IRPS 41 Weather and Climate Data for Philippines Rice Research

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IRPS No. 41 , November 1979

WEATHER AND CLIMATE DATA FOR PHILIPPINE RICE RESEARCHI

ABSTRACT

The climate and weather of Los Banos are describedwith particular reference to the upland-lowlanddifference. A complete file of daily upland weatherdata for the period 1959-1978 has been prepared andits contents, quality control, and means of accessoutlined. Current surface observations at Los Banos

are noted with comments on quality control.Climatic data for 47 Philippine synoptic weatherstations have been collected and an integrated fileof weekly data for periods of up to 24 years hasbeen prepared. Access to its contents is described

IBy J. F. Angus, IRRI visltlng agronomist from the Commonwealth Scientific and Industrial Research Organization,Canberra, Australia, and E. B. Manalo, assistant scientist, Multiple Cropping Department, International RiceResearch Institute, Los Banos, Philippines. Submitted to the IRRI Research Paper Series Committee June 1978.


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4 IRPS No. 41, November 1979

estimates of monthly radiation from 1970 to 1978were compared with measured values (Fig. 5). Thecomparison suggested that the true values hadbeen underestimated by 10-15% and in 1972-73,by up to 30%.

T e mp e ra t u i- e

A comparison of temperature maxima and mlnlma at UPLBand IRRI showed that the IRRI maxima were generallylower than the corresponding maxima at UPLB whereasIRRI minima were slightly higher on the average thanthe corresponding UPLB minima (Fig. 6). The compa-

rison was made on mean weekly values recorded after4 June 1978, when mercury-in-glass thermometers werefirst used to measure screen temperature at IRRI.Before that maxima and minima were recorded from athermograph. When the thermograph da ta we r e plo t tedagainst UPLB data a relationship similar to thatshown in Figure 6 was obtained, but with considerablymore scatter in the data. That may reflect the dif-ficulty of measuring temperature accurately with athermograph.The differences between UPLB and IRRI probablyreflect the upland-lowland difference. The surfacewater on the IRRI lowlands presumably provides aheat buffer that dampens the day-night temperaturedifference.

Table 1. Instruments used and length of record at the University of the Philippines at Los Banos (UPLB) andInternational Rice Research Institute (IRRI) weather stations, Los Banos, 1917-19.

UPLB(Upland)

IRRI(Building)

IRRI-JIO(Lowland)

IRRI-MN IRRI-new farm(Near lowland) (upland)

RainfallStandard gauge 1917-58 old site

1959+ new site(no record 1939-46)Sunken gaugePluviograph

EvaporationClass A pan (screen 197~)Colorado open rim panSunken pan (screen 1978~)

1966~1959-Sep 19771959~

S cr ee n t em pe ra tu reDaily max-min Hg in glass

1959~

0800 wet and dry Sling inside screenHg in glass1959~

Humidity

S un sh in e d ur at io n 1959~ 1965~G lo ba l r ad ia ti on Eppley pyrano- Eppley pyrano-

meter1959-70Actinograph1970~

1966+ 1971-79 Jun 197~

Jun 1978+Jun 1978+

1979+ 1971-79 Jun 1978+

Thermograph1966-Jul 1978Hg in glassJul 1978+

Hg in glassJul 1978+

Sling outside screenApr 1977-Jul 1978Fan psychrometerHg in glass Jul 1978

Fan psychro-meter

Hg in glassJul 1978+Hair hygrograph19fi6-Jul 1978 Hair hygro-graphJun 1978+

meter1966-75Middleton

pyranometer1979~Quantum siliconcell pyranometerJun 1978+

N et r ad ia ti on 1966-74Incomplete--------_ .._---


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!RPS No. 41, November 1979 5

Laguna de 8 a y

!1 0 i(~- : '

IRRI upland .~Jweather station

km~ ~ _ ....

Mt.LUYOn~0 I 2

Scale 1:50,000

Fi!!. 1. Map of the Los Banos area showing location of weather stations.

Climatic normals for Los Banos~1~mm __ /~YW_" _ The monthly values for weather elements at Los Banos

are in Table 2. The solar radiation data werederived from a composite of UPLB data from 1959-68,as corrected by Robertson (1971), and IRRI data for1970-78 with corrections described in this report.Phytoday length was calculated by the method ofFleming (1972).Integrated Los Banos weather data

lOW ,.....- IRRI rrecn 2070._ _ U P L B moon 858

Yea r

To produce a consistent weather record for Los Banoswe selected the upland condition as a standard andcoded and checked a set of weather data from the UPLBweather station from 1959 until the end of 1978. Thonly exception is the radiation data, which are acomposite of UPLB data from 1959-69 as corrected byRobertson (1971), and IRRI data from 1970 onward withcorrections described in this report. The totaldaily weather record is on magnetic tape in EBCDICFig. 2. Los Banos annual rainfall (S-year runningmean) .


