIS CrIS is an imaging interfereometer with a 3 x 3 array covering 3 bands over a spectral range of 3.92 µm to 15.38 µm (650 cm -1 to 2550 cm -1 ).The instrument resolution varies from 0.625 cm-1 to 2.5 cm -1. Picture of prototype COST 723 Training School - Cargese 4 - 14 October 2005
GIFTS overview • GIFTS: Geosynchronous Imaging Fourier Transform Spectrometer. • Agency: NASA • Satellite: GIFTS-IOMI • Launch scheduled for ?? . COST 723 Training School - Cargese 4 - 14 October 2005
GIFTS GIFTS is a geostationary, nadir sounding, imaging interferometer with a detector arrays 128 x 128, operating in the spectral ranges 685 - 1130 cm-1 and 1650 - 2250 cm-1 with a spectral resolution of 0.6 cm-1. COST 723 Training School - Cargese 4 - 14 October 2005
GGOS overview • GGOS: Greenhouse Gas Observing Sensor • Agency: JAXA • Satellite: GOSAT • Launch scheduled for August 2008. COST 723 Training School - Cargese 4 - 14 October 2005
Greenhouse Gas Observing Sensor The Greenhouse Gas Observing Sensor is a nadir-sounding FT spectrometer operating in the visible (three bands) and in the spectral range 645 to 2760 cm-1 (14.3 to 0.75 µm) with a spectral resolution from 0.5 to 0.2 cm-1. IFOV 10 km COST 723 Training School - Cargese 4 - 14 October 2005
REFIR REFIR is a nadir-sounding FT spectrometer operating from balloon in the spectral range from 100 to 1400 cm-1 with a spectral resolution of 0.5 cm-1. Room temperature detectors. First balloon flight on 1st July 2005 COST 723 Training School - Cargese 4 - 14 October 2005
Summary of recent and planned missions COST 723 Training School - Cargese 4 - 14 October 2005
General considerationsspectral resolution On going evolution from radiometers to multichannel grating spectrometer, and to high resolution FT spectrometers. Data analysis is performed with either channel or microwindow selection COST 723 Training School - Cargese 4 - 14 October 2005
Thermal radiation General considerationsemission measurements Few missions use occultation measurements, which, with their high S/N, are best suited for the understanding of radiative transfer. Most of the new mission use emission measurements, which, with their continuous and global coverage, are best suited for the understanding of atmospheric processes. COST 723 Training School - Cargese 4 - 14 October 2005
General considerationsimaging Array detectors are providing imaging capabilities to FT spectrsocpy. IASI TES COST 723 Training School - Cargese 4 - 14 October 2005
General considerationsspatial resolution The large number of observations (both in space and spectral domain) improve the conditioning of the inversion problem. In nadir sounding the good conditioning can be exploited for attaining 1 km vertical resolution. In limb sounding the good conditioning can be exploited for attaining 50 km horizontal resolution. COST 723 Training School - Cargese 4 - 14 October 2005
General considerationsspacecraft orbit Polar platforms are usually the preferred choice because of global coverage requirements. Meteorological and now-casting applications require frequent observations from geostationary platforms. COST 723 Training School - Cargese 4 - 14 October 2005