Diurnal and seasonal variability of TKE dissipation rate in the ABL over a tropical station using UHF wind profiler

Kalapureddy, M. C. R.; Kumar, K. Kishore; Sivakumar, Venkataraman; Ghosh, Apurna; Jain, A. R.; Reddy, K. Krishna

doi:10.1016/j.jastp.2006.10.016

Cited by 28 publications

(21 citation statements)

References 37 publications

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“…Satheesan and Krishna Murthy () showed that log ε varies from −4 at 5 km to −3.2 at 12 km to −3.5 in the lower stratosphere from January to March 1999. Kalapureddy et al () reported that log ε within the range of 0.5–4.0 km is from −5 to −1 on a clear air day in July 1999. The results of the UHF wind profiler radar at Pune (18.32°N, 73.51°E) suggested that log ε varies from −6 to −3 at 1.05–10.35 km and exhibits weak seasonal variation with an increase in altitude (Singh et al, ).…”

Section: Resultsmentioning

confidence: 99%

Latitudinal and Topographical Variabilities of Free Atmospheric Turbulence From High‐Resolution Radiosonde Data Sets

Zhang

Huang

et al. 2019

JGR Atmospheres

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This study aims to determine the latitudinal and topographical dependencies of turbulent flow by applying Thorpe analysis to abundant high‐resolution radiosonde data sets. Results show that turbulent energy dissipation rates are lognormally distributed with average central values of 2.7 × 10−4 and 2.9 × 10−4 m2/s3 in the troposphere and stratosphere, respectively. Moreover, they exhibit similar vertical variations at different latitudes from the lower free troposphere up to the tropopause region. Dissipation rates are quantitatively comparable at all latitudes but do exhibit significant seasonal variability. Thus, these rates have apparent seasonal cycles at middle latitudes but weak cycles at low and high latitudes. The influence of terrain is an important feature of turbulent motions. Turbulent activities over mountainous topographies exhibit larger variances than those over flat terrains in the lower troposphere and more outstanding enhancements in the tropopause region. In general, these results are comparable with those of radars in terms of magnitude, and the differences between them can be related to different measurement principles.

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Section: Resultsmentioning

confidence: 99%

Latitudinal and Topographical Variabilities of Free Atmospheric Turbulence From High‐Resolution Radiosonde Data Sets

Zhang

Huang

et al. 2019

JGR Atmospheres

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“…The bottom panel shows the diurnal evolution of vertical velocity. This plot readily reveals the updrafts throughout the day in the boundary layer, whereas the rest of the seasons show downdrafts during this period (Kalapureddy et al, 2007). During the monsoon season, these low-level updrafts aid in pumping more moisture into the free atmosphere and help in the formation of convective clouds.…”

Section: General Llj Characteristic Features Over Gadankimentioning

confidence: 96%

“…The LAWP at Gadanki is the first boundary layer wind profiler dedicated to the detailed investigation of the Atmospheric Boundary Layer (ABL) characterization via winds, turbulence and precipitating systems in the tropical latitudes (Krishna Reddy et al, 2002;Krishna Reddy, 2003a, b, c, d;Krishnan and Kunhikrishnan, 2004;Krishnan et al, 2005;Kalapureddy et al, 2007). Gadanki is an ideal site to serve as ground validation of the Tropical Rainfall Measuring Mission (TRMM) satellite because of its location and availability of multiple sensors at NARL.…”

Section: Site System and Data Descriptionmentioning

confidence: 99%

“…Hence, this gradient feature, from here on, is utilized to find the boundary-layer depth/top from sole radar measurements. The detailed estimation of C 2 n and ε used in this study can be found in Kalapureddy et al (2007). Figure 2 shows the seasonal features of the low-level winds, averaged for 5 days, for all the months during 1998, 1999 and 2000.…”