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code with a format shown in Table 3. The tape isheld for public access at the Agricultural ResourcesCenter (ARC), Los Banos. Because the total weatherrecord refers to an upland site, it is not fullyapplicable to the lowland environment. Adjustmentfactors for evaporation and screen temperature tomake the data more relevant to the lowland environ-ment are:o maximum temperatures should be decreased by 2C

and minimum temperatures increased by 0.5C, and estimates of Class A pan evaporation for the

lowland environment (Y) can be obtained fromupland measurements (X) by

Y 1.8637 + 0.5288X, X> 4 (1 ' 0.93)y X

Comparisons between upland and lowland estimatesof other weather elements (such as humidity) havenot been made for a sufficiently long period forrelationships to be established.

C ur re nt s ur fa ce o bs er va ti on sSurface observations are made at two IRRI sites(Fig. 1). The lowland site was established in itspresent form in 1966 and the upland site was estab-lished in 1978 to conform with the World Meteorol-ogical Organisation recommendation that surface

Class A panEvaporation12

III line

:O~----~~----~------_L------~------~----~o 2 10 126 8

Coloradoopen-rimpanFig. 3. Relationship between evaporation from aColorado open rim pan and a Class A pan at the UPLBw ea t.her station.

observations be made at upland sites. The lowlandsite was retained to clarify the lowland-uplandweather differences noted in the previous section.The weather elements observed and the instrumentsused in collecting data are listed in Table 4. Notall recorded data are reported in the weekly andmonthly weather bulletins, but IRRI researchers mayhave access to all records of the AgroclimaticService Unit.The data are stored on magnetic tape cassettes witha minicomputer which is also used to print the weeklyand monthly bulletins. The quality of the data ischecked with a computer program that makes compari-sons between weather elements (e.g. radiation vssunshine duration, radiation vs evaporation, resetof maximum temperature thermometer vs dry bulb,reset of minimum temperature thermometer vs dry bulb)The calculation of the humidity parameters (dewpoint, relative humidity, and vapor pressure deficit)are by the Tetens formula (Lowe 1977); the vaporpressure deficit is based on the mean daily tempera-ture l(max + minl/. Phytoday length, the durationof the period when the sky brightness is sufficientto activate plant phytochrome receptors, is estimatedby the method of Fleming (1972).At the time of establishment of the new uplandstation, two changes were made in the observations.1) The pyranometer and sunshine recorder weremoved to the roof of the LTCC building and a cali-bration system established, based on a standard

IRRI MN evaporation (mm/day)10 III lin

8

6

4

2

2 5 9 104 6 7 8UPLB evaporation (mm/day)

Fig. 4. Comparison of pan evaporation from adjacenupland and lowland sites.


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The relative humidity is calculated from the wet- anddry-bulb data using the Tetens formula (Lowe 1977),and the mean wee~ly phytoday length by the methodof Fleming (1972). Evaporation and solar radiationare not recorded at Philippine synoptic stations,

IRRI J -10 lowland Temperoture toe)35

30

25

Minima

Maxima

20 30 355UPLB upland Tempera ture (Oe)

Fig. 6. Comparison of screen temperatures foradjacent upland and lowland sites.

Measured mean monthly solar radiation (cal/cmZ day)

but estimates of mean monthly potential evapotran-spiration and solar radiation for most of thePhilippine synoptic stations have been made byTamisin (1977). In that study solar radiation wasestimated using the duration of bright sunshine, orwhere these data were not available, from recordsof observed cloudiness. The records of estimatedradiation were used along with measurements of windrun and vapor pressure deficit, to calculate evaporation using the modified Penman method (Doorenbosand Pruitt 1977).We found good relationships between Tamisin'sestimates of evapotranspiration and class A panevaporation for four sites in the Philippines, andalso between his estimates and measured mean solarradiation for Los Banos (Fig. 7).Using these relationships we were able to estimatemean monthly class A pan evaporation and solar radiation for 32 of the 47 synoptic stations. To makeestimates for the remaining stations we plotted theavailable monthly estimates on base maps of thePhilippines and interpolated from freehand isoplethsThe monthly estimates for all stations were thenplotted on a graph and mean weekly values wereestimated by interpolation. Estimates of potentialevapotranspiration have also been made by Obradovich(1973) using the Thornthwaite method, and the mapsproduced from his analysis are qualitatively similarto the maps we produced.

