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Sahai, A. K.
- Real-Time Performance of a Multi-Model Ensemble-Based Extended Range Forecast System in Predicting the 2014 Monsoon Season Based on NCEP-CFSv2
Abstract Views :269 |
PDF Views:114
Authors
A. K. Sahai
1,
R. Chattopadhyay
1,
S. Joseph
1,
R. Mandal
1,
A. Dey
1,
S. Abhilash
1,
R. P. M. Krishna
1,
N. Borah
1
Affiliations
1 Indian Institute of Tropical Meteorology, Pune 411 008, IN
1 Indian Institute of Tropical Meteorology, Pune 411 008, IN
Source
Current Science, Vol 109, No 10 (2015), Pagination: 1802-1813Abstract
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 MME employed on experimental basis to forecast the salient features of the real-time evolution of the 2014 monsoon season during June to September. The MME is successful in predicting both these features well in advance (3-4 pentad or 15-20 days lead time). The assessment of the model performance at pentad scale lead time shows that the weak monsoon conditions that are evident in precipitation and lower level wind anomalies are well captured as a whole up to four pentad advance lead time. The subseasonal propagation during onset and withdrawal is also evident in the forecast. Finally, the region-wise performance shows that the spatial extent of the skillful forecast encompasses central India as well as the monsoon zone for the 2014 monsoon season. Considering the natural variation in the forecast skill of extended range forecast itself as reported in earlier studies, the 2014 monsoon forecast seems to be skillful for operational purposes. For other regions (e.g. North East India), the forecast could be skillful at times, but it still requires further research on how to improve the same.Keywords
Monsoon Forecast, Multi-Model Ensemble, Pentad, Lead Time.Full Text
References
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- Impact of Observed Climate Change on the Classification of Agroclimatic Zones in India
Abstract Views :211 |
PDF Views:73
Authors
N. Chattopadhyay
1,
A. K. Sahai
1,
P. Guhathakurta
1,
S. Dutta
1,
A. K. Srivastava
1,
S. D. Attri
2,
R. Balasubramanian
1,
K. Malathi
1,
Swati Chandras
1
Affiliations
1 India Meteorological Department, Shivajinagar, Pune 411 005, IN
2 India Meteorological Department, New Delhi 110 003, IN
1 India Meteorological Department, Shivajinagar, Pune 411 005, IN
2 India Meteorological Department, New Delhi 110 003, IN
Source
Current Science, Vol 117, No 3 (2019), Pagination: 480-486Abstract
The classification of agroclimatic zones in India was made in the 1990s for identifying priorities and developing strategies for location-specific and need-based research as well as overall agricultural development in the country. Long-term climatic parameters, particularly temperature and rainfall along with soil and crop information were used for the classification of agroclimatic zones. It has been documented with a fair degree of accuracy that overall climate is changing, particularly with respect to temperature over the Indian region. Thus it is anticipated that in the recent past, climate change may be reflected in the agroclimatic zones as well and ultimately affect the criteria of their classification based on climatic parameters. The objective of the present study is to examine the trends and spatial/temporal variability of temperature, rainfall, rainy days, and heavy rainfall in different agroclimatic zones of the country, which may help in better understanding of the further initiatives on reclassification of agroclimatic zones, if required. Using various long-term gridded data from 1985 and instrumental datasets starting from 1951 to 1980, studies have been made to observe changes in different components of the climatic variables, i.e. temperature and rainfall. It has been observed that there are significant changes in temperature and rainfall, both temporally and spatially, across India and there is a definite shift in temperature and rainfall patterns in the recent past compared to 1951–1980. It has also been inferred that there is a need to reconsider the classification of agroclimatic zones in India under the scenario of observed climate changes in the country.Keywords
Agroclimatic Zones, Classification, Climatic Parameters, Climate Change.Full Text
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