Toward Operational Calibration and Validation

for HY-1 SeriesDr. Junwu Tang,

National Satellite Ocean Application Service (NSOAS)WGCV28, 2008.2.26~29,Sanya,China

Contents• Background & Requirements

– Without onboard solar calibrator– To Derive continuous Cal/Val results

• Methodology– Vicarious Cal over ocean– Vicarious Cal over land– System Cal over ocean– Cross- or Inter-Calibration by other sensors– Natural Targets [Rayleigh, Dissert, Cloud]

• Data Set– In-Situ measured & Synchronous data– Other satellite data– Shared & open data from network

• Software System• HY-1B Cal/Val

HY-1 Cal/Val Background & Requirements

There is no onboard solar calibrator on: HY-1B(2007.4) HY-1C/D(2010 or 2011)

HY-1E/F(2013) is going to has full aperture solar calibrator.

Vicarious calibration based on earth targets becomes the one of the most important processes for China ocean satellites.

Traditional vicarious calibrationsIn-situ experiment: hard work and low efficient 2~3 times at most per yearNot operational.manual procedures of calculations

From HY-1B, We proposed an operational Cal/Val scheme for ocean color sensors.

Methodology Combine following methods together:

– Vicarious Cal over ocean– Vicarious Cal over land– System Cal over ocean– Cross- or Inter-Calibration with other sensors– Natural Targets

• Rayleigh scattering: over open sea• Dissert: Dunhuang or other sites• Sun-glint• Cloud

– To achieve 5% uncertainty goal without onboard solar and moon calibration.

Data Set In-Situ measured & Synchronous data

Cruise optical measurementBuoy data [under construction]Oil platform data [Just approved, 2008~2010]Ferry Boat data [under investigating]

Other satellite data for cross-Cal/ValOcean Color : SeaWiFS, MODIS, MerisSST: AATSR, AVHRR, MODIS

Shared & open data from network– GTS, TAO-Buoy, NDBC– NCEP, EMWCF– EP-TOMS Ozone

成果提交

多源数据导入显示

HY－1B卫星影像

其它卫星影像

处理后的多源现场仪器测量数据

辅助与共享数据

遥感器参数文件

现场采集外网下载

子库管理数据外部获取

定标与检验数据管理子系统

其它地面应用分系统

定标与检验子系统

相对定标 真实性检验

满足定标与检验的数据

海洋卫星影像、其它卫星影像、现场与辅助数据

相对定标结果

真实性检验结果

最终成果中间结果

入库

数据流

控制流

现场数据管理子系统

运控分系统产品存档与分发分系统

遥感器性能跟踪子系统

入库

下载

辐射校正

遥感器性能跟踪自动运行

中间处理

结果影

像

辐射校正结果

规范化的现场数据

定标检验数据源制作

遥感器性能参数

遥感器性能分析

原始的多源现场仪器测量数据

仪器处理

卫星影像处理子系统

定标检验中

间参数

数据

下载

入库

下载入库

入库

各种作业成果

系统的数据出入口

内嵌

影像数据处理

遥感器性能分析结果

数据录入

原始的现场数据

综合数据库

下载

子库管理

定标与检验数据子库

现场数据子库

入库

卫星影像处理子系统

高速数字传输网络

应用支撑平台

遥感技术平台

综合数据库

业务层

支撑层

数据层

设备层

用户层

辐射校正 真实性检验 遥感器性能跟踪子系统

定标与检验子系统

业务平台

现场数据管理子系统

真实性检验作业员

性能跟踪作业员

统一

标准

与作业规范

定标与检验数据管理子系统

业务模型

分系统主管

现场数据管理作业员

相对定标

现场数据子库定标与检验数据子库

辐射校正作业员

TeamLeader

In-Situ Data Processing

Calibrator Validator Performance Tracking

Goals of Integrated Cal/Val Software System• To choose “Good-data” manually

– Clear sky over pre-defined calibration sites• Initiate Cal/Val job;• Well-trained operators do following works

– Destrip DN image[relative Cal] & evaluate the results;– Check in-situ data,– Check other satellite data and initiate downloading tas

k– Downloading NCEP and Ozone data– To start Cal/Val processing– To fill in Cal/Val job log everyday.

• To obtain a group of Cal/Val coefficients every month.

HY-1B Calibration & Validation

• HY-1B Calibrations:– Vicarious Cal with ocean synchronous data– Vicarious Cal with land synchronous data– Cross-cal with Aqua-MODIS & SeaWiFS

109 109.5 110 110.5 111 111.5 112 112.5 113 113.5 114 114.5 11517

17.5

18

18.5

19

19.5

20

20.5

21

21.5

22

22.5

23

23.5

24

Southern China Sea Cruise

Sanya

HongkongApril 20~

May 16

2008

南海主试验区归一化离水辐亮度2007.4.24~5.14

0

0. 5

1

1. 5

2

2. 5

400 500 600 700 800(nm)波长

Lwn(

uW/c

m2 nm

sr)

Normalized water-leaving radiance

南海主试验区表层荧光叶绿素浓度2007.04.24～05.14

0.00

0.020.04

0.06

0.080.10

0.12

0.14

0.160.18

0.20

0 20 40 60 80 100 120 140

站位

Chl-a(mg/m3)

Surface Chl-a concentration

Station No.

Test HY-1B Vicarious Calibration methods with Aqua/MODIS data

MODISBands JD163

2008JD1642008 Average

Diff. with MODIS L1B Relative Error

of two Cals.

Ch8 0.953193

0.954787

0.953990 4.6% 0.17％

Ch9 0.958683

0.957510

0.958096 4.2% 0.12％

Ch10 0.955721

0.949798

0.952759 4.7% 0.62％

Ch11 0.962394

0.952856

0.957625 4.2% 1.00％

Ch12 0.964561

0.947657

0.956109 4.4% 1.77％

Ch13 1.088690

1.044089

1.066389 6.6% 4.18％

Ch15 0.975630

0.944168

0.959899 4.0% 3.28％

ch16 0.985969

0.939564

0.962766 3.7% 4.82％

Thanks !