20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ GMES-GATO: Atmospheric correction using atmospheric composition satellite data J.J. Remedios EOS-SRC, Dept. of Physics and Astronomy, University of Leicester, U.K.

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Structure Influence of the atmosphere on surface observations –Atmospheric correction –Issues requiring surface and atmosphere information Requirements for atmospheric correction What are the technical issues? Current developments? Rational system needs (existing data/systems) What is missing (future systems)? GMES objectives

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Atmospheric influence on Systems Observing the Earth’ s Surface I 1.Satellite observations of the surface must intrinsically account for the atmosphere (atmospheric correction) Atmospheric effects are present at almost all wavelengths Example of 1. is correction of phytoplankton (ocean colour) data for ozone contribution. 2.Atmospheric composition may also affect surface properties and also the reverse –Direct e.g., chemical action, deposition, emitted flux of gases. –Indirect, e.g., control of surface temperature or photosynthetic radiation. User requirements include combined surface and atmosphere datasets, e.g., forestation and carbon dioxide, vegetation and water vapour, U/V radiation. Example of 2. is dependence of phytoplankton concentrations on U/V radiation (and hence ozone) Concentrate on 1 here: atmospheric correction

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ SOURCES OF RADIATION AT THE TOP OF THE ATMOSPHERE; RADIATION BALANCE

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ ATMOSPHERIC GASES AND THE SOLAR SPECTRUM

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Infra-red emission spectrum to space [Nadir signal for an i/r instrument 10  m 4  m20  m 5  m Wavenumber = 1/  but in cm -1. Ref. pt. 10  m = 1000 cm  m window 8  m window CO 2 O3O3 N 2 O, CH 4 H2OH2O

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ I/R EMISSION SPECTRA Sahara Mediterranean Antarctic

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Atmosphere influence on surface systems II Policy issues in this area arise from two sources: Requirements for atmospheric correction to surface data Requirements for atmosphere data relevant to interpretation of surface measurements. [cross-cutting BICEPS level] Concentrate on 1 here. User requirements for surface data can be grouped into three areas, for which a number of key issues can be identified. Environmental hazards [GMES] Environmental monitoring [GMES] Commercial remote sensing

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Volcanic Activity

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ MODIS/AQUA – FIRES/AEROSOL MAY RUSSIA FIRES 2003 MOPITT CO. MAY

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ VEGETATION ATSR-2 IMAGE: VEGETATION DIFFERENCES AT THE BORDERS OF ISRAEL ATSR-2 IMAGE: DERIVED VEGETATION COVER (06/09/95)

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Atmospheric correction? 1.Most common atmospheric factors are a)Clouds (troposphere – optically thick, thin, broken) b)Tropospheric Aerosols (lower 2-3 km) c)Tropospheric water vapour (lower 2-3 km) d)Tropospheric CO 2, CH 4 (near-surface) e)Molecular density (ground to approximately tropopause) f)Stratospheric ozone (above 15/20 km) g)Stratospheric aerosols (volcanic eruption) h)O 4 complex 2.Would also include ionosphere for radio/microwave

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ x1 Block: Dual SST Matchups 30 June 2003 Overpass ± 60 min Key - matchups:  - within ± 0.3 K X- > ± 0.3 K  - AATSR cloud Increasing time PUERTO RICO Colour indicates dual-view SST

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ ATSR2 SST (dual-nadir) vs TOMS Aerosol DUAL-NADIR ATSR-2 SST TOMS AEROSOL

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ ATSR SST-AEROSOL: 07/1999 ATSR-2 VS AVHRR TOMS AEROSOL INDEX

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Dust Storm over Red Sea (MODIS) August 14 th ov/

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Box14 Red Sea Mean SST difference versus Time TOMS Aerosol Index versus Time Correlation=0.79

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Scatter Plot of Mean SST Difference versus Aerosol Index Over the Red Sea Pixel by Pixel Correlation=0.544