Mean monthly pan evaporation (mm/day)

8 (b)

6

4

2 IRR I, Los Banoso Pototan, Iloilo* Gen. Santos, S. Cotobato

O~~ ___L__i___L_~ __ _L__~~o 2 4 6 8

Estimated monthly evapotranspiratIOn(rrrn / day)stimated monthly solar radiation at LosBanos(mm/day of water vaporization)

Fig. 7. Relationship between (a) measured monthly solar radiationand the estimates of Tamisin (1977) for radiation at Los Banos, and(b) measured mean monthly pan evaporation and the estimates ofTamisin (1977) for evapotranspiration at 4 well-distributed sitesin the Philippines.


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Completed data filesThe estimates of weekly class A pan evaporation andsolar radiation were combined with the data formeasured weather elements supplied by PAGASA and thecalculated elements of relative humidity and phytodaylength.Because two of the important weather elements, classA pan evaporation and solar radiation, are availableonly as mean data we computed the means of allweather elements, but retained actual weekly rain-fall totals because of its variability. An exampleof a complete weather file for one station is shownin Table 6. The data are stored as: punched cards containing the actual weekly

PAGASA data. These data would be useful only tothose requiring actual weekly temperature data.(Weekly rainfall in each year of record is in-cluded on magnetic tape.)

magnetic tape held at the ARC. Computer usershave access to data for all stations, or for anystation identified by its PAGASA number. Datamay be printed directly, or used in other ways,such as simulation or classification of climaticregions.

IRPS No. 41, November 1979

a master list held by the Agroclimatic ServiceUnit, IRRI, which also has copies of the monthlyevaporation and radiation maps used in estimatingweekly data for these elements.

Table 3. Contents of the integrated weather file fLos Banos. The data are stored in EBCDIC code withe integer format 1115.

YearJulian dayRainEvaporationMaximum screen temperatureMinimum screen temperatureDry bulb screen temp. (0800 h)Wet bulb screen temp. (0800 h)Global radiation fluxDuration of bright sunshinePhytoday length

1-6-1rom x 10 ll-1rom x 10 16-2c x 10 21-2c x 10 26-3c x 10 31-3c x 10 36-4

cal/cm2 per day 41-4h x 10 46-5h x 10 51-5

Table 2. Climate normals for Los Banos for 1959-78a with standard deviations in brackets. All data exceptsolar radiation are from the upland site at UPLB. Solar radiation is from a composite of data from UPLB1959-69 as modified by Robertson (1971), and from IRRI 1970-78 as modified in this report.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec AnnuaRainfall (rom) 44 20 27 30 189 237 266 256 273 235 280 178 2036b

(46) (31) (24) (33) (195) (1l6) (158) (109) (150) (176) (143) (143) (454Class A pan evapora- 132 156 209 242 208 156 138 135 122 132 109 109 l843btion (mm/month) (15) (20) (14) (25) (42) (23) (25) (23) (23) (23) (17) (17) (132Solar radiation 360 442 523 588 510 458 410 371 384 374 317 305 426c(cal/cm2 per day) (35) (43) (39) (26 ) (62) (39) (38) (65) (30) (56) (95) (53) (20Sunshine duration 5.4 6.4 7.4 8.6 7.6 5.8 5.3 5.1 5.3 5.3 4.7 4.5 5.92c(h / day) (1.1) (1. 7) (1.2) (1.7) (2.0) (1.5) (1.2) (1.5) (1.2) (1.3) (1. 5) (1. 3) (0.85)Ma x.imum temperature 28.9 29.9 31.6 33.7 34.0 32.8 31.8 31.4 31.4 31.0 30.1 29.1 31. 3(0 C) (0.9) (0.9) (1.1) (0.8) (1. 4, ) (0.9) (0.8) (0.6) (0.6) (0.5) (0.6) (0.8) (0.4Minimum temperature 20.8 20.7 21.4 22.7 23.6 23.4 23.3 23.2 23.0 22.8 22.4 21.9 22.4(0 C) (0.5) (0.6) (0.7) (0.6) (0.6) (0.4) (0.6) (0.4) (0.5) (0.3) (0.5) (0.6) (0.3)Dry bulb at 0800 24.0 24.3 25.8 27.8 28.8 28.0 27.3 27.0 26.8 26.5 15.9 14.9 26.4(OC) (0.7) (0.6) (0.7) (0.7) (0.9) (0.5) (0.4) (0. il) (0.5) (0.5) (0.5) (0.6) (0.3Wet bulb at 0800 22.2 22.2 23.1 24.4 25.6 25.4 25.2 25.1 24.9 24.6 23.9 23.2 24.1(0 C) (0.8) (0.7) (0.6) (0.5) (0.4) (0.5) (0.3) (0.6) (0.3) (0.4) (0.7) (0.5) (0.6)Relative humidity at 86 84 80 76 77 82 84 85 86 86 85 87 880800 (%) 0.3) (2.3) (2.3) (3.6) (5.6) (3.1) (2.4) (2.5) (3.3) 0.8) 0.1) (2.9) (1 8Phyto-day length 11. 59 1l.87 12.23 12.63 12.98 13.15 13.07 12.78 12.40 12.01 11. 68 11.51a b cClass A pan evaporation is for 1966-78. Annual totals. Daily means.


