A Physically Based Stochastic Boundary Layer Perturbation Scheme. Part II: Perturbation Growth within a Superensemble Framework

التفاصيل البيبلوغرافية
العنوان: A Physically Based Stochastic Boundary Layer Perturbation Scheme. Part II: Perturbation Growth within a Superensemble Framework
المؤلفون: David L. A. Flack, Nigel Roberts, Carol Halliwell, Suzanne L. Gray, Humphrey W. Lean, Robert S. Plant, Peter Clark
المصدر: Journal of the Atmospheric Sciences. 78:747-761
بيانات النشر: American Meteorological Society, 2021.
سنة النشر: 2021
مصطلحات موضوعية: Atmospheric Science, 010504 meteorology & atmospheric sciences, Turbulence, Mesoscale meteorology, Probabilistic logic, Perturbation (astronomy), 01 natural sciences, Ensemble learning, 010305 fluids & plasmas, Boundary layer, 0103 physical sciences, Precipitation, Statistical physics, Boundary value problem, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Mathematics
الوصف: Convection-permitting forecasts have improved the forecasts of flooding from intense rainfall. However, probabilistic forecasts, generally based upon ensemble methods, are essential to quantify forecast uncertainty. This leads to a need to understand how different aspects of the model system affect forecast behavior. We compare the uncertainty due to initial and boundary condition (IBC) perturbations and boundary layer turbulence using a superensemble (SE) created to determine the influence of 12 IBC perturbations versus 12 stochastic boundary layer (SBL) perturbations constructed using a physically based SBL scheme. We consider two mesoscale extreme precipitation events. For each, we run a 144-member SE. The SEs are analyzed to consider the growth of differences between the simulations, and the spatial structure and scales of those differences. The SBL perturbations rapidly spin up, typically within 12 h of precipitation commencing. The SBL perturbations eventually produce spread that is not statistically different from the spread produced by the IBC perturbations, though in one case there is initially increased spread from the IBC perturbations. Spatially, the growth from IBC occurs on larger scales than that produced by the SBL perturbations (typically by an order of magnitude). However, analysis across multiple scales shows that the SBL scheme produces a random relocation of precipitation up to the scale at which the ensemble members agree with each other. This implies that statistical postprocessing can be used instead of running larger ensembles. Use of these statistical postprocessing techniques could lead to more reliable probabilistic forecasts of convective events and their associated hazards.
تدمد: 1520-0469
0022-4928
DOI: 10.1175/jas-d-19-0292.1
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::ca195b80ef3ff5af820c3dd895ef2e01
https://doi.org/10.1175/jas-d-19-0292.1
Rights: OPEN
رقم الانضمام: edsair.doi...........ca195b80ef3ff5af820c3dd895ef2e01
قاعدة البيانات: OpenAIRE
الوصف
تدمد:15200469
00224928
DOI:10.1175/jas-d-19-0292.1