Symons Gold Medal Symons Gold Medal Lecture 2019 Lecture 2019 A Century of Remote Measurements of the Atmosphere Clive Rodgers University of Oxford
George James Symons Elected a fellow of the Society in 1856 at age 17 President 1880 and 1900 Council member for 37 years Secretary for 24 years Founder of the British Rainfall Organisation and the Meteorological Magazine
James Glaisher and Henry Coxwell ballooning 5 Sep 1862
Teisserenc de Bort 1908
REMOTE SOUNDING What can you measure without going there? Globally?
1920 - Lindemann & Dobson Symons
x Density at appearance • Density at disappearance Extrapolation assuming 220K Density from sondes
Dobson’s Ozone Spectrometer 1924 - 1926 1938
Paul Götz – The Umkehr Method 1929 Götz found that by observing solar UV scattered from the zenith sky as the sun set, he could determine something about the vertical distribution of ozone.
Hans Dütsch 1957 Developed a method to be used on a digital computer Linearise the model equations, solved for nine layers. Recompute with the full equations, and iterate.
Jean King 1956 Thermal infrared emission “The emergent intensity is simply the Laplace Transform of the Planck intensity considered as a function of optical depth” From: Scientific Uses of Earth Satellites, Ed J. A. Van Allen Univerity of Michigan Press Ann Arbor, Michigan, 1956
Lewis Kaplan 1959 Proposed looking at CO 2 in several spectral locations where there are different absorption coefficients
Dave Wark, 1961 Simulated this idea, retrieved two layer temperatures and lapse rates from three radiances.
Giichi Yamamoto 1961
Nimbus 3 Two sounders - SIRS 1969 IRIS
Nimbus B in test
PI Rudolph Hanel NASA Goddard I nfra- R ed I nterferometer S pectrometer
P.I. David Q Wark NOAA SIRS Satellite Infra-Red Spectrometer 8 channel grating spectrometer SIRS-B prototype, National Air & Space Museum
Harold W. Yates , Space Technology and the Optical Sciences APPLIED OPTICS/ Vol. 21, No. 2 / 15 January 1982
INNOVATIONS Year Innovation Instrument Satellite 1969 Fourier Transform Spectrometer IRIS Nimbus 3 “ Grating Spectrometer SIRS 1970 BUV Nimbus 4 Solar UV Scattering “ Filter Radiometer SCR “ Gas Correlation SCR 1972 Off-Axis Scanning ITPR Nimbus 5 “ Microwave Radiometer NEMS “ First Operational Sounder VTPR NOAA-2 1975 Detector Cooling LRIR Nimbus 6 “ Limb View LRIR 1981 First Geostationary Sounder VAS GOES-4 1984 Solar Occultation SAGE II ERBS 1994 GPS Radio Occultation GPS/MET MicroLab-1 1994 Lidar LITE STS 2002 Stellar Occultation GOMOS Envisat
PI Don Heath NASA Goddard Backscatter Ultraviolet Radiometer Nimbus 4 1970 Nadir viewing grating spectrometer measuring scattered solar UV at 12 wavelengths to obtain the vertical profile of ozone Had over 20 flights: – 1975 Atmosphere Explorer – 1978 SBUV Nimbus 7 – SSBUV Shuttle flights – NOAA/POES series ongoing
SBUV/2 Layer Ozone (Southern Hemisphere) 5 Dec 2019
John Houghton Filter Radiometers Oxford With a new idea - gas correlation Match the spectral response of the 1990 (Church Times) radiometer to the spectrum of CO2 Desmond Smith Reading/Heriot Watt Nimbus 4 Selective Chopper Radiometer Nimbus 4 1970
N6 PMR 1975 modulate gas pressure Weighting functions for three nadir sounding instruments N4 SCR 1970 N5 SCR 1972 Move mirror Move gas cells
From Nimbus 4 SCR
Nimbus 4 SCR Southern Hemisphere warming Sept 5 1970 10-1 mb thickness
PI Bill Smith NOAA Cross-track Scanning Infrared Temperature Profile Radiometer Nimbus 5 1972 FOV 32 km, 14 views cross track 7 spectral channels: 19.7, 14.96, 14.5, 14.0, 13.4, 11.1, 3.7 µm Followed by: VTPR NOAA 2-5 1973-79 Was an operational follow on to ITPR HIRS Nimbus 6 1975 Also a follow on to ITPR: 17 spectral channels Field of view: 0.04 rad, 25 km at nadir, sidescan to 42 fov’s
500 mb Temperature 1200Z 6 March 1973 Intense low, North Pacific NMC analysis –––––– ITPR suggested adjustment - - - -
Followed by: VTPR NOAA 2-5 1973-79 HIRS Nimbus 6 1975 With 23 FOV’s cross track Also a follow on to ITPR: 17 spectral channels was an operational follow on to ITPR Field of view: 0.04 rad, 25 km at nadir, sidescan to 42 fov’s VTPR (NOAA 2-5) Scan Pattern
PI Dave Staelin Nimbus E Microwave Spectrometer MIT NEMS Nimbus 5 1972 Straightforward microwave receiver pointing downwards FOV ~190 km 3 channels in the O 2 band near 5mm for temperature 2 channels for water Clouds are almost transparent in the microwave
Waters et al, J Atmos Sci, 32 p1953
TOVS Scan Pattern HIRS and MSU on NOAA series
PI John Gille NCAR Limb Radiance Inversion Radiometer Nimbus 6 1975 New ideas: Measuring Temperature, • Limb scanning Ozone, Water • Cooled detector
Comparison with radiosonde & rocketsonde
Zonal mean cross section of LIMS V6 data for May 6, 1979. (a) Temperature with contour increment of 5 K, (b) ascending (daytime) ozone with contour increment of 0.5 ppmv.