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Tab Le 4. Wea ther da ta co l.Lecred and reported by the IRRI Agroclima tic Service Unit. Records are taken and chartschanged at 0800 except for radiation totals, which are observed after sundown. Observations marked with an * arenot reported but the data are obtainable on request.Heather element Upland site Lowland site IRRI building

Rainfall Phil. standard gaugePhil. standard gauge withsurface-level orifice

Casella pluviograph (24 h) *Phil. standard gauge

Evaporation Class A pan with spike gauge(uris creened)

Class A pan with spikegauge (unscreened)

Solar (global radiation) Gunn-Bellani radiationintegrator

Middleton pyranometer withBreck-Bowles integrator

Lambda pyranometer andintegrator

Sunshine duration Campbell stokessunshine recorder,Casella (London)

Temperature Screen max - (Hg in glass) Screen max - Hg in glassScreen min - (alcohol in glass) Screen min - alcohol in glassContinuous screen temperatureWeather Measurethermohyd rogr aphScreen wet and dry -Soil temperatureThermograph 5 and 10 ern deepWeather Measure (Hg in steel)t,Grass minimum-(alcohol in glass)

Continuous screen temperatureHeather Measure

thermohyd r og r aphHg in glass Screen we t and dry at 0800 - Hgin glass

Dew fall Dew recorderR. Fuess (110 cm2 collector)Berlin-Steglitz

Wind run 2 m Weather Measureanemometer (1 mlsspeed)0.75 m Casella cup(0.5 mls starting10 m prope l.Ler=

cupstarting 2 m Weather Measure cupanemometer (1 mls startingspeed)anemometer;'

speed)

Barometric pcessure Microbarograph (7-day chart)(Weather Measure)

Hg barometer with attachedthermometer

lhnd-direction Indicating console Observations


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Table 5. Weather stations included in the file of Philippine Weather data.

IRPS No. 41, November 1979 11

PAGASAIndex

NumberSynoptic stations of

the PhilippinesCoordinates

Latitude Longitude Elevation(ill )

Start ofrecord(yy)

End ofrecord(yy)

Type ofenvirgn-men t

44 413 313 543 275 123 223 343 953 844 664 575 455 322 322 263 755 054 374 832 864 274 654 632 943 152 663 061 832 543 543 733 333 643 442 742 953 654 885 183 065375 574 183 632 464 464 6

Legaspi, A1bayCa1ayan, BabuyanBasco, BatanesAmbulong, BatangasMa1ayba1ay, BukidnonAparri, CagayanTug~egarao, CagayanDaet, Camarines NorteRoxas, CapizVirac, CatanduanesCebu, CebuDavao del SurBorongan, Eastern SamarLaoag, I10cos NorteVigan, I10cos SurIloilo, IloiloTac10ban, LeyteMasbate, MasbateCagayan de Oro, Mis. Or.Baguio, Mt. ProvinceDumaguete, Negro Or.Cotabato, North CotabatoCatarman, Northern SamarCabanatuan, Nueva EcijaCa1apan, Or. MindoroCoron, Pa1awanCuyo, Pa1awanPuerto Princesa, Pa1awanDagupan, PangasinanA1abat, QuezonAurora, QuezonBaler, QuezonCasiguran, QuezonInfanta, QuezonLucena, QuezonManila, Metro ManilaR o r n b L o n , R o m b l o nCatba10gan, SamarGeneral Santos, Cotabato1010, Su1uSurigao, Surieao del NorteHinatuan, Surigao del SurDipo10g, Zamboanga del NorteZamboanga, Zamboanga del SurIba, Zamba1esTagbi1aran, Boho1Mactan, Cebu

1 3 . 1319.2620.4514.0808.1518.3617.6114.0811.5813.5810.3307.06ll.6118.1817.5610.70ll.2512.3608.4816.4109.3007.2512.4815.4813.4112.0010.8509.7516.0514.0813.3315.7616.2814.7513.9314.5812.5811. 7806.ll06.0509.8008.3608.6006.9015.3309.6310.30

