Identifying Meteorological Controls on Open and Closed Mesoscale Cellular Convection Associated with Marine Cold Air Outbreaks

Abstract

Mesoscale cellular convective (MCC) clouds occur in large‐scale patterns over the ocean and have important radiative effects on the climate system. An examination of time‐varying meteorological conditions associated with satellite‐observed open and closed MCC clouds is conducted to illustrate the influence of large‐scale meteorological conditions. Marine cold air outbreaks (MCAO) influence the development of open MCC clouds and the transition from closed to open MCC clouds. MCC neural network classifications on Moderate Resolution Imaging Spectroradiometer (MODIS) data for 2008 are collocated with Clouds and the Earth's Radiant Energy System (CERES) data and ERA‐Interim reanalysis to determine the radiative effects of MCC clouds and their thermodynamic environments. Closed MCC clouds are found to have much higher albedo on average than open MCC clouds for the same cloud fraction. Three meteorological control metrics are tested: sea‐air temperature difference (ΔT), estimated inversion strength (EIS), and a MCAO index (M). These predictive metrics illustrate the importance of atmospheric surface forcing and static stability for open and closed MCC cloud formation. Predictive sigmoidal relations are found between M and MCC cloud frequency globally and regionally: negative for closed MCC cloud and positive for open MCC cloud. The open MCC cloud seasonal cycle is well correlated with M, while the seasonality of closed MCC clouds is well correlated with M in the midlatitudes and EIS in the tropics and subtropics. M is found to best distinguish open and closed MCC clouds on average over shorter time scales. The possibility of a MCC cloud feedback is discussed.

A New Stochastic Model for the Boundary Layer Clouds and Stratocumulus Phase Transition Regimes: Open Cells, Closed Cells, and Convective Rolls

“…It plateaus around zero throughout the transition region suggesting nearly symmetric distributions during this regime and quickly plunges toward negative values when σ is driven toward a full coverage equilibrium with the strong positive forcing. These variations in mean, STD, and SKW are consistent with the observations of CAF distributions of stratocumulus during open versus closed cell convection (McCoy et al, ).…”

“…Interestingly, however, the distribution has a maximum variation when the mean CAF takes on an intermediate value of nearly 0.5; with a standard deviation of nearly 0.5, we have an almost flat distribution in this case contrasted with the case of high coverage where the CAF distribution peaks at 1 and plunges abruptly with nonnegligible tail at the zero coverage limit. This is consistent with the observed CAF distributions corresponding, respectively, to closed and open cell convection regimes (McCoy et al, ).…”

Tropical Precipitation and Cross‐Equatorial Heat Transport in Response to Localized Heating: Basin and Hemisphere Dependence

“…Sensitivity to ocean basin: For NH heating, ΔTHT 0 is approximately 3.6 times greater in response to extratropical Pacific heating (NXPac) than extratropical Atlantic (NXAtl), with a strong TOA hemispheric response in NXPac: positive feedbacks amplify heating in the NH Pacific. This feedback is consistent with a large reduction in low cloud amount in the northern extratropical Pacific in NXPac (Figures 2 and S3); in this area low cloud can be associated with cold-air outbreaks and impacted by surface temperatures (e.g., McCoy et al, 2017).…”

Aerosol midlatitude cyclone indirect effects in observations and high-resolution simulations

“…7 and 8). This increase in MAC-LWP CLWP is particularly interesting as this is the region typically inhabited by open cellular convection trailing the cold front and a major source of error in simulated cyclone properties (Bodas-Salcedo et al, 2012Naud et al, 2014;I. L. McCoy et al, 2017).…”