Grid concentrations not what I expect

[dmbakker]

I'm simulating four fires emitting 15000 g/hr PM2.5 per hour, for 24 hours, starting 2024 30 00, and the particle plot (PARTPLOT) shows what I would expect. Particles being emitted for 24 hours, dispersing and then ceasing to emit after 24 hours. The grid concentrations however, seem to show emissions for a couple hours at height of 1m, then almost nothing (as shown by the grid concentrations around the emission points after 4-5 hours at a height of 1m), then a slight increase in concentration about 18 hours after emission started. The graph (Picture 3) enclosed are the average concentrations for 5 different heights across the whole area where grid concentrations have been detected at 5 different levels. The weather is nothing special. The PBLH and the surface temp (TMPS, see graph) however vary significantly during the day, the wind is a little breeze. I can't explain the lack of concentrations around these emission points while the particles tell a different story. Can someone shed some light on this for me please?

[Tianfeng.Chai]

Can you please post your CONTROL and SETUP files ?

[dmbakker]

A small update in this area. I realised that the various particle parameters were set too low for what I was trying to, and emissions were aborted prematurely. By greatly increasing the number of particles emitted in one cycle the emission reflected what I thought they should be. Emissions happened for the entire duration as set, it slowed down the calculations but the output was much improved.