In the conterminous States, APT and many of the other satellite products are distributed nationwide over the Forecast Office Facsimile Network (FOFAX) as well as other facsimile networks of the Department of Commerce. This provides additional data and makes the system more easily adaptable to future changes. Most of the products collected at Suitland or developed by NESS can be distributed on FOFAX, including APT received at such distant points as Honolulu, Hawaii, provided that no conflicts occur with conventional products being transmitted.

In FY 72, the Navy plans to spend $480,000 for purchase of 16 APT photorecorders to provide higher quality display on present sites. Also, Defense is upgrading a number of Automatic Picture Transmission (APT) ground equipments to receive the transmissions from the newer satellites, particularly the NOAA and GOES series.

More expensive and complex ground equipment in development will be required to receive VHRR data in full resolution from ITOS and the VISSR

data from GOES. The direct VISSR transmission from the SMS/GOES will be receivable only at major CDA stations such as Wallops. This wideband transmission will be processed at the Wallops CDA Station to reduce transmission bandwidth and relayed in real-time back through the GOES spacecraft to suitably equipped remote ground receiving stations. The Navy plans an FY 72 expenditure of $220,000 to convert 11 shipboard antennas and receivers to utilize GOES-relayed transmis

sions.

DATA PROCESSING

The NESS and the AFGWC receive all stored data from the CDA stations for computer processing. The NESS uses the NOAA central computers, smaller computers, and manual techniques to convert observational data into forms suitable for immediate operational use in analysis and forecasting routines and for subsequent research and climatological uses.

In Commerce, emphasis in FY 72 is placed on

preparations to handle new data-analysis, processing, dissemination, and archiving-from the GOES operational prototype and the advanced ITOS sensors, the VHRR and VTPR. Commerce is budgeting an increase of $3,817,000 in FY 72 for these purposes.

Equipment and staff will be added to the NESS central analysis and processing facility, the National Hurricane Center (NHC), the National Severe Storms Forecast Center (NSSFC), and the San Francisco WSFO to acquire, process, and display data from GOES for environmental warning and service programs. Major new tasks to be initiated at the NESS central analysis and processing facility will be to derive atmospheric soundings and winds for use in numerical prediction and to prepare special service-oriented products from VHRR data such as sea-surface temperature, ice, and snow distributions for use in marine, hydrologic, and flood warning services. Equipment and staff will be added to the Environmental Data Service (EDS) of NOAA to assimilate the voluminous new data from GOES, VHRR, and VTPR into data archives for retrieval by governmental and private users on a reimbursable basis. The NESS of NOAA will establish regional facilities for stretched VISSR data readout at San Francisco, Kansas City, Mo., Miami, Fla., and Suitland in FY 72; in later years, NOAA will provide additional regional readouts and facilities for intraregional distribution. TECHNICAL MANAGEMENT AND SUPPORT

Technical management and engineering support for the operational weather program are provided by NASA, on a reimbursable basis, and by NESS. With the evolution of the GOES program, reimbursement to NASA will increase by $300,000 to

cover services provided through the SMS/GOES Project Office.

SUPPORTING RESEARCH

This meteorological research conducted by NASA and the Departments of Commerce and Defense provides the technology and data utilization techniques necessary to meet the major long-term objectives set by these Federal agencies in their planning for a coordinated meteorological satellite program. For FY 72, planned meteorological satellite research and development programs total $47,771,000, a decrease of $1,339,000 from the FY 71 program.

Developments necessary for the global-viewing first objective of NOMSS were largely achieved with TIROS M and ITOS spacecraft. Efforts continue toward improved resolution, location, and display. Attention will also be given to the development of methods for measuring additional environmental properties, to the solution of data and product distribution problems, and to the improvement of ground stations.

The second NOMSS objective includes both continuous viewing and the collection and relaying of meteorological data from instrumented platforms such as buoys, ships, automatic stations, aircraft, and balloons. NASA conducts experiments in support of this objective with its Nimbus and ATS series. In addition, NASA is funding the SMS prototypes for the GOES operational spacecraft.

