Raghavendra Ashrit

Raghavendra Ashrit
National Centre for Medium Range Weather Forecasting | NCMRWF · Ministry of Earth Sciences

Ph D

About

89
Publications
22,110
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1,407
Citations
Citations since 2016
61 Research Items
873 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150

Publications

Publications (89)
Article
Accurate forecasts of visibility are important to avoid disruption in air and highway traffic caused due to the formation of dense fog. However, accurate forecasting of visibility/fog remains a challenge as the genesis and development of fog is a result of many processes. In view of this, models have been developed in recent years to forecast visib...
Conference Paper
Full-text available
As a part of the New Generation Verification (NGVer) being developed at the UK Met Office, the Model Evaluation Tools Plus (METplus) package is now being used for seamless verification of operational forecasts (global and regional) at the National Centre for Medium-Range Weather Forecasting (NCMRWF). MET version 10.0 along with METPLUS 4.0.0 is ins...
Conference Paper
As a part of the New Generation Verification (NGVer) being developed at the UK Met Office the Model Evaluation Tools Plus (METplus) package is now being used for seamless verification of operational ensemble forecasts (global and regional) at the National Centre for Medium Range Weather Forecasting (NCMRWF). MET version 10.0 along with METPLUS 4.0....
Conference Paper
Full-text available
As a part of the New Generation Verification (NGVer) being developed at the UK Met Office, the Model Evaluation Tools Plus (METplus) package is now being used for seamless verification of operational forecasts (global and regional) at the National Centre for Medium-Range Weather Forecasting (NCMRWF). MET version 10.0 along with METPLUS 4.0.0 is ins...
Article
Full-text available
Operational forecasting of tropical cyclone (TC) track and intensity in the India Meteorological Department (IMD) relies more and more on the numerical weather prediction (NWP) model guidance from national and international agencies particularly, on the medium range (24–120 h). Any improvement in TC forecasts by the NWP models enhances the operatio...
Article
Increased resolution of Numerical Weather Prediction (NWP) models can lead to improved prediction of heavy rains; however, the forecasts often suffer from location mismatch and intensity errors which can lead to poor traditional verification scores. Spatial verification can provide more realistic statistics to ascertain the quality of forecasts. Th...
Article
This study focuses on assessing different quantile mapping (QM) bias correction approaches based on empirical and parametric methods to bias-correct the Indian Monsoon Data Assimilation and Analysis (IMDAA) precipitation data subsequently calibrate the National Centre for Medium Range Weather Forecasting (NCMRWF) Unified Model operational forecasts...
Article
Full-text available
Forecasting of heavy rainfall events is still a challenge even for the most advanced state-of-art high resolution NWP modelling systems. Very often the models fail to accurately predict the track and movement of the low pressure systems leading to large spatial errors in the predicted rain. Quantification of errors in forecast rainfall location and...
Article
Full-text available
Countries adjoining the North Indian Ocean (NIO) region are among the world's worst affected areas by tropical cyclones (TCs). An increase in frequency and intensity of TCs affecting this basin is noticed in recent years. Timely and accurate prediction of a TC can lead to a decrease in damages to life and property caused by the cyclone. In recent t...
Article
The ensemble predictions were more skillful than the deterministic forecasts , as they were able to predict rainfall anomalies.
Article
Performance of four mesoscale models namely, the MM5, ETA, RSM and WRF, run at NCMRWF for short range weather forecasting has been examined during monsoon-2006. Evaluation is carried out based upon comparisons between observations and day-1 and day-3 forecasts of wind, temperature , specific humidity, geopotential height, rainfall, systematic error...
Article
During August 2018 and 2019 the southern state of India, Kerala received unprecedented heavy rainfall which led to widespread flooding. We aim to characterize the convective nature of these events and the large-scale atmospheric forcing, while exploring their predictability by three state of the art global prediction systems, the National Centre fo...
Article
Full-text available
Prediction of heavy/extreme rains is still a challenge, even for the most advanced state-of-the-art high-resolution Numerical Weather Prediction (NWP) modelling systems. Hydrological models use the rainfall forecasts from the NWP models as input. This study evaluates the performance of the UK Met Office Unified Model (UM) in predicting the rainfall...
Article
Full-text available
Verification of forecasts and warnings of high-impact weather is needed by the meteorological centres, but how to perform it still presents many open questions, starting from which data are suitable as reference. This paper reviews new observations which can be considered for the verification of high-impact weather and provides advice for their usa...
