Summing grids for radar data

[John Murray]

Hello GrADS users,

 I am working on severe weather radar climatologies of parameters such as the frequency of 50+ DBZ over an area. I have downloaded radar data from NCDC and converted it to GrADS Binary format. Then, I changed the descriptor file for one day and made it a template so that it would aggregate all radar files for one day. For each day, I can filter out any values less than 50 dBZ and define it as its own variable.

 I want to take all of these filtered out images and sum them up for the day, and for each year between the months of May and August for all days in which severe weather was reported. In this way, the frequency of 50+ DBZ over a certain area over the course of a summer season or a series of summer seasons can be calculated. Is there a way to loop through .ctl aggregate files for each day in order to accomplish this or can a loop be created in which each data file is opened, then the filter is applied, and then the file is closed? The only problem is that the time intervals between successive radar images are not evenly spaced apart; sometimes there would be 4 minutes in between and sometimes there would be 10 minutes. I have tried to apply the filtering over one day to an aggregate file and an error comes up regarding the inability to allocate enough memory to complete the operation.


 John M

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