Research and development for precise quantitative atmospheric sounding, the third program objective of NOMSS, are emphasized in NASA's Nimbus program and in NOAA's program for developing sensing techniques.

The Departments of Commerce and Defense conduct a wide variety of studies on applications of meteorological satellite data to improve services— the fourth NOMSS program objective. Major efforts will be directed to developing new methods for using satellite data in environmental analysis and forecasting. The radiative and optical properties of atmospheric constituents will be studied to aid with the design of satellite-borne sensors and with the interpretation of data from these sensors. Special attention is given to the interpretation and validation of new data acquired by operational and research satellites and to the application of these data as inputs to numerical analysis and forecasting.

Meteorological satellite research efforts, by agency, for FY 71 and FY 72 have been divided into four functional categories as shown in the accompanying funding table.

SATELLITE FLIGHT PROJECTS

The major portion of the funding for supporting research in meteorological satellites is allocated to satellite flight projects in the TIROS, Nimbus, and ATS research and development programs of NASA.

The NASA meteorological spacecraft efforts fall into two broad categories. The first is the development, fabrication, and launch of experimental spacecraft specifically designed to serve as test platforms for new satellite-borne sensing and communication equipment. The second is the design of improved operational meteorological spacecraft, the building of prototypes, the launching of spacecraft, and the evaluation of performance. In conjunction with its flight programs, NASA conducts efforts to improve the data output of the satellites, including the computer programs for processing and analyzing spacecraft data and those for initial processing of experimental data.

The Nimbus and ATS series are research and test platforms. The Nimbus 3, launched in April 1969, demonstrated infrared atmospheric sounding and remote data collection capability, carried a line-scanning image dissector camera to provide continuous daylight pictures, and collected data on the rate of solar ultraviolet energy incidence upon the atmosphere for further correlation studies on atmospheric dynamics and weather phenomena. Nimbus 4, launched on April 8, 1970, carries nine experiments to extend the systematic exploration of the structure of the atmosphere. The extension in capability of Nimbus 4 incorporates significant improvements to six experiments of Nimbus 3 and inIcludes three new experiments designed to cover

previously uninvestigated and potentially important regions of the electromagnetic-sensing spectrum.

The payload for Nimbus E has been selected and that for Nimbus F is in the final selection process, with anticipated launchings of these spacecraft in FY 72 and FY 73, respectively. New experiments include those to extend remote sensing of the atmosphere and of the earth's surface to the "windows" and absorption bands in the microwave portion of the electromagnetic spectrum. Passive microwave radiometer and spectroscopy experiments are designed to provide a means for determining vertical profiles of temperature and water vapor through cloud cover to the earth's surface. In the infrared spectrum, advanced sensors will provide improved spatial and spectral resolution of infrared radiometers for day or night imaging of clouds, cloud heights, and surface features and will provide data on water vapor distribution and on sounding the atmosphere in the presence of clouds.

The ATS 1, containing both the Spin-Scan Cloud Camera (SSCC) and Weather Facsimile (WEFAX) experiments, was launched in December 1966 over the Pacific Ocean and has proven highly successful. The vidicon camera aboard ATS 2 operated satisfactorily, but minimal meteorological data were returned because of the poor orbit. The ATS 3, launched in November 1967, has continued to return excellent black-and-white cloud cover pictures from its position above the Equator facing toward the North American continent and the Atlantic Basin. The red color channel of the color camera has ceased to function; however, the green and blue channels are operating as designed. The ATS 4, launched in August 1968, did not achieve a satisfactory orbit for taking cloud cover pictures with the Image Orthicon Camera (IOC) which was developed to return both daytime and nighttime monochrome cloud-cover pictures. Plans are now underway to define meteorological experiments for ATS F and G.

The prototype ITOS, TIROS M, was launched on January 23, 1970; upon successful completion of its in-orbit engineering aspects and evaluation by NASA, the spacecraft was transferred to the NESS for operational use on June 15, 1970. This satellite provides global day and night viewing and direct readout to fulfill the first NOMSS objective, adding a temperature-sensing capability and local very high resolution readout. Work continues on the development of hardware for the SMS, the prototype of the GOES, to satisfy the second NOMSS objective of continuous viewing and data collectionand-relay. The TIROS M and SMS/GOES

flight projects are covered in some detail in the preceding section, Operational Plan.

