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Dr. Abbot comments on the solar constant
W h i l e t h e v o l u m e of cistern n e e d e d has b e e n b ased on p a r t i c u l a r v a l u e s of rainfall d i s t r i b u t i o n , it is realized t h a t this v a r i e s w i d e l y f r o m y e a r "to y e a r , p a r t i c u l a r l y in t h e d r y period. T h e t w o entries for R a n g i r o a i l l u s t r a t e this point. I f a cistern on this atoll were sized on t h e basis of t h e a v e r a g e y e a r , it w o u l d h a v e b e e n t o o s m al l for a y e a r w i t h rainfall such as in 1963. H o w e v e r , in a y e a r of this t y p e t h e w a t e r p r o d u c e d b y distillation w oul d be g r e a t e r t h a n in t h e a v e r a g e y e a r a n d w ou l d be p a r t i c u l a r l y v a l u a b l e , e v e n t h o u g h t h e a v e r a g e permissible d ai l y w i t h d r a w a l r a t e w o u ld be m u c h reduced.
Acknowledgments The experimental program described in this report has been underwritten by the South Pacific Commission and was initiated at. the request of Dr. Guy Loison, the Commission's Executive Officer for Health. In 1965, Mr. George Chan, Sanitary Engineer for the Commission, participated in the installation at Lautoka, Fiji, and was most helpful in accomplishing that task. Mr. IV[. Pomier, Director of the Institut de Recherches des Huiles et Oleagineux, at Rangiroa, furnished the personnel for assembling the solar stills and supervised the operation of the still and data collection. M. Labrousse, Chef du Service du Plan, of the French Polynesian Government, was most helpful in arranging for local transportation at Tahiti
Dr. Abbot
Comments
on
Solar
Constant
In Science of 4 February, 1966, Dr. David M. Gates makes these statements regarding the solar constant of radiation: "There is little doubt but this amount of solar radiation (the solar constant) is slightly variable over time (the variation is less than 1.5 percent) but whether or not there is any systematic variation has not been determinable." I regard this as misleading. Smithsonian measures show nearly 3 percent variation. An harmonic family of 27 periods, exact submultiples of 273 months, is known. ])r. Gates cites the excellent paper of F. S. Johnson, who states: "The most extensive investigation of the solar constant has been made by Abbot, Fowle, Aldrich, and Hoover, of the Astrophysical Observatory of the Smithsonian Institution . . . . Their primary purpose has been to detect variation in the solar constant, and their interest in its absolute value has always been secondary. Nevertheless, the data of the Smithsonian Institution provides the best source of information on the absolute vahm of the solar constant." I was in close association with that Observatory from 1895 to 1952, and have published many papers based on its work up to the present. I also designed and supervised the construction of many of its instruments of research, and observed myself many months at its field stations on high mountains. In 1913, with L. B. Aldrich and F. E. Fowle, we completed and used the water-flow standard pyrheliometer to establish the "Smithsonian Radiation Scale of 1913." As modified by the suggestion of V. M. Shulgin in 1927, it furnishes even now the primary standard for the world. 1)uring our long research we made many alterations and improvements of instruments and methods. In each instance, by scores of tests, we determined the effect of the change upon the observed values. Thereby we maintained all of the Smithsonian publications of radiation, 1902-1965, as exactly as possible on the "Smithsonian Scale of 1913."
Vol. 10, No. 4, 1966
and for contacts with various governmental agencies. Arrangements in Fiji were handled through Dr. Desmond Beckett, Medical Department, Suva. Dr. G. Y. MeCririck, the District Medical Officer resident in Lautoka, arranged for personnel from the Department of Public Works to prefabricate parts for the still and to assemble it. Mr. Robert Potter, Superintendent of the Department of Public Works, was helpful not only in furnishing capable artisans during construction, but also in supervising the operation and data-gathering process. The writer is grateful to all of the above people in the South Pacific area and, more particularly, to Mr. B. W. Tleimat, of the Sea Water Conversion Laboratory, in Richmond, who started with general ideas, evolved the designs, and supervised the preparation of forms and materials to be shipped to the islands.
