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CRISM Targeted Reduced Data Record (TRDR)

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TRDR – Targeted Reduced Data Record

 

Instrument: Compact Reconnaissance Imaging Spectrometer for Mars

PDS Data Set ID: MRO-M-CRISM-3-RDR-TARGETED-V1.0

For more information about CRISM products, go to the CRISM Product Primer.

For more information about TRDRs, see the CRISM Data Product SIS.

 

A Targeted Reduced Data Record (TRDR) is a radiometrically calibrated CRISM spectral image cube derived from raw Experiment Data Record (EDR) products, i.e. from a single observation.  TRDRs have been resampled in the spectral or spatial direction.  If resampling has been performed, that is indicated in the label and file name.

 

TRDRs contain one or more multiple-band images that have been converted from EDRs to units of spectral radiance or I/F.

 

Spectral radiance is defined as:  W / (m2 micrometer steradians).

 

I/F is defined as the spectral radiance divided by the spectral radiance of the Sun at Mars distance at the time of observation.  Another way to put it is that it is the ratio of the radiance observed from a surface to that of a perfect white Lambertian surface illuminated by the same light source but at normal incidence.

 

 I is defined as:  power / area / I / steradians

 F is defined as:  (solar irradiance at Mars) / pi

Where the (solar irradiance at Mars) is the solar spectral irradiance as seen by a normally illuminated surface 1 AU from the sun adjusted for the distance of Mars from the sun for that particular observation.

 

 

 

CRISM Observing Modes Used

Mode

Pointing

Description

Coverage

Targeted (hyperspectral)

Tracking as shown, once per target

Full resolution (FRT)

Spatial pixels unbinned for target – 18 m/pixel @ 300 km, 10x binned for EPF

~6500 per Mars year

Half resolution short (HRS)

Spatial pixels 2x binned for target – 36 m/pixel @ 300 km, 10x binned for EPF; same swath length as above

Half resolution long (HRL)

Spatial pixels 2x binned for target – 36 m/pixel @ 300 km, 10x binned for EPF; twice swath length as above

Full resolution short (FRS)

Spatial pixels unbinned for target – 18 m/pixel @ 300 km; half swath length as above

Along-track oversampled (ATO)

Spatial pixels unbinned for target – 18 m/pixel cross-track, up to ~3 m/pixel downtrack, requires special processing for increased resolution; half swath length as above

Along-track undersampled (ATU)

Spatial pixels unbinned for target – 18 m/pixel cross-track, 36 m/pixel downtrack; half swath length as above

Atmospheric (hyperspectral)

Tracking as shown but only center of target measured

EPFs

Spatial pixels 10x binned (~200 m/pixel @ 300 km)

Lat./lon. grids every ~9° of Ls

Nadir-pointed

Tracking Optical Depth (TODs)

Spatial pixels 10x binned (~200 m/pixel @ 300 km)

Between other scheduled observations

Limb scans

Limb scan measurements (LMBs)

Spatial pixels 10x binned; ~200 m vertical sampling

2 orbits every 2 months

Mapping (selected wavelengths)

Nadir-pointed

Multispectral survey (MSP or MSV)

73/74 or 94/94 selected channels, spatial pixels 10x binned (~200 m/pixel @ 300 km)

~80% of Mars

Multispectral windows (MSW)

73/74 or 94/95 selected channels, spatial pixels 5x binned (~100 m/pixel @ 300 km)

Select areas plus sampling of seasonal variation at polar cap

Hyperspectral survey (HSP or HSV)

262 channels, spatial pixels 10x binned (~200 m/pixel @ 300 km)

Select areas plus sampling of seasonal variation at polar cap

Radiometric Calibration (CAL)

-

Observations of onboard integrating sphere

Daily

Bias Calibration

-

Dark observations at multiple exposure times

Daily

Flat-Field Calibration (FFC)

Nadir-pointed

Observations of bland regions of Mars

Every month

 

 