Experience gained with TIROS M and the Nimbus, ATS, and SMS spacecraft will provide guidance for subsequent operational meteorological satellites. NASA's meteorological research and development program will contribute significantly to the World Weather Program; the experience gained will be invaluable in the design of the World Weather Program meteorological satellites.

As part of NASA's TIROS follow-on program, the objective of which is the development of further advanced earth-orbiting operational-prototype spacecraft and systems in support of the NOMSS, the next major change will be evident in TIROS N. This satellite will be the forerunner of the third-generation operational spacecraft needed to meet additional NOMSS requirements and to provide support to the Global Atmospheric Research Program (GARP) in the post ITOS G timeframe. With TIROS N, the major emphasis will be placed on improving and extending the capability of the System to obtain quantitative measurement of environmental parameters needed for improvements in numerical weather prediction and those needed for improvements in NOAA services relating to oceanography and hydrology. The attainment of the goal of accurate weather forecasts for periods of up to 2 weeks through numerical weather prediction is absolutely dependent upon the availability of quantitative environmental data on a global scale.

The requirements which must be fulfilled by the operational meteorological satellites of the post ITOS G timeframe will be further defined in FY 72. The feasibility of effecting the desired sensor and spacecraft technology improvements will be investigated, carrying forward the efforts initiated at the NASA Goddard Space Flight Center in FY 71. Where appropriate, major tradeoff areas will be developed and evaluated.

SATELLITE INSTRUMENTS AND EXPERIMENTS

This category for funding of supporting research includes the cost of sensors, sensor development, in-house support, supporting research and technology for all meteorological experiments, and experiments for locating, interrogating, recording, and relaying meteorological data relative to the TIROS, Nimbus, and ATS-SMS-GOES systems. This research is being conducted by NASA and NOAA.

Emphasis in NOAA's sensor research program will be placed on indirect sounding techniques. Satellite sensor systems are being designed and engineered to obtain new or improved measurements of

parameters for use in environmental analysis and forecasting. Currently, the major effort is in the development of satellite sounding instruments to determine globally the vertical distribution of temperature and of water vapor in the atmosphere. An improved experimental sounding system, the Infrared Temperature Profile Radiometer (ITPR), is being designed and developed by the NESS, under NASA funding, for flight on the Nimbus E satellite in early FY 73.

Work has begun in NOAA, with NASA funding, on the Earth Radiation Budget (ERB) experiment scheduled to fly on Nimbus F. The objective of the experiment is to measure the net radiative flux of the earth/atmosphere system and to measure various critical angular components of the flux to allow deduction of synoptic scale variations. Spectral components of the solar radiation will be measured to isolate those regions contributing to any observed variation in the mean solar constant. The instrument is being designed to achieve absolute and relative accuracies better than 1 percent and 0.1 percent respectively. The ERB measurements will be processed and analyzed to establish a baseline of the Earth's radiation budget.

Current preliminary studies on possible satellite techniques for sensing aerosols and gaseous atmospheric constituents related to air pollution will be expanded in FY 72. Studies of microwave technology will be continued to develop a sensor for measuring surface variables-temperature, sea state, snow and ice cover--both day and night, irrespective of cloud cover.

Under the TIROS/TOS Improvements Program of NASA, effort will be continued toward the development of advanced sensors and subsystems such as improved high resolution radiometers and advanced vertical temperature sounders which will be incorporated into future operational spacecraft.

In FY 71, work continues on the development of the VTPR and the VHRR which will be flown on ITOS D, E, F, and G to increase the capability of the satellite to meet user needs. In FY 72, NASA efforts will focus on the preliminary design and development of the advanced sensors and subsystems to be flown on the third-generation operational meteorological satellite series.

On September 25, 1970, Nimbus 3 had completed 17 months and 11 days in orbit. On that date, a failure of the after-horizon scanner severely degraded the stability of the spacecraft. Usefulness of the experiment data is under study; however, it is not expected that data will continue to be obtained routinely from the meteorological sensors.

