Reprocess a global composite to apply atmospheric correction
Reprocess existing global composites to apply atmospheric correction to AVHRR bands 1 and 2 considering water vapor effects.
- IN
- Input image. IN must specify two LAS image bands which may be of any data type. Band one must contain AVHRR channel 1 data and band two must contain AVHRR channel 2 data. The image cannot be subwindowed. The values contained within IN must represent calibrated AVHRR data, such as that produced by AVHRRCAL. NOTE: If the two specified bands are not within the same image, REATMO will copy them into a temporary two-band image (thus requiring additional processing disk space).
- SCALE
- Scale method. Scaling method used to store IN, ANGLES, and OUT. The data type indicated in the image's DDR will be used to determine the scaling factor and offset value to use when scaling/unscaling the data.
= GLOBAL: Global scaling = US: US scaling
- RADOPT
- Radiance flag. Flag to indicate if IN contains radiance or reflectance values.
= RADIANCE: Input radiance = REFLECT: Input reflectance
- DATEBAND
- Date band. Image containing the date band from the compositing process. This image must be the same size and in the same projection space as IN.
- DATELOG
- Date log. The log file associated with the DATEBAND image which specifies the scenes used to generate the composite.
- PERIODS
- Period name(s). The period names that were included in the composite. For example, '1995p31' for a global composite (period 31 for 1995), '008014' for a US composite (julian days 008 through 014).
- ANGLES
- Angles image. The image containing the necessary view angles. Three bands are expected, the first band being satellite zenith angles, the second band being solar zenith angles, and the third band being relative azimuth angles. This image may be generated using ANGINTERP. This image must be the same size and projection as IN. Subwindowing is not allowed. NOTE: If the three specified bands are not within the same image, REATMO will copy them into a temporary three-band image (thus requiring additional processing disk space).
- SOLZEN
- Solar zenith band. The solar zenith angles which coincide with the composite specified in IN. This band must be the same band that is specified as the second band in ANGLES.
- ELEV
- Elevation image. A single band image containing elevation in kilometers. The image must be in geographic projection with units of degrees.
- WATERBASEDIR("/SGS4/KM1/ADAPS/IMAGES/")
- Water directory. The base directory in which the water vapor climatology images are stored.
- SILOBASEDIR("/DMF/EDC/AVHRR/")
- Water silo directory. The base directory on the silo in which the water vapor acquisition images are stored.
- OZONEBASEDIR("/SGS4/DSB1/DDPS/GLOBAL/OZONE/")
- Ozone directory. The base directory in which the ozone images are stored.
- WORKDIR
- Working directory. The directory wherein processing will occur.
- NDVI
- Output NDVI image. The image containing the resulting normalized difference image computed from the atmospherically corrected AVHRR channels 1 and 2.
- OUT
- Output image containing the atmospherically corrected AVHRR channels 1 and 2. The output image is the same size, data type, and in the same projection as the input image specified by IN. Output values are expressed as a percentage of surface reflectance with atmospheric correction applied.
- WATER
- Water vapor image. The water vapor output image consisting of one band for each day used in the composite followed by the QC bands corresponding to the water bands. This image will be in geographic space.
- QC
- Quality control. The Quality control output image. This image is in the same size and projection as IN. This image will contain the following quality control values:
0: Water vapor value taken from a daily acquisition, normal solar zenith angle 1: Water vapor value taken from a daily climatology, normal solar zenith angle 2: Water vapor value taken from a monthly climatology, normal solar zenith angle 3: Water vapor value created using nearest- neighbor fill, normal solar zenith angle
100: Water vapor value taken from a daily acquisition, extreme solar zenith angle 101: Water vapor value taken from a daily climatology, extreme solar zenith angle 102: Water vapor value taken from a monthly climatology, extreme solar zenith angle 103: Water vapor value created using nearest- neighbor fill, extreme solar zenith angle 255: Undefined pixel value
- INWATER(--)
- Input water vapor image. If specified, this image will be used instead of loading water vapor images from the water base directories. The image is expected to be in the same format as the image created by REATMO as the WATER image. The format is N water vapor bands followed by N QC bands where N is the number of days in the composite. The band sequence is:
Band 1: water vapor image for datelist(1) Band 2: water vapor image for datelist(2) ... Band N: water vapor image for datelist(N) Band N+1: QC image for datelist(1) Band N+2: QC image for datelist(2) ... Band 2*N: QC image for datelist(N)Datelist is a list of dates returned from REATMOINFO.
- SAVECOMPH2O(--)
- Composite water vapor image. If specified the composite water vapor image will be saved.
The composite 'compimg' is to be processed using global scaling. The atmosperically corrected image will be expressed as radiance values. The date band image to be used is 'dateimg', the coinciding date log file is 'datefile;txt'. All images in period '1995p31' referenced in 'datefile;txt' are presumed to have been used in the composite. All intermediate files will be written to the working directory '[ddps.reatmo]'. The atmospherically corrected AVHRR bands 1 and 2 will be written to 'newcomp'. The coinciding quality control bands will be written to 'newqc'. The new ndvi band generated from 'newcomp' will be written to 'newndvi'. The water vapor bands used to atmospherically correct the data will be returned in 'newh2o' (one band for each day used in the composite).
Get all the relevant information from the date log file. Get a TOVS water vapor image for each day within the composite (in geographic space). Generate an elevation band, a 'line' band and a 'sample' band (all in composite space). The 'line' and 'sample' band will be used as an index into the water/ozone images in geographic space. Generate the water vapor image, ozone image, and QC band (all in the composite projection space). All of the required input files are now available and atmospheric correction is applied to AVHRR channels 1 and 2. The NDVI band is regenerated, since AVHRR channels 1 and 2 have changed. All intermediate image files are deleted once they are no longer needed (to minimize the amount of disk space required).
None
An error occurred extracting the necessary information from the date log file. Ensure that the log file has been correctly specified.
An error occurred generating the water vapor images in geographic space. Ensure that the parameters to GETWATER have been specified correctly.
An error occurred generating the DEM/line/sample bands in composite space. Contact the system administrator if this error persists.
The ozone image specification was not successful. Ensure that the expected ozone images reside in OZONEBASEDIR.
An error occurred generating the water/ozone/qc bands in composite space. Contact the system administrator if this error persists.
The intermediate files could not be deleted as expected. Contact the system administrator for further assistance.
An error occurred estimating the composites julian date. Contact the system administrator for further assistance.
An error occurred while applying atmospheric correction to AVHRR channels 1 and 2. Contact the system administrator if this error persists.
The NDVI band could not be regenerated. Contact the
An error occurred generating the image specified in WATER. Contact the system administrator if this error persists.
A fatal error was encountered. Refer to the preceding error message for specific details.