Averaging kernels
In order to properly compare MOPITT Level 2 Data with models or other measurements the MOPITT averaging kernels MUST be used. The averaging kernels are also valuable as an indication of the vertical resolution of the measurements.
Please consult the document, Calculation and Application of MOPITT Averaging Kernels by Merritt Deeter (AVK_application) for the details on calculating and using averaging kernels.
Examples of averaging kernels over the Australian desert and the South Pacific can be seen below:
A priori data
MOPITT retrievals rely on CO and CH4 a priori data. MOPITT data users need these data in order to calculate the MOPITT averaging kernels. Different versions of archived MOPITT retrieval data may be based on somewhat different a priori data. Therefore, it is important that MOPITT data users download the a priori file which is consistent with the specific version of MOPITT retrieval data being analyzed.
A priori data can be found here.
Version 3 a priori CO, and the diagonal of the covariance matrix, can be seen below:
Sample programs
Below are some sample IDL programs for calculating averaging kernels from the covariance matrix and the application of averaging kernels to a 'true' profile.
IDL sample reading program: sampleRead_pro
NCL sample reading program: sampleRead_ncl
IDL sample data application program: example_avgker_calc
(Program that shows how to construct the retrieved covariance matrix from the form in the data files, calculates the averaging kernels, and applies it to a comparison profile. Below is an example output plot)
