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N. Borah
Indian Institute of Tropical Meteorology
14Publications
9H-index
219Citations
Publications 15
Newest
#1A. K. Sahai (IITM: Indian Institute of Tropical Meteorology)H-Index: 19
#2N. Borah (IITM: Indian Institute of Tropical Meteorology)H-Index: 9
Last.S. Abhilash (CUSAT: Cochin University of Science and Technology)H-Index: 11
view all 5 authors...
If a coarse resolution dynamical model can well capture the large-scale patterns even if it has bias in smaller scales, the spatial information in smaller domains may also be retrievable. Based on this hypothesis a method has been proposed to downscale the dynamical model forecasts of monsoon intraseasonal oscillations in the extended range, and thus reduce the forecast spatial biases in smaller spatial scales. A hybrid of clustering and analog technique, used in a self organizing map (SOM)-base...
2 CitationsSource
#1S. Joseph (IITM: Indian Institute of Tropical Meteorology)H-Index: 13
#2A. K. Sahai (IITM: Indian Institute of Tropical Meteorology)H-Index: 19
Last.R. Phani (IITM: Indian Institute of Tropical Meteorology)H-Index: 2
view all 10 authors...
The onset/progression phase of theIndian summer monsoon (ISM) is very crucial for the agricultural sector of the country as it has strong bearing on the sowing of kharif crops, which in turn affects overall food grain production and hence food security. The recent ISMs of 2013 and 2014 exhibited quite distinct progression phases. While 2013 had one of the fastest advancement in the last 70 years, 2014 witnessed a comparatively lethargic progression phase. The major difference was felt in the ear...
5 CitationsSource
#1A. K. Sahai (IITM: Indian Institute of Tropical Meteorology)H-Index: 19
#2R. Chattopadhyay (IITM: Indian Institute of Tropical Meteorology)H-Index: 16
Last.N. Borah (IITM: Indian Institute of Tropical Meteorology)H-Index: 9
view all 8 authors...
The real-time validation of any strategy to forecast the Indian summer monsoon rainfall requires comprehensive assessment of performance of the model on sub-seasonal scale. The multi-model ensemble (MME) approach based on the NCEP-CFS version 2 models, as developed and reported earlier, has been employed to forecast the 2014 monsoon season on the extended range scale with 3-4 pentad lead time (where a pentad corresponds to five-day average). The present study reports the broad performance of the...
9 CitationsSource
#1S. Joseph (IITM: Indian Institute of Tropical Meteorology)H-Index: 13
#2A. K. Sahai (IITM: Indian Institute of Tropical Meteorology)H-Index: 19
Last.A. A. KumarH-Index: 9
view all 8 authors...
AbstractThis study reports an objective criterion for the real-time extended-range prediction of monsoon onset over Kerala (MOK), using circulation as well as rainfall information from the 16 May initial conditions of the Grand Ensemble Prediction System based on the coupled model CFSv2. Three indices are defined, one from rainfall measured over Kerala and the others based on the strength and depth of the low-level westerly jet over the Arabian Sea. While formulating the criterion, the persisten...
6 CitationsSource
#1N. Borah (IITM: Indian Institute of Tropical Meteorology)H-Index: 9
#2A. K. Sahai (IITM: Indian Institute of Tropical Meteorology)H-Index: 19
Last.A. Kumar (Silver Spring Networks)H-Index: 1
view all 7 authors...
Several aspects of real-time forecast of Indian summer monsoon (ISM) in 3–4 pentad lead time (extended range) are discussed in this study to explore the operational capability of the Climate Forecast System model version 2 (CFSv2) developed by National Centre for Environmental Prediction (NCEP). 2013 summer monsoon was a near excess monsoon year in terms of seasonal mean and was a result of rich diversity of phenomena including strong intraseasonal variations and intense northward propagations o...
12 CitationsSource
#1S. Abhilash (UM: University of Miami)H-Index: 1
#2A. K. Sahai (IITM: Indian Institute of Tropical Meteorology)H-Index: 19
Last.A. A. KumarH-Index: 9
view all 9 authors...
AbstractThis study describes an attempt to overcome the underdispersive nature of single-model ensembles (SMEs). As an Indo–U.S. collaboration designed to improve the prediction capabilities of models over the Indian monsoon region, the Climate Forecast System (CFS) model framework, developed at the National Centers for Environmental Prediction (NCEP-CFSv2), is selected. This article describes a multimodel ensemble prediction system, using a suite of different variants of the CFSv2 model to incr...
13 CitationsSource
#1A. K. Sahai (IITM: Indian Institute of Tropical Meteorology)H-Index: 19
#2S. Abhilash (IITM: Indian Institute of Tropical Meteorology)H-Index: 11
Last.M. Rajeevan (Government of India)H-Index: 33
view all 7 authors...
Optimization of computational efficiency is indispensable in the incorporation of numerical complexity in a pragmatic climate forecast system. From the resource optimization standpoint, the debate regarding, to what extent increased computing efficiency and expense on resources has reduced the signal-to-noise ratio and improved our understanding towards future climate states on different time scales, still continues. With the recent advancement of real time climate forecasts from different opera...
18 CitationsSource
#1S. Joseph (IITM: Indian Institute of Tropical Meteorology)H-Index: 13
#2A. K. Sahai (IITM: Indian Institute of Tropical Meteorology)H-Index: 19
Last.Arun KumarH-Index: 57
view all 9 authors...
The Indian summer monsoon of 2013 covered the entire country by 16 June, one month earlier than its normal date. Around that period, heavy rainfall was experienced in the north Indian state of Uttarakhand, which is situated on the southern slope of Himalayan Ranges. The heavy rainfall and associated landslides caused serious damages and claimed many lives. This study investigates the scientific rationale behind the incidence of the extreme rainfall event in the backdrop of large scale monsoon en...
45 CitationsSource
#1N. Borah (IITM: Indian Institute of Tropical Meteorology)H-Index: 9
#1N. BorahH-Index: 9
Last.Arun KumarH-Index: 57
view all 8 authors...
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