Z. P. Szewczyk GIST 25, Oct Recent Field Campaigns with CERES Instruments Z. Peter Szewczyk Kory J. Priestley Lou Smith Remote Sensing of Clouds and the Atmosphere XI, Stockholm, 09/11-14, 2006

Z. P. Szewczyk GIST 25, Oct Presentation Outline CERES mode for special observations Planning tools under new restrictive rules Field campaigns of 2006 –FM1/FM3 comparison –FM2/GERB1 comparison –AMMA support –SCALES support –True AT Summary

Z. P. Szewczyk GIST 25, Oct Clouds and the Earth’s Radiant Energy System Instrument CERES Narrow field-of-view (15x30km at nadir) scanning radiometer: Shortwave channel (0.3-5  m), Total channel (  m), Window channel (8-12  m) PFM on board TRMM (1998, failed 06/2000) FM1 & FM2 on board Terra (in service from 03/2000) FM3 & FM4 on board Aqua (from 06/2002, SW of FM4 is out )

Z. P. Szewczyk GIST 25, Oct Terra & Aqua orbits Terra Aqua Sun-synchronous, inclination angle 98.2 o and 81.8 o Equator crossing time: 10:30AM Terra and 1:30PM Aqua about 15 minutes apart at nodes

Z. P. Szewczyk GIST 25, Oct CERES normal operation modes Cross-track (XT) Scan Rotational Azimuth Plane Scan (RAPS) Constant RAZ rate Ram direction restrictions Suspended due to degradation investigation

Z. P. Szewczyk GIST 25, Oct Scan mode for special operations In Programmable Azimuth Plane Scan (PAPS) mode, scanning plane orientation follows a prescribed schedule Step-wise changes of the azimuth angle Time and angle changes depend on satellite position in an orbit New elevation profile due to ram direction restrictions Increases sampling by orders of magnitude

Z. P. Szewczyk GIST 25, Oct CERES special operation tools Objectives of special observations using PAPS: Earth targets Matching viewing geometry of other instruments Sampling within required scan plane orientation Relative azimuth (RAZ) predictions (web-based) –Obtain 7-day satellite ground track file from Goddard –Compute scanner orientation for each scan (every 6.6s) –Generate daily RAZ prediction files for commanding Automated Command uploads –One-day sequences (ODS) formatted for a direct upload

Z. P. Szewczyk GIST 25, Oct Field campaigns of 2006 Summer of 2006: Terra-Aqua (FM1/FM3) comparison in June CERES-GERB (FM2/GERB1) comparison in June African Monsoon Multidisciplinary Analysis (AMMA) in July Ground validation for GERB2 and GERB1 at Valencia Anchor Station (VAS) early August True along-track (AT) scan every other Tuesday starting on 08/22

Z. P. Szewczyk GIST 25, Oct Terra-Aqua comparison CERES radiances belong to two-decade long Earth’s radiation budget dataset Greenland is the most homogenous: FM1 and FM3 15 minutes apart Scans orthogonal to the solar plane Using short nadir scan profile to avoid ram directions Validation campaign: 06/05 – 06/30, orbital crossings of about 90 seconds each Significant amount of data for statistical analysis

Z. P. Szewczyk GIST 25, Oct FM1/FM3 scanning pattern 15:04 (GMT) on 06/05/ :19 (GMT) on 06/05/2006

Z. P. Szewczyk GIST 25, Oct FM1 daily scanning Filtered shortwave radiances on 06/05/ Watts per square meter per steradian

Z. P. Szewczyk GIST 25, Oct FM2/GERB1 comparison GERB radiances part of the ERB dataset Campaign around the summer solstice of 2006 CERES matches GERB viewing geometry (located at 6.5W) FM2 on Terra in the PAPS mode for 25 days 4 daytime orbits per day for about 45 min scanning Ram restrictions result in the Northern Hemisphere data only The use of the short nadir scan profile doubles matched footprints

Z. P. Szewczyk GIST 25, Oct GERB measurements Geo-stationary Earth Radiation Budget instrument On board Meteosat-9 located at 6.5W in June Array of 256 detectors covering the visible portion of the Earth Short and long-wave radiation image every 15min.

Z. P. Szewczyk GIST 25, Oct FM2-GERB1 Pass at 9:44 (GMT) on 06/18/2006 Pass at 11:21 (GMT) on 06/18/2006

Z. P. Szewczyk GIST 25, Oct GERB ground validation To validate GERB radiances with ground data Geo Earth Radiation Budget instrument with 256 detectors Valencia Anchor Station (VAS): o N and 1.17 o W Of GERB pixel size (50x50 km) and quite homogenous Ground instrumentation by University of Valencia CERES measurements on July 31- August 6, 2006: FM2 on Terra – one or two passes per day about 2.5 minutes of data

Z. P. Szewczyk GIST 25, Oct FM2 daily scanning over VAS Pass at 10:09 (GMT) on 08/01/2006 Pass at 11:47 (GMT) on 08/01/2006

Z. P. Szewczyk GIST 25, Oct African Monsoon Multidisciplinary Analysis (AMMA) To understand the impact of monsoons Niamey/Niger site: o N and 2.17 o E Focus on clouds dynamics, air pollution CERES measurements in July (10 th on) of 2006: FM2 on Terra One orbit per day for about 2.5 minutes

Z. P. Szewczyk GIST 25, Oct FM2 over Niamey (AMMA) Command sequence at 10:51 (GMT) on 07/26/2006 Targeting the site

Z. P. Szewczyk GIST 25, Oct True along-track scan To eliminate a spatial mismatch between nadir and oblique observations Original implementation: RAZ fixed, along the satellite velocity vector Earth’s rotation causes a wide swath of footprints New implementation: RAZ changes to account for the Earth’s rotation Significantly reduced spread of footprints

Z. P. Szewczyk GIST 25, Oct Footprints spread swath shown on a 5º by 10º grid RAZ corrections: ±4º about 80km mismatch between nadir and oblique (55º VZA) observations reduced to 3km

Z. P. Szewczyk GIST 25, Oct campaign summary CampaignDurationOrbitsAmount of data Terra/Aqua07/05–07/ min FM2/GERB107/05–07/ min VAS07/31–08/ min AMMA07/10–07/ min True AT08/22, 09/ min

Z. P. Szewczyk GIST 25, Oct Concluding remarks Busy summer of 2006 for CERES Programmable Azimuth mode used for meeting data collection goals Planning tools reside on the website Despite ram restrictions, large amount of data was collected Free service to the science community