Validation of 205 MHz wind profiler radar located at Cochin, India, using radiosonde wind measurements

Kottayil, Ajil; Mohanakumar, K.; Samson, Titu; Rebello, Rejoy; Manoj, M. G.; Varadarajan, Rakesh; Santosh, K.; Mohanan, Pezholil; Vasudevan, K.

doi:10.1002/2015rs005836

Cited by 34 publications

(18 citation statements)

References 40 publications

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“…This work also demonstrates that there is a higher likelihood of predicting such events of heavy rainfall at least 2 days in advance provided a continuous monitoring of MLLJ is made. In this context, the wind profiler radar at 205 MHz operational at Cochin (10.04°N; 76.32°E), India, has a significant role to play (Kottayil et al ., ; Samson et al ., ). This radar provides three‐dimensional wind profiles for an altitude of 315 m to 20 km.…”

Section: Discussionmentioning

confidence: 97%

The role of monsoon low‐level jet in modulating heavy rainfall events

Xavier

Kottayil

Mohanakumar

et al. 2017

Intl Journal of Climatology

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Monsoon low‐level jet (MLLJ) is an important component of Asian summer monsoon circulation, which is responsible for large‐scale distribution and variability of rainfall over the Indian subcontinent. The evolution of MLLJ characteristics prior to heavy rainfall days and its changes which lead to instances of heavy rainfall over the south‐western coast of India are studied. The European Centre for Medium Range Weather Forecasts (ECMWF) re‐analysis data and India Meteorological Department (IMD) rainfall data during 1979–2007 were used for this study. It is found that the MLLJ core speed, westerly wind depth, zonal water vapour flux, horizontal wind shear and cyclonic vorticity show a steady increase towards the day of heavy rainfall and gradually decrease thereafter. The intensification of these parameters not only brings in abundant moisture but also triggers convection, thereby resulting in the formation of heavy rainfall during monsoon season. The large‐scale advection of moisture brought about by strengthening of MLLJ is shown to be a prerequisite for heavy rainfall over the Indian subcontinent. An interesting result of this study is that heavy rainfall days may have some predictability by continuous monitoring of the progression of MLLJ.

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Section: Discussionmentioning

confidence: 97%

The role of monsoon low‐level jet in modulating heavy rainfall events

Xavier

Kottayil

Mohanakumar

et al. 2017

Intl Journal of Climatology

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“…Upper-air measurements from radiosondes (commonly called weather balloons) have long been the primary source of information, with measurements going back more than 60 years and the radiosonde measurements are unique with regard to the length of the available time series as well as with their high vertical resolution [21] . The unique features of radiosondes might have instigated several researchers around the world to make validation studies of various atmospheric parameters (temperatures, winds, and humidity and others) between radiosonde-measured and other remote sensing instruments including, advanced microwave sounding units (AMSU) and the microwave humidity sounders [22] , radio occultation (RO) technique performed on COSMIC micro-satellites [23][24] , and ground-based wind profiling radars [25] . Table 1.…”

Section: Data and Methods Of Analysismentioning

confidence: 99%

Anomalous wind circulation over Taipei, Taiwan during the northern winter seasons of 2004 and 2005- A case study

Babu¹,

Kumar²,

Brahmanandam³

et al. 2018

som

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This research reports, for the first time, an anomalous wind circulation over Taipei (Latitude 25.030N, Longitude 121.510E), Taiwan during the northern hemisphere winter season (December, January, and February) of years 2004 and 2005. The anomalous wind circulation of meridional winds, which showed southward directions during the winter seasons of 2004 and 2005 instead of northward winds, is noticed from one kilometer altitude range (lower troposphere) and that trend continued till around 20 km altitude range (lower stratosphere). To ascertain whether such a disturbed nature of wind pattern existed over nearby locations to Taipei, we have analyzed radiosonde-measured meridional and zonal winds over four nearby stations station to Taipei including, Roig, Xiamen, Minami and Fuzhou. Surprisingly, no anomalous wind behavior is seen except over Taipei during the northern winter seasons of 2004 and 2005. On the other hand, the European Centre for Medium-Range Weather Forecasts (ECMWF) model-predicted winds do not show any anomalous wind patterns over Taipei and other nearby stations, possibly due to the large averaging of internal variabilities of reanalysis databases. The plausible physical mechanisms of these disturbed meridional wind patterns are not understood at this juncture, but it is believed that local winds and atmospheric pollutants might have created an amicable environment as to provide such a disturbed meridional wind pattern over Taipei, Taiwan in the winter season of 2004 and 2005.

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“…Cochin is a tropical coastal region located at the Gateway of the Indian summer monsoon, with the Arabian Sea in the west and Western Ghats mountain peaks in the east. The technical details and scientific applications of the 205 MHz ST radar (STR) at Cochin were reported in the literature (Kottayil et al ., 2016; 2019; Samson et al ., 2016; Mohanakumar et al ., 2017; 2018).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of global reanalysis winds and high‐resolution regional model outputs with the 205 MHz stratosphere–troposphere wind profiler radar observations

Sivan

Rakesh

Abhilash

et al. 2021

Quart J Royal Meteoro Soc

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A stratosphere–troposphere (ST) wind profiler radar operating at a high VHF range (205 MHz) installed at Cochin (10.03°N, 76.33°E), India, provides high‐resolution winds in time and altitude extending from 315 m to 20 km. We evaluated the horizontal and vertical winds obtained from atmospheric global reanalyses (ERA5, ERA‐Interim, MERRA‐2 and NCEP) data and the high‐resolution regional model (WRF) output winds with the ST radar (STR) wind observations at Cochin. The data for one whole year, from 1 August 2018 to 31 July 2019, for 0600 UTC and 1200 UTC were used. Wind data appraisal has been carried out at 24 levels from 315 m to 18.5 km altitude for the reanalyses datasets and 29 levels for model‐simulated winds in different seasons. Vertical profiles of horizontal winds from reanalysis and model‐simulated data somewhat catch the major changes observed from STR. The zonal winds match very well with the STR, whereas meridional winds show moderate similarity. Higher correlations in zonal winds are found during the summer monsoon, whereas meridional winds show apparent likeness during winter. The ERA5, ERA‐Interim, and model‐simulated winds have better agreement with the STR winds. Observed vertical winds from STR displays large fluctuations, while the estimated vertical winds in reanalysis are highly smoothed. Vertical profiles of vertical winds from the reanalysis datasets are not uniform. The reliability of vertical winds in reanalysis and WRF model output values are dubious compared to that of the directly observed winds from STR. The study indicates that improved quality of vertical and meridional winds in reanalysis data is needed by assimilating directly observed data from the available advanced facilities.

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Validation of 205 MHz wind profiler radar located at Cochin, India, using radiosonde wind measurements

Cited by 34 publications

References 40 publications

The role of monsoon low‐level jet in modulating heavy rainfall events

The role of monsoon low‐level jet in modulating heavy rainfall events

Anomalous wind circulation over Taipei, Taiwan during the northern winter seasons of 2004 and 2005- A case study

Evaluation of global reanalysis winds and high‐resolution regional model outputs with the 205 MHz stratosphere–troposphere wind profiler radar observations

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