Contents of each type of CRISM observation

Class of observation

Frame rate, Hz

Activity

Pixel binning

#

Wave-lengths

Frames (typical)

Full resolution targeted (FRT)

3.75

central scan

1

1

545

390

EPF scans

10

10

15

dark sets

1

4

12

Half resolution short targeted (HRS)

3.75

central scan

2

1

545

243

EPF scans

10

10

15

dark sets

2

4

12

Half resolution long targeted (HRL)

3.75

central scan

2

1

545

487

EPF scans

10

10

15

dark sets

2

4

12

Full resolution short (FRS)

3.75

half central scan

1

1

545

195

dark sets

4

12

Along-track oversampled (ATO)

3.75

half central scan

1

1

545

195

dark sets

4

12

Along-track undersampled (ATU)

3.75

half central scan

1

1

545

195

dark sets

4

12

Atmospheric survey (EPF)

3.75

EPF scans

10

11 or 13

545

15

dark sets

4

12

Limb scan (LMB)

3.75

Individual scans

10

variable

545

540

dark sets

same

12

Tracking optical depth (TOD)

3.75

3-second segments

10

12

545

12

dark sets

4

Multispectral survey (MSP or MSV)

15

3-minute segments

10

8

73/74 or 94/95

2700

dark sets

9

12

Hyperspectral survey (HSP or HSV)

15

3-minute segments

10

8

262

2700

dark sets

9

12

Multispectral window (MSW)

30

1 3-minute segment

5

1

73/74 or 94/95

5400

dark sets

2

12

Radiometric calibration (CAL)

1 (VNIR),

1 (IR)

sphere background

1

2

545

12

sphere frames

1

32

1 (VNIR),

3.75 (IR)

sphere background

2

12

sphere frames

1

32

1 (VNIR),

15 (IR)

sphere background

10

2

73

12

sphere frames

1

32

1 (VNIR),

30 (IR)

sphere background

5

2

12

sphere frames

1

32

Bias calibration

1

dark frames, several integration times

1

4

438 (IR only)

10

3.75

5

15

10

4

55 (IR only)

30

5

Flat field calibration (only 1 frame rate at a time) (FFC)

1

dark sets

1

2

545

12

3-minute segments

1

180

3.75

dark sets

2

12

3-minute segments

1

675

15

dark sets

10

2

73

12

3-minute segments

1

2700

30

dark sets

5

2

12

3-minute segments


1

5400

 

CRISM TRDR products have the following file names:

tttnnnnnnnn_mm_aabbbc_TRRv.IMG (with detached PDS label)

where:

ttt = class type

FRT = Full Resolution Targeted Observation

HRL = Half Resolution Long Targeted Observation

HRS = Half Resolution Short Targeted Observation

FRS = Full Resolution Short Observation

ATO = Along-track Oversampled Observation

ATU = Along-track Undersampled Observation

EPF = Atmospheric Survey EPF

TOD = Tracking Optical Depth Observation

LMB = Limb Scan Observation

MSV = Multispectral Survey, lossy compressed

MSP = Multispectral Survey, losslessly compressed

HSP = Hyperspectral Survey, losslessly compressed

HSV = Hyperspectral Survey - VNIR only, losslessly compressed

MSW = Multispectral Window

FFC = Flat Field Calibration

nnnnnnnn = observation ID, unique for the whole CRISM mission, expressed as a hexadecimal number

mm = ordinal counter carried through from the source EDR ID, expressed as a hexadecimal number

aa = type of observation

RA = Radiance

SU = Summary products

IF = I/F

AL = Lambert albedo

bbb = macro #

c = sensor ID

S = VNIR

L = IR

v = version, 0-9, a-z

 

CRISM TRDR housekeeping files have the following file names:

tttnnnnnnnn_mm_aabbbc_HKPv.TAB (all variables match corresponding TRDR product)

 

In ODE, TRDR products, with their associated housekeeping files, have the following product IDs:

TTTNNNNNNNN_MM_AABBC_TRRV