GOSAT mission schedule 29 21 12 1 2 3 4 6 7 8 9 1 11 12 1 2 214 1 2 3 ~ Jan. 23 Launch Initial Checkout Initial function check Initial Cal. and Val. Mission life Normal observation operation Extra Operati ~ on Critical phase Nov. 21 Mar. 212 Dec. 212 Level 1 (Observation spectra) to public Level 2 (SWIR CO 2 and CH 4 of column averaged dry air mole fraction global distribution) to public Level 3 (SWIR CO 2 and CH 4 column averaged dry air mole fraction global distribution in monthly mean) to public Level 2 (TIR CO 2 and CH 4 density profile global distribution) to public Level 4A (CO 2 flux estimation) and Level 4B (Simulated CO 2 distribution) to public. 1
Status of GOSAT calibration (1) TIR radiometric calibration (The latest L1B v16) Blackbody (BB) and Deep Space (DS) views for onboard calibration (2- time in dayside, 4-time in nightside) Polarization correction (mirrors, beamsplitter, dichroic filters) BB emissivity (EM evaluated by heated halo method at UW-Madison) Sensor background temperature estimation (2) SWIR radiometric calibration (Sensitivity degradation factor) Onboard solar diffuser monitoring per month Vicarious calibration field campaign (with NASA/OCO-2, Ames), Lunar calibration, Sahara desert monitoring (3) Geometric correction (Estimated geolocation data) Pointing offset evaluated by onboard IFOV camera Estimated geolocation after correction 2
Status of GOSAT intercalibration The GOSAT TIR spectra are compared with Aqua/AIRS and Metop- A/IASI at Simultaneous Nadir Observations (SNOs). - This work is collaborated with SSEC, Univ. Wisconsin-Madison. The coincidences are located at mid-latitudes for AIRS and highlatitudes for IASI. SNOs with IR spectrometers are useful for evaluating the spectral radiometric accuracy in the same geometry, surface, and atmospheric conditions. We have just compared with GOSAT V1 (and former version). Next, with latest version V16 released in May 213. GOSAT - AIRS SNOs Latitude (deg) 1 8 6 4 2 2 GOSAT AIRS SNOs: 2946T18178 291231T23271 GOSAT - IASI SNOs Latitude (deg) 1 8 6 4 2 2 snotimes_gosat_metop_a_2111_211231 4 6 8 1 2 1 1 1 1 2 Longitude (deg) 4 6 8 1 2 1 1 1 1 2 Longitude (deg) 3
GOSAT V1 - AIRS SNOs v1.1 Apr.,212 Bug in estimation of DC offset trend (impact on v1.11 Jun.,212 BT~3K) v1.11(se) Nov. 8, 212 Bug fixed version v16.16 May, 213 The latest version A time dependent bias error was identified in the GOSAT TIR L1B data using a trend analysis performed with the GOSAT-AIRS SNOs matchup dataset which apparently started about October 211. The source of this error was found and corrected by JAXA leading to a software update (v111se) announced Nov. 8, 212. But, GOSAT has long-term stability from 29 to 211. 4
GOSAT V1 - IASI SNOs Scatterplot of GOSAT-IASI Brightness Temperatures at selected wavenumbers from the SNOs matchup in April December 29 for scenes variability < 1 K. GOSAT IASI B.T. (K) 1 wn 67.7 cm 1 1 wn 7.2179 cm 1 NH (18) SH (148) 1 2 22 24 26 28 1 2 22 24 26 28 1 wn 77.2327 cm 1 1 wn 9.398 cm 1 GOSAT IASI (K) 1 2 22 24 26 28 IASI B.T. (K) 1 2 22 24 26 28 IASI B.T. (K)
GOSAT summary GOSAT is normally operated over 4 years and acquires fine absorption spectra in SWIR to TIR regions with cloud/aerosol imager. Radiometric calibration on orbit in 4 years TIR inter-comparison by Simultaneous Nadir Observations (SNOs) with AIRS and IASI SWIR vicarious calibration field campaign with in-situ measurements and aircraft over-flight collaborated with NASA OCO-2 and Ames Continuous operations of lunar calibration and solar diffuser Future plan Long-term inter-comparison the latest v16 with IASI and AIRS Simultaneous Off-Nadir Observations (SONOs) for scan angle dependency evaluation 6
BACKUP 7
Vicarious calibration at Railroad Valley Railroad Valley field - Nevada/USA Base-camp: 38.4973 N; 11.6913 W Height : about 143m path37 path36 1 km ALOS/AVNIR-2 (R/G/B=3/2/1) JAXA 8
Railroad Valley experiments deployment Path 37 from West 33.deg 2deg 19deg 19.9deg High altitude Path 36 from East TOA Spectral radiance Vertical CO 2 CH 4 Horizontal CO 2 CH 4 Surface Thermal radiation Aerosol Optical Thickens Surface CO 2 CH 4 BRDF Surface Spectral Reflectance Variability Surface and Profile of Pressure, Temperature, Humidity 9