Article
Full-text available
NCMRWF global ensemble prediction system (NEPS-G) is being used for operational forecasting of tropical cyclones (TC) since the year 2016. The NEPS-G was upgraded and its horizontal resolution was increased from 33 km to 12 km in the year 2018. The upgraded NEPS-G has shown improved performance in forecasting tropical cyclones over the North Indian...
Conference Paper
There are various methods available for the verification of cyclones. The Object-based diagnostic evaluation is one of the techniques. This is an object-based technique of spatial verification methods that provides information that is not possible to obtain using general traditional grid-point based verification methods. It objectively identifies s...
Article
This paper deals with the analysis of the ability of the operational global ensemble prediction system (EPS) at the National Centre for Medium Range Weather Forecasting (NCMRWF, NEPS in predicting the probabilities of the maximum 2 m temperature (TMAX). The mean of the TMAX forecasts from NEPS are bias corrected (1st moment) using the technique of...
Conference Paper
The Object-based diagnostic evaluation is one of the advanced verification techniques. This is an object-based technique of spatial verification methods which provides information which is not possible to obtain using general traditional grid-point based verification methods. It objectively identifies simple objects in rainfall fields at different...
Article
Full-text available
In recent times, instances of intense heat waves have increased over the Indian subcontinent. This increase in temperature has an adverse effect on human health and the economy. Over India, such high temperatures are usually seen during the months of March–May (summer). For weather forecasters, it is a challenging job to accurately predict the timi...
Preprint
Full-text available
Verification of high-impact weather is needed by the Meteorological Centres, but how to perform it still presents many open questions, starting from which data are suitable as reference. This paper reviews new observations which can be considered for the verification of high-impact weather, and provides advice for their usage in objective verificat...
Technical Report
Full-text available
This report provides a compilation rainfall forecast verification for the MoES models during monsoon season (JJAS) 2019. The verification results are focused on the rainfall forecasts since the India Meteorological Department (IMD) is using the NWP model precipitation forecast for day to day operational weather forecast in short to medium range. Th...
Article
Full-text available
This report provides a compilation of the NWP model forecast verification for the MoES models during monsoon season (JJAS) 2019. The verification results are focused on upper air fields from the two high resolution deterministic models namely (i) IMD’s GFS and (ii) NCMRWF’s NCUM generating real time NWP forecasts in the medium range time scale (up...
Article
Full-text available
The monsoon Depressions form significant rainfall activity and havoc, at times, along their track particularly over eastern India. NWP models still have challenge in accurate prediction of track and intensity of the Depressions. This often leads to inaccurate forecast in rainfall intensity, area and distribution. This report summarizes the results...
Research
This report provides a compilation of the NWP model forecast verification for the MoES models during monsoon season (JJAS) 2019. The verification results are focused on upper air fields from the two high resolution deterministic models namely (i) IMD’s GFS and (ii) NCMRWF’s NCUM generating real time NWP forecasts in the medium range time scale (up...
Research
This report provides a compilation rainfall forecast verification for the MoES models during monsoon season (JJAS) 2019. The verification results are focused on the rainfall forecasts since the India Meteorological Department (IMD) is using the NWP model precipitation forecast for day to day operational weather forecast in short to medium range. Th...
Research
Full-text available
This report gives a detailed summary of the verification of the NCMRWF model forecasts during the recent Super Cyclone (SUCS) ‘Amphan’ during (16-21 May2020). The mean (all models) initial position error is 48 km with highest error of 53 km in NCUM-R. The mean (all models) 24-hr track error is around 54 km with highest error of 78 km in NCUM-R. Sim...
Research
Full-text available
This report provides a compilation of the verification for the MoES operational NWP model forecast during monsoon season (JJAS) 2019. The verification and intercomparison results are presented for few large scale upper air fields from the two high resolution deterministic models namely (i) GFS and (ii) NCUM and ensemble models namely (iii) GEFS and...
Article
Full-text available
This paper deals with the comparison of cyclone forecasts from the two versions of the operational global ensemble prediction system (EPS) at the National Centre for Medium Range Weather Forecasting (NEPS). The previous version had a horizontal resolution of 33 km with 44 ensemble members (NEPS) whereas the updated version of this EPS has a resolut...
Article
Full-text available
The southern Indian state of Kerala experienced exceptionally high rainfallduring August 2018, which led to devastating floods in many parts of the state.Prediction and early warning of severe weather events in vulnerable areas iscrucial for disaster management agencies in order to protect life and property.In recent years, state-of-the-art numeric...
