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Mean Monthly Streamlines For Selected Pressure Levels Over Southeast Asia And Neighboring Areas

Juan F. Asuncion
1973

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.

Maximum Rainfall Values Over Luzon For Duration of 1 And 2 Days And Return Period From 2 To 50 Years

Cipriano C. Ferraris, Bernardo M. Soriano, Jr.
1973

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.

A Study On The Effectiveness Of Four Mathematical Models On The Development Of Sweet Corn (H801) And The Daily Variations Of Solar Radiation And Air Temperature

Emma P. Amores-Vergara
1973

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.

The triquadratic model consists of three quadratic terms. They are solar radiation, maximum air temperature and minimum air temperature. The equation integrates these three factors over reasonably short phenological periods during which the physiological processes of the crop are relatively uniform.
Furthermore, the triquadratic equation treats the day temperature and the night temperature separately on a daily basis so that extreme conditions are included. These give the triquadratic estimates on crop-weather relationship a more sound physical basis. Moreover, the triquadratic model requires electronic data processing procedures since it has to cope with the series of iteration processes and regression analyses for its mathematical calculations.
Some notable observations emerged from this study as a result of the experiments on sweet corn conducted in the Science Garden. Prominent among these findings were: (1) the average span of time from one stage to another of the crop was dependent on the meteorological environment and (2) the Reaumur's degree-day equation and the Nuttonson's photothermal equation could not fully explain the effects of weather variables on the rate of plant development throughout the different stages of the crop.
One significant conclusion which surfaced from the triquadratic analysis of sweet corn is that the crop's response to solar radiation and air temperature vary from one phenological period to another and that this behavior, inherent in the development stage, is obviously reflected from its coefficients whose value change with the life cycle of the plant.