Subsequent limb sounders On Nimbus 7: LIMS - update of LRIR SAMS - a limb sounding version of SCR/PMR On UARS: CLAES, ISAMS, MLS, HALOE, HRDI, WINDII On Envisat: MIPAS, SCIAMACHY
UARS Upper Atmosphere Research Satellite 12 Sept 1991 CLAES - high spectral resolution limb sounding tuneable etalon HALOE - solar occultation, gas correlation radiometer ISAMS - Improved SAMS MLS - Microwave Limb Sounder WINDII - Limb interferometer measuring Doppler shift of airglow lines for mesosphere and thermosphere winds HRDI - High Resolution Doppler Imager
Mount Pinatubo June 15 1991 We had not planned for this in the design of ISAMS… Even so, our window channel was very useful.
Pat McCormick Solar Occultation NASA Langley Oct 1978 Stratospheric Aerosol Measurement II (SAM II) Nimbus 7 Feb 1979 Stratospheric Aerosol and Gas Experiment (SAGE) on AEM-B
Solar Occultation 1985 Atmospheric Trace Molecule Spectroscopy Experiment (ATMOS) on Spacelab and STS 1992-4 1991 Halogen Occultation Experiment (HALOE) on UARS HF, HCl, CH4, NO, H2O, O3, NO2 and pressure 2003 ACE - Atmospheric Chemistry Experiment Fourier Transform Spectrometer Polar orbiter 2002 SCIAMACHY - Envisat Occultation & Scattering
Rick Anthes NCAR Radio Occultation GPS/MET flown on a tiny satellite MicroLab-1 1995
COSMIC-1 2016 COSMIC-2a 2019 Cluster of six satellites daily geographic coverage provided by COSMIC-2. The locations of radio occultation profiles are shown in green, ground based radiosonde locations are in red.
Stellar Occultation Global Ozone Monitoring by Occultation of Stars (GOMOS) on Envisat 2002 Spatio-temporal observations of the tertiary ozone maximum, Sofieva V, Kyrölä E, Verronen P et al. Atmospheric Chemistry and Physics (2009) 9(13) 4439-4445
Data Analysis
How was all this data analysed? As Dütsch had found with ozone in 1957, the obvious method wasn’t easy It usually turned out to be very ill-conditioned
Classic Paper: Sean Twomey US Weather Bureau On the Numerical Solution of Fredholm Integral Equations of the First Kind by the Inversion of the Linear System Produced by Quadrature Journal of the ACM Volume 10 Issue 1, Jan. 1963 pp 97-101 Jointly minimised: The fit of the solution to the measurements, plus some smoothness criterion, e.g. squared second differences of the profile, or squared departure from some a priori profile Book: Introduction to the mathematics of inversion in remote sensing and indirect measurements Elsevier Science & Technology, 1977
Carl Mateer Empirical orthogonal functions - Lorenz 1956 (Factor Analysis - Spearman 1904, Singular Vector Decomposition) “There are at most four pieces of information about the vertical distribution to be obtained”
square roots 1 0.88 2 0.40 3 0.17 4 0.13 5 0.08 Eigenvalues of a sample of about 100 measurements
George Backus and Freeman Gilbert Scripps Institute of Oceanography Uniqueness in the Inversion of Inaccurate Gross Earth Data Phil Trans 266 p 123-192 March 1970 The Averaging Kernel describes how the retrieval is related to the actual profile
Miscellaneous approaches to finding a solution e.g. Smoothest ‘exact’ linear solution - turns out to be a linear combination of weighting functions Ad Hoc relaxation methods , e.g. Chahine 1968 Direct multiple regression : using a set of computed radiances (or a sample of coincident direct measurements to get coefficients). Rodgers 1966, Smith, Woolf & Jacob 1970 Onion Peeling - for limb sounding, work down from the top. Russell & Drayson 1972 Optimal Estimation : Combining the measured quantities with a properly characterised prior estimate in a statistically optimal way, e.g. using Bayes Theorem Review : Rodgers (1976) Retrieval of Atmospheric Temperature and Composition from Remote Measurements of Thermal Radiation Rev Geophys and Space Phys 14 p609
Rod Jones
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