The most significant result from Nimbus 3 was the demonstration that atmospheric soundings can be obtained by indirect sensing from satellites. This objective has been met outstandingly. The experiments flown aboard Nimbus 3 are described briefly below:

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The Infrared Interferometer Spectrometer (IRIS) continuously sampled the spectrum of the earth's radiation in the 5- to 20-micron region to determine the amount of ozone and water vapor and to infer the vertical temperature profile of the atmosphere.

The Satellite Infrared Spectrometer (SIRS) measured the earth's spectral radiances in the carbon-dioxide-absorption band to infer the atmospheric temperature structure by using narrow intervals within the 15-micron carbon dioxide band.

The Interrogation, Recording, and Location System (IRLS) collected scientific data relating to the surface of the earth and its atmosphere from fixed and free-floating platforms, and provided location data for these platforms. The Image Dissector Camera System (IDCS) furnished high-quality daytime cloud-cover pictures in both real-time to APT ground stations and by stored playback data to CDA stations. The High Resolution Infrared Radiometer (HRIR measured the thermal radiation from the earth. These measurements provided earth and cloud-cover images, both day and night, and temperatures of cloud tops and of terrain features during the night portion of the orbit. The data were provided in both real-time to APT ground stations and by stored playback data to CDA stations. Spatial resolution is 4 nautical miles.

The Medium Resolution Infrared Radiometer (MRIR) measured the intensity and distribution of emitted infrared and reflected radiation of the earth and atmosphere in five selected channels from 0.2 to 30 microns. Nimbus 4. launched on April 8, 1970, carries six improved versions of experiments that are on Nimbus 3 and three new meteorological experiments. The six improved experiments are as follows:

The continuous-mapping Image Dissector Camera System (IDCS) provides visual reference for the other experiments.

The Temperature-Humidity Infrared Radiometer (THIR) measures the infrared radiation in two narrow bands (from 10 to 12 microns and at 6.3 microns). This information will furnish

surface or cloud-top temperatures, both day and night.

The Satellite Infrared Spectrometer (SIRS) model B, a modification of the one successfully flown on Nimbus 3, measures infrared radiation emitted by carbon dioxide and water vapor and by the surface and cloud tops in narrow spectral intervals (channels) in three distinct spectral regions-seven channels in the watervapor rotation bands between about 18 and 36 microns, and one channel in the 11.1-micron window. The objective of obtaining distribution of temperature and water vapor information is being successfully met.

The Infrared Interferometer Spectrometer (IRIS), a modification of the one flown on Nimbus 3, measures the intensity of the earth's spectral radiance in the continuous wavelength interval between 8 and 40 microns. Of particular interest are the carbon-dioxide-absorption band near 15 microns for temperature profile, the atmospheric window at 10 to 11 microns for surface or cloud-top temperatures, the watervapor-rotation bands from 20 and 40 microns for water vapor profile, and the ozone-absorption band at 8 to 10 microns for ozone determination.

The Interrogation, Recording, and Location System (IRLS) experiment has been expanded to obtain wind and other parameters from additional platforms. The IRLS on Nimbus 4 has a much greater capability than that on Nimbus 3 to command and store data; this capability. makes it possible to command many more platforms and to store more data from each platform.

The Monitor of Ultraviolet Solar Energy (MUSE) serves as a support to the new Backscatter Ultraviolet (BUV) Spectrometer experiment. The sensor measures solar flux using five photodiodes that have peak sensitivities at 1500A, 2100A, 2600A, and 1216A.

The three new experiments on Nimbus 4 are as follows:

The Selective Chopper Radiometer (SCR), using a carbon dioxide cell with a vibrating vane chopper, measures infrared radiation emitted from the earth's atmosphere in each of six spectral regions, centered on wave numbers between 668 and 712 within the 15-micron carbon-dioxide-absorption band. This experiment yields sharper height discrimination in the resulting vertical-temperature profile.

The Filter Wedge Spectrometer (FWS) was to