Nasuno, T., K. Kikuchi, M. Nakano, Y. Yamada, M. Ikeda, and H. Taniguchi, 2017: Evaluation of the near real-time forecasts using a global nonhydrostatic model during the CINDY2011/DYNAMO. J. Meteor. Soc. Japan, 95, 345-368.
Special Issue on the Coordinated International Field Campaign on the Madden-Julian Oscillation
https://doi.org/10.2151/jmsj.2017-022 Graphical Abstract with highlights
- The near real-time forecasts using Nonhydrostatic Icosahedral Atmospheric Model (NICAM) for the CINDY2011/DYNAMO were evaluated in comparison with observations. A week-long forecast was run each day with the finest mesh size of 14 km over the tropical Indian Ocean.
- The simulated precipitation time series fairly represented the sharp contrast associated with the MJO events (Fig. 1), although a 30% overprediction of precipitation was found on average. Frequencies of strong (>40 mm day-1) precipitation were overpredicted, while those of weak precipitation were underpredicted against satellite observations. Compared with the sounding observations, lower to middle tropospheric dry (∼1 g kg-1) and warm (∼1 K) biases were found.
- The moisture and energy budgets were investigated using the forecast data. The diagnosis using the 7-day-mean fields captured the observed features of the MJO events. Meanwhile, significant upward transport of moisture by the grid-resolved high-frequency variability was detected throughout the period (Fig. 2), which was markedly different from the diagnosis using ERA-interim (Fig. 2, gray lines). The high-frequency effects in NICAM partly accounted for the above mentioned performance and the moistening in the preconditioning period of the MJO.