123.73121.46121.96121.05125.081 21 . 6 3121. 73122.98122.75124.23123.90125.60125.43120.53120.38122.56124.00123.61124.63120.60123.30124.25124.63120.96121.18120.20121.03118.73120.33122.01122.50121. 56122.11121.65121.61120.98122.26124.88125.18121.18125.50126.33123.35122.06119.96123.85123.96

19131111627424436

352075

3314211161501614632

40144

16214647157

1547515

1321356558

19511951195119511952195119511951195119511951195119511951195219511951195119521951195119511951195119511951195119511951195119511951195119511951195119511951195119511951195119511951195119611972

19741974197419741974197419741974197419741974197419741974197419741974197419741974197419741974197419741974197419741974197419741974197419731970197419741974197419721974197419741974197419741974

LLLLULLLLULLLLLLULLUULLLULLLLLLLLLULLLLLLLLLLLL

L ; lowland, U ; upland.


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Table 6. Example of complete weather file for one station.PACASA LOCATION LAT. LONG. ELEV. ( rn) YEARS OF RE CO RD S UPLAND OR LOWLANDNo. 64 4 Tagbilaran, Bohol 5.63 23.85 5 61-74 (1 - UPLAND)Week Hean Hean class A Hean global Haximum Hinimum Dry bulb Het bulb Relative PhytNo. rainfall/ pan evap/ day rad/day 2 temperature temper- at 0800 at 0800 humidity len

wee k cal J2er em ( 0c) ature (C) ( 0 C) (C) at 0800 (OC) (h1 32.5 4. 0 287.0 30.5 21.8 25.6 23.7 83.8 112 19.4 4. 2 294.0 30.1 21.3 25.4 23.1 80.7 113 22.8 4. 4 300.0 38.2 21.2 25.4 23.2 81.7 114 15.7 4. 5 306.0 30.6 21.2 25.5 23.2 81.7 115 16.8 4.7 309.0 30.5 21.0 23.6 2 1. 3 80.5 116 28.6 4. 8 310.0 30.5 21.3 23.7 21.5 81.3 127 26.8 4. 9 312.0 30.7 21.5 23.8 21.7 81.9 128 17.8 4.9 3 22 . 0 30.9 21.3 25.7 23.2 79.8 129 25.8 4. 9 331.0 30.9 21.4 25.8 23.3 79.6 12

10 22.1 4. 9 340.0 31.1 21.3 25.9 23.3 79.0 1211 32.6 5. 0 349.0 31.2 21.7 26.1 23.6 79.6 1212 12.6 5. 2 356.0 31.7 21.3 26.9 23.7 75.7 1213 9.1' 5. 3 366.0 32.2 21.6 26.7 23.8 7 7 . 3 1214 18.7 5. 5 375.0 32.5 2l.5 26.8 23.8 76.7 1215 14.0 5.7 383.0 32.7 22.1 27.3 24.2 75.7 1216 9. 8 5. 6 385.0 33.0 22 .5 27.7 24.5 75.8 1217 22.1 5.5 385.0 32.8 22.7 27.7 24.7 76.7 1218 16.1 5. 3 384.0 33.3 22.9 28.0 24.9 77 .0 1219 18.8 5. 2 378.0 33.2 23.2 28.0 25.1 77 .8 1220 22.6 5.0 365.0 33.0 23.2 28.0 25.1 77 .4 1221 20.7 4.9 354.0 33.2 23.7 28.2 25.3 78.4 1222 2l.0 4. 8 339.0 33.1 23.7 28.1 25.3 78.6 1223 36.2 4.7 326.0 30.7 22.4 26.2 23.4 78.1 1224 37.5 4. 7 319.0 30.5 21.8 25.7 23.3 80.2 1225 36.2 4.8 312.0 30.1 21.8 25.5 23.3 81.6 1226 30.7 5. 0 310.0 31.9 23.4 27.3 24.9 81.6 1227 41.3 5. 1 309.0 32.0 23.4 27.3 24.9 81.2 1228 35.1 5. 2 310.0 32.1 23.2 27.4 24.9 80.4 1229 20.0 5.2 310.0 32.6 23.6 27.9 25.0 78.2 1230 31.3 5. 1 308.0 32.5 23.7 27.8 24.9 77 .8 1231 12.0 5.1 303.0 33.2 23.8 28.2 25.0 75.8 1232 26.8 5. 0 298.0 30.3 22.1 25.8 23.1 78.5 1233 IG .3 5. 0 293.0 30.4 22.0 26.0 23.2 77 . 4 1234 31.1 4.8 294.0 30.3 21. 9 25.7 23.3 80.3 1235 26.9 4.7 295.0 32.3 23.4 27.8 24.9 78.0 1236 15.5 4.5 295.0 32.9 23.7 28.0 25.1 77.9 1237 26.5 4. 5 296.0 33.1 23.7 28.1 25.1 76.8 1238 34.5 4. 6 295.0 32.7 23.4 27.5 25.0 80.5 1239 41.6 4. 7 294.0 32.3 23.4 27.4 24.9 81.0 1240 53.8 4.8 290.0 32.2 23.0 27.2 24.9 82.1 1241 35.1 4.9 284.0 32.1 23.2 27.3 25.0 82.0 1242 51.7 4.7 280.0 32.3 23.0 27.0 24.8 82.7 1243 21.4 4.5 279.0 32.3 22.8 27.1 24.8 82.4 1244 44.5 4.2 279.0 32.3 22.7 27.0 24.7 82.4 1245 52.0 3.9 279.0 32.0 22.6 26.7 24.6 83.2 1146 55.3 3. 8 278.0 31.8 22.4 26.5 24.4 83.3 1147 55.1 3.7 273.0 31.5 22.6 26.6 24.5 83.3 1148 25.9 3. 7 269.0 31.5 22.3 26.4 24.3 82.9 1149 33.7 3.8 262.0 31.4 21.9 26.3 24.1 82.9 1150 22.5 3.8 259.0 31.6 22.3 26.4 24.2 82.9 1151 23.6 3.7 261.0 31.2 22.2 26.1 24.1 84.0 1152 30.2 3.6 265.0 30.8 22.0 25.9 23.9 83.8 11


