Hello,
I’d appreciate your input on a few questions related to trajectories initialized at or near the surface:
1.Reading through the HYSPLIT user guide PDF and tutorial sect. 4-6, I understand (mostly implicitly) that the trajectory model in its recent versions applies a PBL mixing scheme (I currently use the hyts_std program in v.5.3.2). This also seems to be the case based on runs in which the airmass trajectory intersects the surface but can then increase in altitude and exit the PBL. Several years ago, while I was still using version 4, a simulated airmass would have “stuck” to the 0 m AGL and didn’t climb up, somewhat consistent with a forum communication Ariel Stein had back in 2014. I think a response provided to a forum user in 2018 supports my current interpretation, but I’d be happy to hear whether my interpretation is correct.
2.If my interpretation is correct and a PBL mixing scheme takes place, I suppose that initialization at 0 m AGL (after verifying that kmsl=0 in SETUP.CFG) should still be valid given that the airmass is lifted up (as long as kmix0 is a few hundred meters). Do you think that is correct, or do you have other suggestions? (For PBL height, I use the input data from ERA5 using kmixd=0, if that matters)
Thank you,
Israel
I’d appreciate your input on a few questions related to trajectories initialized at or near the surface:
1.Reading through the HYSPLIT user guide PDF and tutorial sect. 4-6, I understand (mostly implicitly) that the trajectory model in its recent versions applies a PBL mixing scheme (I currently use the hyts_std program in v.5.3.2). This also seems to be the case based on runs in which the airmass trajectory intersects the surface but can then increase in altitude and exit the PBL. Several years ago, while I was still using version 4, a simulated airmass would have “stuck” to the 0 m AGL and didn’t climb up, somewhat consistent with a forum communication Ariel Stein had back in 2014. I think a response provided to a forum user in 2018 supports my current interpretation, but I’d be happy to hear whether my interpretation is correct.
2.If my interpretation is correct and a PBL mixing scheme takes place, I suppose that initialization at 0 m AGL (after verifying that kmsl=0 in SETUP.CFG) should still be valid given that the airmass is lifted up (as long as kmix0 is a few hundred meters). Do you think that is correct, or do you have other suggestions? (For PBL height, I use the input data from ERA5 using kmixd=0, if that matters)
Thank you,
Israel
Statistics: Posted by isilber — July 31st, 2024, 12:43 pm