2 



on the coast line, this cannot be taken as a fixed rule. 

 At Kikori the seasons are reversed, and the months of 

 May, June, and September are the wettest in the year. 

 From the present available data the region around the 

 head of the Gulf of Papua would appear to receive a 

 larger fall of rain than any other part of Papua. 



■ 



The following are the average rainfall returns at 

 various stations, taken over several years^ 1 ) : 





Period 



8 years 

 1 1 years 



11 years 



t 



• • 



ear* 



1 2 y 



12 years 



13 year* 



11 years 



12 years 

 15 years 



5 year* 



5 yei 

 15 years 



■ 



Station. 



Division. 



• • 



Kikori, 230 inches 



Delta 



• • 



Lakekamu, 197 inches 



. Delta 



1 



• • 



Ionia, l(il inches 



Northern 



• • 



Cape Nelson, 135 inches 



North-East 



• • 



K<>koda, 131 inches 



Northern 



• • 



Kerema, 123 inches 



Gulf 



• • 



Samarai, 117 inches 



Eastern 



• • 



Buna, 1 13 inches 



Northern 



* * 



Darn, 90 inches 



Western 



• • 



Kairuku, 61 inches 



Central 



• . 



Kigo, 48 inches 



Central 



• • 



Port Moresby, 38 inches 



Central 



Two points of interest arise from these rainfall 

 figures. In the first place it will be noticed that the 

 stations along the coast of the Central Division receive 

 a very low lainfall for the tropics, and as would be 

 expected, this is reflected in the silva, which is decidedly 



This is known 



to W. is the prevailing wind direction in latitudes 

 9 deg. to 11 deg. during the months of January, 

 February and March. This slight increase in the 

 angle of incidence of the wind -flow against the 

 coast-line would account for the occurence of the 

 maximum rainfall in the Yule Island to 

 Rigo region in the first three months of the year, 



when the N.W. winds are prevalent, and they 



strike the coast at least as directly as the south- 

 easterlies in the winter months/' 



In regard to the second dry belt that I have referred 

 to, the Commonwealth Meteorologist writes: — 



u The Territory between Taupoto and the junc- 

 tion of the Eastern and North-eastern Divisions is 

 also relatively dry, and this effect is also partly 



due to the direction of the coast-line. In addition, 

 the dry belt is screened to the S.E. by the Stirling 



Range, and to the N.E.by the Territory between 

 Goodencugh Bay and Collingwood Bay." 



The floral composition of these dry belts is dealt 

 with later, in the section " Forest Regions." 



The second interesting point arising from the 



average rainfall returns given on page 4 is the very 



marked difference of rainfall between Kikori and Daru 



stations. These are the administrative centres of the 

 Gulf 



and Western Divisions, respectively, and 



are 



sclerophyllous. mis is 

 here the south-east 



as 



th 



drought. 



as follow : 



Th 



( 



season is a period of partial 

 averages for the last fifteen years are 



about 140 miles apart, yet Kikori receives 230 inches 



dry*" belt" and anc * ^ aru on ^ ^0 inches. Further, at Kikori the wet 

 y ' season is the period of the south-east monsoon, while 



the north-west is what the Magistrate stationed there 

 humorously calls (i 



the 



The actual 



North-west season, 29 inches. 

 South-east season, 9 inches. 



7 



The length of the belt is roughly 250 miles, stretching 

 from Hula, to the cast of Port Moresby, to Maiva, 

 west of Yule Island. Its depth is not known, but it 

 is generally considered not to extend more than 20 

 or 30 miles inland. Its land boundary must be very 

 irregular, depending en the topography of the country. 

 Sclerophyllous floral regions, differing only in the com- 

 position of the savannah forests from the grass and 

 eucalyptus belt on the coast, are to be found up to 

 4,500, and even 5,000 feet, on the S.E. flanks of the 

 Owen Stanley Range, between Mount Obree and Kagi. 

 While this dry belt is the largest in the Territory, it 

 is probable that others exist which are quite large 



rainy season, 

 monthly figures for the two stations are as follows. 



