Figure 16. JJA diurnal cycle of precipitation as a function of
local solar time in a 10-year S-SHiELD climate integration with the MLO
nudged towards climatological SSTs, and from days 6–10 of three years
of 13-km SHiELD hindcasts (initialized every five days), compared to
TRMM 2011-2018 observations. Means are given in the legends as mm/day.
Hagos et al. (2016) found that the diurnal cycle of cloudiness and
precipitation plays a key role in the propagation of the MJO through the
Maritime Continent. Since S-SHiELD has considerably better diurnal
cycles of precipitation and temperature over land, especially over
tropical land, than do most climate models, we might expect that this
improved representation of the diurnal cycle may be contributing to the
improved representation of the MJO seen above.
4 Conclusion and Prospects
We have developed the SHiELD modeling system as a research tool to
demonstrate new capabilities of the FV3 Dynamical Core and of our
physical parameterizations, develop new ideas in atmospheric prediction
modeling, and to explore processes and phenomena within the atmosphere.
Since late 2015 when FV3 was first coupled to the then-operational GFS
Physics Driver we have developed SHiELD into a promising vehicle for
improving the prediction and understanding of atmospheric phenomena.
SHiELD also demonstrates the potential and viability of unified modeling
in which there is a single modeling system with one codebase, one
executable, one preprocessor, one set of runscripts, and one set of
post-processing tools. This greatly simplifies the modeling suite and
allows improvements to be exchanged between configurations.
The fundamental characteristics of SHiELD compared to
previous-generation and existing operational models are documented in
this and other publications. For some applications we have previously
demonstrated capabilities similar to that of existing modeling systems,
such as severe-storm prediction in C-SHiELD (Harris et al 2019) and
tropical cyclone intensity prediction in T-SHiELD (Hazelton et al
2018a,b). We have shown significant improvements over existing models,
especially over existing global models, for large-scale and hurricane
prediction skill in 13-km SHiELD (Zhou et al 2019, Chen et al 2019a),
and the diurnal cycle and MJO prediction in S-SHiELD. We have even shown
entirely new possibilities for prediction modeling, such as skillful
hurricane intensity forecasts in 13-km SHiELD (Chen et al. 2019b), and
the possibility of medium-range convective-scale prediction in C-SHiELD.