Microwave Sensors Subgroup (MSSG) Report
DONG, Xiaolong, MSSG Chair
National Space Science Center, Chinese Academy of Sciences & National Remote Sensing Center of China (NSSC/CAS, NRSCC) Email: [email protected]
CEOS WGCV-38 co-hosted by NOAA, USGS & NASA Sept 30-Oct 2, College Park, MD, USA
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
OUTLINE
Missions and objectives Recent requirements and challenges Focuses and progresses Future work and recommendations
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Missions & Objectives of MSSG Missions:
The mission of the Microwave Sensors subgroup is to foster high quality calibration and validation of microwave sensors for remote sensing purposes. These include both active and passive types, airborne and spaceborne sensors.
Objectives Facilitate international cooperation and co-ordination in microwave sensor
calibration / validation activities by sharing information on sensor development and field campaigns.
Promote accurate calibration and validation of microwave sensors, through standardisation of terminology and measurement practices.
Provide a forum for discussion of current issues and for exchange of technical information on evolving technologies related to microwave sensor calibration / validation.
Provide calibration/validation support to CEOS virtual constellations and data application groups/communities by coordination of reference sites for both passive and active microwave sensors, and standardization of quality assurance of microwave remote sensing data.
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
MSSG covers passive and active…
All EO sensors operated in microwave spectrum, except SAR
Works currently focuses on: Microwave Radiometers (sounders, imagers) Radar Scatterometers Radar Altimeters
Other related aspects: GNSS and GNSS-Reflected signal applications Spaceborne weather radars: Cloud and Precipitation Radars (e.g
PR, CPR) Ice sounders and GPR
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Characteristics of Microwave Sensors
Relatively low spatial resolution (km, tens of km, hundreds of km) for atmospheric, oceanic, large-scale terrestrial environmental applications
Data dependent on sensor and processing (model, retrieval, algorithm, cal/val)
Importance of processing and quality control
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Recent Requirements and Challenges
Climate and global change applications Higher requirements, especially for climate and global change
applications: sensitivity, accuracy, stability, traceability; Cross-calibration requirements of sensors flown on different
spacecrafts and developed by different agencies;
No traceable standards available for microwave sensors; New developed sensors
Polarized radiometers and scatterometers Interferometric synthetic aperture radiometers Scatterometers for terrestrial applications Wide swath and SAR altimeters…
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Many new techniques need to be developed for cal/val…
High precision requirements: Brightness temperature: 0.1K Sea level: 1mm Backscattering coefficient: 0.1dB
Cross-calibration/validation requirements: Traceable reference for processing or historical data Small shift of sensor parameters (frequency,
bandwidth, on-board calibrators,…) Calibration models/algorithms for different sensors by
different agencies
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Priorities and focuses
Level 1 data Brightness temperature for MW radiometer Backscattering coefficient for radar scatterometer
Models and algorithms Radiometric standard for MW Noise source calibrator RAM calibrator Measurement and characterization
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Current status and difficulty of the group
No focused tasks and fixed active group members
Activities constrained by non-technical factors Data access and exchange
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Updates from WGCV-38
Attend GSICS Microwave Subgroup tele-meeting (March 28)
Attend International Ocean Surface Wind Vector (IOSWV) Science Team meeting (June 2-4)
Organized invited sessions in IGARSS 2014, discussion with OSVW VC people (July 18)
Progresses on calibration of altimeter Progresses on evaluation of wet tropspheric
path delay Progresses on scatterometer
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Cross-calibration of altimetry requirements and progresses
Climate and global change research requires long-term data with continuance;
Sea level products related to orbit and algorithms (corrections) and requires x-cal and val
HY-2A altimeter with Jason-1/2 (NSOAS, CNES, ESA), cross comparison/calibration by NSOAS/SOA, CNES and ESA with very good encouraging results.
Based on bilateral cooperation, no OST involvement.
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Sea level Cross-comparison: HY-2A with Janson-2
Statistics of coincidence locations
Absolute RMS deviation with average offset correction:
8.3cm, with correlation coefficient of 0.978.