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I RPS N o. 4 1, No vem ber 19 79 1 3

Actual week I y rainfall for th e le ngt h of record

21.5 48.5 1.5 2. 2 49.5 21.8 36.3 1. 5 24.1 0. 0 118.3 0.0 7. 664.5 0.2 0.0 12.4 11.4 41.9 13.7 2.0 36.3 12.6 52.3 49.7 16.773.1 19.5 31.2 1.5 0. 7 17.0 33.5 11.4 9. 6 6.0 0.0 39.3 28.157.1 5.8 45.4 10.9 0.2 24.1 47.4 25.9 40.1 57.1 25.1 46.7 27.924.6 23.8 0.5 0.5 1.5 102.6 2.2 39.6 35.0 28.9 43.4 4.8 22.63.5 11.9 2.0 0.7 0.7 1.0 19.5 34.7 3.3 7.1 91.1 50.5 38.336.5 18.5 0. 0 88.3 4.3 61.7 30.9 48.0 16.2 27.4 84.5 42.1 4.88.3 25.3 76.9 3.8 105.9 9.6 1.2 66.0 68.0 14.9 5.8 16.7 40.8111. 7 1.7 16.2 22 .0 1. 5 16.5 48.7 29.9 20.8 75.4 9. 1 35.5 0.00. 0 6.3 1.0 27.9 0.0 0.0 l3.2 0.7 4. 8 0. 0 0. 5 5.3 3.33. 8 39.3 19.3 13.2 5 1. 3 2lj.3 24.3 52.3 8. 8 5. 5 1. 0 59.6 27.449.7 12.4 16.7 24.3 46.7 136.9 50.0 49.7 14.4 12.4 27.4 16.7 8. 325.9 22.4 14.6 26.3 15.6 4.5 43.6 12.8 55.0 0.0 0.6 0.0 6.324.8 66.3 48.5 71.0 28.0 92.1 41.0 4. 0 22.3 6. 3 37.3 43.1 34.588.1 65.3 6.5 33.0 2.0 10.0 0.0 47.0 30.0 13.0 105.5 16.0 80.062.5 14.0 51.0 27.0 84.8 42.0 58.6 151.1 15.6 15.6 0.5 37.0 59.320.6 40.6 62.0 11.5 12.1 7.8 8.2 37.7 0.8 38.4 28.2 46.0 1. 034.1 67.6 12.3 2. 0 0.0 19.0 l3.5 4.1 14.3 32.0 47.5 2.8 21.614.4 52.8 2.5 24.0 7.1 38.4 15.7 34.5 9.2 75.6 3.3 0.5 31.166.9 20.9 82.6 l3.7 56.9 14.0 28.0 55.5 22.7 3. 5 27.2 17.2 8.31.0 7.6 6.3 5.0 0.0 0.5 12.8 22.9 78.0 2.8 10.9 2.8 0. 00.0 0.0 3.5 6.6 0.0 19.1 36.5 13.2 4.7 11.6 56.0 34.4 5.635.0 35.1 55.7 96.3 19.1 30.7 0. 0 29.5 68.1 0.0 10.5 16.2 15.476.6 l3.1 42.9 20.5 2.9 83.6 103.2 10.6 26.2 105.5 .35.2 38.6 12.550.8 40.6 131. 9 23.5 3.1 63.2 71.5 21.9 17.6 69.6 61.5 0. 0 11.60. 0 2. 5 39.3 7. 2 41.0 5.1 18.8 33.5 0.0 0.0 33.0 75.5 22.242.8 79.6 37.9 5. 6 0. 0 19.2 5.8 35.9 4.9 7.3 0.0 26.5 12.595.6 71.9 11.2 3.2 110.4 67.6 35.9 3. 8 14.3 0.5 69.8 25.0 19.22. 3 6.4 3.3 31. 5 11.9 28.9 0.0 1.0 0.0 25.8 l3.7 5.3 0.035.9 0.3 0.3 2. 3 39.7 4.8 5.6 30.8 0.5 8.7 17.7 10.7 113.36. 3 2. 7 34.9 8.5 48.2 35.4 4.8 5. 4 0. 0 1.3 41.3 14.6 30.656.5 20.6 26.5 7.5 17.1 24.1 46.2 143.7 3.2 24.2 0.4 6.2 72.8

