Juan F. Asuncion
Mean monthly streamlines and isotachs for selected pressure levels (850-700-500-300 and 200 mb) over Southeast Asia and neighboring areas have been analyzed with variable (non-hemogeneous) periods of record. The horizontal and vertical, month to month and season to season behavior and characteristics of the different flow patterns and the more salient features of the atmosphere, viz., the intertropical convergence zone (ITCZ) with the associated vortices, convergence and equatorial troughs; the sub-tropical centers of outflows and their associated latitudinal axes; the seasonal monsoon flow; the low and high level equatorial easterlies; the Bengal Bay trough and the northern hemisphere westerly (short wave) trough; the northern hemisphere upper level westerlies; the northern hemisphere sub-tropical jet stream and the equatorial easterly jet stream, at these levels and from one level to another, as depicted by the charts are also discussed. There was no attempt made whatsoever, to explain dynamically the causes behind these changes. The adequacy and availability of these charts and what they have depicted will be invaluable to Philippine requirements as well as to new and non-tropical meteorologists. To meteorological analysts, a more thorough analysis of the upper air flow can be made by referring to these charts and will be a necessary tools for operational forecasters in their prognostic techniques.
Cipriano C. Ferraris, Bernardo M. Soriano, Jr.
This paper represents an attempt to elaborate the generalized charts of maximum rainfall for different durations and return periods required for the design of small hydraulic structures. In this study, the generalized charts are given for one-day and two-day rainfall and return periods of 2, 5, 10, 15, 25 and 50 years. The results should be applied in a precautionary manner taking into consideration that some of the stations have rainfall data for a continuous period of only 8 years.
Emma P. Amores-Vergara
Different mathematical models for assessing the effects of weather on crop development were considered and reviewed. Three popularly used in linear models - the average span, the Reaumur's degree-day equation and the Nuttonson's photothermal equation - and the non-linear equation called the triquadratic model as postulated by Robertson (1968) were tested using meteorological and astronomical data from the Science Garden and the Radiation Center, Philippine Weather Bureau, in Diliman, Quezon City. However, evidences gathered from a year's experiment in the Science Garden consisting of twelve (12) monthly plantings of sweet corn of the H801 variety and also from other investigations along this area pointed to the triquadratic model as postulated by Robertson in 1968 to be the best mathematical expression for calculating the effects of the thermal and solar radiation environment on crop development among the models employed.