With 13 bureaus, 63 field offices, 11 overseas trade offices, its own naval and air fleets, research laboratories, extensive statistica resources, a $2.3 billion budget and a staff that fluctuates between 35,000 and 38,000, the Commerce Department is better equipped than some nations.

To some careerists in the department, it's a running joke.

"Each year they give us less and less money to do at least the same, if not more, work," one statistician said. "We'd do better and get a bigger budget if we just declared ourselves a sovereign state and asked for foreign aid."

Since its inception in 1903 with a mandate to promote the commercial activities of the nation, the department has discovered that thousands of seemingly unrelated areas affect U.S. business. Over the years, small units and sometimes entire divisions have been created to oversee the disparate facets of American capitalism.

The National Weather Service, for instance, started out in the Department of Agriculture because its forecasts are essential to the farmer. But farming is a commercial activity measured in the gross national product. So the Weather Service was moved to Commerce.

Most people think that the nation's natural resources are protected by the Department of Agriculture because its forecasts are essential to the farmer. But farming is a commercial activity measured in the gross national product. So the Weather Service was moved to Commerce.

Most people think that the nation's natural resources are protected by the Department of the Interior and that environmentl problems come under the jurisdiction of the Environmental Protection Agency. But coastal zone management, deep seabed mining, oceans policy and the fight between the tuna fishermen and porpoise preservationists are handled by the National Oceanic and Atmopsheric Administration, a division of Commerce.

Copyrights - the ownership rights to published works - are processed and registered with the Library of Congress. But patents and trademarks - similar rights to inventions, chemcial processes, logos, slogans and other insignia - are the domain of a Commerce bureau.

In her Cabinet presentation about the direction she hopes the department will take, Secretary Juanita Kreps borrowed a familiar observation: that there is a great similarity between Commerce and Noah's ark. The difference between them, she said, is that Commerce has just one of everything.

"We have a lot of animals on our ship, some of which may have climbed on board because they didn't have anywhere else to go," she said. "What we have, however, adds up not to a hodgepodge, but to potential threads of a common purpose."

While the Secretary emphasized the department's responsibility for promoting U.S. commercial interests, she rejected criticism voiced both within and outside the department that Commerce spends too much f its budget on peripheral issues and neglects the American businessman.

"I would not feel that the private sector is best served by having a 'spokesman' for it," Kreps said in a recent interview. "That kind of delineation would pit the business representative in the Cabinet against the labor representative (Labor Secretary Ray Marshall) against the spokesman for People who live in cities (Patricia Harris, Housing and Urban Development Secretary) and the spokesman for those who live in rural areas (Agriculture Secretary Bob Bergland)."

Rather, she said, the American people are best served through Commerce's current activities.

"Promoting international trade aids the balance of trade, while helping domestic trade increases the GNP, and economic development projects put people back to work which also promotes the growth of the GNP," she said. "Business is helped through all of these activities and in a much more effective manner than if I were a 'spokesman.'"

Central to the department's responsibilities for the economy is its role as the nation's statistician. Economists not only take the nation's pulse via a laundry list of private and public-sector data, but they use the figures to forecast economic trends.

Two of the smaller units of Commerce - the Census Bureau and the Bureau of Economic Analysis - collect, analyze and report a dazzling array of data on topics ranging from the population, housing and agriculture to foreign trade.

The regular reports of these bureaus affect trading in stock, commodities and foreign exchange markets, influence private business decisions and shape government policies.

The BEA is charged with providing a clear picture of the overall economic health of the nation.

It maintains the national income and product accounts, which are summarized in the gross national product figure. The bureau also tracks manufacturing and trade inventories, sales estimates, and a variety of estimates of fixed business and residential capital.

The Census Bureau began counting heads in 1790, but in the intervening years it also became responsible for reporting on a range of economic indicators and social statistics covering the housing, manufacturing and mineral industries, retail, wholesale and service business, agriculture, local and state government spending, transportation, construction and foreign trade. In 1976, it published more than 1,500 regular statistical reports.

Planning for the 1980 census began more than two years ago. Testing of the revised questionnaire that each American household will receive involved 28,000 families last year. Since then, a special unit has been established to handle the polling in minority and inner-city communities in order to eliminate the undercount which had been worsenign with each 10-year survey. The estimates of how many "hidden" Americans were missed by the 1970 census exceed 2 million.