TY - JOUR
T1 - Sensitivities of parcel trajectories beneath the lowest scalar model level of a Lorenz vertical grid
AU - Guchte, Andrew Vande
AU - Dahl, Johannes M.L.
N1 - Publisher Copyright:
© 2018 American Meteorological Society.
PY - 2018/5/1
Y1 - 2018/5/1
N2 - Parcel trajectory analysis has become commonplace in the study of simulated severe convection, particularly that which deals with the development and maintenance of near-ground vertical vorticity. However, there are a number of unsolved problems with analyzing simulated trajectories that exist near the ground. One of these unsolved problems is how to deal with parcels that pass beneath the lowest scalar model level. Using the CM1 model, which uses a Lorenz grid, the sensitivity of parcel characteristics such as location or potential temperature to the choice of common extrapolation methods is documented. Using potential temperature as an example, it is explained why unphysical tendencies of scalar variables along trajectories may arise once parcels descend beneath the lowest scalar model level. Given the poorly constrained flow (and scalar) fields beneath the lowest scalar model level, errors such as those documented here appear unavoidable when using free-slip boundary conditions.
AB - Parcel trajectory analysis has become commonplace in the study of simulated severe convection, particularly that which deals with the development and maintenance of near-ground vertical vorticity. However, there are a number of unsolved problems with analyzing simulated trajectories that exist near the ground. One of these unsolved problems is how to deal with parcels that pass beneath the lowest scalar model level. Using the CM1 model, which uses a Lorenz grid, the sensitivity of parcel characteristics such as location or potential temperature to the choice of common extrapolation methods is documented. Using potential temperature as an example, it is explained why unphysical tendencies of scalar variables along trajectories may arise once parcels descend beneath the lowest scalar model level. Given the poorly constrained flow (and scalar) fields beneath the lowest scalar model level, errors such as those documented here appear unavoidable when using free-slip boundary conditions.
KW - Cloud resolving models
KW - Subgrid-scale processes
KW - Trajectories
UR - http://www.scopus.com/inward/record.url?scp=85047084833&partnerID=8YFLogxK
U2 - 10.1175/MWR-D-17-0190.1
DO - 10.1175/MWR-D-17-0190.1
M3 - Article
AN - SCOPUS:85047084833
VL - 146
SP - 1427
EP - 1435
JO - Monthly Weather Review
JF - Monthly Weather Review
SN - 0027-0644
IS - 5
ER -