Investigating the Role of Kilometer-scale Surface Thermal Heterogeneity in Secondary Circulations Using Satellite Remote Sensing and Doppler Lidars

Spatially organized km-scale surface thermal heterogeneity can lead to the formation of secondary circulations, which, in turn, can influence the boundary layer and the initiation, development, and enhancement of cumulus clouds. While the importance of this process is becoming well recognized, quantitative understanding of the relationship between thermal heterogeneity and the corresponding circulations remains largely confined to modeling studies. In this study, we use observational data from the ARM Southern Great Plains (SGP) site to explore how combining satellite remote sensing of land surface temperature (LST) with a mesoscale network of Doppler lidars can help understand the role of surface thermal heterogeneity in driving secondary circulations.
We analyze data from five Doppler lidars at SGP, which have been continuously measuring vertical profiles of wind components (u, v, w) at high temporal frequency since 2016. The combination of the five time-varying profiles are used to compute vertically integrated dispersive kinetic energy (DKE) at each time step as an indirect measure of circulation strength. LST data from GOES-16/17 is then used to quantify surface thermal heterogeneity, particularly in the morning hours. Our analysis focuses on days with minimal synoptic forcing to isolate local effects. Preliminary results show a statistically significant positive correlation between surface thermal heterogeneity and DKE, suggesting a link to the strength of secondary circulations. This study highlights the potential to improve our understanding of this process and provides a valuable tool for evaluating Earth system models that aim to represent the role of km-scale thermal heterogeneity in the atmosphere.