Section: Site System and Data Descriptionmentioning

confidence: 99%

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Wind profiler observations of a monsoon low-level jet over a tropical Indian station

et al. 2007

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Abstract. Three-year high-resolution wind observations of the wind profiler have been utilized to characterize the diurnal and seasonal features of the monsoon Low-Level Jet (LLJ) over a tropical station, Gadanki (13.5 • N, 79.2 • E), with a focus on the diurnal variability of low-level winds. The Boreal summer monsoon winds show a conspicuously strong westerly LLJ with average wind speed exceeding 20 m s −1 . The L-band wind profiler measurements have shown an advantage of better height and time resolutions over the conventional radiosonde method for diurnal wind measurements. An interesting diurnal oscillation of LLJ core has been observed. It is varying in the height range of 1.8±0.6 km with the maximum and minimum intensity noticed during the early morning and afternoon hours, respectively. The jet core (wind maxima) height is observed to coincide with the inversion height. Strong wind shears are normally located beneath the LLJ core. The sole wind profiler observations are capable of identifying the monsoon phases, such as onset, break and active spells, etc. The mutual influence between the LLJ and the boundary layer has been discussed. One notices that the observed LLJ diurnal structures depend on the local convective activity, wind shears and turbulence activity associated with boundary layer winds. The day-to-day change in the LLJ structure depends on the latitudinal position of the LLJ core.

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“…Kalapureddy et al . [] analyzed the diurnal and seasonal variability of the turbulence kinetic energy (TKE) dissipation rate in the ABL over Gadanki and reported larger TKE during summer and monsoon seasons and smaller TKE in postmonsoon and winter seasons. Karanam Kishore Kumar and Jain [] reported CBL variations during dry convection (nonprecipitating) days (CBL gradually increases in morning hours and drastically decreases in evening hours), premonsoon precipitation days (CBL shows a continuously growing trend), and monsoon precipitating days (CBL is shallow and gradually ascending and gradually descending).…”

Section: Introductionmentioning

confidence: 99%

Improved boundary layer height measurement using a fuzzy logic method: Diurnal and seasonal variabilities of the convective boundary layer over a tropical station

et al. 2017

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This paper presents the efficacy of a “tuned” fuzzy logic method at determining the height of the boundary layer using the measurements from a 1280 MHz lower atmospheric radar wind profiler located in Gadanki (13.5°N, 79°E, 375 mean sea level), India, and discusses the diurnal and seasonal variations of the measured convective boundary layer over this tropical station. The original fuzzy logic (FL) method estimates the height of the atmospheric boundary layer combining the information from the range‐corrected signal‐to‐noise ratio, the Doppler spectral width of the vertical velocity, and the vertical velocity itself, measured by the radar, through a series of thresholds and rules, which did not prove to be optimal for our radar system and geographical location. For this reason the algorithm was tuned to perform better on our data set. Atmospheric boundary layer heights obtained by this tuned FL method, the original FL method, and by a “standard method” (that only uses the information from the range‐corrected signal‐to‐noise ratio) are compared with those obtained from potential temperature profiles measured by collocated Global Positioning System Radio Sonde during years 2011 and 2013. The comparison shows that the tuned FL method is more accurate than the other methods. Maximum convective boundary layer heights are observed between ~14:00 and ~15:00 local time (LT = UTC + 5:30) for clear‐sky days. These daily maxima are found to be lower during winter and postmonsoon seasons and higher during premonsoon and monsoon seasons, due to net surface radiation and convective processes over this region being more intense during premonsoon and monsoon seasons and less intense in winter and postmonsoon seasons.

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Diurnal and seasonal variability of TKE dissipation rate in the ABL over a tropical station using UHF wind profiler

Cited by 28 publications

References 37 publications

Latitudinal and Topographical Variabilities of Free Atmospheric Turbulence From High‐Resolution Radiosonde Data Sets

Latitudinal and Topographical Variabilities of Free Atmospheric Turbulence From High‐Resolution Radiosonde Data Sets

Wind profiler observations of a monsoon low-level jet over a tropical Indian station

Improved boundary layer height measurement using a fuzzy logic method: Diurnal and seasonal variabilities of the convective boundary layer over a tropical station

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