A Doppler radar study of convective draft lengths over Darwin, Australia

Data from an upward-pointing wind profiler radar pair at Darwin in tropical Australia are used to determine the characteristics of individual convective up- and downdrafts observed at the site. Drafts are identified as vertically contiguous regions of instantaneous upward or downward motion exceeding 0.2 ms−1. Most updrafts and downdrafts found are less than 2 km in vertical extent, and updrafts exceeding 5 km vertical length carry no more than 33% of the total upward mass flux. Updraft length correlates positively with rain rates, and on very high rain rates (greater than 20 mm/hr), average updraft lengths are ~5 km. Typical peak updraft velocities increase from ~2.5 ms−1 for the smallest to ~ 4 ms−1 for the largest drafts, while those for downdrafts remain ~ 2 ms−1 regardless of size. These results are broadly consistent with other numerical modeling studies, but contrast with the common view of deep convection as being dominated by continuous, deep drafts.

Characteristics Analysis of Wind Components according to the Typhoon Track Influenced in the Korean Peninsula Using a Wind Profiler Radar

<p> </p><p> Typhoon is a tropical cyclone accompanied by strong wind and heavy precipitation. It induces high human and property damages depending on typhoon track. The typhoon influenced in the Korean Peninsula mainly passes through Jeju Island and the Southern costal area from northward the East China Sea. In this study, wind components analysis using a wind profiler radar close to the shoreline is conducted. The wind profiler radar observes the three-dimensional wind components for a fixed-point regardless of precipitation and provides high-resolution (10 min., 100 m) data for continuous analysis. The wind characteristics according to the typhoon track was investigated using the Boseong wind profiler radar (34.76 °N, 127.21 °E) located on the south coast in Korea.</p><p> Some cases were selected as typhoons that occurred in 2010 (Dianmu, Kompasu, Malou), 2011 (Meari, Muifa) and 2012 (Khanun). For the horizontal wind analysis, there were distributed the preprocessed zonal (U) and meridional (V) wind components with time. As a result, the shape of the scatter plot and their distribution characteristics were differently shown according to the typhoon track. Dianmu and Malou had circle-shape and distributed similarly over time, however Muifa, Meari, Kompasu and Khanun displayed the line-shape, relatively. Their differences were confirmed through the quadratic regression equations by each typhoon track. In addition, the amount of change in U and V was analyzed in time series.</p><p> These wind components analysis using ground-based observation data are expected to be applied for typhoon track analysis, prediction and natural disaster prevention.</p>

Lower Atmospheric Wind Dynamics as Measured by the 1290 MHz Wind Profiler Radar Located at Cardington (Lat. 52.10ºN, Long. 0.42ºE), UK and Their Comparisons with Near-by Radiosonde Instrument

This study reports diurnal variations of wind directions, wind speed of vector winds, and the evolution of boundary layer (BL) over a mid-latitude measured using a transportable 1290 MHz wind profiling radar located at Cardington (Lat. 52.10ºN; Long. 0.42ºE), Bedfordshire, UK from 17 to 28 April 2010. The horizontal winds show benign behavior during nighttime hours, while winds during daytime hours had magnitudes around, on average, 10-20 m/s, in the majority of the cases. The heights of the boundary layer (BL) varied from as low as ~1100 m to ~2600 km and BL height had shown to have evolved from 0700 universal time (UT) onwards and collapsed by 0000 UT. Besides, a comparison made between winds measured by the 1290 MHz radar and near-by radiosonde showed a moderate similitude between them, albeit a few discrepancies are found in wind directions and speeds. The possible reasons for these discrepancies could be different volume sensing of observations of these independent observations. An attempt is, therefore, made to calculate radiosonde balloon drifts [1] for the ascending node of the balloons, which had confirmed that the balloons often drifted horizontally as long as up to 100 km. The large drifts, most probably, are the possible reasons for the mismatching of winds measured by these two independent remote sensing instruments.

Design and Analysis of Sierpinski Carpet Fractal Antenna for UHF Spaced Antenna Wind Profiler Radar

This paper emphasizes the design of Sierpinski carpet fractal antenna to miniaturize the antenna array of UHF Spaced antenna Wind profiler radar that operates at 445 MHz. The proposed antenna is designed using High Frequency Structure Simulator (HFSS) where aluminium is used as a patch and ground with air as dielectric substrate due to it’s zero loss tangent .patch is separated from ground with help of hinges and fed with 50 ohm coaxial probe. The Sierpinski fractal antenna is designed till third iteration so as to reduce its size and weight by 33 percent