JMSJ, 2016, Vol. 94, No. 4 (August)
Invited Review Articles
- The super-parameterization (SP) approach, illustrated in Fig. 1, originally called the cloud-resolving convection parameterization (CRCP; Grabowski and Smolarkiewicz 1999) revolutionized representation of clouds in climate system modeling, especially for the tropical climate (e.g., representation of convectively-coupled equatorial waves and the Madden-Julian Oscillation). This paper provides a review of various studies conducted applying the SP methodology during the last two decades.
- Continuously increasing computational power makes it possible to foresee application of the LES methodology over the entire Earth to better represent small-scale processes, such and boundary-later dynamics, shallow convection, or entrainment in deep convection, as well as the coupling between cloud microphysics cloud dynamics. However, applying traditional parallel processing methodologies (such as the horizontal domain decomposition) leads to a communication bottleneck because of the large amount of data that needs to be transferred every model time step between neighboring domains. Moreover, compressible equations, needed for the representation of the entire range of spatial scales, from small-scale turbulence to synopticand planetary-scale circulations, are cumbersome because of the presence of sound waves that are marginally (if at all) relevant for weather and climate.
- If the SP methodology is applied in a LES global model as shown in Fig. 2, then the communication bottleneck no longer exists as the neighboring LES models communicate only through the large-scale model. Moreover, the outer model can apply hydrostatic equations and LES models can be analestic. This eliminates the need to apply compressible equations. Finally, there are also other benefits as illustrated in the paper by a computational expample.
Weng et al (2016)
Weng, Y., and F. Zhang, 2016: Advances in convection-permitting tropical cyclone analysis and prediction through EnKF assimilation of reconnaissance aircraft observations. J. Meteor. Soc. Japan, 94, 345-358.
http://doi.org/10.2151/jmsj.2016-018 Graphical Abstract
- Overviewing of the recent advances in analysis and prediction of tropical cyclones through assimilation of reconnaissance aircraft observations; and designed a cycling WRF-EnKF analysis and prediction system to evaluate the impact of airborne reconnaissance data assimilation on hurricane intensity forecast.
- Assimilating of reconnaissance data shows positive impacts on both hurricane track and intensity forecasts with an reduction of 2∼14% for position forecast errros and 1∼37% for minimal sea level pressure forecast errors for forecast lead times 0∼126 h, and 1∼11% for maximal 10-m wind speed forecast errors during the 24∼114 h leadtimes averaged over all 636 applicable cases during 2008-2012.
- The aircraft hurricane reconnaissance data is now routinely assimilated into the operational hurricane forecast model HWRF performed at NOAA.
Feng et al (2016)
Feng, J., J. P. Li, F. Zheng, F. Xie, and C. Sun, 2016: Contrasting impacts of developing phases of two types of El Niño on southern China rainfall. J. Meteor. Soc. Japan, 94, 359-370.
http://doi.org/10.2151/jmsj.2016-019 Graphical Abstract
- The CP (EP) El Niño-developing summers (autumns) are associated with increased rainfall over southern China.
- The different impacts on southern China rainfall are due to the different Rossby wave responses to the two types of El Niño events.
Rao, S., 2016: Sensitivity of the tropical easterly jet to the distribution and magnitude of latent heating in an aqua-planet model. J. Meteor. Soc. Japan, 94, 371-388.
http://doi.org/10.2151/jmsj.2016-020 Graphical Abstract
- A heat source at 20°N is more to be robust in generating zonal wind speeds comparable to that of the TEJ. But this heating cannot generate a true TEJ vertical structure. Equatorial heating is required to impart a realistic vertical baroclinic structure in the tropical longitudes where the TEJ is located. However it is insufficient in generating a true TEJ horizontal structure.
- Both equatorial and higher tropical heating is required for generating a true TEJ horizontal and vertical structure.
- If the precipitation patterns are similar then the TEJ is similar with or without land. Hence latent heat release is the dominant control on the TEJ.