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Coincidence point distribution of HY-2A and Jason-1/2
HY-2A vs Jason-1
HY-2A vs Jason-2 RMS deviation: HY-2A vs Jason-1: 0.84m/s HY-2A vs Jason-2: 0.78m/s
Wind speed Cross-comparison with Janson-1/2
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
HY-2A vs Janson-1 HY-2A vs Jason-2
RMS deviations: vs Jason-1: 0.19m; vs Jason-2: 0.16m
Significant wave height Cross-comparison with Janson-1/2
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Altimetry calibration with GNSS buoy
NSSC & NSOAS (China), TUC (Greece) & CNES Provide absolute reference for altimetry Model development ongoing
0 5 10 15 20 2511.8
12
12.2
12.4
12.6
12.8
13
13.2
13.4
13.6
13.8
测量点序号
海面
高(
m)
海面高测量点
五阶多项式拟合
6 6.2 6.4 6.6 6.8 714.5
14.51
14.52
14.53
14.54
14.55
14.56
14.57
14.58
14.59
14.6
北京时间(h)
海面
高(
m)
奇异谱估计海面高
线性拟合海面高
过顶时刻
HY-2 SSH GNSS SSH Bias
7月31日 14.639 m 14.543 m 0.096 m
8月3日 13.232 m 13.064 m 0.073 m
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Cross-calibration/comparison for wet tropspheric path delay
HY-2A ACMR and Jason-2 AMR ACMR: tri-frequency (18.7, 23.8, 37GHz) AMR: dual-frequency (18.7, 23.8, 34GHz)
Cross comparisons Brightness temperature Path delay (ACMR vs AMR, ACMR vs ECMWF)
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Brightness temperature
f=18.7GHz Std=1.17K,r=0.98 f=23.8GHz Std=1.74K,r=0.93 f=34GHz/37GHz Std=1.56K,r=0.95
Jason-2 AMR 亮度温度(K)
HY-2
A AC
MR
亮度
温度
(K
)
18.7 GHz 亮度温度比对
y = 0. 945 x + 12. 236
130 135 140 145 150 155
130
135
140
145
150
155
5
10
15
20
25
30
35
40
45
Jason-2 AMR 亮度温度(K)
HY-2
A AC
MR
亮度
温度
(K)
23.8 GHz 亮度温度比对
y = 0. 939 x + 14. 818
140 150 160 170 180 190 200
140
150
160
170
180
190
200
10
20
30
40
50
60
Jason-2 AMR 亮度温度(K)
HY-2
A AC
MR
亮度
温度
(K
)
37 GHz 亮度温度比对
y = 0. 944 x + 17. 897
150 155 160 165 170155
160
165
170
175
180
5
10
15
20
25
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Path delay: ACMR vs AMR & ACMR vs ECMWF
Jason-2 AMR 湿路径延迟(m )
HY-
2A A
CM
R
湿路
径延
迟
(m)
湿路径延迟比对
r mse = 1. 437 cmmean = - 1. 266 cmst d = 0. 679 cm
y = 1. 053 x - 0. 004
-0.3 -0.25 -0.2 -0.15 -0.1 -0.05
-0.35
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
10
20
30
40
50
60
70
80
HY-2A ACMR 湿路径延迟(m )E
CM
WF
湿路
径延
迟
(m)
r mse = 1. 455 cmmean = 0. 023 cmst d = 1. 455 cm
y = 1. 014 x + 0. 002
Val i d dat a :256802( 96. 479%)21- Jan- 2013
-0.5 -0.45 -0.4 -0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05
-0.4
-0.35
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
500
1000
1500
2000
2500
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Future works-MW radiometry
MW radiometry Formulate tasks on specific variables: water vapor by
nadir-looking radiometer (ACMR, AMR, MWR) (ESA, NSSC/NSOAS, NOAA)
Validation of MW radiometer data with GNSS-Occultation Coordination with GSICS Microwave Subgroup
(cooperation to avoid duplicate work) Coordination with VCs (P-VC and SST-VC) for demand of
cal/val support Information change on MW radiometric references (noise
source and RAM) and standard radiometers (NSSC & BIRMM/China, NIST/US, FSUE «VNIIFTRI»/Russia, NPL/UK)
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Future works-radar altimetry
Radar altimetry Exchange cross-comparison Development of absolute validation (GNSS-buoy) Development of modeling for validation (satellite with
in-situ data) Exchange of calibration site data Coordination with OST VC
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Future works-scatterometer
Radar scatterometer Exchange of cross-comparison by global ocean
calibration data Continue to coordinate sigma 0 data cross-
comparison for reference sites (Amazon, Antarctic, ocean)
Standards of quality control (participation) Further support to OSVW-VC
CEOS WGCV-38 Sept 30-Oct 2,2014, College Park, MD, USA
Recommendations and proposals
Agency support with L1 data for specific cross-calibration/comparison purpose, and improve calibration and validation.
Encourage close collaboration between instrument teams and science/user community.
Thanks !