Studying the Earth from space has evolved from the realm of pure research to that of worldwide, day-to-day applications. We depend on satellite sensors to assist in tasks ranging, for example, from weather prediction, crop forecasting, mineral exploration, pollution detection, and rangeland monitoring. The development of remote sensing and its use have occurred in a very short period of time and continues to change as new and/or improved satellite sensors are placed into earth's orbit.

The most important outcome of development of spaceborne remote sensing has been the role these technologies have played in conceiving the earth as a system. They fundamentally changed our perception of the Earth from a set of distant, isolated continents to an integrated system of land, ocean, atmosphere, and living things. Satellite remote sensing has brought a new dimension of understanding of the processes that govern our earth-atmosphere system and also the impacts of man.

This lecture focuses on the historical development of remote sensing. Key individuals and organizations at the forefront in the development of satellite system are discussed.

Early History of Satellite Remote Sensing

A. Prior to Launch of First Satellite

Satellite remote sensing predates the launch of the first meteorological satellite.

As early as 1860s, Jules Verne wrote about "Lunanauts" observing cloud systems.

By the late 1940s, rockets carrying cameras were being launched into suborbital flights. The photographs that they returned gave rise by the early 1950s to serious scientific discussion of the possibility of observing the weather from space. Several groups pursued the idea of launching a weather satellite -

- U.S. Army Evans Signal Laboratory
- University of Wisconsin

Efforts were intensified after the launch by the Soviet Union on Oct 4, 1957 of the first successful Earth Satellite, Sputnik 1.
- era of satellite meteorology began
- provided first space views of our planet's surface and atmosphere

First successful U.S. satellite, Explorer 1, was launched on Jan 31, 1958 (123 days later).

Of particular importance to space flight, in general, and satellite meteorology, in particular, was the formation of the National Aeronautics and Space Adminstration (NASA) on Oct 1, 1958.

- for more than 30 yrs, NASA has lead the development of all types of scientific satellites used for civilian purposes
- involved from the 1st in satellite meteorology were agencies that now are components of U.S. National Oceanic and Atmospheric Adminstration (NOAA), particularly the U.S. Weather Bureau

The first satellite with a meteorological instrument was Vanguard 2 launched in Feb 17, 1959. Figure
- developed by U.S. Army's Evans Signal Laboratory, data unusable

Second satellite, Explorer 6 launched on Aug 7, 1959 with meteorological instruments.

- carried imaging system and Suomi radiometer
- returned first Earth photo
- essentially unusable, high elliptical orbit although it did return 1st Earth photo

First successful meteorological instrument on orbiting satellite - Explorer 7

- developed by Verner Suomi and colleagues at University of Wisconsin
- maps of radiation (reflected and emitted) were mapped for the first time

First satellite completely dedicated to satellite meteorology - Television and Infrared Observation Satellite, TIROS-1 launched on Apr 1, 1960. (22nd successfully launched satellite)

- imaging-making instrument on TIROS 1 was a vidicon camera (adaption of a standard television camera)
- 1st image returned by TIROS 1 ? find it
-- although crude by today standards, TIROS 1 image generated immense excitement
-- for the 1st time we could view the Earth and its weather systems as a whole
-- not only have satellite observations become essential for meteorology; they have fundamentally changed our perception of the Earth from a set of distant, isolated continents to an integrated, inseparable system of land, ocean, atmosphere, and living things
-- nearly 23,000 images were returned in the 79-day lifetime of TIROS 1

TIROS series
- TIROS 8 launched on Dec 21, 1963 introduced Automatic Picture Transmission (APT). A new camera with 800-line resolution was scanned at slow rate of 4 lines/s and dadta were immediately broadcast to the Earth at very high frequency (VHF). Slow transmission rate meant that inexpensive equipment could be used to receive and display the images. Thus anyone w/ proper equipment could directly receive weather satellite images as the satellite passed by 2/day. APT is still an important function on today's polar-orbiting weather satellites

- TIROS 9 launched on Jan 22, 1965 introduced new satellite configuration, "cartwheel"
-- first photomosaic of the entire world's cloud cover was achieved via a composite of 450 photos taken on Feb 13, 1965

- Total of 10 TIROS satellites were launched with last on July 2, 1965 which carred vidicon camera systems for daytime visible imaging and passive infrared radiometer for sensing during both day and night.

