High-resolution operational monsoon forecasts: an objective assessment

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 operational agencies with increased computational efficiencies and resources, it has become necessary to perform an objective evaluation of the high resolution operational monsoon forecasts to conform if the high resolution outlooks are skillful enough as compared to a low resolution version. In this paper, we have performed a quantitative comparison of the extended range (~2-3 weeks) forecasts of monsoon intraseasonal oscillations (MISO) obtained from the climate forecast system model version 2 developed at National Centre for Environmental Prediction USA at two different resolutions: T126 (~100 km) and T382 (~38 km). It is observed that, higher model resolution (T382) has provided better basic state for MISO along with large reduction in climatological biases in June-September precipitation than the lower resolution forecast (T126). However, compared to the computing resources, there is no significant improvement in the prediction skill from increased horizontal resolution