13.3 7.1 3.1 1.0 0.0 3.0 0.0 0.0 0.0 14.5 0.0 15.8 0.00. 0 0.5 3.0 10.7 0.0 18.1 11.6 2.5 9.3 164.5 18.3 40.5 6. 354.9 29.6 59.9 20.0 1.8 24.0 41.7 26.7 63.4 15.2 11.5 29.2 11.071.4 16.0 35.5 69.8 3. 3 14.0 91.2 29.2 0.0 37.0 12.0 34.8 24.414.5 44.2 18.6 42.2 43.6 34.0 17.2 6.4 29.3 0.0 13.1 4.3 8.66.1 6.1 0.3 1.3 32.8 7.1 0.0 15.5 17.6 131. 8 25.2 70.1 86.8

10.2 49.4 3.1 0.8 5.1 0.0 20.1 33.3 0.0 3.3 31. 5 14.13 49.42.9 74.7 6.4 21.0 53.3 103.9 6.3 66.0 53.2 6.9 38.3 25.4 11.7

57.5 0.8 0.0 11. 7 68.3 79.6 53.1 28.7 0.0 29.0 55.4 0. 0 20.45. 0 9.4 0.3 16.1 53.9 17.1 37.3 77 .2 30.7 -2.0 -2.0 -2.0 0. 075.8 26.8 0.8 2. 7 0. 0 -2.0 -2.0 -2.0 0.0 16.0 0.0 13.7 77 .6

44.8 46.9 218.1 61.6 54.8 80.9 15.0 15.0 68.0 23.5 5.8 22.2 27.585.0 18.5 56.0 0.8 6.6 10.7 6.3 27.2 39.4 2.3 93.5 24.7 8.717.7 3.3 2.8 1.3 18.3 4.6 0. 0 l3.5 120.3 0.0 0.5 65.5 20.89.8 0.0 0.0 0.0 1.8 8. 8 32.5 31.0 109.8 8.3 28.0 5.8 l37.710.0 7.3 22.5 1.5 5.9 25.0 80.1 36.0 25.0 109.2 3.7 3.3 3.39.0 8.8 0.0 0.0 8. 2 1.8 0.3 0.0 0.5 1.0 0.3 1.6 32.832.8 11.7 8.8 16.7 0. 0 3. 4 3.4 25.0 21.5 0. 0 8. 6 19.2 1. 580.3 62.7 5. 3 78.8 17.8 77 . 1 2. 3 48.3 52.0 35.6 36.1 170.8 74.676.8 2. 8 22.9 20.2 67.9 77 . 6 l35.0 100.3 6.3 39.6 38.8 28.9 68.316.7 0.8 5.0 41.0 13.0 26.2 74.5 19.1 61.0 21.7 8. 2 36.2 7.937.4 10.4 14.7 l33.3 0. 0 30.2 102.7 33.5 8. 2 96.6 99.8 3.8 59.347.6 9.1 22 .5 65.6 8.3 1.6 0.5 0.5 4. 9 2.9 18.4 34.2 2.174.3 160.4 64.8 14.5 13.2 25.2 75.5 19.8 0.5 21.8 25.2 11.5 39.1


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ACKNOI.JLEDGMENTWe are grateful to PAGASA for supplying the weatherdata, and to Ms. Z. L. Punzalan for managing andediting the files.

REFERENCES CITED

Doorenbos, J., and W. O. Pruitt. 1977. Guidelinesfor predicting crop water requirements. FAOIrrigation Drainage Pap. 24. FAO, Rome.

