Miyakoda, K., J. Smagorinsky, R. F. Strickler, and G. D. Hembree, 1969: Experimental extended predictions with a nine-level hemispheric model. Monthly Weather Review, 97 (1), 1-76.
Abstract: Two-week predictions were made for two winter cases by applying the Geophysical
Fluid Dynamics Laboratory high-resolution, nine-level, hemispheric, moist
general circulation model. Three versions of the model are discussed: Experiment
1 includes the orography but not the radiative transfer or the turbulent
exchange of heat and moisture with the lower boundary; Experiment 2 accounts
for all of these effects as well as land-sea contrast; Experiment 3 allows,
in addition, the difference in thermal properties between the land-ice and
sea-ice surfaces, as well as an 80% relative humidity condensation criterion
reduced from the 100% criterion in Experiments 1 and 2.
The computed results are compared with observed data in terms of the evolution
of individual cyclonic and anticyclonic patterns, the zonal mean structure
of temperature, wind, and humidity, the precipitation over the United States,
and the hemispheric energetics.
The forecast near sea level was considerably improved in Experiments 2
and 3 over Experiment 1. The experiment succeeded in forecasting the birth
of second and third generation extratropical cyclones and their behavior
thereafter. The hemispheric sum of precipitation was increased five times
in Experiment 2 over that in Experiment 1, and even more in Experiment 3,
the greatest contribution occurring in the Tropics. Two winter cases were
considered. The correlation coefficients between the observed and the forecast
patterns for the change of 500-mb geopotential height from the initial time
remained above 0.5 for 13 days in one case and for 9 days in the other.
There are, however, several defects in the model. The forecast temperature
was too low. In the flow pattern the intensities of the Highs and Lows weakened
appreciably after 6 or 8 days, reflecting the fact that the forecast of
eddy kinetic energy was less than the observed. On the other hand, the intensity
of the tropospheric westerlies was too great.