NO. 8 BAROMETRIC PRESSURE — DUELL AND DUELL 3I 



CONCLUSIONS 



III conclusion, it must he emphasi/cd that the results dcscrihed 

 in this pajier are hy no means so unequivocal that their immediate 

 application to short- or middle-term weather forecasting would he 

 possible. Before rules for the forecaster can be worked out, there is 

 need of further investij^ations, i)erforme(l on a very broad scale. 

 Essential improvements of that working basis seem to be possible. 

 For instance, to characterize the occurrence and intensity of iono- 

 spheric storms, direct data, provided by means of the impulse-echo 

 method, should be used, instead of the geomagnetic character numbers 

 for such statistics. Also the occurrence frequency and intensity of 

 ultraviolet invasions could possibly be better characterized by sys- 

 tematically recorded data concerning the appearance of an abnormal 

 D-layer on the sunlit earth hemisphere, than by direct observations 

 of the brii,dit chromospheric eruptions. The reason for this is that 

 a really reliable international sun-control service, observing the chro- 

 mosphere \.-ithout any interruptions, does not yet exist. I'urthermore, 

 it will prove of particular importance to subdivide such statistics 

 into several groups, which correspond to the different thermodynamic 

 initial states of the troposphere over the considered area at the time 

 of the solar-ionospheric impulses. Probably only by means of such 

 a refined analysis will the difTerent reactions of the troposphere to 

 certain solar-iojiospheric impulses of equal size be clarified to such 

 a degree that the forecaster can derive advantages from this research. 



REFERENCES 



( 1 ) Abbot, C. G. 



1940. The variation of the sun and the wcatlicr. Riill. .Xmcr. Mctcorol. 

 Soc, vol. 21, No. 10, pp. 407-416. 



1944. Weather predetermined by solar variation. Smithsonian Misc. 



Coll., vol. 104, No. 5. 



1945. Solar variation and weather. Ann. Rep. Smithsonian Inst, for 



1944, pp. 119-154- 



(2) Arctowski, H. 



1917. Sunspots, magnetic storms and rainfall. Month. Weather Rev., 



November, p. 538. 

 1940. Researches on temperature changes from day to day and solar 



constant variations. Bull. .\mer. Mctcorol. Soc., vol. 21, 



No. (), pp. 257-261. 



(3) ClAVTOX, H. H. 



1925. Solar radiation and weather. Smithsonian Misc. Coll., vol. 77, 



No. 6. 

 C4) Hlntington, E. 



1923. Earth and sun. A hypothesis of weather and sunspots. Yale 



Univ. Press, New Haven. 