Article
Full-text available
The southern Indian state of Kerala experienced exceptionally high rainfall during August 2018, which led to devastating floods in many parts of the state. Prediction and early warning of severe weather events in vulnerable areas is crucial for disaster management agencies in order to protect life and property. In recent years, state‐of‐the‐art num...
Technical Report
An international conference on “Ensemble Methods in Modelling and Data Assimilation (EMMDA)” was organised by NCMRWF during 24-26 February 2020. The international conference was inaugurated by the Chief Guest Dr. M. Mohapatra, Director General of Meteorology, IMD & Permanent Representative to WMO on 24th February in the presence of Dr. Vipin Chandr...
Article
The Indian Monsoon Data Assimilation and Analysis (IMDAA) is a regional high‐resolution atmospheric reanalysis over the Indian subcontinent. This regional reanalysis over India is the first of its kind and is produced by the National Centre for Medium Range Weather Forecasting and Met Office, UK, in collaboration with the India Meteorological Depar...
Conference Paper
Full-text available
सार: मॉडल भौतिकी और रिजोलूशन में प्रमुख सुधार सहित एन.डब्लू.पी. मॉडल में कई महत्वपूर्ण सुधार के बावजूद, इन मॉडलों में अभी भी सिस्टेमेटिक बायस (व्यवस्थित अभिनति) से ग्रसित हैं। एक मॉडल से इन सिस्टेमेटिक बायसों को दूर करने के लिए कई तरीके उपलब्ध हैं, उदाहरण के लिए सांख्यिकीय प्रोसेसिंग विधि को लागू करके। वर्तमान अध्ययन में हमने डिकेयिगिं एवरेज बायस क...
Conference Paper
इस अध्ययन में उपग्रह से प्राप्त आंकडे तथा पुनर्विश्लेषण आंकडों का उपयोग करके मध्य और उत्तर भारती क्षेत्र में हुई भारी वर्षा के प्रकरण की नैदानिक जांच किया है । 1 जनवरी 2012 को संगठित उष्णकटिबंधीय और बहिउष्णकटिबंधीय बल ने तीव्र वर्षा को प्रेरित किया, यह घटना इस मायने में अद्वितीय है। समीपवर्ती उष्णकटिबंधीय महासागर से आने वाली नमी विंडसैट (मल्टी-फ़...
Conference Paper
Full-text available
This study, first of its kind evaluates the suitability of Indian Monsoon Data Assimilation and Analysis (IMDAA) reanalysis data products for offshore wind resource assessment. IMDAA is a high resolution (12km) reanalysis data over Indian region spanning 1979-2018. Near surface (at 50m) wind speed and direction from IMDAA have been validated agains...
Article
Full-text available
The Indian Monsoon Data Assimilation and Analysis (IMDAA) is a regional high‐resolution atmospheric reanalysis over the Indian subcontinent. This regional reanalysis over India is the first of its kind and is produced by the National Centre for Medium Range Weather Forecasting (NCMRWF) and Met Office (MO), U. K, in collaboration with the India Mete...
Conference Paper
In spite of many significant improvements in NWP models including major improvements in the model physics and resolution, these models still suffer from systematic biases. There are several methods available to remove these systematic errors from a model, for example by applying statistical post processing algorithms. In the current study we have m...
Conference Paper
In spite of many significant improvements in NWP models including major improvements in the model physics and resolution, these models still suffer from systematic biases. There are several methods available to remove these systematic errors from a model, for example by applying statistical post processing algorithms. In the current study we have m...
Presentation
Full-text available
This presentation highlights two major research findings (wind power perspective): - 1. How the wind speed has decreased in the last four decades over different wind rich states in India using MERRA data? 2. What is the future trend of wind speed using one of the CMIP5 climate models data?
Article
Full-text available
Prediction of heavy rains associated with orography is still a challenge, even for the most advanced state-of-art high-resolution Numerical Weather Prediction (NWP) modeling systems. The aim of this study is to evaluate the performance of UK Met Office Unified Model (UM) in predicting heavy and very heavy rainfall exceeding 80th and 90th percentile...
Article
Full-text available
The operational medium range rainfall forecasts of the Met Office Unified Model (UM) are evaluated over India using the Contiguous Rainfall Area (CRA) verification technique. In the CRA method, forecast and observed weather systems (defined by a user-specified rain threshold) are objectively matched to estimate location, volume, and pattern errors....