REFERENCES 1. A. A. Delyannis, "Solar Stills Provide an Island's Inhabitants with Water," Sun at Work, First Quarter 1965, pp. 6-8. 2. E. D. Howe, "Solar Distillation on the Pacific Atolls," South Pacific Bulletin, Vol. 14, No. 2, pp. 57-59, April 1964. 3. W. It. Read, "A Solar Still for Water Desalination," Report E.D.9, Division of Mechanical Engineering, CSIRO, Melbourne, Australia, September 1965, 23 pp. 4. J. W. Bloemer, J. A. Eibling, J. It. Irwin, G. O. G. LSf, "A Practical Basin-Type Solar Still," Solar Energy, IX, No. 4, pp. 197-200, October-December 1965. 5. E. 1). Howe, "Solar Distillation Research at the University of California," United Nations Conference on New Sources of Energy, Paper No. 35/S/29, 22 pp. September 1961.
It was impossible for us to exactly determine daily the corrections for ultraviolet and infrared solar radiation beyond the limits of 0.35 and 2.3 microns. Our daily observations after 1922 included spectrum intensity and atmospheric transmission for 40 wavelengths inside those limits. Corrections were estimated as best we could for ultraviolet and infrared solar rays. See Gerland's Beitrage fiir Geophysik, Bd. XVI, Heft 4, Leipzig, 1927. F. S. Johnson (J. Meteorology, 23, No. 6, p. 431, 1954) obtained larger ultraviolet and infrared corrections than ours, and published his preferred value of the solar constant, 2.00 4- 2 percent, which is now accepted generally. The Smithsonian Institution has just published two papers (Smith, Misc. Coll., Vol. 148, No. 7 and No. 8, Pubs. 4656 and 4659, March 23, 1966), which, together with its former publications (ibid Vol. 146, No. 3, Pub. 4545, 1963) shows the error of Dr. Gates' statement, which I have quoted above. I quote from Pub. 4659 as follows: "The identical family of harmonic periods found in solar variation is also present strongly in terrestrial precipitation, and may be used for long-range forecasting . . . . The curves A in Fig. 7 and 8 are made from observations recorded after it happened. The curves B, which for practical purposes are nearly identical with curves A, could be predicted and were actually predicted from records of observations made long before the events happened." This relates to Rochester and Nashville, 1921-1957. These predictions employed mean monthly official vahms, all observed beginning with 1884, to compute what would happen after 1921 for 36 years. They revealed weather periods identical in length with those we discovered in the sun's radiation. The average deviation between forecasts and events for 60 years is 3 percent of normal precipitation. C h a r l e s G. A b b o t Smithsoni'm Institution Research Associate 181
Acknowledgments The experimental program described in this report has been underwritten by the South Pacific Commission and was initiated at. the request of Dr. Guy Loison, the Commission's Executive Officer for Health. In 1965, Mr. George Chan, Sanitary Engineer for the Commission, participated in the installation at Lautoka, Fiji, and was most helpful in accomplishing that task. Mr. IV[. Pomier, Director of the Institut de Recherches des Huiles et Oleagineux, at Rangiroa, furnished the personnel for assembling the solar stills and supervised the operation of the still and data collection. M. Labrousse, Chef du Service du Plan, of the French Polynesian Government, was most helpful in arranging for local transportation at Tahiti
Dr. Abbot
Comments
on
Solar
Constant
In Science of 4 February, 1966, Dr. David M. Gates makes these statements regarding the solar constant of radiation: "There is little doubt but this amount of solar radiation (the solar constant) is slightly variable over time (the variation is less than 1.5 percent) but whether or not there is any systematic variation has not been determinable." I regard this as misleading. Smithsonian measures show nearly 3 percent variation. An harmonic family of 27 periods, exact submultiples of 273 months, is known. ])r. Gates cites the excellent paper of F. S. Johnson, who states: "The most extensive investigation of the solar constant has been made by Abbot, Fowle, Aldrich, and Hoover, of the Astrophysical Observatory of the Smithsonian Institution . . . . Their primary purpose has been to detect variation in the solar constant, and their interest in its absolute value has always been secondary. Nevertheless, the data of the Smithsonian Institution provides the best source of information on the absolute vahm of the solar constant." I was in close association with that Observatory from 1895 to 1952, and have published many papers based on its work up to the present. I also designed and supervised the construction of many of its instruments of research, and observed myself many months at its field stations on high mountains. In 1913, with L. B. Aldrich and F. E. Fowle, we completed and used the water-flow standard pyrheliometer to establish the "Smithsonian Radiation Scale of 1913." As modified by the suggestion of V. M. Shulgin in 1927, it furnishes even now the primary standard for the world. 1)uring our long research we made many alterations and improvements of instruments and methods. In each instance, by scores of tests, we determined the effect of the change upon the observed values. Thereby we maintained all of the Smithsonian publications of radiation, 1902-1965, as exactly as possible on the "Smithsonian Scale of 1913."