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Schroedter, M., 1997 Diplomarbeit and M. Schrodter, F. Olesen, H. Fischer, 2003 IJRS TOVS versus ECMWF profiles Difference between LST: TOVS - ECMWF Atmospheric correction AVHRR afternoon Bias TOVS vs. ECMWF 0.23 K Stdv. TOVS – ECMWF 0.27 K Black: clouds, water, snow AVHRR afternoon Bias TOVS vs. ECMWF 0.82 K Stdv. TOVS – ECMWF 0.82 K

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Table of Requirements Parameterλ regionTypical λTypical spatial resn. Atmospheric correction requirements Sea/land surface temperature Infra-red11 μm, 12 μm 3.7 μm (night) 1 x 1 km 2 Aerosol, water vapour (T) Surface reflectance/imager y visible470 nm -2.2 μm (discrete channels or low spectral resn.) 30 x 30 m 2 to 5 x 5 m 2 Aerosol, water vapour, ozone, O 4 Vegetation indices (derived from reflectance) visible600 nm – 1 μm1 x 1 km 2 Aerosol, water vapour, ozone Ocean colourvisible nm1 x 1 km 2 Aerosol, water vapour, ozone, O 4 Sea/land surface height (SH) [single channel] microwav e , 5.3, 3.2 GHz <2 x 2 km 2 Water vapour 0 cm (poles)- 40 cm (tropics) Ocean salinitymicrowav e 1.4 GHz35-50 x km 2 Water vapour

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Current and future developments Current:  Hyperspectral  Multi-angle  Dedicated channels for atmospheric correction Future:  Future instruments: potential for joint surface/atmosphere measurements (e.g., aerosols from imagers, H 2 O from SAR)  Role of assimilation models, e.g., ECMWF, KNMI Ozone

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ What are the technical issues? 1.The latest sensors often incorporate a spectral channel for determining atmospheric correction factors. a)Are all the relevant atmospheric factors measured b)Is vertical resolution required? c)Is the information measured at the correct wavelengths – particularly aerosols? 2.Surface products and imagers often require a high spatial resolution ( < 5 x 5 km 2 ) with specific temporal resolution. What is the ability of atmospheric GMES systems to deliver this information? Spectral vs Spatial resolution 3.Will atmospheric instruments measure the “correct” (relevant) types of aerosol? 4.What is the accuracy of assimilation and the potential for improved spatial scales?

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Rational System Needs (European) 1.Communication between surface sensing and atmospheric sensing communities (network) 2.Research into the exploitation of independent atmospheric sensing information within surface sensors. 3.Establish accuracies of ECMWF/ other assimilation systems for ozone/water vapour 4.Research into radiative transfer systems and models of the atmosphere 5.Inter-instrument research on aerosol across the e/m spectrum. 6.Operational data processing for multi-system data, e.g. ENVISAT/Metop 7.Continuity in the observation of key atmospheric variables and intercalibrated datasets relevant to surface products

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ What is missing (in European systems)? 1.Research into the derivation of atmospheric correction information at high spatial scales. 2.Development of synergistic mission system concepts – formation flying 3.Development of assimilation systems providing atmospheric information to surface sensing communities 4.High spatial resolution aerosol mission to establish aerosol climatology/radiative properties [air quality] 5.[“Quick reaction” system for volcanic eruption into stratosphere]

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Overall surface-atmosphere system An integration of surface and atmosphere systems: Observation systems  Use of atmospheric sensors in other GMES (sub-) system.  Exploitation of atmospheric information derived from other GMES systems (two-way)  High spatial resolution aerosol mission  Continuity of measurements for water vapour, ozone. Accessible and linked databases /processing centres [*] NRT capabilities including data assimilation [*]

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Volcanic Activity (c) Dr. A. Richter, IFE/IUP Bremen Andreas Richter and John Burrows – IUP Bremen

20/1/2004Dr. J.J. Remedios, Leicester. ACAW, 21/1/ Mt Etna