Chapter
State-of-the-art Numerical Weather Prediction (NWP) models can provide useful weather information in the medium-range timescales (3 to 10 days ahead) which can be applied for decision-making in different sectors like agriculture, power distribution, disaster management and water resource management. Forecasting of monsoon weather system and associa...
Conference Paper
Full-text available
There are various methods of bias corrections (BC), out of them the decaying average bias correction technique we have chosen to serve the purpose. It has been recognized as an essentially useful technique for the medium range weather forecasting and is now finding its place in forecasting the extreme events. In the present study we have investigat...
Article
Full-text available
Indian summer monsoon rainfall shows predominant intraseasonal variability with extremes such as droughts and floods being a part of its natural variability. In this aspect, forecast from the National Centre for Medium Range Weather Forecasting based global model (NCUM) with 17 km horizontal resolution is examined for the synoptic features associat...
Chapter
There are two tropical cyclone (TC) seasons over the North Indian Ocean (NIO), (including the Bay of Bengal (BOB) and the Arabian Sea (AS)), i.e. during the pre-monsoon months (April–early June) and the post-monsoon months (October–December) (Mohanty et al., Mar Geod 33:294–314, 2010). Further the Indian subcontinent happens to be one of the world’...
Chapter
During October 2013 Bay of Bengal (BOB) tropical cyclone (TC) ‘Phailin’ hit east coast of India. This was the most intense cyclone that made landfall over India after the Odisha Super Cyclone (29 October 1999). This TC originated from a remnant cyclonic circulation from the South China Sea. It intensified into a cyclonic storm on the 9 October 2013...
Article
Full-text available
The quantitative precipitation forecast (QPF) performance for heavy rains is still a challenge, even for the most advanced state-of-art high-resolution Numerical Weather Prediction (NWP) modeling systems. This study aims to evaluate the performance of UK Met Office Unified Model (UKMO) over India for prediction of high rainfall amounts (>2 and >5 c...
Article
Full-text available
The operational medium-range weather forecasting based on numerical weather prediction (NWP) models are complemented by the forecast products based on ensemble prediction systems (EPSs). This change has been recog-nised as an essentially useful tool for medium-range forecasting and is now finding its place in forecasting the extreme events. Here we...
Article
Full-text available
The operational medium-range weather forecasting based on Numerical Weather Prediction (NWP) models are complemented by the forecast products based on Ensemble Prediction Systems (EPS). This change has been recognized as an essentially useful tool for the medium range forecasting and is now finding its place in forecasting the extreme events. Here...
Article
Full-text available
Forecasting rainfall in the tropics is a challenging task further hampered by the uncertainty in the numerical weather prediction models. Ensemble prediction systems (EPSs) provide an efficient way of handling the inherent uncertainty of these models. Verification of forecasts obtained from an EPS is a necessity, to build confidence in using these...
Conference Paper
Last decade has seen a tremendous improvement in the forecasting skill of numerical weather prediction (NWP) models. This is attributed to increased sophistication in NWP models, which resolve complex physical processes, advanced data assimilation, increased grid resolution and satellite observations. However, prediction of heavy rains is still a c...
Article
The daily rainfall over India during the monsoon season (June-September) is governed by the interplay of the large-scale, synoptic and mesoscale disturbances, many of which are sporadic rainfall spells and extremely intense. These spells often bring extreme amounts of rain over only a few days, which can have sizable impacts on the estimated season...
Article
Full-text available
The real time medium range rainfall forecasts of NCMRWF's Global Forecast System (NGFS) are evaluated over India (land only) against 0.5 degree gridded rainfall (IMD-NCMRWF) observations during JJAS of 2010-2013 using the features-based Contiguous Rain Area (CRA) method. The model resolution is about similar to 35 km in 2010 and 25 km during 2011-2...
Article
The North Indian Ocean is one of the world's worst affected areas by tropical cyclones. It is because of its vast coastline and high population density in the coastal areas that the damage to life and property caused by a landfalling tropical cyclone is huge. Therefore, timely prediction of the cyclone track, landfall location and time is of critic...
Article
Full-text available
This study presents an intercomparison of four cumulus parameterization schemes (CPS) in the prediction of three cases of tropical cyclones in the north Indian Ocean. The study makes use of the Weather Research and Forecasting model of Non-hydrostatic Mesoscale Model version with a horizontal resolution of 27 km. The four deep cumulus schemes studi...