Use of polarimetric radar measurements to constrain simulated convective cell evolution: a pilot study with Lagrangian tracking

Abstract

Abstract. To probe the potential value of a radar-driven field campaign to constrain simulation of isolated convection subject to a strong aerosol perturbation, convective cells observed by the operational KHGX weather radar in the vicinity of Houston, Texas, are examined individually and statistically. Cells observed in a single case study of onshore flow conditions during July 2013 are first examined and compared with cells in a regional model simulation. Observed and simulated cells are objectively identified and tracked from observed or calculated positive specific differential phase (KDP) above the melting level, which is related to the presence of supercooled liquid water. Several observed and simulated cells are subjectively selected for further examination. Below the melting level, we compare sequential cross sections of retrieved and simulated raindrop size distribution parameters. Above the melting level, we examine time series of KDP and radar differential reflectivity (ZDR) statistics from observations and calculated from simulated supercooled rain properties, alongside simulated vertical wind and supercooled rain mixing ratio statistics. Results indicate that the operational weather radar measurements offer multiple constraints on the properties of simulated convective cells, with substantial value added from derived KDP and retrieved rain properties. The value of collocated three-dimensional lightning mapping array measurements, which are relatively rare in the continental US, supports the choice of Houston as a suitable location for future field studies to improve the simulation and understanding of convective updraft physics. However, rapid evolution of cells between routine volume scans motivates consideration of adaptive scan strategies or radar imaging technologies to amend operational weather radar capabilities. A 3-year climatology of isolated cell tracks, prepared using a more efficient algorithm, yields additional relevant information. Isolated cells are found within the KHGX domain on roughly 40 % of days year-round, with greatest concentration in the northwest quadrant, but roughly 5-fold more cells occur during June through September. During this enhanced occurrence period, the cells initiate following a strong diurnal cycle that peaks in the early afternoon, typically follow a south-to-north flow, and dissipate within 1 h, consistent with the case study examples. Statistics indicate that ∼ 150 isolated cells initiate and dissipate within 70 km of the KHGX radar during the enhanced occurrence period annually, and roughly 10 times as many within 200 km, suitable for multi-instrument Lagrangian observation strategies. In addition to ancillary meteorological and aerosol measurements, robust vertical wind speed retrievals would add substantial value to a radar-driven field campaign.

Spatio-Temporal Analysis of Intense Convective Storms Tracks in a Densely Urbanized Italian Basin

“…This is a typical unstable situation favorable to convection processes, where air with low temperature is above air with high temperature. Other research on convective rain events show similar results for other locations [53][54][55][56]. As expected, the convective events also exhibit a seasonal periodicity (Figure 7).…”

An Analysis of the Performance of the Houston Lightning Mapping Array During an Intense Period of Convection During Tropical Storm Harvey

“…Lightning detection networks are crucial in analyzing the behavior of electrically active, deep convective storms over land and ocean (Fridlind et al., 2019; Shao et al., 2005; Solorzano et al., 2018; Stolz et al., 2014; Thornton et al., 2017; Xu et al., 2017; Zhang et al., 2015). There are various ground‐ and space‐based networks that are capable of analyzing lightning activity.…”

“…Although the sensor cannot detect all forms of lightning from space, it is extremely useful as a prognostic tool for forecasting thunderstorm behavior (Borque et al., 2020; E. Bruning et al., 2019; Xu et al., 2017). Lightning mapping arrays (LMAs) can analyze the evolution of a lightning flash by detecting and grouping individual electromagnetic pulses in the very high frequency (VHF) range (60–66 MHz) in space and time (E. C. Bruning & MacGorman, 2013; Chmielewski et al., 2016; Fridlind et al., 2019; Fuchs et al., 2016; Ren et al., 2018; Rison et al., 1999; Thomas et al., 2004; Weiss et al., 2018).…”

“…The Texas Gulf Coast is a major urban/industrial region that is, impacted by mesoscale and synoptic weather patterns (e.g., sea breeze thunderstorms, frontal passages, and tropical systems) throughout the year (Fridlind et al., 2019; Levy et al., 2013; Orville et al., 2001). Houston ranks as the fourth largest city in the United States in terms of population and is a major metropolitan hub for residential, medical, tourism, and commercial activities.…”

“…Houston ranks as the fourth largest city in the United States in terms of population and is a major metropolitan hub for residential, medical, tourism, and commercial activities. In addition, the Houston Metropolitan Area is not only home to numerous petrochemical refineries and service facilities, but also several major shipping ports with direct access to the Gulf of Mexico (Fan et al., 2006; Fridlind et al., 2019; Levy et al., 2013; Orville et al., 2001). The Houston LMA (HLMA) observed the lightning activity of Harvey from landfall on August 26, 2017 until its eventual exit from Texas on August 30, 2017.…”