GIS scripting with backward trajectories
Posted: March 3rd, 2016, 10:19 am
Hi Hysplit users,
I'm new to Hysplit, so a fascinating world just opened up for me. I am looking in to the effect of wild fires on N deposition. I want to check whether I can explain the seasonality in my N deposition (field measurements) by combining Terra and Aqua fire detections and backward trajectories starting from my measuring spot. For this, I have succeeded in batch generating daily trajectories (backwards, starting at 500 m agl, one week back) for a whole year. Additionally, I have a shape file with daily fire detections in my study area.
So far so good. However, I'm having difficulties now. I'm trying to combine both datasets in such way that I want to count the fire incidents in a 20 km buffer along the trajectory, keeping in mind a one-day buffer. This means that for a parcel arriving at my site on the 7th of april, I want to see where this trajectory passed subsequently on the 1st of April, and whether there was a fire within a 20 km radius on the 31st of March, or 1st of April. Then go one time step further to the 2nd of April and so on..
I can not do this manually, since there are 4 trajectories a day, times 365 days. Additionally there are over a million fires..
I suspect some of you are working with more or less the same concept, so I was wondering if anyone can help me out. And what implementation I should use (Python?? but I'm myself more of an R man...never used Python before...)
Thanks in advance!
Marijn
I'm new to Hysplit, so a fascinating world just opened up for me. I am looking in to the effect of wild fires on N deposition. I want to check whether I can explain the seasonality in my N deposition (field measurements) by combining Terra and Aqua fire detections and backward trajectories starting from my measuring spot. For this, I have succeeded in batch generating daily trajectories (backwards, starting at 500 m agl, one week back) for a whole year. Additionally, I have a shape file with daily fire detections in my study area.
So far so good. However, I'm having difficulties now. I'm trying to combine both datasets in such way that I want to count the fire incidents in a 20 km buffer along the trajectory, keeping in mind a one-day buffer. This means that for a parcel arriving at my site on the 7th of april, I want to see where this trajectory passed subsequently on the 1st of April, and whether there was a fire within a 20 km radius on the 31st of March, or 1st of April. Then go one time step further to the 2nd of April and so on..
I can not do this manually, since there are 4 trajectories a day, times 365 days. Additionally there are over a million fires..
I suspect some of you are working with more or less the same concept, so I was wondering if anyone can help me out. And what implementation I should use (Python?? but I'm myself more of an R man...never used Python before...)
Thanks in advance!
Marijn