Nimbus Series
- Nimbus 1 launched on Aug 28, 1964, 2 notable firsts
-- first three-axis stablized metsat (it rotated once/orbit so that its instrument constantly pointed toward Earth
- first sunsynchronous satellite (passed over any point on Earth at approximately the same time each day). This regularity increased its utility in operational forecasting and used ever since for U.S. operational metsats in near-polar orbits..
High Resolution Infrared Radiometer (HRIR) - provided day and night coverage

- Total of 7 Nimbus satellites launched (NIMBUS 7 launched on Oct 24, 1978)

- Nimbus Series tested many new remote sensing concepts and instruments that have lead to operational instruments in use today
see if NIMBUS 7 still in operation

An important accomplishment of satellite meteorology is that since mid-1960s there have been no undetected tropical cyclones anywhere on Earth.
 

E. Operational Series of Meteorological Satellites

By 1966, the U.S. was ready to inititate an operational (as opposed to experimental) series of metsats. Environmental Science Service Administration (NOAA's predecessor) (ESSA) exploited the TIROS developments on a fully operational basis.

ESSA commissioned 9 satellites which were launched between Feb 3, 1966 and Feb 26, 1969. ESSA series

- each was essentially like TIROS 9

- odd-numbered satellited had Advanced Vidicon Camera Systems (AVCSs) which could record images for later playback to Earth receiving stations; even-numbered satellites had APT cameras for immediate broadcast to Earth.

U.S. Air Force launched a series of meteorological satellites called Defence Meteorological Satellite Program (DMSP) beginning in Sep 16, 1966. Series called DMSP Block 4 and included 7 satellites with last launched on July 23, 1969.

ATS Series

- Another leap forward took place with the launch of the first Applications Technology Satellite (ATS 1) on Dec 7, 1966.
-- carrying spin scan cloud camera developed by Verner Suomi and Robert Parent at the Unv of Wisconsin placed into a geostationary orbit to view the Western Hemisphere in visible light
-- enables 1/2 hr hemispheric visible viewing, thus began time domain observation of weather patterns
-- for the first time, rapid-imaging of nearly an entire hemisphere was possible

- ATS 3 launched on Nov 5, 1967 carried a Multicolor Spin Scan Cloud Camera which employed a filter wheel to make the first color images of Earth.

Nimbus Series

- Very important event occurred on Apr 14, 1969 with launch of Nimbus 3
-- carried two instruments - satellite infrared spectrometer (SIRS) (measurements in 15um portion of spectrum and forerunner to today's operational sounding instruments) and infrared interferometer spectrometer (IRIS) (measured spectra in infrared from 6 to 25um)
-- designed to provide atmospheric soundings from space
-- for first time, satellite data used quantitatively in numerical weather-prediction models

-- IRIS also flew on Voyager spacecraft to Jupiter, Saturn, Uranus, and Neptune

- accurate temperature retrievals were accomplished with the SIRS aboard Nimbus-4 in 1969

-- comparison with radiosonde observed profiles showed that the satellite derived temperature profile was very representative overall with detailed vertical features smoothed out
-- major problem clouds w/i instrument's FOV (225km)
-- SIRS data immediately showed promise of benefiting current weather analysis/forecast operation and was put into operational use on May 24, 1969

- an extremely long-lasting instrument and first ultraviolet instrument in space was Backscatter Ultraviolet (BUV) launched on Nimbus 4 on Apr 8, 1970. BUV measured ozone for nearly 10 yrs.

- First microwave sounding device, Nimbus Experimental Microwave Spectrometer (NEMS) was onboard Nimbus-5

-- nadir viewing 5-channel instrument
-- demonstrated the capability to probe through clouds, even dense overcast
-- good comparisons of ITPR, NEMS, and radiosonde data were acheived
-- found that best results were achieved from an amalgamation of infrared and microwave radiance data in the temperature profile inversion process thereby proving maximum available thermal information, regardless of cloud condition

From studies in the early 1970s, it was recognized that the optimum temperature profile results would be achieved by taking advantage of the unique characteristics offered by the 4.3um, 15um and 0.5cm absorption bands. Nimbus 6 High resolution Infra_Red Sounder (HIRS) experiment successfully demonstrated an improved sounding capability in the lower troposphere due to the inclusion of 4.3um observations.

