Synoptic conditions related to soil moisture‐atmosphere interactions and unorganized convection in Oklahoma

Abstract

Atmospheric modification by anomalously dry or wet soils can both enhance and suppress convective activity. However, the local‐scale and mesoscale feedback governing soil moisture‐precipitation coupling are embedded within the larger synoptic‐scale environment. Despite their importance, synoptic‐scale atmospheric conditions are rarely considered in studies examining soil moisture‐atmosphere interactions. We combine self‐organizing maps of 500 hPa geopotential height, spatial synoptic classification, and Hybrid Single‐Particle Lagrangian Integrated Trajectory model air mass trajectories to determine if the synoptic‐scale environment affects the ability of the land surface to force unorganized convection in Oklahoma. We identify several synoptic patterns that significantly impact the frequency of unorganized convection. Synoptic patterns characterized by midlevel troughs over the Southern Great Plains are less frequently associated with unorganized convective events. These patterns exhibit cool air advection in the midlevel and lower level of the atmosphere and are linked to suppression of convective activity. The synoptic patterns characterized by 500 hPa ridging over the study region are more frequently associated with unorganized convective events. These patterns likely result in increased net radiation, vapor pressure deficit, and more homogenously dry soils. Unorganized convective events that occur during these synoptic conditions initiate preferentially over dry soils. We present evidence that the synoptic‐scale environment can influence whether and how the land surface has an impact on convection.

The Sensitivity of North American Terrestrial Carbon Fluxes to Spatial and Temporal Variation in Soil Moisture: An Analysis Using Radar‐Derived Estimates of Root‐Zone Soil Moisture

“…Soil moisture is a key variable of the earth system influencing terrestrial water, carbon and nutrient cycling, and the exchange of carbon, water, and energy between the land‐surface and atmosphere. In particular, it impacts meteorological, hydrological, and ecological processes and properties including surface energy balance (Berg et al, ; Ford et al, ; Gallego‐Elvira et al, ; Lin & Cheng, ; Suarez et al, ), land surface albedo (Liu et al, ; Zhang et al, ), soil thermal properties (Juszak et al, ; Sugathan et al, ), runoff (Crow & Ryu, ; Morbidelli et al, ), plant water stress (He et al, ), and resulting vegetation productivity and ecosystem carbon fluxes (Huang et al, ; Jia et al, ; McInerney & Helton, ; Xu et al, ; Xu & Zhou, ).…”

“…Soil moisture is a key variable of the earth system influencing terrestrial water, carbon and nutrient cycling, and the exchange of carbon, water, and energy between the land-surface and atmosphere. In particular, it impacts meteorological, hydrological, and ecological processes and properties including surface energy balance (Berg et al, 2014;Ford et al, 2015;Gallego-Elvira et al, 2016;Lin & Cheng, 2016;Suarez et al, 2014), land surface albedo Zhang et al, 2014), soil thermal properties (Juszak et al, 2016;Sugathan et al, 2014), runoff (Crow & Ryu, 2009;Morbidelli et al, 2016), plant water stress (He et al, 2016), and resulting vegetation productivity and ecosystem carbon fluxes (Huang et al, 2016;Jia et al, 2016;McInerney & Helton, 2016;Xu et al, 2004;Xu & Zhou, 2005). Improved measurements of spatial and temporal patterns of variation in soil moisture are therefore essential for improved characterization of meteorological, hydrological, and ecological processes for hydrological forecasting, weather prediction, and estimates of terrestrial carbon, water, and energy fluxes.…”

Moisture transport associated with large precipitation events in the Upper Colorado River Basin

“…One back trajectory is calculated per LPE day, terminating at 18 UTC on each LPE day, representing roughly midday on an LPE day in local time. NARR reanalysis data have been used for calculating back trajectories for various applications, in part due to these advantages (e.g., Ford et al, 2015). Considering the complex topography of the western United States, the NARR dataset is particularly advantageous, as it represents the highest resolution (~32 km grid spacing) spatiotemporal dataset that spans the period of study, which is also readily available and compatible for use in HYSPLIT calculations.…”

Using ARM Observations to Evaluate Climate Model Simulations of Land‐Atmosphere Coupling on the U.S. Southern Great Plains

“…One is that the coupling of soil moisture with surface atmospheric variables such as evaporation or temperature is generally more robust than its coupling with local precipitation via convective processes. Indeed, the extent to which soil moisture significantly impacts precipitation in different locations still remains unresolved, despite receiving much scientific attention (e.g., Findell et al, ; ; Ford, Quiring et al, ; Ford, Rapp, Quiring, ; Ford, Rapp, Quiring, Blake, ; Guillod et al, , ; Lamb et al, ; Phillips & Klein, ; Ruiz‐Barradas & Nigam, ; Taylor et al, ; Tuttle & Salvucci, ). A conceptual framework for addressing the coupling of soil moisture with precipitation is to view this as a two‐legged process: a terrestrial component involving soil moisture coupling with surface evaporation, and an atmospheric linkage between surface evaporation and convective precipitation (Dirmeyer, ; Santanello, Ferguson et al, ; Tawfik et al, , ).…”