Evaluation of Extratropical Cyclone Precipitation in the North Atlantic Basin: An Analysis of ERA-Interim, WRF, and Two CMIP5 Models

Abstract

The representation of extratropical cyclones (ETCs) precipitation in general circulation models (GCMs) and a weather research and forecasting (WRF) model is analyzed. This work considers the link between ETC precipitation and dynamical strength and tests if parameterized convection affects this link for ETCs in the North Atlantic Basin. Lagrangian cyclone tracks of ETCs in ERA-Interim reanalysis (ERAI), the GISS and GFDL CMIP5 models, and WRF with two horizontal resolutions are utilized in a compositing analysis. The 20-km resolution WRF model generates stronger ETCs based on surface wind speed and cyclone precipitation. The GCMs and ERAI generate similar composite means and distributions for cyclone precipitation rates, but GCMs generate weaker cyclone surface winds than ERAI. The amount of cyclone precipitation generated by the convection scheme differs significantly across the datasets, with GISS generating the most, followed by ERAI and then GFDL. The models and reanalysis generate relatively more parameterized convective precipitation when the total cyclone-averaged precipitation is smaller. This is partially due to the contribution of parameterized convective precipitation occurring more often late in the ETC life cycle. For reanalysis and models, precipitation increases with both cyclone moisture and surface wind speed, and this is true if the contribution from the parameterized convection scheme is larger or not. This work shows that these different models generate similar total ETC precipitation despite large differences in the parameterized convection, and these differences do not cause unexpected behavior in ETC precipitation sensitivity to cyclone moisture or surface wind speed.

Linkage between Dust Cycle and Loess of the Last Glacial Maximum in Europe

“…This implies that the corresponding emissions could have been triggered by easterlies on the northern flanks of the cyclones. Dust was hardly emitted from areas on the southern flanks of the cyclones which are commonly affected by fronts and precipitation (Booth et al, 2018). In addition to the dust emission areas that occurred equally during both regimes (cyclonic and east sector winds), the east sector winds also generated emissions in Austria, Slovakia, Hungary, Ukraine, central Germany, the Danube Basin and the North Sea Basin.…”

The Ongoing Need for High-Resolution Regional Climate Models: Process Understanding and Stakeholder Information

“…4 and the associated animation ES1 in the online supplemental material (https://doi.org/10.1175 /BAMS-D-19-0113.2). Reanalysisdriven RCM simulations are also commonly used in configuring and assessing a model with respect to the mean climate and phenomena of interest in a region (e.g., Booth et al 2018).…”

Process-Oriented Evaluation of Climate and Weather Forecasting Models

“…GCMs need to capture the dynamics and thermodynamic properties of both the individual cyclone events and their accumulated behavior. Eulerian storm-track analysis revealed that model sea surface temperature biases impact the surface storm tracks and precipitation near ocean western boundary currents (Booth et al 2017;Small et al 2019). Targeted analyses of features in cyclones and/or their fronts were carried out using Lagrangian tracking algorithms and compositing.…”

“…10). Task force efforts on cyclone-centered precipitation led to 1) a satellite-based benchmarks (Naud et al 2019), and 2) results showing GCMs represent cyclone total precipitation as well as reanalysis, but the models have markedly different levels of contributions from their convection parameterizations (Booth et al 2018). The Lagrangian metrics require 6-hourly, three-dimensional data, some of which are not standard in the CMIP archive.…”