Strange output when hitting the ground
Posted: June 16th, 2020, 6:28 pm
I'm running HYSPLIT trajectories on Linux (compiled from source code, Last Changed Rev 1011), using data I've converted from the Community Atmosphere Model v4 to ARL with MeteoInfo. Many of my trajectories are close to the ground, so I expect some to hit ground, but I am confused by the output produced in the trajectory files and would like to know more about how "grounding" is determined. I've seen three different behaviors that I would like to understand:
1. Switch to NaN: sometimes, when the height is very low, all columns from the latitude column on will become NaN:
2. Recovery from height of zero: in other cases, trajectories will sit at a height of 0.0 meters for many time steps without becoming NaN, and then recover and increase in height again
3. Row of asterisks: sometimes, the switch to NaN as the trajectory presumably hits the ground will be preceded by a row of asterisks (see trajectory 1 in sample_traj_asterisks.txt)
What leads to these three different output behaviors? I would attach files with examples, but the post interface says the board attachment quota has been reached and won't let me.
1. Switch to NaN: sometimes, when the height is very low, all columns from the latitude column on will become NaN:
Code: Select all
1 1 11 1 18 5 0 99 -25.0 44.440 -111.338 0.3 786.2 248.2 1864.3
2 1 11 1 18 5 0 99 -25.0 46.052 -109.776 0.0 824.1 243.8 1517.5
3 1 11 1 18 5 0 99 -25.0 46.920 -108.695 0.0 865.8 243.8 1154.2
4 1 11 1 18 5 0 99 -25.0 38.079 -109.228 144.2 768.0 267.3 2018.2
5 1 11 1 18 5 0 99 -25.0 40.467 -120.049 4855.3 433.6 234.7 1437.5
1 1 11 1 18 4 0 99 -26.0 44.442 -111.374 0.8 786.3 248.6 1862.8
2 1 11 1 18 4 0 99 -26.0 46.056 -109.825 0.0 823.5 244.4 1522.2
3 1 11 1 18 4 0 99 -26.0 46.928 -108.785 0.3 864.7 244.3 1161.7
4 1 11 1 18 4 0 99 -26.0 37.715 -109.474 109.2 773.8 267.9 1999.5
5 1 11 1 18 4 0 99 -26.0 41.374 -120.266 4947.3 435.0 234.9 1324.2
1 1 11 1 18 3 0 99 -27.0 NaN NaN NaN NaN NaN NaN
2 1 11 1 18 3 0 99 -27.0 NaN NaN NaN NaN NaN NaN
3 1 11 1 18 3 0 99 -27.0 NaN NaN NaN NaN NaN NaN
4 1 11 1 18 3 0 99 -27.0 37.374 -109.690 74.4 779.8 268.6 1982.3
5 1 11 1 18 3 0 99 -27.0 42.310 -120.455 5040.4 436.7 234.9 1202.4
1 1 11 1 18 2 0 99 -28.0 NaN NaN NaN NaN NaN NaN
2 1 11 1 18 2 0 99 -28.0 NaN NaN NaN NaN NaN NaN
3 1 11 1 18 2 0 99 -28.0 NaN NaN NaN NaN NaN NaN
4 1 11 1 18 2 0 99 -28.0 37.096 -109.923 43.7 784.9 269.2 1957.8
5 1 11 1 18 2 0 99 -28.0 43.262 -120.624 5140.0 438.2 235.1 1093.9
3. Row of asterisks: sometimes, the switch to NaN as the trajectory presumably hits the ground will be preceded by a row of asterisks (see trajectory 1 in sample_traj_asterisks.txt)
Code: Select all
1 1 15 12 30 15 0 99 -21.0 28.243 -82.265 15.0 1024.5 285.9 -112.1
2 1 15 12 30 15 0 99 -21.0 33.475 -84.965 111.1 988.4 274.9 82.0
3 1 15 12 30 15 0 99 -21.0 33.758 -86.949 318.6 965.4 277.5 65.5
4 1 15 12 30 15 0 99 -21.0 33.949 -88.400 672.7 928.3 277.8 33.7
5 1 15 12 30 15 0 99 -21.0 44.433 -110.504 5582.3 377.4 237.2 1812.3
1 1 15 12 30 14 0 99 -22.0********* -82.368 ******** ******** ******** ********
2 1 15 12 30 14 0 99 -22.0 33.505 -85.006 118.9 986.2 275.2 98.4
3 1 15 12 30 14 0 99 -22.0 33.778 -87.046 324.1 964.5 277.5 67.0
4 1 15 12 30 14 0 99 -22.0 33.954 -88.617 674.6 928.6 277.9 27.0
5 1 15 12 30 14 0 99 -22.0 44.862 -112.152 5663.4 380.9 237.6 1696.1
1 1 15 12 30 13 0 99 -23.0 NaN NaN NaN NaN NaN NaN
2 1 15 12 30 13 0 99 -23.0 33.547 -85.068 127.6 984.3 275.5 100.1
3 1 15 12 30 13 0 99 -23.0 33.819 -87.158 329.9 963.8 277.6 66.3
4 1 15 12 30 13 0 99 -23.0 33.970 -88.828 677.2 929.1 278.0 20.6
5 1 15 12 30 13 0 99 -23.0 45.156 -113.749 5758.5 386.9 238.4 1501.9
1 1 15 12 30 12 0 99 -24.0 NaN NaN NaN NaN NaN NaN
2 1 15 12 30 12 0 99 -24.0 33.603 -85.154 137.3 982.4 275.7 102.3
3 1 15 12 30 12 0 99 -24.0 33.881 -87.284 335.7 963.1 277.6 66.3
4 1 15 12 30 12 0 99 -24.0 33.995 -89.033 680.2 929.4 278.1 14.6
5 1 15 12 30 12 0 99 -24.0 45.332 -115.290 5822.3 392.6 239.3 1337.5