Those for Kikori are the average for eight; and those 



enough to form separate climatic districts. 



Th 



e one 



lying between Gcodenough Bay and Emurimuri Point, 

 on the east coast, probably ranks second in importance. 



Am 



■ The usual explanation for the presence of these dry 

 Delts is that the coast-line lies more or less N.W. and 

 S.E., but this does not appear to be wholly adequate. 



The Commonwealth Meteorologist^, while pointing out 

 the insufficiency of the data, and the consequent im- 

 possibility of making a detailed analysis of any of the 

 climatic factors 





(iu x wj- in l,^-«: 



vii y ecu 



O^ ' % — 













• 









* 















KIKORI. 



DARU. 





f November 



• • 



• • 



13-52 



i::ches 



4-73 



inches 





December 



• 



• ■ 



11-70 



* ? 



7-98 



• * 



N.W. \ 



January 



• • 



* • 



14-21 



* * 



• m 



15-77 



" 7 





| February 



1 ^tt ^F~ V 



• • 



• • 



13"39 



» 



9*78 



99 





^ March . . 



• ■ 



• • 



14-34 



*? 



13-25 



• 9 





[April . . 



• • 



• • 



17-70 



99 



12-07 



* * 

 % 5 





May 



• 9 



• • 



32-57 



99 



10*88 



99 





June . . 



• • 



■ - 



28-15 



J 9 



4-39 



• * 



S.E. < 



July . . 



■ • 



• • 



19-26 



9) 



2-61 



" 7 



M 



August 



» . 



• • 



1822 



9 9 



3-16 



9 9 





September 



• • 



• • 



26-99 



w 



99 



202 



* * 

 9 f 





^October 



• • 



• • 



20-07 



^> 



2'51 



99 





230 in. 



ches 



90 inches 



affecting the Territory, or 



coming 



to 



final conclusions on the matter, explains the Central 

 Division dry belt as follows : 



" The dry belt from Yule Island to Kigo 

 is partly due to the approximately N.W. to S.E. 

 direci ion of the coast-line in that region, but an at 

 least equally important influence is the inter- 

 ference of the MacGuillivry Range and other 

 mountains near the south-cast end of that belt, 

 these mountains intercepting or deflecting portion 

 J of the rain-bearing south-easterly winds. Though 

 wind direct ion data is. unfortunately, incomplete, 

 there is reason to believe that the north-west mou- 



lt will be seen that the wet seasons are reversed at 

 these two stations. Daru's wettest months are January, 

 March and April, and Kikori's May, June and Sep- 

 tember. Commenting on this remarkable difference in 

 climate, the Government Meteorologist writes: — 



"The marked contrast between the two low-level 

 stations, Kikori and Daru, at once arrests attention, 

 - especially as both stations are apparently fully ex- 

 posed to the south-east winds, during the preva- 

 lence of which all the disparity accrues. In this 



coast-line 



the 



includes 



soon includes a 

 W.N.W. to AY. winds, 



of the 



considerable portion 



and a Dutch East Indies 



meteorological publication indicates that W.N. AY." 



_ 



instance, configuration of the coast-line is ___ 

 principal influence responsible for the irregularity 

 of the rainfall, the converging shores of the Gulf 

 of Papua producing a convergence of the winds 

 entering the Gulf from the south-east and south. 

 It will be apparent that the south-easterly winds 

 passing between Daru and Redscar Head will 

 be restricted to leas than half as much sea-way 



when they reach the latitude of Kerema. ___ 

 effect of this convergence and of the friction with 



The 



er side of the Gulf, is to 



(1) Annual Report Papua, 11)22-3. 



('!) Department of Lands and Agriculture, Port Moresby. File: Kcteutoloffv 

 11th January, 1923. 



the land mass on eith 



cause a certain amount of " bunkering up "'of the 



air in the region near the head of the Gulf, and 



- .. 





(1) Annual Report, Papua. 1921-22. Agricultural Department. 



