Microwave Radiometer (MWR) template description

Document history

Overview

Template description

• Instrument Naming
Although microwave radiometer systems have the capability to measure multiple entities simultaneously, the instrument names of the different MWR systems are based on the primary measured entity [GAS] to be reported in the file, as shown in Tables below.


• Variable Reporting
Each measured primary entity [GAS] requires a list of 22 mandatory variables to be reported within a file MWR.[GAS] (24 variables for MWR.O3), and 1 optional variable (see Tables below):


• Additional Notes
DATETIME - is a single weighted mean time of the measurement - i.e. after accounting for periods where there are no measurements because of poor weather conditions, calibrations etc.

INTEGRATION.TIME - the effective integration time of the spectra used in the retrieval, which will generally be less than the difference between the start and stop times (after accounting for non-spectral, bad or missing measurements).

[GAS].MIXING.RATIO.VOLUME_EMISSION_AVK - if averaging kernels are routinely generated for each measurement as part of the retrieval, these should be reported in the HDF file, otherwise a generic set may be used. Averaging kernel and a-priori measurements are included in the file so users have the option to convolve higher resolution datasets to the microwave resolution. This means that the reported altitude range will typically be wider than the normal measurement range. However, this does not mean that all data variables should be reported over the full range.
The following variables would generally be reported over the full range:
ALTITUDE,
PRESSURE.INDEPENDENT,
TEMPERATURE.INDEPENDENT,
[GAS].MIXING.RATIO.VOLUME_EMISSION_APRIORI,
[GAS].MIXING.RATIO.VOLUME_EMISSION_AVK

The remaining data variables from Tables below should contain measurements over the normal measurement range of the instrument only (i.e. not including measurements where the averaging kernels are not well resolved, or the errors are high, or the a-priori dependence is high etc). Fill values (see Tables below) should then be used over the remaining altitude range.

SOURCE.PRODUCT - only used when the HDF file is converted from another format e.g. NDACC NASA/Ames. The format of the entry is ORIGINAL.ARCHIVE_ORIGINAL.FILENAME_ORIGINAL.FILE.CREATION.DATE e.g. NDACC_LAHO1208.NDM_20120820


• Variable Fill Values
The variable fill value is a number inserted as a substitute data element if a data element of a variable is default or missing.


• File Granularity
The reporting granularity for MWR measurements should be daily or, for instruments with lower temporal resolution, one measurement per file.


• Metadata - Global Attributes
Each MWR.[GAS] file requires one set of Global Attributes. These have been grouped in to three categories describing the file contents, namely Originator Attributes, Dataset Attributes and File Attributes. An example of a microwave ozone global attributes measurement at Mauna Loa, Hawaii is given in Tables below.


• Metadata - Variable Attributes
Each variable reported in a MWR.[GAS] file requires one set of Variable Attributes. An example of an attribute set is given in Tables below.

Templates and examples