about the unit of deposition

[niuniu]

I am doing some research by using HYSPLIT, and I have some questions about HYSPLIT. If you can help me, and I will appreciate it very much.

Firstly, I wonder the unit of deposition. if my particle unit is grain, so after a period of 2 hours emitting, the unit of output deposition is grains/m2 or grains/m2/hour?

Secondly, what is the minimum grid resolution? Now I assign the 0.001 to spacing lat and lon. But I want to set them as 0.0001 to get higher resolution, is it ok?


Thank you very much.

[barbara.stunder]

With emissions in units of grains, deposition is in grains/m2.

With a fine resolution of 0.0001, you need to emit more particles. You also need to be aware of the uncertainties in the gridded meteorology and your source term as to how to interpret the results.

[niuniu]

So ,because the unit is grains/m2, and whether it means :if emission time is 2 hours, the deposition output is the accumulation of 2 hours? In the setup menu "Definition of Concentration Grid", the final bar is about (Avg:0 Now:1 Max:2) (hrs) (min), we choose the Avg:0, so we originally thought the output deposition is the avg value of the 2 hours, and the unit is grains/m2/hour. We still puzzle about this.

Thank you.

[barbara.stunder]

Yes, the 0 means average. Let's say the average deposition over 2 hours is 100 grains/m2. That means that on average the deposition at any time during that 2 hour period is 100 grains/m2. If you want the total deposition, you would multiply 100 grains/m2 by 2 hours. When you plot the deposition, there are "removal" options of none, time, sum, and total. See the "Concentration Display" window at Concentration / Display / Concentration / Contours. In the HELP there, see option 21 -r[Removal] (pasted below). If you want the average at each of your 2-h periods choose "Time". If you want the accumulation choose either "Sum" or "Total" depending on how many plots you want.

21 -r[Removal: 0-none, (1)-each time, 2-sum, 3-total]

= 0 - No deposition plots are produced even if the model produced deposition output.
= 1 - One deposition plot is produced for each time period.
= 2 - The deposition is summed such that each new time period represents the total accumulation.
= 3 - Similar to =2, deposition is accumulated to the end of the simulation and but only one plot is produced at the end.

[niuniu]

Dear sir/Madam,
Thank you very much! I am very clear about it.