Unravelling the turbulent structures of temperature variations during a gust front event: a case study

The characterization of turbulent heat and moisture transport during a gust-front event over the Indian peninsula

“…To investigate the characteristics of the turbulent heat and moisture fluxes during the gust-front event, we used the same micrometeorological dataset from a 50-m instrumented tower as described in Chowdhuri et al [12]. This tower was erected over a non-irrigated and nearly-flat grassland in Solapur, India (17.6 • N, 75.9 • E, 510 m above mean sea level), equipped with time-synchronized eddy-covariance (EC) systems at four levels with heights z = 4, 8, 20, and 40 m (z is the height above the ground).…”

“…21(1):263-281, 2021) have shown that, the cold pool associated with the gust-front creates two distinct regimes in ASL turbulence, where the temperature fluctuations display contrasting behavior. To evaluate the corresponding impacts on the moisture fluctuations and turbulent heat and moisture transport, we extend our analysis by using the same field-experimental dataset of Chowdhuri et al (2021). We discover that, the topology of the turbulent structures which govern the temperature and moisture fluctuations clearly exhibit a regime-wise distinction.…”

“…To close this gap, a detailed micrometeorological observation system was established over the rain shadow region of the Western Ghat as part of the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX), in an effort to understand the linkage between the cloud processes and the surface-atmosphere exchanges. By using CAIPEEX datasets from a C-Band Doppler weather radar and 50-m micrometeorological tower, Chowdhuri et al [12] studied the impact of a gust-front event on the ASL turbulence. They discovered that, similar to mid-latitude studies [27,33], the incidence of the gust front was followed by a convergence of cold air pool, which in turn affected the turbulent temperature structure in the ASL.…”

“…Due to such event, two distinct regimes were visible, where in one regime the turbulent temperature fluctuations remained quite intense analogous to daytime convective periods, whereas in the second regime the fluctuations diminished significantly as in stable conditions. Additionally, Chowdhuri et al [12] demonstrated that the time scales of the temperature fluctuations displayed a power-law behavior whose exponents changed between the two regimes. By drawing an analogy with self-organized criticality in complex systems [2,20,1], they interpreted this as, the deep-convective cells whose outflows generated the gust front, acted as an external stimuli which disturbed its surroundings beyond the tipping point and created a scale-free response.…”

“…In this article, we attempt to answer these questions through novel data analysis techniques employed on the same 50-m micrometeorological dataset from CAIPEEX, used in Chowdhuri et al [12]. During our presentation, we arrange the paper in three different sections.…”