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Journal ArticleDOI

Prediction of convective events using multi-frequency radiometric observations at Kolkata

01 Mar 2016-Atmospheric Research (Elsevier)-Vol. 169, pp 24-31
TL;DR: In this article, the effectiveness of nowcasting convective activities using a microwave radiometer has been examined for Kolkata (22.65° N, 88.45° E), a tropical location.
About: This article is published in Atmospheric Research.The article was published on 2016-03-01. It has received 26 citations till now. The article focuses on the topics: Nowcasting.
Citations
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Journal ArticleDOI
TL;DR: In this article, a random forest based machine learning algorithm is tested for nowcasting of convective rain with a ground-based radiometer and the results indicate that the proposed model is very sensitive to the boundary layer instability as indicated by the variable importance measure.

36 citations

Journal ArticleDOI
TL;DR: In this article, an evaluation of convective cloud forecasts performed with the numerical weather prediction (NWP) model COSMO and extrapolation of cloud fields is presented using observed data derived from the geostationary satellite Meteosat Second Generation (MSG).

27 citations

Journal ArticleDOI
01 May 2017
TL;DR: In this paper, the authors investigated the behavior of various meteorological parameters during 1981-2010 to obtain any asymmetric variability of summertime near surface wind over Indian coastal boundaries, and found that no significant changes were obtained in the trends of surface pressure, surface relative humidity, 2-metre temperature and surface precipitation.
Abstract: The behaviors of various meteorological parameters during 1981–2010 are investigated to obtain any asymmetric variability of summertime near surface wind over Indian coastal boundaries. No significant changes were obtained in the trends of surface pressure, surface relative humidity, 2-metre temperature and surface precipitation; although, near surface wind speed is found to have significantly declined on the eastern coast with respect to the western coast during this period. Summertime surface wind speed on the eastern coast have decreased from 3.5 to 2.5 m s − 1 (7 to 5 knots) whereas 4.5 to 4 m s − 1 (9 to 8 knots) during the last three decades (statistical significance level ~ 95%). A decrease in the atmospheric instability may serve as the potential reason for the suppression of severe convective occurrences manifested by a parallel decrease in surface wind speeds over these regions. The local heating up of middle atmosphere (300–500 hPa pressure level) due to increased humidity and the difference in net heat flux over Arabian Sea and Bay of Bengal due to the variance of temperature gradient (1000–925 hPa) along the coastal boundaries might be responsible for this climatic disparity between the coastal regions of India since the last three decades. Summertime near surface wind speed projections for Indian sub-continent based on 7 best climate models, for RCP8.5 scenarios, has been calculated to show a mean increase by ~ 10–15% on the eastern coast (Eastern Ghats), ~ 1–2% on the western coasts (Western Ghats), ~ 1–5% decrease in the Indo-Gangetic Basin and ~ 3% decrease in the Gangetic West Bengal and adjoining Bangladesh.

26 citations

Journal ArticleDOI
TL;DR: In this article, the authors analyzed thermodynamic indices variation over three sites of eastern Indian region: Bhubaneswar, Kolkata and Ranchi, associated with pre-monsoon thunderstorms for 20-year period (1987-2006) for Bhubaneh and Kolkatha and 15-years (1996-2010) for Ranchi.
Abstract: The present study analyses thermodynamic indices variation over three sites of eastern Indian region: Bhubaneswar, Kolkata and Ranchi, associated with pre-monsoon thunderstorms for 20-year period (1987–2006) for Bhubaneswar and Kolkata and 15 years (1996–2010) for Ranchi. All three sites are showing a rise in humidity over the period, unveiling the climate change over the region. We evaluated the threshold values of various thermodynamic indices for periods of 5-year intervals at each site based on skill score analysis. The indices associated with potential, convective, latent instability and moisture are showing varying threshold values over all the sites, and some of the indices are showing a definite increase/decrease in these threshold values. All three sites are showing a decrease in thunderstorm frequency over the study period. The work identifies the thermodynamic indices, which tend to capture the global warming impact in the threshold values by either showing an increase or decrease with the time at each site. The results advocate that for a long-term analysis of thermodynamic indices, the threshold values may change from one period to another.

23 citations

Journal ArticleDOI
TL;DR: In this paper, three retrieval techniques have been used to obtain the temperature and relative humidity profiles from brightness temperatures, namely; piecewise linear regression, feed forward neural network and neural back propagation network.

21 citations

References
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Journal ArticleDOI
TL;DR: In this article, the authors used the Arrival Time Difference (ATD) lightning detection and location system from the UK Met Office to evaluate 32 different thunderstorm predictors, derived from rawinsonde observations.

167 citations

Journal ArticleDOI
TL;DR: In this article, a tracking algorithm extrapolates radar images in space and time to evaluate the quality of the extrapolation, a parameter scheme is introduced, able to distinguish between errors in the position and the intensity of the predicted precipitation.

100 citations

Journal ArticleDOI
01 Mar 1994
TL;DR: In this paper, the authors describe the current status of techniques for vertical profiling of mean wind speeds, temperature, and humidity, and discuss options for combining them and discuss how to combine them.
Abstract: Over the last 25 years, ground-based remote profiling has found increasing applications in atmospheric studies where its high vertical and temporal resolution and extended vertical coverage are giving scientists a clearer understanding of atmospheric processes in the troposphere. The authors describe the current status of techniques for vertical profiling of mean wind speeds, temperature, and humidity, and discuss options for combining them. >

94 citations

Journal ArticleDOI
TL;DR: In this article, a wind index based on the knowledge of microburst evolution is proposed to provide some warning to the public and aviation, which can be easily computed from soundings.
Abstract: Microbursts are small-scale phenomena that have been viewed by many meteorologists as difficult to predict. However, there exists sufficient knowledge of microburst evolution by some in the research and operational communities that can be applied on the mesoscale to provide some warning to the public and aviation. This paper introduces a wind index or WINDEX that is based on this knowledge. It can be easily computed from soundings. The WINDEX is calculated from soundings known to have been taken in microburst environments and previously presented in the literature. The WINDEX can also be computed from surface observations using appropriate assumptions. This paper shows how to use the hourly surface-based WINDEX information (data) by showing its application to the infamous DFW microburst on 2 August 1985 and for three consecutive days in August 1993. The surface-based WINDEX analyses reveal a common pattern first noted by Ladd (1989); that is, microbursts primarily occur with new convection on old...

65 citations