Search

Extended Range of Forecast Service (ERFS) is highly useful for planning of cropping season and midterm correction at the farm level. The medium-range and long-range forecast validation have many studies, whereas ERF has less that needs to be studied. Maize is an important field crop in India after rice and wheat. Therefore, the prediction of maize yield has significant importance. In the present study, ERFS data were validated by correlation analysis using monthly observed rainfall frequency and intensity. This data was imported to DSSAT (Decision Support System for Agro-technology Transfer) to simulate maize yield of Erode district of Tamil Nadu. The model output and actual yield data from Erode were compared. Forecasted monthly total rainfall was correlated at a rate of 0.97r value with that observed. Yield simulation of maize was done using DSSAT by integrating ERFS data and the observed monthly data. Mean per cent deviation among the yields of observed weather and the disaggregated one tended to be -15.7 %. The average deviation between the yields of ERF forecasted weather data and actual yield was very high (-29.7 %) for Erode. Mean % deviation between the yields of observed weather and the actual yield was - 14.7 %. Downscaled and accurate weather forecasts could be facilitated for yield prediction of crops by DSSAT model. Yield prediction by the model under observed weather was convenient and usable. Model under-predicted the yields when using ERF data. Both model and ERF forecast need to be improved further for higher resolution. [ABSTRACT FROM AUTHOR]

To assess the drought hazard for different agro-climatic zones of Tamil Nadu (TN), India, the present study deals with temporal trend and spatial pattern of drought over the period 1981-2019. Standardized Precipitation Index (SPI) has been used to detail the geographical variations of drought intensity, duration and frequency at multiple time steps. The spatial rainfall variability of the Southwest monsoon (SWM) ranged from 69.3 mm (Tuticorin) to 772.8 mm (the Nilgiris), and that for the Northeast monsoon (NEM) ranged from 277.8 mm (Krishnagiri) to 825.9 mm (Nagapattinam), while annual rainfall variability ranged from 558.8 mm (Tuticorin) to 1466.8 mm (the Nilgiris) for TN. Irrespective of all the regions, the frequency of moderate drought occurrence was higher compared to other drought nomenclature. The NEM season recorded on par and higher number of drought occurrences with respect to SWM season. Out of 39 years, TN experienced severely dry to extremely dry climate during 2002. The result underlines the potential of SPI in drought identification and also revealed that the rainfall is strongly linked to drought policies and measures implemented for the state. [ABSTRACT FROM AUTHOR]