Recent Field Campaigns with CERES Instruments Z Peter

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, 23 -25 Oct. 2006

Presentation Outline • CERES mode for special observations • Planning tools under new restrictive rules • Field campaigns of 2006 – – – FM 1/FM 3 comparison FM 2/GERB 1 comparison AMMA support SCALES support True AT • Summary Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

Clouds and the Earth’s Radiant Energy System Instrument • CERES Narrow field-of-view (15 x 30 km at nadir) scanning radiometer: • Shortwave channel (0. 3 -5 mm), • Total channel (0. 3 -100 mm), • Window channel (8 -12 mm) • PFM on board TRMM (1998, failed 06/2000) • FM 1 & FM 2 on board Terra (in service from 03/2000) • FM 3 & FM 4 on board Aqua (from 06/2002, SW of FM 4 is out ) Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

Terra & Aqua orbits Aqua Terra • Sun-synchronous, inclination angle 98. 2 o and 81. 8 o • Equator crossing time: 10: 30 AM Terra and 1: 30 PM Aqua • about 15 minutes apart at nodes Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

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, 23 -25 Oct. 2006

Scan mode for special operations • In Programmable Azimuth Plane Scan (PAPS) mode, scanning plane orientation follows a prescribed schedule ü Step-wise changes of the azimuth angle ü 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, 23 -25 Oct. 2006

CERES special operation tools • Objectives of special observations using PAPS: ü Earth targets ü Matching viewing geometry of other instruments ü 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. 6 s) – Generate daily RAZ prediction files for commanding • Automated Command uploads – One-day sequences (ODS) formatted for a direct upload Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

Field campaigns of 2006 Summer of 2006: • Terra-Aqua (FM 1/FM 3) comparison in June • CERES-GERB (FM 2/GERB 1) comparison in June • African Monsoon Multidisciplinary Analysis (AMMA) in July • Ground validation for GERB 2 and GERB 1 at Valencia Anchor Station (VAS) early August • True along-track (AT) scan every other Tuesday starting on 08/22 Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

Terra-Aqua comparison CERES radiances belong to two-decade long Earth’s radiation budget dataset • Greenland is the most homogenous: • FM 1 and FM 3 15 minutes apart • Scans orthogonal to the solar plane • Using short nadir scan profile to avoid ram directions • Validation campaign: • 06/05 – 06/30, 2006 • 600 orbital crossings of about 90 seconds each • Significant amount of data for statistical analysis Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

FM 1/FM 3 scanning pattern 15: 04 (GMT) on 06/05/2006 15: 19 (GMT) on 06/05/2006 Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

FM 1 daily scanning Filtered shortwave radiances on 06/05/2006 0 100 Watts per square meter per steradian Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006 217

FM 2/GERB 1 comparison GERB radiances part of the ERB dataset • Campaign around the summer solstice of 2006 ü CERES matches GERB viewing geometry (located at 6. 5 W) ü FM 2 on Terra in the PAPS mode for 25 days ü 4 daytime orbits per day for about 45 min scanning ü Ram restrictions result in the Northern Hemisphere data only ü The use of the short nadir scan profile doubles matched footprints Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

GERB measurements • Geo-stationary Earth Radiation Budget instrument ü On board Meteosat-9 located at 6. 5 W in June ü Array of 256 detectors covering the visible portion of the Earth ü Short and long-wave radiation image every 15 min. Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

FM 2 -GERB 1 Pass at 9: 44 (GMT) on 06/18/2006 Pass at 11: 21 (GMT) on 06/18/2006 Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

GERB ground validation To validate GERB radiances with ground data • Geo Earth Radiation Budget instrument with 256 detectors • Valencia Anchor Station (VAS): 39. 34 o. N and 1. 17 o. W • • • Of GERB pixel size (50 x 50 km) and quite homogenous Ground instrumentation by University of Valencia CERES measurements on July 31 - August 6, 2006: • FM 2 on Terra – one or two passes per day • about 2. 5 minutes of data Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

FM 2 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, 23 -25 Oct. 2006

African Monsoon Multidisciplinary Analysis (AMMA) To understand the impact of monsoons • Niamey/Niger site: 13. 47 o. N and 2. 17 o. E • • Focus on clouds dynamics, air pollution CERES measurements in July (10 th on) of 2006: • FM 2 on Terra • One orbit per day for about 2. 5 minutes Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

FM 2 over Niamey (AMMA) Command sequence at 10: 51 (GMT) on 07/26/2006 Targeting the site Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

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, 23 -25 Oct. 2006

Footprints spread swath shown on a 5º by 10º grid • RAZ corrections: ± 4º • about 80 km mismatch between nadir and oblique (55º VZA) observations reduced to 3 km Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

2006 campaign summary Campaign Duration Orbits Amount of data Terra/Aqua 07/05– 07/30 350 900 min FM 2/GERB 1 07/05– 07/30 100 1100 min VAS 07/31– 08/06 11 30 min AMMA 07/10– 07/28 15 40 min True AT 08/22, 09/05 28 700 min Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006

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 http: //asd-www. larc. nasa. gov/PAPS/cgi-bin/rygar. cgi Z. P. Szewczyk GIST 25, 23 -25 Oct. 2006