Skill of monthly rainfall forecasts over India using multi‐model ensemble schemes

Abstract

Rainfall in the month of July in India is decided by large-scale monsoon pattern in seasonal to interannual timescales as well as intraseasonal oscillations. India receives maximum rainfall during July and August. Global dynamic models (either atmosphere only or coupled models) have varying skills in predicting the monthly rainfall over India during July. Multi-model ensemble (MME) methods have been utilized to evaluate the skills of five global model predictions for . The objective has been to develop a prediction system to be used in real time to derive the mean of the forecast distribution of monthly rainfall. It has been found that the weighted multi-model ensemble (MME) schemes have higher skill in predicting July rainfall compared to individual models. Through the MME methods, skill of rainfall predictions improved significantly over eastern parts of India. However, there is a region over India where none of the models or the MME scheme has any useful skill. Similarly, there are few typical years in which the mean distribution of July rainfall cannot be predicted with higher skill using the available statistical post-processing methods. A simple MME probabilistic scheme has been utilized to show that skill of probabilistic predictions improved when the representation of mean of forecast distribution has better skill.

Prediction of Indian summer monsoon rainfall (ISMR) using canonical correlation analysis of global circulation model products

“…The last two models, referred to as ECHcasst and ECHcfssst, are two twotier versions of ECHAM4.5 forced with constructed analog SST and CFS forecast SST (Li and Goddard, 2005), respectively. All these models are also discussed in detail in Kar et al (2011). The number of ensemble members and spatial resolution of these models are given in Table 1.…”

“…Kang et al, 2004;Krishna Kumar et al, 2005;Sahai et al, 2008;Pattanaik and Kumar, 2010;Acharya et al, 2011;Janakiraman et al, 2011;Kar et al, 2011). Preethi et al (2010) have analysed the skill of some of the coupled models for the hind-cast run from 1959 to 1979 and found the skill of the models to be positive.…”

Temperature and Precipitation Climatology Assessment over South Asia using the Regional Climate Model (RegCM4.3): An Evaluation of the Model Performance

“…Previous studies have shown that the simulation of South Asian summer monsoon precipitation by RegCM is sensitive to the physics parameterization used. Kar et al [33] and Acharya et al [34] also found that RCM has some systematic biases while simulating the summer monsoon precipitation over this region. As described in section 2.1.3, RegCM4.3 simulated excessive precipitation with the MIT convective scheme.…”

Performance of Multimodel Schemes for Seasonal Precipitation over Indian Region

“…Advances in Meteorology schemes were tested on the Indian region for rainfall forecast [19][20][21]. On examination of 5-multimodel schemes they realized that the accuracy of the rainfall forecasts can be increased over Indian region.…”