Fleming, P. M. 1972. Subroutine RADAY to give daylength and radiation level. Grazing SystemsNewsl. (Australia) 6:4.

Jose, A. M. 1971. An analysis of Manila rainfalldata. WMO/UNDP project M et eo ro lo gi ca l T ra in in ga nd Res ear ch , M ani la. Tech. Ser. 9. Philippine

Wea ther Burea u and Depa rtmen t of lieteorology,University of the Philippines.

Lowe, P. R. 1977. An approximating polynomial forthe computation of saturation vapor pressure.J. Appl. Meteorol. 16:100-103.

Obradovich, M. M. 1973.in the Philippines.ogical Training andSer. 13.

A study of the water balanceWMO/UNDP project Meteorol-

R es ea rc h, M an il a. Tech.

Robertson, G. W. 1971. Solar radiation data foreleven years at Los Banos, Philippines inrelation to bright sunshine. IVMO/UNDP projectMet eor ol ogi cal Tr ain in g an d Re se arc h, Ma nil a.Tech. Ser. 6. Philippine Weather Bureau andDepartment of Meteorology, University of thePhilippines.

Tamisin, M. M. 1977. Numerical modelling of poten-tial evapotranspiration in different regions ofthe Philippines. MS thesis, University of thePhilippines at Los Banos.


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Other papers in this seriesNo. 1 Recent studies on the rice tungro disease at IRRINo.2 Specific soil chemical characteristics for rice production in

AsiaNo.3 Biological nitrogen fixation in paddy field studies by in situ

acetylene-reduction assaysNo.4 Transmission of rice tungro virus at various temperatures: A

transitory virus-vector interactionNo.5 Physicochemical properties of submerged soils in relation to

fertilityNo.6 Screening rice for tolerance to mineral stressesNo.7 Multi-site tests environments and breeding strategies for new

rice technologyNo.8 Behavior of minor elements in paddy soilsNo.9 Zinc deficiency in rice: A review of research at the

Internat ional Rice Research InstituteNo. 10 Genetic and sociologic aspects of rice breeding in IndiaNo. 11 Utilization of the Azolla-Anabaena complex as a nitrogen

fer til izer for riceNo. 12 Scientific communication among rice breeders in 10 Asian

nationsNo. 13 Rice breeders in Asia: A l O-country survey of theirbackgrounds, attitudes, and use of genetic materialsNo. 14 Drought and rice improvement in perspectiveNo. 15 Risk and uncertainty as factors in crop improvement researchNo. 16 Rice ragged stunt disease in the PhilippinesNo. 17 Residues of carbofuran applied as a systemic insecticide in

irrigated wetland rice: Implications for insect controlNo. 18 Diffusion and adoption of genetic materials among rice

breeding programs in AsiaNo. 19 Methods of screening rices for varietal resistance toCercospora leaf spotNo. 20 Tropical climate and its influence on riceNo.21 Sulfur nutrition of wetland rice

No.22 Land preparation and crop establishment for rainfed andlowland rice

No. 23 Genetic interrelationships of improved rice varieties in AsiNo. 24 Barriers to efficient capital investment in Asian agricultureNo. 25 Barriers to increased rice production in eastern IndiaNo. 26 Rainfed lowland rice as a research priority - an economist's

viewNo. 27 Rice leaf folder: Mass rearing and a proposal for screeningfor varietal resistance in the greenhouse

No. 28 Measuring the economic benefits of new technologies tosmall r ice farmers

No. 29 An analysis of the labor-intensive continuous rice productiosystems at IRRI

No. 30 Biological constraints to farmers' rice yields in threePhilippine provinces

No. 31 Changes in rice harvesting systems in Central Luzon andLaguna

No. 32 Variation in varietal reaction to rice tungro disease: Possibcauses

No. 33 Determining superior cropping patterns for small farms indryland environment: Test of a methodologyNo. 34 Evapotranspiration from rice fields

No. 35 Genetic analysis of traits related to grain characteristics anquality in two crosses of rice

No. 36 Aliwalas to rice garden: A case study of the intensificationof rice farming in Camarines Sur, Phil ippines

No. 37 Denitrification loss of fertilizer nitrogen in paddy soils -recogni tion and impact

No. 38 Farm mechanization, employment, and income in Nepal:Traditional and mechanized farming in Bara District

No. 39 Study on kresek (wilt) of the rice bacterial blight syndromeNo. 40 Implication of the international rice blast nursery data to

the genetics of resi stance

The International Rice Research InstitutePO. Box 933, Manila, PhilippinesStamp

Documents

IRPS 41 Weather and Climate Data for Philippines Rice Research