Articles written in Journal of Earth System Science
Volume 128 Issue 6 August 2019 Article ID 0155 Research Article
A global forecast system model at a horizontal resolution of T1534 ($\sim$12.5 km) has been evaluated for the monsoon seasons of 2016 and 2017 over the Indian region. It is for the first time that such a high-resolution global model is being run operationally for monsoon weather forecast. A detailed validation of the model therefore is essential. The validation of mean monsoon rainfall for the season and individual months indicates a tendency for wet bias over the land region in all the forecast lead time. The probability distribution of forecast rainfall shows an overestimation (underestimation) of rainfall for the lighter (heavy) categories. However, the probability distribution functions of moderate rainfall categories are found to be reasonable. The model shows fidelity in capturing the extremely heavy rainfall categories with shorter lead times. The model reasonably predicts the large-scale parameters associated with the Indian summer monsoon, particularly, the vertical profile of the moisture. The diurnal rainfall variability forecasts in all lead times show certain biases over different land and oceanic regions and, particularly, over the north–west Indian region. Although the model has a reasonable fidelity in capturing the spatio-temporal variability of the monsoon rain, further development is needed to enhance the skill of forecast of a higher rain rate with a longer lead time.
Volume 129 All articles Published: 15 June 2020 Article ID 0138 Research Article
While the numerical models are being run with increasing resolutions, the parameterization of cumulus convection used in the general circulation models, irrespective of closure assumption and trigger mechanism, continue to use the mass flux framework. To address one of the most important components of convective parameterization, vertical profile of mass flux is examined. We have compared the convective mass flux of the Coupled Model Intercomparison Project Phase 5 (CMIP5) models during Boreal summer over the Eastern Pacific, Western Pacific and Indian Ocean with that of ERA – Year of Tropical Convection (YOTC) reanalysis dataset. The analyses suggest that most of the models overestimate the mass flux by an order over all the oceanic basins and interestingly the vertical structure also appears similar for all the CMIP5 models irrespective of ocean basins. In view of this, we state that the improper mass flux distribution in the cumulus parameterization schemes of global models need to be improved to reduce some of the uncertainties arising from the cumulus schemes of climate models which in turn impact the precipitation bias of the models.
Volume 129 All articles Published: 10 August 2020 Article ID 0170 Erratum
Volume 129, 2020
Continuous Article Publishing mode
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