Geostationary meteorological satellites

First generation of semioperational geostationary meteorological satellites began with the launch of the Synchronous Meteorological Satellite 1 (SMS 1) on May 17, 1974.

These SMS satellites carried the first Data Collection Platform (DCP) repeater. Data from meteorological or other platforms on the surface could be relayed by the satellite to a central receiving site.

Since Jun 27, 1974, when SMS 1 became operational, we have had continuous, uninterruped, 24hr/day monitoring of most of the Western Hemisphere from space

Era of Geostationary sounding began in Sept 1980 with launch of Visible Infrared Spin Scan Radiometer (VISSR) Atmospheric Sounding (VAS)

- time continuous 3-D probing of atmosphere is accomplished using 12 infrared spectral bands in imaging or a sounding mode
- filter wheel in front of the detector package is used to achieve spectral selection
- central wavelengths of spectral bands lie between 3.9 and 15um
- VAS radiometer observes upwelling radiatioin in 2 windows (4.0 and 11um), 3 water vapor channels, and 7 regions of 4.3 and 15um CO2 bands
- housed in GOES satellite, VAS spins in west to east direction at 100 rpm and achieves spatial coverage at resolutions of 1km in visible and 7 or 14 km in infrared

- spatial coverage, time of observation, and spectral bands are programmed into an onboard processor from the ground

The first truly operational geostationary meteorological satellite, the Geostationary Operational Satellite 1 (GOES 1), was launched on Oct 16, 1975.

- GOES Program

- U.S. has generally maintained 2 geostationary satellites in orbit, 1 at 75 degrees W and another at 135 degrees W longitude

In 1977 and 1978, two more meteorological satellites launched -

Japan's Geostationary Meteorological Satellite (GMS)
European Space Agency's Meteosat
- first to make images of mid- to upper-tropospheric water vapor at 6.7um

India's geostationary satellite, Insat 1B was launched on Aug 31, 1983.

- stationed at 74 degrees E longitude, completed geostationary coverage of the tropics and midlatitudes around the Earth
- first three-axis stabilized geostationary metsat

GOES 4 launched on Sep 9, 1980 was first of the second generation GOES satellites. Discuss in more detail when cover Satellite Systems later in semester
Launch of Meteor-3 1 on Jul 26, 1988 by Soviet Union

Polar-Orbiting Satellites

Landsat Program
The Landsat Program designed for land remote sensing with extremely high resolution with 80m in first satellite and up to 30m in the lasted (Landsat 5). Landsat 1 was called Earth Resources Technology Satellite (ERTS) launched on July 23, 1972.

Third generation of U.S. polar-orbiting metsats began on Oct 13, 1978 with launch of TIROS N. This series continues today.

Two Indian polar orbiters have been launched -

- Bhaskara 1 on Jun 7, 1979
- Bhaskara 2 on Nov 20, 1981

First satellite dedicated to climate research was launched on Oct 5, 1984 from Space Shuttle Challenger called Earth Radiation Budget Satellite (ERBS)

- carried two instruments
Earth Radiation Budget Experiment (ERBE)
Stratospheric Aerosol and Gas Experiment II
- nonsunsynchronous orbit so that its measurements will sample all local times

Spot System

F.  SUMMARY

History of satellite meteorology has many facets in addition to the hardware that has been launched into orbit.

Interactive Processing Capability

Another very important tool for satellite data interpretation was developed during 1970s -
------> man-computer interactive processing
- through manual editing and enhancement of satellite data, it has been shown that soundings with high quality resolution were possible on a system such as Man-computer Interactive Data Access System (McIDAS) at Unv of Wisconsin.

The explosion in computer and communications technology during the space age has literally made weather satellites possible. This technology has also made possible the dissemination of satellite data and products to the operational forecastin and research sites where they are needed.

Lecture materials from Kidder and Haar (1995, 1-11) and Menzel
Background readings:

Operational implementation of these instruments was achieved on TIROS-N/NOAA space craft in 1978 which carry the HIRS and Microwave Sounding Unit (MSU).

- channels carefully selected to cover the depth of the atmosphere
- infrared and microwave instruments aboard each of polar orbiting spacecraft provided complete global coverage of vertical T and moisture profile data every 12 hr at 250km spacing.