I am working with MODIS Aqua satellite imagery for the full period of operation of this sensor. My AOI consists of more than 500 000 square kilometers in the central Indian Ocean. The very high revisit frequency of this sensor is one of its great advantages.
I realized that for the full period starting with the 4th July 2002 until the end of 2017 there is no data provided for my research area for the the following dates (year-month-day): 2002-07-30, 2002-07-31, 2002-08-01, 2002-08-02, 2002-08-03, 2002-08-04, 2002-08-05, 2002-08-06, 2005-10-18, 2007-12-02, 2008-04-11 and 2009-02-03. Does anybody know something about potential reasons for this?
That page notes, for instance, that MODIS Aqua was in safe mode from July 29, 2002 - August 08, 2002.
IDL> Result = NCDF_INQUIRE(Cdfid)
IDL> help, result
** Structure <f7d928>, 4 tags, length=16, data length=16, refs=1:
NDIMS LONG 5
NVARS LONG 0
NGATTS LONG 51
RECDIM LONG -1
The above result seems to indicate that there are no named variables in the file. In the past, I would get the data using an id of "chlor_a" for a variable, for instance. It looks like there is data in the file, but how do I access the data using IDL library functions or procedures?
Thank you for your help.
NetCDF4 files are also HDF5 files:
IDL> H5_LIST, "T2000091000000.L2_LAC_OC.nc"
% Loaded DLM: HDF5.
dataset /geophysical_data/chlor_a H5T_FLOAT [1354, 2030]
NASA's IDL Library has
;+NAME/ONE LINE DESCRIPTION OF ROUTINE:
; READL2NC reads a geophysical dataset from an l2gen netcdf4 file, applies scaling
; Simplifies the reading of standard k2gen netcdf4 file. Auto
; applies slope/intercept scaling. Can read multiple band-specific
; SDS products into a single array.
; CALLING SEQUENCE:
; data = readl2nc(filename,prodname)
; filename - L2 filename string.
; prodname - L2 product name string. If this ends in '_', all
; products of name prodname_nnn (where nnn is wavelength)
; will be returned.
; data - 1, 2, or 3-dimensional array containing the requested product.
; SUBROUTINES CALLED:
; WRITTEN BY:
; B. Franz, October 2014.