A Geostationary View of a Liquid water Path Adjustment dependence on Cloud Regime

Abstract

<p>Aerosol-cloud-interactions remain a large climate uncertainty; especially uncertain is the liquid water path (LWP) adjustment to varying aerosol concentrations in stratocumulus (StCu). Large-eddy simulations (LES) have found that the LWP response of StCu to aerosol can be either positive or negative depending on the cloud regime, whereas climate models simulate uniformly positive correlations. Observations of the real-world evolution of LWP in varying aerosol environments are needed to resolve the nature of the correlation between LWP and aerosol. We address this by analyzing a large ensemble of parcel trajectories over the southeast Pacific within the GOES-16 field of regard. Preliminary results are consistent with LES, showing consistent regime dependent evolution of the LWP depending on the initial cloud state, with LWP generally decreasing with varying number concentrations (N). However, LWP generally increases at low N, potentially supporting LES conclusions showing a cloud-regime dependence. To investigate this further, we will further condition observations by MERRA-2 large-scale environmental variables (e.g. estimated inversion strength, moisture, and boundary-layer decoupling). We expect environmental differences will correlate with the differences between changes in LWP at low and high N.</p>

Diurnal Patterns in the Observed Cloud Liquid Water Path Response to Droplet Number Perturbations

“…The AMSR-2 warm rain product can be downloaded from Eastman et al (2019Eastman et al ( -2021. The code used to create and plot the output trajectory data used in this study are permanently archived at Smalley et al (2023).…”

“…GOES-16 Advanced-Baseline Imager cloud optical thickness and effective radius can be downloaded from Straka (2019-2021a) and Straka (2019-2021b) respectively. Derived ABI liquid water path was corrected using lookup tables available at Smalley and Lebsock (2023b). The following MERRA-2 products: inst3_3d_asm_Np (Global Modeling and Assimilation Office (GMAO), 2015b) and inst1_2d_asm_Nx (Global Modeling and Assimilation Office (GMAO), 2015a) can be downloaded from the Goddard Space Flight Center Distributed Active Archive Center.…”