Vol. 10, No. 4, 1966
and for contacts with various governmental agencies. Arrangements in Fiji were handled through Dr. Desmond Beckett, Medical Department, Suva. Dr. G. Y. MeCririck, the District Medical Officer resident in Lautoka, arranged for personnel from the Department of Public Works to prefabricate parts for the still and to assemble it. Mr. Robert Potter, Superintendent of the Department of Public Works, was helpful not only in furnishing capable artisans during construction, but also in supervising the operation and data-gathering process. The writer is grateful to all of the above people in the South Pacific area and, more particularly, to Mr. B. W. Tleimat, of the Sea Water Conversion Laboratory, in Richmond, who started with general ideas, evolved the designs, and supervised the preparation of forms and materials to be shipped to the islands.
REFERENCES 1. A. A. Delyannis, "Solar Stills Provide an Island's Inhabitants with Water," Sun at Work, First Quarter 1965, pp. 6-8. 2. E. D. Howe, "Solar Distillation on the Pacific Atolls," South Pacific Bulletin, Vol. 14, No. 2, pp. 57-59, April 1964. 3. W. It. Read, "A Solar Still for Water Desalination," Report E.D.9, Division of Mechanical Engineering, CSIRO, Melbourne, Australia, September 1965, 23 pp. 4. J. W. Bloemer, J. A. Eibling, J. It. Irwin, G. O. G. LSf, "A Practical Basin-Type Solar Still," Solar Energy, IX, No. 4, pp. 197-200, October-December 1965. 5. E. 1). Howe, "Solar Distillation Research at the University of California," United Nations Conference on New Sources of Energy, Paper No. 35/S/29, 22 pp. September 1961.
It was impossible for us to exactly determine daily the corrections for ultraviolet and infrared solar radiation beyond the limits of 0.35 and 2.3 microns. Our daily observations after 1922 included spectrum intensity and atmospheric transmission for 40 wavelengths inside those limits. Corrections were estimated as best we could for ultraviolet and infrared solar rays. See Gerland's Beitrage fiir Geophysik, Bd. XVI, Heft 4, Leipzig, 1927. F. S. Johnson (J. Meteorology, 23, No. 6, p. 431, 1954) obtained larger ultraviolet and infrared corrections than ours, and published his preferred value of the solar constant, 2.00 4- 2 percent, which is now accepted generally. The Smithsonian Institution has just published two papers (Smith, Misc. Coll., Vol. 148, No. 7 and No. 8, Pubs. 4656 and 4659, March 23, 1966), which, together with its former publications (ibid Vol. 146, No. 3, Pub. 4545, 1963) shows the error of Dr. Gates' statement, which I have quoted above. I quote from Pub. 4659 as follows: "The identical family of harmonic periods found in solar variation is also present strongly in terrestrial precipitation, and may be used for long-range forecasting . . . . The curves A in Fig. 7 and 8 are made from observations recorded after it happened. The curves B, which for practical purposes are nearly identical with curves A, could be predicted and were actually predicted from records of observations made long before the events happened." This relates to Rochester and Nashville, 1921-1957. These predictions employed mean monthly official vahms, all observed beginning with 1884, to compute what would happen after 1921 for 36 years. They revealed weather periods identical in length with those we discovered in the sun's radiation. The average deviation between forecasts and events for 60 years is 3 percent of normal precipitation. C h a r l e s G. A b b o t Smithsoni'm Institution Research Associate 181