U.S. Naval Weather Service Numerical Environmental Products Manual


Book Description

During the past decade, numerical forecasting has assumed a dominant role in Naval Weather Service operations. Numerical objective analyses and prognoses have largely replaced the old ponderously-produced, subjective manual products. The decision to explore the feasibility of adopting numerical forecasting in the Navy was motivated by the growing evidence that the huge volume of available hemispheric data had outrun man's ability to digest it efficiently. Computers offered an exciting prospect of being able to do a much better job. A strong consideration for computers was the growing demand in the Navy for a wider range of high-quality products, particularly oceanographic products. The decision to explore the Navy potential in numerical forecasting was not one to be taken lightly, since this would ultimately involve a large allocation of Naval Weather Service assets in men and money with no assurance that these assets could be provided by drawing from existing field activities. Numerical forecasting was still a struggling infant as a scientific tool, and many were convinced that numerical forecasting would remain forever in the R and D stage, never to appear operationally. The founding fathers of today's Fleet Numerical Weather Central (FNWC) were aggressive and knowledgeable. In a surprisingly short time, programs were developed, rapid communications methods were devised, and computer products were receiving favorable evaluations in the field. This early success encouraged further support for an expansion of the numerical development group. The goal was to build toward a Naval Weather Service System around FNWC.



















Climatological Marine-fog Frequencies Derived from a Synthesis of the Visibility-weather Group Elements of the Transient-ship Synoptic Reports


Book Description

The study presents the essentials of a method of synthesizing the visibility-weather group elements of marine synoptic reports into a computerized scheme for the purpose of deriving frequencies of marine-fog occurrence. The program, based on an interpretation of reporting guidelines in the Synoptic Code Manual, uses 16 combinations of present and past weather, and visibility, to identify fog in the reports. The program then objectively assigns the duration of fog for the period represented by each of the reports. A prototype climatology of marine-fog occurrence for July, over the North Pacific Ocean, is derived from application of the method to a ten-year data base (1963-72). Results are compared and discussed in relation to other published coastal and marine-fog climatologies. Diurnal fog frequencies at sea and the compatibility of fog observations from Ocean Weather Stations and transient ships are also treated. The continuing work and its goals are described.